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llvm/llvm-project/6b26457a0ef2994de54606eb5c356cb897cadda2/./llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
blob: bbb38cb49ee61e8887dff63dfb16362a783d7810 [file]
//===- InstCombineCalls.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the visitCall, visitInvoke, and visitCallBr functions.
//
//===----------------------------------------------------------------------===//
#include "InstCombineInternal.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/Bitset.h"
#include "llvm/ADT/STLFunctionalExtras.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumeBundleQueries.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/AttributeMask.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/BundleAttributes.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsAArch64.h"
#include "llvm/IR/IntrinsicsAMDGPU.h"
#include "llvm/IR/IntrinsicsARM.h"
#include "llvm/IR/IntrinsicsHexagon.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/ProfDataUtils.h"
#include "llvm/IR/Statepoint.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/KnownFPClass.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/TypeSize.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/InstCombine/InstCombiner.h"
#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <optional>
#include <utility>
#include <vector>
#define DEBUG_TYPE "instcombine"
#include "llvm/Transforms/Utils/InstructionWorklist.h"
using namespace llvm;
using namespace PatternMatch;
STATISTIC(NumSimplified, "Number of library calls simplified");
static cl::opt<unsigned> GuardWideningWindow(
"instcombine-guard-widening-window",
cl::init(3),
cl::desc("How wide an instruction window to bypass looking for "
"another guard"));
/// Return the specified type promoted as it would be to pass though a va_arg
/// area.
static Type *getPromotedType(Type *Ty) {
if (IntegerType* ITy = dyn_cast<IntegerType>(Ty)) {
if (ITy->getBitWidth() < 32)
return Type::getInt32Ty(Ty->getContext());
}
return Ty;
}
/// Recognize a memcpy/memmove from a trivially otherwise unused alloca.
/// TODO: This should probably be integrated with visitAllocSites, but that
/// requires a deeper change to allow either unread or unwritten objects.
static bool hasUndefSource(AnyMemTransferInst *MI) {
auto *Src = MI->getRawSource();
while (isa<GetElementPtrInst>(Src)) {
if (!Src->hasOneUse())
return false;
Src = cast<Instruction>(Src)->getOperand(0);
}
return isa<AllocaInst>(Src) && Src->hasOneUse();
}
Instruction *InstCombinerImpl::SimplifyAnyMemTransfer(AnyMemTransferInst *MI) {
Align DstAlign = getKnownAlignment(MI->getRawDest(), DL, MI, &AC, &DT);
MaybeAlign CopyDstAlign = MI->getDestAlign();
if (!CopyDstAlign || *CopyDstAlign < DstAlign) {
MI->setDestAlignment(DstAlign);
return MI;
}
Align SrcAlign = getKnownAlignment(MI->getRawSource(), DL, MI, &AC, &DT);
MaybeAlign CopySrcAlign = MI->getSourceAlign();
if (!CopySrcAlign || *CopySrcAlign < SrcAlign) {
MI->setSourceAlignment(SrcAlign);
return MI;
}
// If we have a store to a location which is known constant, we can conclude
// that the store must be storing the constant value (else the memory
// wouldn't be constant), and this must be a noop.
if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength((uint64_t)0);
return MI;
}
// If the source is provably undef, the memcpy/memmove doesn't do anything
// (unless the transfer is volatile).
if (hasUndefSource(MI) && !MI->isVolatile()) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength((uint64_t)0);
return MI;
}
// If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
// load/store.
ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getLength());
if (!MemOpLength) return nullptr;
// Source and destination pointer types are always "i8*" for intrinsic. See
// if the size is something we can handle with a single primitive load/store.
// A single load+store correctly handles overlapping memory in the memmove
// case.
uint64_t Size = MemOpLength->getLimitedValue();
assert(Size && "0-sized memory transferring should be removed already.");
if (Size > 8 || (Size&(Size-1)))
return nullptr; // If not 1/2/4/8 bytes, exit.
// If it is an atomic and alignment is less than the size then we will
// introduce the unaligned memory access which will be later transformed
// into libcall in CodeGen. This is not evident performance gain so disable
// it now.
if (MI->isAtomic())
if (*CopyDstAlign < Size || *CopySrcAlign < Size)
return nullptr;
// Use an integer load+store unless we can find something better.
IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3);
// If the memcpy has metadata describing the members, see if we can get the
// TBAA, scope and noalias tags describing our copy.
AAMDNodes AACopyMD = MI->getAAMetadata().adjustForAccess(Size);
Value *Src = MI->getArgOperand(1);
Value *Dest = MI->getArgOperand(0);
LoadInst *L = Builder.CreateLoad(IntType, Src);
// Alignment from the mem intrinsic will be better, so use it.
L->setAlignment(*CopySrcAlign);
L->setAAMetadata(AACopyMD);
MDNode *LoopMemParallelMD =
MI->getMetadata(LLVMContext::MD_mem_parallel_loop_access);
if (LoopMemParallelMD)
L->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD);
MDNode *AccessGroupMD = MI->getMetadata(LLVMContext::MD_access_group);
if (AccessGroupMD)
L->setMetadata(LLVMContext::MD_access_group, AccessGroupMD);
StoreInst *S = Builder.CreateStore(L, Dest);
// Alignment from the mem intrinsic will be better, so use it.
S->setAlignment(*CopyDstAlign);
S->setAAMetadata(AACopyMD);
if (LoopMemParallelMD)
S->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD);
if (AccessGroupMD)
S->setMetadata(LLVMContext::MD_access_group, AccessGroupMD);
S->copyMetadata(*MI, LLVMContext::MD_DIAssignID);
if (auto *MT = dyn_cast<MemTransferInst>(MI)) {
// non-atomics can be volatile
L->setVolatile(MT->isVolatile());
S->setVolatile(MT->isVolatile());
}
if (MI->isAtomic()) {
// atomics have to be unordered
L->setOrdering(AtomicOrdering::Unordered);
S->setOrdering(AtomicOrdering::Unordered);
}
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength((uint64_t)0);
return MI;
}
Instruction *InstCombinerImpl::SimplifyAnyMemSet(AnyMemSetInst *MI) {
const Align KnownAlignment =
getKnownAlignment(MI->getDest(), DL, MI, &AC, &DT);
MaybeAlign MemSetAlign = MI->getDestAlign();
if (!MemSetAlign || *MemSetAlign < KnownAlignment) {
MI->setDestAlignment(KnownAlignment);
return MI;
}
// If we have a store to a location which is known constant, we can conclude
// that the store must be storing the constant value (else the memory
// wouldn't be constant), and this must be a noop.
if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength((uint64_t)0);
return MI;
}
// Remove memset with an undef value.
// FIXME: This is technically incorrect because it might overwrite a poison
// value. Change to PoisonValue once #52930 is resolved.
if (isa<UndefValue>(MI->getValue())) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength((uint64_t)0);
return MI;
}
// Extract the length and validate the fill type.
ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength());
Value *Fill = MI->getValue();
if (!LenC || !Fill->getType()->isIntegerTy(8))
return nullptr;
const uint64_t Len = LenC->getLimitedValue();
assert(Len && "0-sized memory setting should be removed already.");
const Align Alignment = MI->getDestAlign().valueOrOne();
// If it is an atomic and alignment is less than the size then we will
// introduce the unaligned memory access which will be later transformed
// into libcall in CodeGen. This is not evident performance gain so disable
// it now.
if (MI->isAtomic() && Alignment < Len)
return nullptr;
// memset(s,c,n) -> store s, c (for n=1,2,4,8)
if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) {
Value *Dest = MI->getDest();
// Extract the fill value and store. A one-byte memset does not need
// replication so a nonconstant i8 fill can be stored directly.
Value *FillVal;
if (auto *FillC = dyn_cast<ConstantInt>(Fill))
FillVal = ConstantInt::get(MI->getContext(),
APInt::getSplat(Len * 8, FillC->getValue()));
else if (Len == 1)
FillVal = Fill;
else
return nullptr;
StoreInst *S = Builder.CreateStore(FillVal, Dest, MI->isVolatile());
S->copyMetadata(*MI, LLVMContext::MD_DIAssignID);
for (DbgVariableRecord *DbgAssign : at::getDVRAssignmentMarkers(S)) {
if (llvm::is_contained(DbgAssign->location_ops(), Fill))
DbgAssign->replaceVariableLocationOp(Fill, FillVal);
}
S->setAlignment(Alignment);
if (MI->isAtomic())
S->setOrdering(AtomicOrdering::Unordered);
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength((uint64_t)0);
return MI;
}
return nullptr;
}
// TODO, Obvious Missing Transforms:
// * Narrow width by halfs excluding zero/undef lanes
Value *InstCombinerImpl::simplifyMaskedLoad(IntrinsicInst &II) {
Value *LoadPtr = II.getArgOperand(0);
const Align Alignment = II.getParamAlign(0).valueOrOne();
Value *Mask = II.getArgOperand(1);
// If the mask is all ones or poison, this is a plain vector load of the 1st
// argument.
if (match(Mask, m_AllOnesOrPoison())) {
LoadInst *L = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment,
"unmaskedload");
L->copyMetadata(II);
return L;
}
// If we can unconditionally load from this address, replace with a
// load/select idiom.
if (isDereferenceablePointer(LoadPtr, II.getType(),
SQ.getWithInstruction(&II))) {
LoadInst *LI = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment,
"unmaskedload");
LI->copyMetadata(II);
return Builder.CreateSelect(II.getArgOperand(1), LI, II.getArgOperand(2));
}
return nullptr;
}
// TODO, Obvious Missing Transforms:
// * Single constant active lane -> store
// * Narrow width by halfs excluding zero/undef lanes
Instruction *InstCombinerImpl::simplifyMaskedStore(IntrinsicInst &II) {
Value *StorePtr = II.getArgOperand(1);
Align Alignment = II.getParamAlign(1).valueOrOne();
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(2));
if (!ConstMask)
return nullptr;
// If the mask is all zeros or poison, this instruction does nothing.
if (match(ConstMask, m_ZeroOrPoison()))
return eraseInstFromFunction(II);
// If the mask is all ones or poison, this is a plain vector store of the 1st
// argument.
if (match(ConstMask, m_AllOnesOrPoison())) {
StoreInst *S =
new StoreInst(II.getArgOperand(0), StorePtr, false, Alignment);
S->copyMetadata(II);
return S;
}
if (isa<ScalableVectorType>(ConstMask->getType()))
return nullptr;
// Use masked off lanes to simplify operands via SimplifyDemandedVectorElts
APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask);
APInt PoisonElts(DemandedElts.getBitWidth(), 0);
if (Value *V = SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts,
PoisonElts))
return replaceOperand(II, 0, V);
return nullptr;
}
// TODO, Obvious Missing Transforms:
// * Single constant active lane load -> load
// * Dereferenceable address & few lanes -> scalarize speculative load/selects
// * Adjacent vector addresses -> masked.load
// * Narrow width by halfs excluding zero/undef lanes
// * Vector incrementing address -> vector masked load
Instruction *InstCombinerImpl::simplifyMaskedGather(IntrinsicInst &II) {
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(1));
if (!ConstMask)
return nullptr;
// Vector splat address w/known mask -> scalar load
// Fold the gather to load the source vector first lane
// because it is reloading the same value each time
if (ConstMask->isAllOnesValue())
if (auto *SplatPtr = getSplatValue(II.getArgOperand(0))) {
auto *VecTy = cast<VectorType>(II.getType());
const Align Alignment = II.getParamAlign(0).valueOrOne();
LoadInst *L = Builder.CreateAlignedLoad(VecTy->getElementType(), SplatPtr,
Alignment, "load.scalar");
Value *Shuf =
Builder.CreateVectorSplat(VecTy->getElementCount(), L, "broadcast");
return replaceInstUsesWith(II, cast<Instruction>(Shuf));
}
return nullptr;
}
// TODO, Obvious Missing Transforms:
// * Single constant active lane -> store
// * Adjacent vector addresses -> masked.store
// * Narrow store width by halfs excluding zero/undef lanes
// * Vector incrementing address -> vector masked store
Instruction *InstCombinerImpl::simplifyMaskedScatter(IntrinsicInst &II) {
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(2));
if (!ConstMask)
return nullptr;
// If the mask is all zeros or poison, a scatter does nothing.
if (match(ConstMask, m_ZeroOrPoison()))
return eraseInstFromFunction(II);
// Vector splat address -> scalar store
if (auto *SplatPtr = getSplatValue(II.getArgOperand(1))) {
// scatter(splat(value), splat(ptr), non-zero-mask) -> store value, ptr
if (auto *SplatValue = getSplatValue(II.getArgOperand(0))) {
if (maskContainsAllOneOrUndef(ConstMask)) {
Align Alignment = II.getParamAlign(1).valueOrOne();
StoreInst *S = new StoreInst(SplatValue, SplatPtr, /*IsVolatile=*/false,
Alignment);
S->copyMetadata(II);
return S;
}
}
// scatter(vector, splat(ptr), splat(true)) -> store extract(vector,
// lastlane), ptr
if (ConstMask->isAllOnesValue()) {
Align Alignment = II.getParamAlign(1).valueOrOne();
VectorType *WideLoadTy = cast<VectorType>(II.getArgOperand(1)->getType());
ElementCount VF = WideLoadTy->getElementCount();
Value *RunTimeVF = Builder.CreateElementCount(Builder.getInt32Ty(), VF);
Value *LastLane = Builder.CreateSub(RunTimeVF, Builder.getInt32(1));
Value *Extract =
Builder.CreateExtractElement(II.getArgOperand(0), LastLane);
StoreInst *S =
new StoreInst(Extract, SplatPtr, /*IsVolatile=*/false, Alignment);
S->copyMetadata(II);
return S;
}
}
if (isa<ScalableVectorType>(ConstMask->getType()))
return nullptr;
// Use masked off lanes to simplify operands via SimplifyDemandedVectorElts
APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask);
APInt PoisonElts(DemandedElts.getBitWidth(), 0);
if (Value *V = SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts,
PoisonElts))
return replaceOperand(II, 0, V);
if (Value *V = SimplifyDemandedVectorElts(II.getOperand(1), DemandedElts,
PoisonElts))
return replaceOperand(II, 1, V);
return nullptr;
}
/// This function transforms launder.invariant.group like:
/// launder(launder(%x)) -> launder(%x) (the result is not the argument)
/// This is legal because it preserves the most recent information about
/// the presence or absence of invariant.group.
static Instruction *simplifyInvariantGroupIntrinsic(IntrinsicInst &II,
InstCombinerImpl &IC) {
auto *Arg = II.getArgOperand(0);
auto *StrippedArg = Arg->stripPointerCasts();
auto *StrippedInvariantGroupsArg = StrippedArg;
while (auto *Intr = dyn_cast<IntrinsicInst>(StrippedInvariantGroupsArg)) {
if (Intr->getIntrinsicID() != Intrinsic::launder_invariant_group)
break;
StrippedInvariantGroupsArg = Intr->getArgOperand(0)->stripPointerCasts();
}
if (StrippedArg == StrippedInvariantGroupsArg)
return nullptr; // No launders to remove.
Value *Result =
IC.Builder.CreateLaunderInvariantGroup(StrippedInvariantGroupsArg);
if (Result->getType()->getPointerAddressSpace() !=
II.getType()->getPointerAddressSpace())
Result = IC.Builder.CreateAddrSpaceCast(Result, II.getType());
return cast<Instruction>(Result);
}
static Instruction *foldCttzCtlz(IntrinsicInst &II, InstCombinerImpl &IC) {
assert((II.getIntrinsicID() == Intrinsic::cttz ||
II.getIntrinsicID() == Intrinsic::ctlz) &&
"Expected cttz or ctlz intrinsic");
bool IsTZ = II.getIntrinsicID() == Intrinsic::cttz;
Value *Op0 = II.getArgOperand(0);
Value *Op1 = II.getArgOperand(1);
Value *X;
// ctlz(bitreverse(x)) -> cttz(x)
// cttz(bitreverse(x)) -> ctlz(x)
if (match(Op0, m_BitReverse(m_Value(X)))) {
Intrinsic::ID ID = IsTZ ? Intrinsic::ctlz : Intrinsic::cttz;
Function *F =
Intrinsic::getOrInsertDeclaration(II.getModule(), ID, II.getType());
return CallInst::Create(F, {X, II.getArgOperand(1)});
}
if (II.getType()->isIntOrIntVectorTy(1)) {
// ctlz/cttz i1 Op0 --> not Op0
if (match(Op1, m_Zero()))
return BinaryOperator::CreateNot(Op0);
// If zero is poison, then the input can be assumed to be "true", so the
// instruction simplifies to "false".
assert(match(Op1, m_One()) && "Expected ctlz/cttz operand to be 0 or 1");
return IC.replaceInstUsesWith(II, ConstantInt::getNullValue(II.getType()));
}
// If ctlz/cttz is only used as a shift amount, set is_zero_poison to true.
if (II.hasOneUse() && match(Op1, m_Zero()) &&
match(II.user_back(), m_Shift(m_Value(), m_Specific(&II))))
return CallInst::Create(II.getCalledFunction(),
{Op0, IC.Builder.getTrue()});
Constant *C;
if (IsTZ) {
// cttz(-x) -> cttz(x)
if (match(Op0, m_Neg(m_Value(X))))
return CallInst::Create(II.getCalledFunction(), {X, Op1});
// cttz(-x & x) -> cttz(x)
if (match(Op0, m_c_And(m_Neg(m_Value(X)), m_Deferred(X))))
return CallInst::Create(II.getCalledFunction(), {X, Op1});
// cttz(mul(X, OddC)) -> cttz(X)
if (match(Op0, m_Mul(m_Value(X),
m_CheckedInt([](const APInt &C) { return C[0]; }))))
return CallInst::Create(II.getCalledFunction(), {X, Op1});
// cttz(sext(x)) -> cttz(zext(x))
if (match(Op0, m_OneUse(m_SExt(m_Value(X))))) {
auto *Zext = IC.Builder.CreateZExt(X, II.getType());
auto *CttzZext =
IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, Zext, Op1);
return IC.replaceInstUsesWith(II, CttzZext);
}
// Zext doesn't change the number of trailing zeros, so narrow:
// cttz(zext(x)) -> zext(cttz(x)) if the 'ZeroIsPoison' parameter is 'true'.
if (match(Op0, m_OneUse(m_ZExt(m_Value(X)))) && match(Op1, m_One())) {
auto *Cttz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, X,
IC.Builder.getTrue());
auto *ZextCttz = IC.Builder.CreateZExt(Cttz, II.getType());
return IC.replaceInstUsesWith(II, ZextCttz);
}
// cttz(abs(x)) -> cttz(x)
// cttz(nabs(x)) -> cttz(x)
Value *Y;
SelectPatternFlavor SPF = matchSelectPattern(Op0, X, Y).Flavor;
if (SPF == SPF_ABS || SPF == SPF_NABS)
return CallInst::Create(II.getCalledFunction(), {X, Op1});
if (match(Op0, m_Intrinsic<Intrinsic::abs>(m_Value(X))))
return CallInst::Create(II.getCalledFunction(), {X, Op1});
// cttz(shl(%const, %val), 1) --> add(cttz(%const, 1), %val)
if (match(Op0, m_Shl(m_ImmConstant(C), m_Value(X))) &&
match(Op1, m_One())) {
Value *ConstCttz =
IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, C, Op1);
return BinaryOperator::CreateAdd(ConstCttz, X);
}
// cttz(lshr exact (%const, %val), 1) --> sub(cttz(%const, 1), %val)
if (match(Op0, m_Exact(m_LShr(m_ImmConstant(C), m_Value(X)))) &&
match(Op1, m_One())) {
Value *ConstCttz =
IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, C, Op1);
return BinaryOperator::CreateSub(ConstCttz, X);
}
// cttz(add(lshr(UINT_MAX, %val), 1)) --> sub(width, %val)
if (match(Op0, m_Add(m_LShr(m_AllOnes(), m_Value(X)), m_One()))) {
Value *Width =
ConstantInt::get(II.getType(), II.getType()->getScalarSizeInBits());
return BinaryOperator::CreateSub(Width, X);
}
} else {
// ctlz(lshr(%const, %val), 1) --> add(ctlz(%const, 1), %val)
if (match(Op0, m_LShr(m_ImmConstant(C), m_Value(X))) &&
match(Op1, m_One())) {
Value *ConstCtlz =
IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1);
return BinaryOperator::CreateAdd(ConstCtlz, X);
}
// ctlz(shl nuw (%const, %val), 1) --> sub(ctlz(%const, 1), %val)
if (match(Op0, m_NUWShl(m_ImmConstant(C), m_Value(X))) &&
match(Op1, m_One())) {
Value *ConstCtlz =
IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1);
return BinaryOperator::CreateSub(ConstCtlz, X);
}
// ctlz(~x & (x - 1)) -> bitwidth - cttz(x, false)
if (Op0->hasOneUse() &&
match(Op0,
m_c_And(m_Not(m_Value(X)), m_Add(m_Deferred(X), m_AllOnes())))) {
Type *Ty = II.getType();
unsigned BitWidth = Ty->getScalarSizeInBits();
auto *Cttz = IC.Builder.CreateIntrinsic(Intrinsic::cttz, Ty,
{X, IC.Builder.getFalse()});
auto *Bw = ConstantInt::get(Ty, APInt(BitWidth, BitWidth));
return IC.replaceInstUsesWith(II, IC.Builder.CreateSub(Bw, Cttz));
}
}
// cttz(Pow2) -> Log2(Pow2)
// ctlz(Pow2) -> BitWidth - 1 - Log2(Pow2)
if (auto *R = IC.tryGetLog2(Op0, match(Op1, m_One()))) {
if (IsTZ)
return IC.replaceInstUsesWith(II, R);
BinaryOperator *BO = BinaryOperator::CreateSub(
ConstantInt::get(R->getType(), R->getType()->getScalarSizeInBits() - 1),
R);
BO->setHasNoSignedWrap();
BO->setHasNoUnsignedWrap();
return BO;
}
KnownBits Known = IC.computeKnownBits(Op0, &II);
// Create a mask for bits above (ctlz) or below (cttz) the first known one.
unsigned PossibleZeros = IsTZ ? Known.countMaxTrailingZeros()
: Known.countMaxLeadingZeros();
unsigned DefiniteZeros = IsTZ ? Known.countMinTrailingZeros()
: Known.countMinLeadingZeros();
// If all bits above (ctlz) or below (cttz) the first known one are known
// zero, this value is constant.
// FIXME: This should be in InstSimplify because we're replacing an
// instruction with a constant.
if (PossibleZeros == DefiniteZeros) {
auto *C = ConstantInt::get(Op0->getType(), DefiniteZeros);
return IC.replaceInstUsesWith(II, C);
}
// If the input to cttz/ctlz is known to be non-zero,
// then change the 'ZeroIsPoison' parameter to 'true'
// because we know the zero behavior can't affect the result.
if (!Known.One.isZero() ||
isKnownNonZero(Op0, IC.getSimplifyQuery().getWithInstruction(&II))) {
if (!match(II.getArgOperand(1), m_One()))
return CallInst::Create(II.getCalledFunction(),
{Op0, IC.Builder.getTrue()});
}
// Add range attribute since known bits can't completely reflect what we know.
unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
if (BitWidth != 1 && !II.hasRetAttr(Attribute::Range) &&
!II.getMetadata(LLVMContext::MD_range)) {
ConstantRange Range(APInt(BitWidth, DefiniteZeros),
APInt(BitWidth, PossibleZeros + 1));
II.addRangeRetAttr(Range);
return &II;
}
return nullptr;
}
static Instruction *foldCtpop(IntrinsicInst &II, InstCombinerImpl &IC) {
assert(II.getIntrinsicID() == Intrinsic::ctpop &&
"Expected ctpop intrinsic");
Type *Ty = II.getType();
unsigned BitWidth = Ty->getScalarSizeInBits();
Value *Op0 = II.getArgOperand(0);
Value *X, *Y;
// ctpop(bitreverse(x)) -> ctpop(x)
// ctpop(bswap(x)) -> ctpop(x)
if (match(Op0, m_BitReverse(m_Value(X))) || match(Op0, m_BSwap(m_Value(X))))
return CallInst::Create(II.getCalledFunction(), X);
// ctpop(rot(x)) -> ctpop(x)
if ((match(Op0, m_FShl(m_Value(X), m_Value(Y), m_Value())) ||
match(Op0, m_FShr(m_Value(X), m_Value(Y), m_Value()))) &&
X == Y)
return CallInst::Create(II.getCalledFunction(), X);
// ctpop(x | -x) -> bitwidth - cttz(x, false)
if (Op0->hasOneUse() &&
match(Op0, m_c_Or(m_Value(X), m_Neg(m_Deferred(X))))) {
auto *Cttz = IC.Builder.CreateIntrinsic(Intrinsic::cttz, Ty,
{X, IC.Builder.getFalse()});
auto *Bw = ConstantInt::get(Ty, APInt(BitWidth, BitWidth));
return IC.replaceInstUsesWith(II, IC.Builder.CreateSub(Bw, Cttz));
}
// ctpop(~x & (x - 1)) -> cttz(x, false)
if (match(Op0,
m_c_And(m_Not(m_Value(X)), m_Add(m_Deferred(X), m_AllOnes())))) {
Function *F =
Intrinsic::getOrInsertDeclaration(II.getModule(), Intrinsic::cttz, Ty);
return CallInst::Create(F, {X, IC.Builder.getFalse()});
}
// Zext doesn't change the number of set bits, so narrow:
// ctpop (zext X) --> zext (ctpop X)
if (match(Op0, m_OneUse(m_ZExt(m_Value(X))))) {
Value *NarrowPop = IC.Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, X);
return CastInst::Create(Instruction::ZExt, NarrowPop, Ty);
}
KnownBits Known(BitWidth);
IC.computeKnownBits(Op0, Known, &II);
// If all bits are zero except for exactly one fixed bit, then the result
// must be 0 or 1, and we can get that answer by shifting to LSB:
// ctpop (X & 32) --> (X & 32) >> 5
// TODO: Investigate removing this as its likely unnecessary given the below
// `isKnownToBeAPowerOfTwo` check.
if ((~Known.Zero).isPowerOf2())
return BinaryOperator::CreateLShr(
Op0, ConstantInt::get(Ty, (~Known.Zero).exactLogBase2()));
// More generally we can also handle non-constant power of 2 patterns such as
// shl/shr(Pow2, X), (X & -X), etc... by transforming:
// ctpop(Pow2OrZero) --> icmp ne X, 0
if (IC.isKnownToBeAPowerOfTwo(Op0, /* OrZero */ true))
return CastInst::Create(Instruction::ZExt,
IC.Builder.CreateICmp(ICmpInst::ICMP_NE, Op0,
Constant::getNullValue(Ty)),
Ty);
// Add range attribute since known bits can't completely reflect what we know.
if (BitWidth != 1) {
ConstantRange OldRange =
II.getRange().value_or(ConstantRange::getFull(BitWidth));
unsigned Lower = Known.countMinPopulation();
unsigned Upper = Known.countMaxPopulation() + 1;
if (Lower == 0 && OldRange.contains(APInt::getZero(BitWidth)) &&
isKnownNonZero(Op0, IC.getSimplifyQuery().getWithInstruction(&II)))
Lower = 1;
ConstantRange Range(APInt(BitWidth, Lower), APInt(BitWidth, Upper));
Range = Range.intersectWith(OldRange, ConstantRange::Unsigned);
if (Range != OldRange) {
II.addRangeRetAttr(Range);
return &II;
}
}
return nullptr;
}
/// Convert `tbl`/`tbx` intrinsics to shufflevector if the mask is constant, and
/// at most two source operands are actually referenced.
static Instruction *simplifyNeonTbl(IntrinsicInst &II, InstCombiner &IC,
bool IsExtension) {
// Bail out if the mask is not a constant.
auto *C = dyn_cast<Constant>(II.getArgOperand(II.arg_size() - 1));
if (!C)
return nullptr;
auto *RetTy = cast<FixedVectorType>(II.getType());
unsigned NumIndexes = RetTy->getNumElements();
// Only perform this transformation for <8 x i8> and <16 x i8> vector types.
if (!RetTy->getElementType()->isIntegerTy(8) ||
(NumIndexes != 8 && NumIndexes != 16))
return nullptr;
// For tbx instructions, the first argument is the "fallback" vector, which
// has the same length as the mask and return type.
unsigned int StartIndex = (unsigned)IsExtension;
auto *SourceTy =
cast<FixedVectorType>(II.getArgOperand(StartIndex)->getType());
// Note that the element count of each source vector does *not* need to be the
// same as the element count of the return type and mask! All source vectors
// must have the same element count as each other, though.
unsigned NumElementsPerSource = SourceTy->getNumElements();
// There are no tbl/tbx intrinsics for which the destination size exceeds the
// source size. However, our definitions of the intrinsics, at least in
// IntrinsicsAArch64.td, allow for arbitrary destination vector sizes, so it
// *could* technically happen.
if (NumIndexes > NumElementsPerSource)
return nullptr;
// The tbl/tbx intrinsics take several source operands followed by a mask
// operand.
unsigned int NumSourceOperands = II.arg_size() - 1 - (unsigned)IsExtension;
// Map input operands to shuffle indices. This also helpfully deduplicates the
// input arguments, in case the same value is passed as an argument multiple
// times.
SmallDenseMap<Value *, unsigned, 2> ValueToShuffleSlot;
Value *ShuffleOperands[2] = {PoisonValue::get(SourceTy),
PoisonValue::get(SourceTy)};
int Indexes[16];
for (unsigned I = 0; I < NumIndexes; ++I) {
Constant *COp = C->getAggregateElement(I);
if (!COp || (!isa<UndefValue>(COp) && !isa<ConstantInt>(COp)))
return nullptr;
if (isa<UndefValue>(COp)) {
Indexes[I] = -1;
continue;
}
uint64_t Index = cast<ConstantInt>(COp)->getZExtValue();
// The index of the input argument that this index references (0 = first
// source argument, etc).
unsigned SourceOperandIndex = Index / NumElementsPerSource;
// The index of the element at that source operand.
unsigned SourceOperandElementIndex = Index % NumElementsPerSource;
Value *SourceOperand;
if (SourceOperandIndex >= NumSourceOperands) {
// This index is out of bounds. Map it to index into either the fallback
// vector (tbx) or vector of zeroes (tbl).
SourceOperandIndex = NumSourceOperands;
if (IsExtension) {
// For out-of-bounds indices in tbx, choose the `I`th element of the
// fallback.
SourceOperand = II.getArgOperand(0);
SourceOperandElementIndex = I;
} else {
// Otherwise, choose some element from the dummy vector of zeroes (we'll
// always choose the first).
SourceOperand = Constant::getNullValue(SourceTy);
SourceOperandElementIndex = 0;
}
} else {
SourceOperand = II.getArgOperand(SourceOperandIndex + StartIndex);
}
// The source operand may be the fallback vector, which may not have the
// same number of elements as the source vector. In that case, we *could*
// choose to extend its length with another shufflevector, but it's simpler
// to just bail instead.
if (cast<FixedVectorType>(SourceOperand->getType())->getNumElements() !=
NumElementsPerSource)
return nullptr;
// We now know the source operand referenced by this index. Make it a
// shufflevector operand, if it isn't already.
unsigned NumSlots = ValueToShuffleSlot.size();
// This shuffle references more than two sources, and hence cannot be
// represented as a shufflevector.
if (NumSlots == 2 && !ValueToShuffleSlot.contains(SourceOperand))
return nullptr;
auto [It, Inserted] =
ValueToShuffleSlot.try_emplace(SourceOperand, NumSlots);
if (Inserted)
ShuffleOperands[It->getSecond()] = SourceOperand;
unsigned RemappedIndex =
(It->getSecond() * NumElementsPerSource) + SourceOperandElementIndex;
Indexes[I] = RemappedIndex;
}
Value *Shuf = IC.Builder.CreateShuffleVector(
ShuffleOperands[0], ShuffleOperands[1], ArrayRef(Indexes, NumIndexes));
return IC.replaceInstUsesWith(II, Shuf);
}
// Returns true iff the 2 intrinsics have the same operands, limiting the
// comparison to the first NumOperands.
static bool haveSameOperands(const IntrinsicInst &I, const IntrinsicInst &E,
unsigned NumOperands) {
assert(I.arg_size() >= NumOperands && "Not enough operands");
assert(E.arg_size() >= NumOperands && "Not enough operands");
for (unsigned i = 0; i < NumOperands; i++)
if (I.getArgOperand(i) != E.getArgOperand(i))
return false;
return true;
}
// Remove trivially empty start/end intrinsic ranges, i.e. a start
// immediately followed by an end (ignoring debuginfo or other
// start/end intrinsics in between). As this handles only the most trivial
// cases, tracking the nesting level is not needed:
//
// call @llvm.foo.start(i1 0)
// call @llvm.foo.start(i1 0) ; This one won't be skipped: it will be removed
// call @llvm.foo.end(i1 0)
// call @llvm.foo.end(i1 0) ; &I
static bool
removeTriviallyEmptyRange(IntrinsicInst &EndI, InstCombinerImpl &IC,
std::function<bool(const IntrinsicInst &)> IsStart) {
// We start from the end intrinsic and scan backwards, so that InstCombine
// has already processed (and potentially removed) all the instructions
// before the end intrinsic.
BasicBlock::reverse_iterator BI(EndI), BE(EndI.getParent()->rend());
for (; BI != BE; ++BI) {
if (auto *I = dyn_cast<IntrinsicInst>(&*BI)) {
if (I->isDebugOrPseudoInst() ||
I->getIntrinsicID() == EndI.getIntrinsicID())
continue;
if (IsStart(*I)) {
if (haveSameOperands(EndI, *I, EndI.arg_size())) {
IC.eraseInstFromFunction(*I);
IC.eraseInstFromFunction(EndI);
return true;
}
// Skip start intrinsics that don't pair with this end intrinsic.
continue;
}
}
break;
}
return false;
}
Instruction *InstCombinerImpl::visitVAEndInst(VAEndInst &I) {
removeTriviallyEmptyRange(I, *this, [&I](const IntrinsicInst &II) {
// Bail out on the case where the source va_list of a va_copy is destroyed
// immediately by a follow-up va_end.
return II.getIntrinsicID() == Intrinsic::vastart ||
(II.getIntrinsicID() == Intrinsic::vacopy &&
I.getArgOperand(0) != II.getArgOperand(1));
});
return nullptr;
}
static CallInst *canonicalizeConstantArg0ToArg1(CallInst &Call) {
assert(Call.arg_size() > 1 && "Need at least 2 args to swap");
Value *Arg0 = Call.getArgOperand(0), *Arg1 = Call.getArgOperand(1);
if (isa<Constant>(Arg0) && !isa<Constant>(Arg1)) {
Call.setArgOperand(0, Arg1);
Call.setArgOperand(1, Arg0);
AttributeList CallAttr = Call.getAttributes();
AttributeSet LHSAttr = CallAttr.getParamAttrs(0);
AttributeSet RHSAttr = CallAttr.getParamAttrs(1);
LLVMContext &Ctx = Call.getContext();
Call.setAttributes(CallAttr
.setAttributesAtIndex(
Ctx, AttributeList::FirstArgIndex + 0, RHSAttr)
.setAttributesAtIndex(
Ctx, AttributeList::FirstArgIndex + 1, LHSAttr));
return &Call;
}
return nullptr;
}
/// Creates a result tuple for an overflow intrinsic \p II with a given
/// \p Result and a constant \p Overflow value.
static Instruction *createOverflowTuple(IntrinsicInst *II, Value *Result,
Constant *Overflow) {
Constant *V[] = {PoisonValue::get(Result->getType()), Overflow};
StructType *ST = cast<StructType>(II->getType());
Constant *Struct = ConstantStruct::get(ST, V);
return InsertValueInst::Create(Struct, Result, 0);
}
Instruction *
InstCombinerImpl::foldIntrinsicWithOverflowCommon(IntrinsicInst *II) {
WithOverflowInst *WO = cast<WithOverflowInst>(II);
Value *OperationResult = nullptr;
Constant *OverflowResult = nullptr;
if (OptimizeOverflowCheck(WO->getBinaryOp(), WO->isSigned(), WO->getLHS(),
WO->getRHS(), *WO, OperationResult, OverflowResult))
return createOverflowTuple(WO, OperationResult, OverflowResult);
// See whether we can optimize the overflow check with assumption information.
for (User *U : WO->users()) {
if (!match(U, m_ExtractValue<1>(m_Value())))
continue;
for (auto &AssumeVH : AC.assumptionsFor(U)) {
if (!AssumeVH)
continue;
CallInst *I = cast<CallInst>(AssumeVH);
if (!match(I->getArgOperand(0), m_Not(m_Specific(U))))
continue;
if (!isValidAssumeForContext(I, II, /*DT=*/nullptr,
/*AllowEphemerals=*/true))
continue;
Value *Result =
Builder.CreateBinOp(WO->getBinaryOp(), WO->getLHS(), WO->getRHS());
Result->takeName(WO);
if (auto *Inst = dyn_cast<Instruction>(Result)) {
if (WO->isSigned())
Inst->setHasNoSignedWrap();
else
Inst->setHasNoUnsignedWrap();
}
return createOverflowTuple(WO, Result,
ConstantInt::getFalse(U->getType()));
}
}
return nullptr;
}
static bool inputDenormalIsIEEE(const Function &F, const Type *Ty) {
Ty = Ty->getScalarType();
return F.getDenormalMode(Ty->getFltSemantics()).Input == DenormalMode::IEEE;
}
static bool inputDenormalIsDAZ(const Function &F, const Type *Ty) {
Ty = Ty->getScalarType();
return F.getDenormalMode(Ty->getFltSemantics()).inputsAreZero();
}
/// Flushing a denormal to +0.0 breaks f(-x) = -f(x) for odd f.
static bool mayFlushDenormalsToPositiveZero(const CallInst *CI) {
DenormalMode Mode = CI->getFunction()->getDenormalMode(
CI->getType()->getScalarType()->getFltSemantics());
return Mode.inputsMayBePositiveZero() || Mode.outputsMayBePositiveZero();
}
/// \returns the compare predicate type if the test performed by
/// llvm.is.fpclass(x, \p Mask) is equivalent to fcmp o__ x, 0.0 with the
/// floating-point environment assumed for \p F for type \p Ty
static FCmpInst::Predicate fpclassTestIsFCmp0(FPClassTest Mask,
const Function &F, Type *Ty) {
switch (static_cast<unsigned>(Mask)) {
case fcZero:
if (inputDenormalIsIEEE(F, Ty))
return FCmpInst::FCMP_OEQ;
break;
case fcZero | fcSubnormal:
if (inputDenormalIsDAZ(F, Ty))
return FCmpInst::FCMP_OEQ;
break;
case fcPositive | fcNegZero:
if (inputDenormalIsIEEE(F, Ty))
return FCmpInst::FCMP_OGE;
break;
case fcPositive | fcNegZero | fcNegSubnormal:
if (inputDenormalIsDAZ(F, Ty))
return FCmpInst::FCMP_OGE;
break;
case fcPosSubnormal | fcPosNormal | fcPosInf:
if (inputDenormalIsIEEE(F, Ty))
return FCmpInst::FCMP_OGT;
break;
case fcNegative | fcPosZero:
if (inputDenormalIsIEEE(F, Ty))
return FCmpInst::FCMP_OLE;
break;
case fcNegative | fcPosZero | fcPosSubnormal:
if (inputDenormalIsDAZ(F, Ty))
return FCmpInst::FCMP_OLE;
break;
case fcNegSubnormal | fcNegNormal | fcNegInf:
if (inputDenormalIsIEEE(F, Ty))
return FCmpInst::FCMP_OLT;
break;
case fcPosNormal | fcPosInf:
if (inputDenormalIsDAZ(F, Ty))
return FCmpInst::FCMP_OGT;
break;
case fcNegNormal | fcNegInf:
if (inputDenormalIsDAZ(F, Ty))
return FCmpInst::FCMP_OLT;
break;
case ~fcZero & ~fcNan:
if (inputDenormalIsIEEE(F, Ty))
return FCmpInst::FCMP_ONE;
break;
case ~(fcZero | fcSubnormal) & ~fcNan:
if (inputDenormalIsDAZ(F, Ty))
return FCmpInst::FCMP_ONE;
break;
default:
break;
}
return FCmpInst::BAD_FCMP_PREDICATE;
}
Instruction *InstCombinerImpl::foldIntrinsicIsFPClass(IntrinsicInst &II) {
Value *Src0 = II.getArgOperand(0);
Value *Src1 = II.getArgOperand(1);
const ConstantInt *CMask = cast<ConstantInt>(Src1);
FPClassTest Mask = static_cast<FPClassTest>(CMask->getZExtValue());
const bool IsUnordered = (Mask & fcNan) == fcNan;
const bool IsOrdered = (Mask & fcNan) == fcNone;
const FPClassTest OrderedMask = Mask & ~fcNan;
const FPClassTest OrderedInvertedMask = ~OrderedMask & ~fcNan;
const bool IsStrict =
II.getFunction()->getAttributes().hasFnAttr(Attribute::StrictFP);
Value *FNegSrc;
// is.fpclass (fneg x), mask -> is.fpclass x, (fneg mask)
if (match(Src0, m_FNeg(m_Value(FNegSrc))))
return CallInst::Create(
II.getCalledFunction(),
{FNegSrc, ConstantInt::get(Src1->getType(), fneg(Mask))});
Value *FAbsSrc;
if (match(Src0, m_FAbs(m_Value(FAbsSrc))))
return CallInst::Create(
II.getCalledFunction(),
{FAbsSrc, ConstantInt::get(Src1->getType(), inverse_fabs(Mask))});
if ((OrderedMask == fcInf || OrderedInvertedMask == fcInf) &&
(IsOrdered || IsUnordered) && !IsStrict) {
// is.fpclass(x, fcInf) -> fcmp oeq fabs(x), +inf
// is.fpclass(x, ~fcInf) -> fcmp one fabs(x), +inf
// is.fpclass(x, fcInf|fcNan) -> fcmp ueq fabs(x), +inf
// is.fpclass(x, ~(fcInf|fcNan)) -> fcmp une fabs(x), +inf
Constant *Inf = ConstantFP::getInfinity(Src0->getType());
FCmpInst::Predicate Pred =
IsUnordered ? FCmpInst::FCMP_UEQ : FCmpInst::FCMP_OEQ;
if (OrderedInvertedMask == fcInf)
Pred = IsUnordered ? FCmpInst::FCMP_UNE : FCmpInst::FCMP_ONE;
Value *Fabs = Builder.CreateFAbs(Src0);
Value *CmpInf = Builder.CreateFCmp(Pred, Fabs, Inf);
CmpInf->takeName(&II);
return replaceInstUsesWith(II, CmpInf);
}
if ((OrderedMask == fcPosInf || OrderedMask == fcNegInf) &&
(IsOrdered || IsUnordered) && !IsStrict) {
// is.fpclass(x, fcPosInf) -> fcmp oeq x, +inf
// is.fpclass(x, fcNegInf) -> fcmp oeq x, -inf
// is.fpclass(x, fcPosInf|fcNan) -> fcmp ueq x, +inf
// is.fpclass(x, fcNegInf|fcNan) -> fcmp ueq x, -inf
Constant *Inf =
ConstantFP::getInfinity(Src0->getType(), OrderedMask == fcNegInf);
Value *EqInf = IsUnordered ? Builder.CreateFCmpUEQ(Src0, Inf)
: Builder.CreateFCmpOEQ(Src0, Inf);
EqInf->takeName(&II);
return replaceInstUsesWith(II, EqInf);
}
if ((OrderedInvertedMask == fcPosInf || OrderedInvertedMask == fcNegInf) &&
(IsOrdered || IsUnordered) && !IsStrict) {
// is.fpclass(x, ~fcPosInf) -> fcmp one x, +inf
// is.fpclass(x, ~fcNegInf) -> fcmp one x, -inf
// is.fpclass(x, ~fcPosInf|fcNan) -> fcmp une x, +inf
// is.fpclass(x, ~fcNegInf|fcNan) -> fcmp une x, -inf
Constant *Inf = ConstantFP::getInfinity(Src0->getType(),
OrderedInvertedMask == fcNegInf);
Value *NeInf = IsUnordered ? Builder.CreateFCmpUNE(Src0, Inf)
: Builder.CreateFCmpONE(Src0, Inf);
NeInf->takeName(&II);
return replaceInstUsesWith(II, NeInf);
}
if (Mask == fcNan && !IsStrict) {
// Equivalent of isnan. Replace with standard fcmp if we don't care about FP
// exceptions.
Value *IsNan =
Builder.CreateFCmpUNO(Src0, ConstantFP::getZero(Src0->getType()));
IsNan->takeName(&II);
return replaceInstUsesWith(II, IsNan);
}
if (Mask == (~fcNan & fcAllFlags) && !IsStrict) {
// Equivalent of !isnan. Replace with standard fcmp.
Value *FCmp =
Builder.CreateFCmpORD(Src0, ConstantFP::getZero(Src0->getType()));
FCmp->takeName(&II);
return replaceInstUsesWith(II, FCmp);
}
FCmpInst::Predicate PredType = FCmpInst::BAD_FCMP_PREDICATE;
// Try to replace with an fcmp with 0
//
// is.fpclass(x, fcZero) -> fcmp oeq x, 0.0
// is.fpclass(x, fcZero | fcNan) -> fcmp ueq x, 0.0
// is.fpclass(x, ~fcZero & ~fcNan) -> fcmp one x, 0.0
// is.fpclass(x, ~fcZero) -> fcmp une x, 0.0
//
// is.fpclass(x, fcPosSubnormal | fcPosNormal | fcPosInf) -> fcmp ogt x, 0.0
// is.fpclass(x, fcPositive | fcNegZero) -> fcmp oge x, 0.0
//
// is.fpclass(x, fcNegSubnormal | fcNegNormal | fcNegInf) -> fcmp olt x, 0.0
// is.fpclass(x, fcNegative | fcPosZero) -> fcmp ole x, 0.0
//
if (!IsStrict && (IsOrdered || IsUnordered) &&
(PredType = fpclassTestIsFCmp0(OrderedMask, *II.getFunction(),
Src0->getType())) !=
FCmpInst::BAD_FCMP_PREDICATE) {
Constant *Zero = ConstantFP::getZero(Src0->getType());
// Equivalent of == 0.
Value *FCmp = Builder.CreateFCmp(
IsUnordered ? FCmpInst::getUnorderedPredicate(PredType) : PredType,
Src0, Zero);
FCmp->takeName(&II);
return replaceInstUsesWith(II, FCmp);
}
KnownFPClass Known =
computeKnownFPClass(Src0, Mask, SQ.getWithInstruction(&II));
// If none of the tests which can return false are possible, fold to true.
// fp_class (nnan x), ~(qnan|snan) -> true
// fp_class (ninf x), ~(ninf|pinf) -> true
if (Known.isKnownAlways(Mask))
return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true));
// Clear test bits we know must be false from the source value.
// fp_class (nnan x), qnan|snan|other -> fp_class (nnan x), other
// fp_class (ninf x), ninf|pinf|other -> fp_class (ninf x), other
if ((Mask & Known.getKnownFPClasses()) != Mask) {
II.setArgOperand(
1, ConstantInt::get(Src1->getType(), Mask & Known.getKnownFPClasses()));
return &II;
}
return nullptr;
}
static std::optional<bool> getKnownSign(Value *Op, const SimplifyQuery &SQ) {
KnownBits Known = computeKnownBits(Op, SQ);
if (Known.isNonNegative())
return false;
if (Known.isNegative())
return true;
Value *X, *Y;
if (match(Op, m_NSWSub(m_Value(X), m_Value(Y))))
return isImpliedByDomCondition(ICmpInst::ICMP_SLT, X, Y, SQ.CtxI, SQ.DL);
return std::nullopt;
}
static std::optional<bool> getKnownSignOrZero(Value *Op,
const SimplifyQuery &SQ) {
if (std::optional<bool> Sign = getKnownSign(Op, SQ))
return Sign;
Value *X, *Y;
if (match(Op, m_NSWSub(m_Value(X), m_Value(Y))))
return isImpliedByDomCondition(ICmpInst::ICMP_SLE, X, Y, SQ.CtxI, SQ.DL);
return std::nullopt;
}
/// Return true if two values \p Op0 and \p Op1 are known to have the same sign.
static bool signBitMustBeTheSame(Value *Op0, Value *Op1,
const SimplifyQuery &SQ) {
std::optional<bool> Known1 = getKnownSign(Op1, SQ);
if (!Known1)
return false;
std::optional<bool> Known0 = getKnownSign(Op0, SQ);
if (!Known0)
return false;
return *Known0 == *Known1;
}
// Determines if ldexp(ldexp(x, a), b) -> ldexp(x, sadd.sat(a, b)) is safe.
//
// This is true if, when the add saturates, the resulting ldexp is guaranteed to
// produce 0 or inf.
static bool ldexpSaturatingAddIsSafe(Type *FpTy, Type *ExpTy) {
const fltSemantics &FltSem = FpTy->getScalarType()->getFltSemantics();
if (!APFloat::semanticsHasInf(FltSem))
return false;
// Cap ExpBits at 32 because scalbn takes an int. This is sufficient for any
// reasonable fp type (for example, `double` only has 11 exponent bits).
unsigned ExpBits = std::min(ExpTy->getScalarSizeInBits(), 32u);
int SignedMax = static_cast<int>(maxIntN(ExpBits));
int SignedMin = static_cast<int>(minIntN(ExpBits));
APFloat ScaledUp = scalbn(APFloat::getSmallest(FltSem), SignedMax,
APFloat::rmNearestTiesToEven);
APFloat ScaledDown = scalbn(APFloat::getLargest(FltSem), SignedMin,
APFloat::rmNearestTiesToEven);
return ScaledUp.isInfinity() && ScaledDown.isZero();
}
/// Try to canonicalize min/max(X + C0, C1) as min/max(X, C1 - C0) + C0. This
/// can trigger other combines.
static Instruction *moveAddAfterMinMax(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
Intrinsic::ID MinMaxID = II->getIntrinsicID();
assert((MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin ||
MinMaxID == Intrinsic::umax || MinMaxID == Intrinsic::umin) &&
"Expected a min or max intrinsic");
// TODO: Match vectors with undef elements, but undef may not propagate.
Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1);
Value *X;
const APInt *C0, *C1;
if (!match(Op0, m_OneUse(m_Add(m_Value(X), m_APInt(C0)))) ||
!match(Op1, m_APInt(C1)))
return nullptr;
// Check for necessary no-wrap and overflow constraints.
bool IsSigned = MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin;
auto *Add = cast<BinaryOperator>(Op0);
if ((IsSigned && !Add->hasNoSignedWrap()) ||
(!IsSigned && !Add->hasNoUnsignedWrap()))
return nullptr;
// If the constant difference overflows, then instsimplify should reduce the
// min/max to the add or C1.
bool Overflow;
APInt CDiff =
IsSigned ? C1->ssub_ov(*C0, Overflow) : C1->usub_ov(*C0, Overflow);
assert(!Overflow && "Expected simplify of min/max");
// min/max (add X, C0), C1 --> add (min/max X, C1 - C0), C0
// Note: the "mismatched" no-overflow setting does not propagate.
Constant *NewMinMaxC = ConstantInt::get(II->getType(), CDiff);
Value *NewMinMax = Builder.CreateBinaryIntrinsic(MinMaxID, X, NewMinMaxC);
return IsSigned ? BinaryOperator::CreateNSWAdd(NewMinMax, Add->getOperand(1))
: BinaryOperator::CreateNUWAdd(NewMinMax, Add->getOperand(1));
}
/// Match a sadd_sat or ssub_sat which is using min/max to clamp the value.
Instruction *InstCombinerImpl::matchSAddSubSat(IntrinsicInst &MinMax1) {
Type *Ty = MinMax1.getType();
// We are looking for a tree of:
// max(INT_MIN, min(INT_MAX, add(sext(A), sext(B))))
// Where the min and max could be reversed
Instruction *MinMax2;
BinaryOperator *AddSub;
const APInt *MinValue, *MaxValue;
if (match(&MinMax1, m_SMin(m_Instruction(MinMax2), m_APInt(MaxValue)))) {
if (!match(MinMax2, m_SMax(m_BinOp(AddSub), m_APInt(MinValue))))
return nullptr;
} else if (match(&MinMax1,
m_SMax(m_Instruction(MinMax2), m_APInt(MinValue)))) {
if (!match(MinMax2, m_SMin(m_BinOp(AddSub), m_APInt(MaxValue))))
return nullptr;
} else
return nullptr;
// Check that the constants clamp a saturate, and that the new type would be
// sensible to convert to.
if (!(*MaxValue + 1).isPowerOf2() || -*MinValue != *MaxValue + 1)
return nullptr;
// In what bitwidth can this be treated as saturating arithmetics?
unsigned NewBitWidth = (*MaxValue + 1).logBase2() + 1;
// FIXME: This isn't quite right for vectors, but using the scalar type is a
// good first approximation for what should be done there.
if (!shouldChangeType(Ty->getScalarType()->getIntegerBitWidth(), NewBitWidth))
return nullptr;
// Also make sure that the inner min/max and the add/sub have one use.
if (!MinMax2->hasOneUse() || !AddSub->hasOneUse())
return nullptr;
// Create the new type (which can be a vector type)
Type *NewTy = Ty->getWithNewBitWidth(NewBitWidth);
Intrinsic::ID IntrinsicID;
if (AddSub->getOpcode() == Instruction::Add)
IntrinsicID = Intrinsic::sadd_sat;
else if (AddSub->getOpcode() == Instruction::Sub)
IntrinsicID = Intrinsic::ssub_sat;
else
return nullptr;
// The two operands of the add/sub must be nsw-truncatable to the NewTy. This
// is usually achieved via a sext from a smaller type.
if (ComputeMaxSignificantBits(AddSub->getOperand(0), AddSub) > NewBitWidth ||
ComputeMaxSignificantBits(AddSub->getOperand(1), AddSub) > NewBitWidth)
return nullptr;
// Finally create and return the sat intrinsic, truncated to the new type
Value *AT = Builder.CreateTrunc(AddSub->getOperand(0), NewTy);
Value *BT = Builder.CreateTrunc(AddSub->getOperand(1), NewTy);
Value *Sat = Builder.CreateIntrinsic(IntrinsicID, NewTy, {AT, BT});
return CastInst::Create(Instruction::SExt, Sat, Ty);
}
/// If we have a clamp pattern like max (min X, 42), 41 -- where the output
/// can only be one of two possible constant values -- turn that into a select
/// of constants.
static Instruction *foldClampRangeOfTwo(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
Value *X;
const APInt *C0, *C1;
if (!match(I1, m_APInt(C1)) || !I0->hasOneUse())
return nullptr;
CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE;
switch (II->getIntrinsicID()) {
case Intrinsic::smax:
if (match(I0, m_SMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1)
Pred = ICmpInst::ICMP_SGT;
break;
case Intrinsic::smin:
if (match(I0, m_SMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1)
Pred = ICmpInst::ICMP_SLT;
break;
case Intrinsic::umax:
if (match(I0, m_UMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1)
Pred = ICmpInst::ICMP_UGT;
break;
case Intrinsic::umin:
if (match(I0, m_UMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1)
Pred = ICmpInst::ICMP_ULT;
break;
default:
llvm_unreachable("Expected min/max intrinsic");
}
if (Pred == CmpInst::BAD_ICMP_PREDICATE)
return nullptr;
// max (min X, 42), 41 --> X > 41 ? 42 : 41
// min (max X, 42), 43 --> X < 43 ? 42 : 43
Value *Cmp = Builder.CreateICmp(Pred, X, I1);
return SelectInst::Create(Cmp, ConstantInt::get(II->getType(), *C0), I1);
}
/// If this min/max has a constant operand and an operand that is a matching
/// min/max with a constant operand, constant-fold the 2 constant operands.
static Value *reassociateMinMaxWithConstants(IntrinsicInst *II,
IRBuilderBase &Builder,
const SimplifyQuery &SQ) {
Intrinsic::ID MinMaxID = II->getIntrinsicID();
auto *LHS = dyn_cast<MinMaxIntrinsic>(II->getArgOperand(0));
if (!LHS)
return nullptr;
Constant *C0, *C1;
if (!match(LHS->getArgOperand(1), m_ImmConstant(C0)) ||
!match(II->getArgOperand(1), m_ImmConstant(C1)))
return nullptr;
// max (max X, C0), C1 --> max X, (max C0, C1)
// min (min X, C0), C1 --> min X, (min C0, C1)
// umax (smax X, nneg C0), nneg C1 --> smax X, (umax C0, C1)
// smin (umin X, nneg C0), nneg C1 --> umin X, (smin C0, C1)
Intrinsic::ID InnerMinMaxID = LHS->getIntrinsicID();
if (InnerMinMaxID != MinMaxID &&
!(((MinMaxID == Intrinsic::umax && InnerMinMaxID == Intrinsic::smax) ||
(MinMaxID == Intrinsic::smin && InnerMinMaxID == Intrinsic::umin)) &&
isKnownNonNegative(C0, SQ) && isKnownNonNegative(C1, SQ)))
return nullptr;
ICmpInst::Predicate Pred = MinMaxIntrinsic::getPredicate(MinMaxID);
Value *CondC = Builder.CreateICmp(Pred, C0, C1);
Value *NewC = Builder.CreateSelect(CondC, C0, C1);
return Builder.CreateIntrinsic(InnerMinMaxID, II->getType(),
{LHS->getArgOperand(0), NewC});
}
/// If this min/max has a matching min/max operand with a constant, try to push
/// the constant operand into this instruction. This can enable more folds.
static Instruction *
reassociateMinMaxWithConstantInOperand(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
// Match and capture a min/max operand candidate.
Value *X, *Y;
Constant *C;
Instruction *Inner;
if (!match(II, m_c_MaxOrMin(m_OneUse(m_CombineAnd(
m_Instruction(Inner),
m_MaxOrMin(m_Value(X), m_ImmConstant(C)))),
m_Value(Y))))
return nullptr;
// The inner op must match. Check for constants to avoid infinite loops.
Intrinsic::ID MinMaxID = II->getIntrinsicID();
auto *InnerMM = dyn_cast<IntrinsicInst>(Inner);
if (!InnerMM || InnerMM->getIntrinsicID() != MinMaxID ||
match(X, m_ImmConstant()) || match(Y, m_ImmConstant()))
return nullptr;
// max (max X, C), Y --> max (max X, Y), C
Function *MinMax = Intrinsic::getOrInsertDeclaration(II->getModule(),
MinMaxID, II->getType());
Value *NewInner = Builder.CreateBinaryIntrinsic(MinMaxID, X, Y);
NewInner->takeName(Inner);
return CallInst::Create(MinMax, {NewInner, C});
}
/// Reduce a sequence of min/max intrinsics with a common operand.
static Instruction *factorizeMinMaxTree(IntrinsicInst *II) {
// Match 3 of the same min/max ops. Example: umin(umin(), umin()).
auto *LHS = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
auto *RHS = dyn_cast<IntrinsicInst>(II->getArgOperand(1));
Intrinsic::ID MinMaxID = II->getIntrinsicID();
if (!LHS || !RHS || LHS->getIntrinsicID() != MinMaxID ||
RHS->getIntrinsicID() != MinMaxID ||
(!LHS->hasOneUse() && !RHS->hasOneUse()))
return nullptr;
Value *A = LHS->getArgOperand(0);
Value *B = LHS->getArgOperand(1);
Value *C = RHS->getArgOperand(0);
Value *D = RHS->getArgOperand(1);
// Look for a common operand.
Value *MinMaxOp = nullptr;
Value *ThirdOp = nullptr;
if (LHS->hasOneUse()) {
// If the LHS is only used in this chain and the RHS is used outside of it,
// reuse the RHS min/max because that will eliminate the LHS.
if (D == A || C == A) {
// min(min(a, b), min(c, a)) --> min(min(c, a), b)
// min(min(a, b), min(a, d)) --> min(min(a, d), b)
MinMaxOp = RHS;
ThirdOp = B;
} else if (D == B || C == B) {
// min(min(a, b), min(c, b)) --> min(min(c, b), a)
// min(min(a, b), min(b, d)) --> min(min(b, d), a)
MinMaxOp = RHS;
ThirdOp = A;
}
} else {
assert(RHS->hasOneUse() && "Expected one-use operand");
// Reuse the LHS. This will eliminate the RHS.
if (D == A || D == B) {
// min(min(a, b), min(c, a)) --> min(min(a, b), c)
// min(min(a, b), min(c, b)) --> min(min(a, b), c)
MinMaxOp = LHS;
ThirdOp = C;
} else if (C == A || C == B) {
// min(min(a, b), min(b, d)) --> min(min(a, b), d)
// min(min(a, b), min(c, b)) --> min(min(a, b), d)
MinMaxOp = LHS;
ThirdOp = D;
}
}
if (!MinMaxOp || !ThirdOp)
return nullptr;
Module *Mod = II->getModule();
Function *MinMax =
Intrinsic::getOrInsertDeclaration(Mod, MinMaxID, II->getType());
return CallInst::Create(MinMax, { MinMaxOp, ThirdOp });
}
/// If all arguments of the intrinsic are unary shuffles with the same mask,
/// try to shuffle after the intrinsic.
Instruction *
InstCombinerImpl::foldShuffledIntrinsicOperands(IntrinsicInst *II) {
if (!II->getType()->isVectorTy() ||
!isTriviallyVectorizable(II->getIntrinsicID()) ||
!II->getCalledFunction()->isSpeculatable())
return nullptr;
Value *X;
Constant *C;
ArrayRef<int> Mask;
auto *NonConstArg = find_if_not(II->args(), [&II](Use &Arg) {
return isa<Constant>(Arg.get()) ||
isVectorIntrinsicWithScalarOpAtArg(II->getIntrinsicID(),
Arg.getOperandNo(), nullptr);
});
if (!NonConstArg ||
!match(NonConstArg, m_Shuffle(m_Value(X), m_Poison(), m_Mask(Mask))))
return nullptr;
// At least 1 operand must be a shuffle with 1 use because we are creating 2
// instructions.
if (none_of(II->args(), match_fn(m_OneUse(m_Shuffle(m_Value(), m_Value())))))
return nullptr;
// See if all arguments are shuffled with the same mask.
SmallVector<Value *, 4> NewArgs;
Type *SrcTy = X->getType();
for (Use &Arg : II->args()) {
if (isVectorIntrinsicWithScalarOpAtArg(II->getIntrinsicID(),
Arg.getOperandNo(), nullptr))
NewArgs.push_back(Arg);
else if (match(&Arg,
m_Shuffle(m_Value(X), m_Poison(), m_SpecificMask(Mask))) &&
X->getType() == SrcTy)
NewArgs.push_back(X);
else if (match(&Arg, m_ImmConstant(C))) {
// If it's a constant, try find the constant that would be shuffled to C.
if (Constant *ShuffledC =
unshuffleConstant(Mask, C, cast<VectorType>(SrcTy)))
NewArgs.push_back(ShuffledC);
else
return nullptr;
} else
return nullptr;
}
// intrinsic (shuf X, M), (shuf Y, M), ... --> shuf (intrinsic X, Y, ...), M
Instruction *FPI = isa<FPMathOperator>(II) ? II : nullptr;
// Result type might be a different vector width.
// TODO: Check that the result type isn't widened?
VectorType *ResTy =
VectorType::get(II->getType()->getScalarType(), cast<VectorType>(SrcTy));
Value *NewIntrinsic =
Builder.CreateIntrinsic(ResTy, II->getIntrinsicID(), NewArgs, FPI);
return new ShuffleVectorInst(NewIntrinsic, Mask);
}
/// If all arguments of the intrinsic are reverses, try to pull the reverse
/// after the intrinsic.
Value *InstCombinerImpl::foldReversedIntrinsicOperands(IntrinsicInst *II) {
if (!II->getType()->isVectorTy() ||
!isTriviallyVectorizable(II->getIntrinsicID()))
return nullptr;
// At least 1 operand must be a reverse with 1 use because we are creating 2
// instructions.
if (none_of(II->args(), [](Value *V) {
return match(V, m_OneUse(m_VecReverse(m_Value())));
}))
return nullptr;
Value *X;
Constant *C;
SmallVector<Value *> NewArgs;
for (Use &Arg : II->args()) {
if (isVectorIntrinsicWithScalarOpAtArg(II->getIntrinsicID(),
Arg.getOperandNo(), nullptr))
NewArgs.push_back(Arg);
else if (match(&Arg, m_VecReverse(m_Value(X))))
NewArgs.push_back(X);
else if (isSplatValue(Arg))
NewArgs.push_back(Arg);
else if (match(&Arg, m_ImmConstant(C)))
NewArgs.push_back(Builder.CreateVectorReverse(C));
else
return nullptr;
}
// intrinsic (reverse X), (reverse Y), ... --> reverse (intrinsic X, Y, ...)
Instruction *FPI = isa<FPMathOperator>(II) ? II : nullptr;
Value *NewIntrinsic = Builder.CreateIntrinsic(
II->getType(), II->getIntrinsicID(), NewArgs, FPI);
return Builder.CreateVectorReverse(NewIntrinsic);
}
/// Fold the following cases and accepts bswap and bitreverse intrinsics:
/// bswap(logic_op(bswap(x), y)) --> logic_op(x, bswap(y))
/// bswap(logic_op(bswap(x), bswap(y))) --> logic_op(x, y) (ignores multiuse)
template <Intrinsic::ID IntrID>
static Instruction *foldBitOrderCrossLogicOp(Value *V,
InstCombiner::BuilderTy &Builder) {
static_assert(IntrID == Intrinsic::bswap || IntrID == Intrinsic::bitreverse,
"This helper only supports BSWAP and BITREVERSE intrinsics");
Value *X, *Y;
// Find bitwise logic op. Check that it is a BinaryOperator explicitly so we
// don't match ConstantExpr that aren't meaningful for this transform.
if (match(V, m_OneUse(m_BitwiseLogic(m_Value(X), m_Value(Y)))) &&
isa<BinaryOperator>(V)) {
Value *OldReorderX, *OldReorderY;
BinaryOperator::BinaryOps Op = cast<BinaryOperator>(V)->getOpcode();
// If both X and Y are bswap/bitreverse, the transform reduces the number
// of instructions even if there's multiuse.
// If only one operand is bswap/bitreverse, we need to ensure the operand
// have only one use.
if (match(X, m_Intrinsic<IntrID>(m_Value(OldReorderX))) &&
match(Y, m_Intrinsic<IntrID>(m_Value(OldReorderY)))) {
return BinaryOperator::Create(Op, OldReorderX, OldReorderY);
}
if (match(X, m_OneUse(m_Intrinsic<IntrID>(m_Value(OldReorderX))))) {
Value *NewReorder = Builder.CreateUnaryIntrinsic(IntrID, Y);
return BinaryOperator::Create(Op, OldReorderX, NewReorder);
}
if (match(Y, m_OneUse(m_Intrinsic<IntrID>(m_Value(OldReorderY))))) {
Value *NewReorder = Builder.CreateUnaryIntrinsic(IntrID, X);
return BinaryOperator::Create(Op, NewReorder, OldReorderY);
}
}
return nullptr;
}
/// Helper to match idempotent binary intrinsics, namely, intrinsics where
/// `f(f(x, y), y) == f(x, y)` holds.
static bool isIdempotentBinaryIntrinsic(Intrinsic::ID IID) {
switch (IID) {
case Intrinsic::smax:
case Intrinsic::smin:
case Intrinsic::umax:
case Intrinsic::umin:
case Intrinsic::maximum:
case Intrinsic::minimum:
case Intrinsic::maximumnum:
case Intrinsic::minimumnum:
case Intrinsic::maxnum:
case Intrinsic::minnum:
return true;
default:
return false;
}
}
/// Attempt to simplify value-accumulating recurrences of kind:
/// %umax.acc = phi i8 [ %umax, %backedge ], [ %a, %entry ]
/// %umax = call i8 @llvm.umax.i8(i8 %umax.acc, i8 %b)
/// And let the idempotent binary intrinsic be hoisted, when the operands are
/// known to be loop-invariant.
static Value *foldIdempotentBinaryIntrinsicRecurrence(InstCombinerImpl &IC,
IntrinsicInst *II) {
PHINode *PN;
Value *Init, *OtherOp;
// A binary intrinsic recurrence with loop-invariant operands is equivalent to
// `call @llvm.binary.intrinsic(Init, OtherOp)`.
auto IID = II->getIntrinsicID();
if (!isIdempotentBinaryIntrinsic(IID) ||
!matchSimpleBinaryIntrinsicRecurrence(II, PN, Init, OtherOp) ||
!IC.getDominatorTree().dominates(OtherOp, PN))
return nullptr;
auto *InvariantBinaryInst =
IC.Builder.CreateBinaryIntrinsic(IID, Init, OtherOp);
if (isa<FPMathOperator>(InvariantBinaryInst))
cast<Instruction>(InvariantBinaryInst)->copyFastMathFlags(II);
return InvariantBinaryInst;
}
static Value *simplifyReductionOperand(Value *Arg, bool CanReorderLanes) {
if (!CanReorderLanes)
return nullptr;
Value *V;
if (match(Arg, m_VecReverse(m_Value(V))))
return V;
ArrayRef<int> Mask;
if (!isa<FixedVectorType>(Arg->getType()) ||
!match(Arg, m_Shuffle(m_Value(V), m_Undef(), m_Mask(Mask))) ||
!cast<ShuffleVectorInst>(Arg)->isSingleSource())
return nullptr;
int Sz = Mask.size();
SmallBitVector UsedIndices(Sz);
for (int Idx : Mask) {
if (Idx == PoisonMaskElem || UsedIndices.test(Idx))
return nullptr;
UsedIndices.set(Idx);
}
// Can remove shuffle iff just shuffled elements, no repeats, undefs, or
// other changes.
return UsedIndices.all() ? V : nullptr;
}
/// Fold an unsigned minimum of trailing or leading zero bits counts:
/// umin(cttz(CtOp1, ZeroUndef), ConstOp) --> cttz(CtOp1 | (1 << ConstOp))
/// umin(ctlz(CtOp1, ZeroUndef), ConstOp) --> ctlz(CtOp1 | (SignedMin
/// >> ConstOp))
/// umin(cttz(CtOp1), cttz(CtOp2)) --> cttz(CtOp1 | CtOp2)
/// umin(ctlz(CtOp1), ctlz(CtOp2)) --> ctlz(CtOp1 | CtOp2)
template <Intrinsic::ID IntrID>
static Value *
foldMinimumOverTrailingOrLeadingZeroCount(Value *I0, Value *I1,
const DataLayout &DL,
InstCombiner::BuilderTy &Builder) {
static_assert(IntrID == Intrinsic::cttz || IntrID == Intrinsic::ctlz,
"This helper only supports cttz and ctlz intrinsics");
Value *CtOp1, *CtOp2;
Value *ZeroUndef1, *ZeroUndef2;
if (!match(I0, m_OneUse(
m_Intrinsic<IntrID>(m_Value(CtOp1), m_Value(ZeroUndef1)))))
return nullptr;
if (match(I1,
m_OneUse(m_Intrinsic<IntrID>(m_Value(CtOp2), m_Value(ZeroUndef2)))))
return Builder.CreateBinaryIntrinsic(
IntrID, Builder.CreateOr(CtOp1, CtOp2),
Builder.CreateOr(ZeroUndef1, ZeroUndef2));
unsigned BitWidth = I1->getType()->getScalarSizeInBits();
auto LessBitWidth = [BitWidth](auto &C) { return C.ult(BitWidth); };
if (!match(I1, m_CheckedInt(LessBitWidth)))
// We have a constant >= BitWidth (which can be handled by CVP)
// or a non-splat vector with elements < and >= BitWidth
return nullptr;
Type *Ty = I1->getType();
Constant *NewConst = ConstantFoldBinaryOpOperands(
IntrID == Intrinsic::cttz ? Instruction::Shl : Instruction::LShr,
IntrID == Intrinsic::cttz
? ConstantInt::get(Ty, 1)
: ConstantInt::get(Ty, APInt::getSignedMinValue(BitWidth)),
cast<Constant>(I1), DL);
return Builder.CreateBinaryIntrinsic(
IntrID, Builder.CreateOr(CtOp1, NewConst),
ConstantInt::getTrue(ZeroUndef1->getType()));
}
/// Return whether "X LOp (Y ROp Z)" is always equal to
/// "(X LOp Y) ROp (X LOp Z)".
static bool leftDistributesOverRight(Instruction::BinaryOps LOp, bool HasNUW,
bool HasNSW, Intrinsic::ID ROp) {
switch (ROp) {
case Intrinsic::umax:
case Intrinsic::umin:
if (HasNUW && LOp == Instruction::Add)
return true;
if (HasNUW && LOp == Instruction::Shl)
return true;
return false;
case Intrinsic::smax:
case Intrinsic::smin:
return HasNSW && LOp == Instruction::Add;
default:
return false;
}
}
/// Return whether "(X ROp Y) LOp Z" is always equal to
/// "(X LOp Z) ROp (Y LOp Z)".
static bool rightDistributesOverLeft(Instruction::BinaryOps LOp, bool HasNUW,
bool HasNSW, Intrinsic::ID ROp) {
if (Instruction::isCommutative(LOp) || LOp == Instruction::Shl)
return leftDistributesOverRight(LOp, HasNUW, HasNSW, ROp);
switch (ROp) {
case Intrinsic::umax:
case Intrinsic::umin:
return HasNUW && LOp == Instruction::Sub;
case Intrinsic::smax:
case Intrinsic::smin:
return HasNSW && LOp == Instruction::Sub;
default:
return false;
}
}
// Attempts to factorise a common term
// in an instruction that has the form "(A op' B) op (C op' D)
// where op is an intrinsic and op' is a binop
static Value *
foldIntrinsicUsingDistributiveLaws(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
Value *LHS = II->getOperand(0), *RHS = II->getOperand(1);
Intrinsic::ID TopLevelOpcode = II->getIntrinsicID();
OverflowingBinaryOperator *Op0 = dyn_cast<OverflowingBinaryOperator>(LHS);
OverflowingBinaryOperator *Op1 = dyn_cast<OverflowingBinaryOperator>(RHS);
if (!Op0 || !Op1)
return nullptr;
if (Op0->getOpcode() != Op1->getOpcode())
return nullptr;
if (!Op0->hasOneUse() || !Op1->hasOneUse())
return nullptr;
Instruction::BinaryOps InnerOpcode =
static_cast<Instruction::BinaryOps>(Op0->getOpcode());
bool HasNUW = Op0->hasNoUnsignedWrap() && Op1->hasNoUnsignedWrap();
bool HasNSW = Op0->hasNoSignedWrap() && Op1->hasNoSignedWrap();
Value *A = Op0->getOperand(0);
Value *B = Op0->getOperand(1);
Value *C = Op1->getOperand(0);
Value *D = Op1->getOperand(1);
// Attempts to swap variables such that A equals C or B equals D,
// if the inner operation is commutative.
if (Op0->isCommutative() && A != C && B != D) {
if (A == D || B == C)
std::swap(C, D);
else
return nullptr;
}
if (A == C &&
leftDistributesOverRight(InnerOpcode, HasNUW, HasNSW, TopLevelOpcode)) {
Value *NewIntrinsic = Builder.CreateBinaryIntrinsic(TopLevelOpcode, B, D);
return Builder.CreateNoWrapBinOp(InnerOpcode, A, NewIntrinsic, HasNUW,
HasNSW);
}
if (B == D &&
rightDistributesOverLeft(InnerOpcode, HasNUW, HasNSW, TopLevelOpcode)) {
Value *NewIntrinsic = Builder.CreateBinaryIntrinsic(TopLevelOpcode, A, C);
return Builder.CreateNoWrapBinOp(InnerOpcode, NewIntrinsic, B, HasNUW,
HasNSW);
}
return nullptr;
}
static Instruction *foldNeonShift(IntrinsicInst *II, InstCombinerImpl &IC) {
Value *Arg0 = II->getArgOperand(0);
auto *ShiftConst = dyn_cast<Constant>(II->getArgOperand(1));
if (!ShiftConst)
return nullptr;
int ElemBits = Arg0->getType()->getScalarSizeInBits();
bool AllPositive = true;
bool AllNegative = true;
auto Check = [&](Constant *C) -> bool {
if (auto *CI = dyn_cast_or_null<ConstantInt>(C)) {
const APInt &V = CI->getValue();
if (V.isNonNegative()) {
AllNegative = false;
return AllPositive && V.ult(ElemBits);
}
AllPositive = false;
return AllNegative && V.sgt(-ElemBits);
}
return false;
};
if (auto *VTy = dyn_cast<FixedVectorType>(Arg0->getType())) {
for (unsigned I = 0, E = VTy->getNumElements(); I < E; ++I) {
if (!Check(ShiftConst->getAggregateElement(I)))
return nullptr;
}
} else if (!Check(ShiftConst))
return nullptr;
IRBuilderBase &B = IC.Builder;
if (AllPositive)
return IC.replaceInstUsesWith(*II, B.CreateShl(Arg0, ShiftConst));
Value *NegAmt = B.CreateNeg(ShiftConst);
Intrinsic::ID IID = II->getIntrinsicID();
const bool IsSigned =
IID == Intrinsic::arm_neon_vshifts || IID == Intrinsic::aarch64_neon_sshl;
Value *Result =
IsSigned ? B.CreateAShr(Arg0, NegAmt) : B.CreateLShr(Arg0, NegAmt);
return IC.replaceInstUsesWith(*II, Result);
}
// If II is llvm.sin(x) or llvm.cos(x), and there is a matching
// llvm.cos(x) or llvm.sin(x) using the same argument, combine them
// into a single llvm.sincos(x) call. Returns the result for II
// extracted from sincos, or nullptr if no match is found.
static Value *foldSinAndCosToSinCos(IntrinsicInst *II, IRBuilderBase &B,
InstCombinerImpl &IC) {
Intrinsic::ID IID = II->getIntrinsicID();
bool IsSin = IID == Intrinsic::sin;
Intrinsic::ID MatchID = IsSin ? Intrinsic::cos : Intrinsic::sin;
Value *Arg = II->getArgOperand(0);
// Don't bother looking through uses of constants.
if (isa<Constant>(Arg))
return nullptr;
// Look for a matching cos/sin intrinsic with the same argument.
IntrinsicInst *Match = nullptr;
for (User *U : Arg->users()) {
if (auto *Cand = dyn_cast<IntrinsicInst>(U)) {
if (Cand != II && !Cand->use_empty() &&
Cand->getIntrinsicID() == MatchID) {
Match = Cand;
break;
}
}
}
if (!Match)
return nullptr;
// Insert sincos right after the argument definition.
IRBuilderBase::InsertPointGuard Guard(B);
if (auto *ArgInst = dyn_cast<Instruction>(Arg)) {
std::optional<BasicBlock::iterator> InsertPt =
ArgInst->getInsertionPointAfterDef();
if (!InsertPt)
return nullptr;
B.SetInsertPoint(*InsertPt);
} else {
BasicBlock &EntryBB = II->getFunction()->getEntryBlock();
B.SetInsertPoint(&EntryBB, EntryBB.begin());
}
Function *SinCosFunc = Intrinsic::getOrInsertDeclaration(
II->getModule(), Intrinsic::sincos, Arg->getType());
CallInst *SinCos = B.CreateCall(SinCosFunc, Arg, "sincos");
// Intersect fast-math flags from the two calls.
SinCos->setFastMathFlags(II->getFastMathFlags() & Match->getFastMathFlags());
// Propagate the most-generic fpmath metadata from the two original calls.
if (MDNode *MD = MDNode::getMostGenericFPMath(
II->getMetadata(LLVMContext::MD_fpmath),
Match->getMetadata(LLVMContext::MD_fpmath)))
SinCos->setMetadata(LLVMContext::MD_fpmath, MD);
Value *Sin = B.CreateExtractValue(SinCos, 0, "sin");
Value *Cos = B.CreateExtractValue(SinCos, 1, "cos");
// Replace the matching call and erase it.
IC.replaceInstUsesWith(*Match, IsSin ? Cos : Sin);
IC.eraseInstFromFunction(*Match);
return IsSin ? Sin : Cos;
}
/// Fold an scmp/ucmp intrinsic whose operands are extended from a narrower
/// type:
/// scmp (sext X), (sext Y) --> scmp X, Y
/// scmp (zext X), (zext Y) --> ucmp X, Y
/// ucmp (ext X), (ext Y) --> ucmp X, Y
/// Both operands must use the same extend opcode and source type. A constant
/// operand is narrowed instead, if truncating and re-extending it gives back
/// the same constant.
static Value *foldCmpIntrinsicOfExtended(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder,
const DataLayout &DL) {
// scmp/ucmp are not commutative, so the extend may be on either side.
unsigned ExtIdx = 0;
Value *X;
if (!match(II->getArgOperand(0), m_ZExtOrSExt(m_Value(X)))) {
ExtIdx = 1;
if (!match(II->getArgOperand(1), m_ZExtOrSExt(m_Value(X))))
return nullptr;
}
auto CastOpc = static_cast<Instruction::CastOps>(
cast<Operator>(II->getArgOperand(ExtIdx))->getOpcode());
Type *NarrowTy = X->getType();
// The other operand must be the same kind of extend from the same type, or a
// constant that can be narrowed losslessly.
Value *OtherOp = II->getArgOperand(1 - ExtIdx);
Value *Y;
Constant *WideC;
if (match(OtherOp, m_ZExtOrSExt(m_Value(Y)))) {
if (cast<Operator>(OtherOp)->getOpcode() != CastOpc ||
Y->getType() != NarrowTy)
return nullptr;
} else if (match(OtherOp, m_ImmConstant(WideC))) {
Y = getLosslessInvCast(WideC, NarrowTy, CastOpc, DL);
if (!Y)
return nullptr;
} else {
return nullptr;
}
// Both extends preserve the unsigned order, so an unsigned compare of the
// narrow operands is always equivalent. The signed order is only preserved by
// sext; zero extended values are non-negative, so a signed compare of those
// is an unsigned compare of the narrow operands.
Intrinsic::ID NewIID =
II->getIntrinsicID() == Intrinsic::scmp && CastOpc == Instruction::SExt
? Intrinsic::scmp
: Intrinsic::ucmp;
if (ExtIdx != 0)
std::swap(X, Y);
return Builder.CreateIntrinsic(II->getType(), NewIID, {X, Y});
}
/// CallInst simplification. This mostly only handles folding of intrinsic
/// instructions. For normal calls, it allows visitCallBase to do the heavy
/// lifting.
Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
// Don't try to simplify calls without uses. It will not do anything useful,
// but will result in the following folds being skipped.
if (!CI.use_empty()) {
SmallVector<Value *, 8> Args(CI.args());
if (Value *V = simplifyCall(&CI, CI.getCalledOperand(), Args,
SQ.getWithInstruction(&CI)))
return replaceInstUsesWith(CI, V);
}
if (Value *FreedOp = getFreedOperand(&CI, &TLI))
return visitFree(CI, FreedOp);
// If the caller function (i.e. us, the function that contains this CallInst)
// is nounwind, mark the call as nounwind, even if the callee isn't.
if (CI.getFunction()->doesNotThrow() && !CI.doesNotThrow()) {
CI.setDoesNotThrow();
return &CI;
}
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
if (!II)
return visitCallBase(CI);
// Intrinsics cannot occur in an invoke or a callbr, so handle them here
// instead of in visitCallBase.
if (auto *MI = dyn_cast<AnyMemIntrinsic>(II)) {
if (auto NumBytes = MI->getLengthInBytes()) {
// memmove/cpy/set of zero bytes is a noop.
if (NumBytes->isZero())
return eraseInstFromFunction(CI);
// For atomic unordered mem intrinsics if len is not a positive or
// not a multiple of element size then behavior is undefined.
if (MI->isAtomic() &&
(NumBytes->isNegative() ||
(NumBytes->getZExtValue() % MI->getElementSizeInBytes() != 0))) {
CreateNonTerminatorUnreachable(MI);
assert(MI->getType()->isVoidTy() &&
"non void atomic unordered mem intrinsic");
return eraseInstFromFunction(*MI);
}
}
// No other transformations apply to volatile transfers.
if (MI->isVolatile())
return nullptr;
if (AnyMemTransferInst *MTI = dyn_cast<AnyMemTransferInst>(MI)) {
// memmove(x,x,size) -> noop.
if (MTI->getSource() == MTI->getDest())
return eraseInstFromFunction(CI);
}
auto IsPointerUndefined = [MI](Value *Ptr) {
return isa<ConstantPointerNull>(Ptr) &&
!NullPointerIsDefined(
MI->getFunction(),
cast<PointerType>(Ptr->getType())->getAddressSpace());
};
bool SrcIsUndefined = false;
// If we can determine a pointer alignment that is bigger than currently
// set, update the alignment.
if (auto *MTI = dyn_cast<AnyMemTransferInst>(MI)) {
if (Instruction *I = SimplifyAnyMemTransfer(MTI))
return I;
SrcIsUndefined = IsPointerUndefined(MTI->getRawSource());
} else if (auto *MSI = dyn_cast<AnyMemSetInst>(MI)) {
if (Instruction *I = SimplifyAnyMemSet(MSI))
return I;
}
// If src/dest is null, this memory intrinsic must be a noop.
if (SrcIsUndefined || IsPointerUndefined(MI->getRawDest())) {
Builder.CreateAssumption(Builder.CreateIsNull(MI->getLength()));
return eraseInstFromFunction(CI);
}
// If we have a memmove and the source operation is a constant global,
// then the source and dest pointers can't alias, so we can change this
// into a call to memcpy.
if (auto *MMI = dyn_cast<AnyMemMoveInst>(MI)) {
if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource()))
if (GVSrc->isConstant()) {
Module *M = CI.getModule();
Intrinsic::ID MemCpyID =
MMI->isAtomic()
? Intrinsic::memcpy_element_unordered_atomic
: Intrinsic::memcpy;
Type *Tys[3] = { CI.getArgOperand(0)->getType(),
CI.getArgOperand(1)->getType(),
CI.getArgOperand(2)->getType() };
CI.setCalledFunction(
Intrinsic::getOrInsertDeclaration(M, MemCpyID, Tys));
return II;
}
}
}
// For fixed width vector result intrinsics, use the generic demanded vector
// support.
if (auto *IIFVTy = dyn_cast<FixedVectorType>(II->getType())) {
auto VWidth = IIFVTy->getNumElements();
APInt PoisonElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnes(VWidth));
if (Value *V = SimplifyDemandedVectorElts(II, AllOnesEltMask, PoisonElts)) {
if (V != II)
return replaceInstUsesWith(*II, V);
return II;
}
}
if (II->isCommutative()) {
if (auto Pair = matchSymmetricPair(II->getOperand(0), II->getOperand(1))) {
replaceOperand(*II, 0, Pair->first);
replaceOperand(*II, 1, Pair->second);
II->dropPoisonGeneratingAnnotations();
II->dropUBImplyingAttrsAndMetadata();
return II;
}
if (CallInst *NewCall = canonicalizeConstantArg0ToArg1(CI))
return NewCall;
}
// Unused constrained FP intrinsic calls may have declared side effect, which
// prevents it from being removed. In some cases however the side effect is
// actually absent. To detect this case, call SimplifyConstrainedFPCall. If it
// returns a replacement, the call may be removed.
if (CI.use_empty() && isa<ConstrainedFPIntrinsic>(CI)) {
if (simplifyConstrainedFPCall(&CI, SQ.getWithInstruction(&CI)))
return eraseInstFromFunction(CI);
}
Intrinsic::ID IID = II->getIntrinsicID();
switch (IID) {
case Intrinsic::objectsize: {
SmallVector<Instruction *> InsertedInstructions;
if (Value *V = lowerObjectSizeCall(II, DL, &TLI, AA, /*MustSucceed=*/false,
&InsertedInstructions)) {
for (Instruction *Inserted : InsertedInstructions)
Worklist.add(Inserted);
return replaceInstUsesWith(CI, V);
}
return nullptr;
}
case Intrinsic::abs: {
Value *IIOperand = II->getArgOperand(0);
bool IntMinIsPoison = cast<Constant>(II->getArgOperand(1))->isOneValue();
// abs(-x) -> abs(x)
Value *X;
if (match(IIOperand, m_Neg(m_Value(X))))
return CallInst::Create(
II->getCalledFunction(),
{X,
Builder.getInt1(IntMinIsPoison ||
cast<Instruction>(IIOperand)->hasNoSignedWrap())});
if (match(IIOperand, m_c_Select(m_Neg(m_Value(X)), m_Deferred(X))))
return CallInst::Create(II->getCalledFunction(),
{X, II->getArgOperand(1)});
Value *Y;
// abs(a * abs(b)) -> abs(a * b)
if (match(IIOperand,
m_OneUse(m_c_Mul(m_Value(X),
m_Intrinsic<Intrinsic::abs>(m_Value(Y)))))) {
bool NSW =
cast<Instruction>(IIOperand)->hasNoSignedWrap() && IntMinIsPoison;
auto *XY = NSW ? Builder.CreateNSWMul(X, Y) : Builder.CreateMul(X, Y);
return CallInst::Create(II->getCalledFunction(),
{XY, II->getArgOperand(1)});
}
if (std::optional<bool> Known =
getKnownSignOrZero(IIOperand, SQ.getWithInstruction(II))) {
// abs(x) -> x if x >= 0 (include abs(x-y) --> x - y where x >= y)
// abs(x) -> x if x > 0 (include abs(x-y) --> x - y where x > y)
if (!*Known)
return replaceInstUsesWith(*II, IIOperand);
// abs(x) -> -x if x < 0
// abs(x) -> -x if x < = 0 (include abs(x-y) --> y - x where x <= y)
if (IntMinIsPoison)
return BinaryOperator::CreateNSWNeg(IIOperand);
return BinaryOperator::CreateNeg(IIOperand);
}
// abs (sext X) --> zext (abs X*)
// Clear the IsIntMin (nsw) bit on the abs to allow narrowing.
if (match(IIOperand, m_OneUse(m_SExt(m_Value(X))))) {
Value *NarrowAbs =
Builder.CreateBinaryIntrinsic(Intrinsic::abs, X, Builder.getFalse());
return CastInst::Create(Instruction::ZExt, NarrowAbs, II->getType());
}
// Match a complicated way to check if a number is odd/even:
// abs (srem X, 2) --> and X, 1
const APInt *C;
if (match(IIOperand, m_SRem(m_Value(X), m_APInt(C))) && *C == 2)
return BinaryOperator::CreateAnd(X, ConstantInt::get(II->getType(), 1));
break;
}
case Intrinsic::umin: {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
// umin(x, 1) == zext(x != 0)
if (match(I1, m_One())) {
assert(II->getType()->getScalarSizeInBits() != 1 &&
"Expected simplify of umin with max constant");
Value *Zero = Constant::getNullValue(I0->getType());
Value *Cmp = Builder.CreateICmpNE(I0, Zero);
return CastInst::Create(Instruction::ZExt, Cmp, II->getType());
}
// umin(cttz(x), const) --> cttz(x | (1 << const))
if (Value *FoldedCttz =
foldMinimumOverTrailingOrLeadingZeroCount<Intrinsic::cttz>(
I0, I1, DL, Builder))
return replaceInstUsesWith(*II, FoldedCttz);
// umin(ctlz(x), const) --> ctlz(x | (SignedMin >> const))
if (Value *FoldedCtlz =
foldMinimumOverTrailingOrLeadingZeroCount<Intrinsic::ctlz>(
I0, I1, DL, Builder))
return replaceInstUsesWith(*II, FoldedCtlz);
[[fallthrough]];
}
case Intrinsic::umax: {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
Value *X, *Y;
if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_ZExt(m_Value(Y))) &&
(I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y);
return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType());
}
Constant *C;
if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_Constant(C)) &&
I0->hasOneUse()) {
if (Constant *NarrowC = getLosslessUnsignedTrunc(C, X->getType(), DL)) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC);
return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType());
}
}
// If C is not 0:
// umax(nuw_shl(x, C), x + 1) -> x == 0 ? 1 : nuw_shl(x, C)
// If C is not 0 or 1:
// umax(nuw_mul(x, C), x + 1) -> x == 0 ? 1 : nuw_mul(x, C)
auto foldMaxMulShift = [&](Value *A, Value *B) -> Instruction * {
const APInt *C;
Value *X;
if (!match(A, m_NUWShl(m_Value(X), m_APInt(C))) &&
!(match(A, m_NUWMul(m_Value(X), m_APInt(C))) && !C->isOne()))
return nullptr;
if (C->isZero())
return nullptr;
if (!match(B, m_OneUse(m_Add(m_Specific(X), m_One()))))
return nullptr;
Value *Cmp = Builder.CreateICmpEQ(X, ConstantInt::get(X->getType(), 0));
Value *NewSelect = nullptr;
NewSelect = Builder.CreateSelectWithUnknownProfile(
Cmp, ConstantInt::get(X->getType(), 1), A, DEBUG_TYPE);
return replaceInstUsesWith(*II, NewSelect);
};
if (IID == Intrinsic::umax) {
if (Instruction *I = foldMaxMulShift(I0, I1))
return I;
if (Instruction *I = foldMaxMulShift(I1, I0))
return I;
}
// If both operands of unsigned min/max are sign-extended, it is still ok
// to narrow the operation.
[[fallthrough]];
}
case Intrinsic::smax:
case Intrinsic::smin: {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
Value *X, *Y;
if (match(I0, m_SExt(m_Value(X))) && match(I1, m_SExt(m_Value(Y))) &&
(I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y);
return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType());
}
Constant *C;
if (match(I0, m_SExt(m_Value(X))) && match(I1, m_Constant(C)) &&
I0->hasOneUse()) {
if (Constant *NarrowC = getLosslessSignedTrunc(C, X->getType(), DL)) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC);
return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType());
}
}
// smax(smin(X, MinC), MaxC) -> smin(smax(X, MaxC), MinC) if MinC s>= MaxC
// umax(umin(X, MinC), MaxC) -> umin(umax(X, MaxC), MinC) if MinC u>= MaxC
const APInt *MinC, *MaxC;
auto CreateCanonicalClampForm = [&](bool IsSigned) {
auto MaxIID = IsSigned ? Intrinsic::smax : Intrinsic::umax;
auto MinIID = IsSigned ? Intrinsic::smin : Intrinsic::umin;
Value *NewMax = Builder.CreateBinaryIntrinsic(
MaxIID, X, ConstantInt::get(X->getType(), *MaxC));
return replaceInstUsesWith(
*II, Builder.CreateBinaryIntrinsic(
MinIID, NewMax, ConstantInt::get(X->getType(), *MinC)));
};
if (IID == Intrinsic::smax &&
match(I0, m_OneUse(m_Intrinsic<Intrinsic::smin>(m_Value(X),
m_APInt(MinC)))) &&
match(I1, m_APInt(MaxC)) && MinC->sgt(*MaxC))
return CreateCanonicalClampForm(true);
if (IID == Intrinsic::umax &&
match(I0, m_OneUse(m_Intrinsic<Intrinsic::umin>(m_Value(X),
m_APInt(MinC)))) &&
match(I1, m_APInt(MaxC)) && MinC->ugt(*MaxC))
return CreateCanonicalClampForm(false);
// umin(i1 X, i1 Y) -> and i1 X, Y
// smax(i1 X, i1 Y) -> and i1 X, Y
if ((IID == Intrinsic::umin || IID == Intrinsic::smax) &&
II->getType()->isIntOrIntVectorTy(1)) {
return BinaryOperator::CreateAnd(I0, I1);
}
// umax(i1 X, i1 Y) -> or i1 X, Y
// smin(i1 X, i1 Y) -> or i1 X, Y
if ((IID == Intrinsic::umax || IID == Intrinsic::smin) &&
II->getType()->isIntOrIntVectorTy(1)) {
return BinaryOperator::CreateOr(I0, I1);
}
// smin(smax(X, -1), 1) -> scmp(X, 0)
// smax(smin(X, 1), -1) -> scmp(X, 0)
// At this point, smax(smin(X, 1), -1) is changed to smin(smax(X, -1)
// And i1's have been changed to and/ors
// So we only need to check for smin
if (IID == Intrinsic::smin) {
if (match(I0, m_OneUse(m_SMax(m_Value(X), m_AllOnes()))) &&
match(I1, m_One())) {
Value *Zero = ConstantInt::get(X->getType(), 0);
return replaceInstUsesWith(
CI,
Builder.CreateIntrinsic(II->getType(), Intrinsic::scmp, {X, Zero}));
}
}
if (IID == Intrinsic::smax || IID == Intrinsic::smin) {
// smax (neg nsw X), (neg nsw Y) --> neg nsw (smin X, Y)
// smin (neg nsw X), (neg nsw Y) --> neg nsw (smax X, Y)
// TODO: Canonicalize neg after min/max if I1 is constant.
if (match(I0, m_NSWNeg(m_Value(X))) && match(I1, m_NSWNeg(m_Value(Y))) &&
(I0->hasOneUse() || I1->hasOneUse())) {
Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID);
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, Y);
return BinaryOperator::CreateNSWNeg(InvMaxMin);
}
}
// (umax X, (xor X, Pow2))
// -> (or X, Pow2)
// (umin X, (xor X, Pow2))
// -> (and X, ~Pow2)
// (smax X, (xor X, Pos_Pow2))
// -> (or X, Pos_Pow2)
// (smin X, (xor X, Pos_Pow2))
// -> (and X, ~Pos_Pow2)
// (smax X, (xor X, Neg_Pow2))
// -> (and X, ~Neg_Pow2)
// (smin X, (xor X, Neg_Pow2))
// -> (or X, Neg_Pow2)
if ((match(I0, m_c_Xor(m_Specific(I1), m_Value(X))) ||
match(I1, m_c_Xor(m_Specific(I0), m_Value(X)))) &&
isKnownToBeAPowerOfTwo(X, /* OrZero */ true)) {
bool UseOr = IID == Intrinsic::smax || IID == Intrinsic::umax;
bool UseAndN = IID == Intrinsic::smin || IID == Intrinsic::umin;
if (IID == Intrinsic::smax || IID == Intrinsic::smin) {
auto KnownSign = getKnownSign(X, SQ.getWithInstruction(II));
if (KnownSign == std::nullopt) {
UseOr = false;
UseAndN = false;
} else if (*KnownSign /* true is Signed. */) {
UseOr ^= true;
UseAndN ^= true;
Type *Ty = I0->getType();
// Negative power of 2 must be IntMin. It's possible to be able to
// prove negative / power of 2 without actually having known bits, so
// just get the value by hand.
X = Constant::getIntegerValue(
Ty, APInt::getSignedMinValue(Ty->getScalarSizeInBits()));
}
}
if (UseOr)
return BinaryOperator::CreateOr(I0, X);
else if (UseAndN)
return BinaryOperator::CreateAnd(I0, Builder.CreateNot(X));
}
// If we can eliminate ~A and Y is free to invert:
// max ~A, Y --> ~(min A, ~Y)
//
// Examples:
// max ~A, ~Y --> ~(min A, Y)
// max ~A, C --> ~(min A, ~C)
// max ~A, (max ~Y, ~Z) --> ~min( A, (min Y, Z))
auto moveNotAfterMinMax = [&](Value *X, Value *Y) -> Instruction * {
Value *A;
if (match(X, m_OneUse(m_Not(m_Value(A)))) &&
!isFreeToInvert(A, A->hasOneUse())) {
if (Value *NotY = getFreelyInverted(Y, Y->hasOneUse(), &Builder)) {
Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID);
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, A, NotY);
return BinaryOperator::CreateNot(InvMaxMin);
}
}
return nullptr;
};
if (Instruction *I = moveNotAfterMinMax(I0, I1))
return I;
if (Instruction *I = moveNotAfterMinMax(I1, I0))
return I;
if (Instruction *I = moveAddAfterMinMax(II, Builder))
return I;
// minmax (X & NegPow2C, Y & NegPow2C) --> minmax(X, Y) & NegPow2C
const APInt *RHSC;
if (match(I0, m_OneUse(m_And(m_Value(X), m_NegatedPower2(RHSC)))) &&
match(I1, m_OneUse(m_And(m_Value(Y), m_SpecificInt(*RHSC)))))
return BinaryOperator::CreateAnd(Builder.CreateBinaryIntrinsic(IID, X, Y),
ConstantInt::get(II->getType(), *RHSC));
// smax(X, -X) --> abs(X)
// smin(X, -X) --> -abs(X)
// umax(X, -X) --> -abs(X)
// umin(X, -X) --> abs(X)
if (isKnownNegation(I0, I1)) {
// We can choose either operand as the input to abs(), but if we can
// eliminate the only use of a value, that's better for subsequent
// transforms/analysis.
if (I0->hasOneUse() && !I1->hasOneUse())
std::swap(I0, I1);
// This is some variant of abs(). See if we can propagate 'nsw' to the abs
// operation and potentially its negation.
bool IntMinIsPoison = isKnownNegation(I0, I1, /* NeedNSW */ true);
Value *Abs = Builder.CreateBinaryIntrinsic(
Intrinsic::abs, I0,
ConstantInt::getBool(II->getContext(), IntMinIsPoison));
// We don't have a "nabs" intrinsic, so negate if needed based on the
// max/min operation.
if (IID == Intrinsic::smin || IID == Intrinsic::umax)
Abs = Builder.CreateNeg(Abs, "nabs", IntMinIsPoison);
return replaceInstUsesWith(CI, Abs);
}
if (Instruction *Sel = foldClampRangeOfTwo(II, Builder))
return Sel;
if (Instruction *SAdd = matchSAddSubSat(*II))
return SAdd;
if (Value *NewMinMax = reassociateMinMaxWithConstants(II, Builder, SQ))
return replaceInstUsesWith(*II, NewMinMax);
if (Instruction *R = reassociateMinMaxWithConstantInOperand(II, Builder))
return R;
if (Instruction *NewMinMax = factorizeMinMaxTree(II))
return NewMinMax;
// Try to fold minmax with constant RHS based on range information
if (match(I1, m_APIntAllowPoison(RHSC))) {
ICmpInst::Predicate Pred =
ICmpInst::getNonStrictPredicate(MinMaxIntrinsic::getPredicate(IID));
bool IsSigned = MinMaxIntrinsic::isSigned(IID);
ConstantRange LHS_CR = computeConstantRangeIncludingKnownBits(
I0, IsSigned, SQ.getWithInstruction(II));
if (!LHS_CR.isFullSet()) {
if (LHS_CR.icmp(Pred, *RHSC))
return replaceInstUsesWith(*II, I0);
if (LHS_CR.icmp(ICmpInst::getSwappedPredicate(Pred), *RHSC))
return replaceInstUsesWith(*II,
ConstantInt::get(II->getType(), *RHSC));
}
}
if (Value *V = foldIntrinsicUsingDistributiveLaws(II, Builder))
return replaceInstUsesWith(*II, V);
break;
}
case Intrinsic::scmp:
case Intrinsic::ucmp: {
if (Value *V = foldCmpIntrinsicOfExtended(II, Builder, DL))
return replaceInstUsesWith(CI, V);
if (IID == Intrinsic::ucmp)
break;
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
// scmp(X, 0) -> sext_or_trunc(X) if X is known to be one of -1, 0, 1.
if (match(I1, m_Zero())) {
ConstantRange Range = computeConstantRange(I0, /*ForSigned=*/true,
SQ.getWithInstruction(II));
if (Range.getSignedMin().sge(-1) && Range.getSignedMax().sle(1))
return replaceInstUsesWith(
CI, Builder.CreateSExtOrTrunc(I0, II->getType()));
}
Value *LHS, *RHS;
if (match(I0, m_NSWSub(m_Value(LHS), m_Value(RHS))) && match(I1, m_Zero()))
return replaceInstUsesWith(
CI,
Builder.CreateIntrinsic(II->getType(), Intrinsic::scmp, {LHS, RHS}));
break;
}
case Intrinsic::bitreverse: {
Value *IIOperand = II->getArgOperand(0);
// bitrev (zext i1 X to ?) --> X ? SignBitC : 0
Value *X;
if (match(IIOperand, m_ZExt(m_Value(X))) &&
X->getType()->isIntOrIntVectorTy(1)) {
Type *Ty = II->getType();
APInt SignBit = APInt::getSignMask(Ty->getScalarSizeInBits());
SelectInst *SI = SelectInst::Create(X, ConstantInt::get(Ty, SignBit),
ConstantInt::getNullValue(Ty));
// Mark the branch weights explicitly unknown as in the general case we
// cannot infer the probability of the condition without additional value
// profiling.
setExplicitlyUnknownBranchWeightsIfProfiled(*SI, DEBUG_TYPE, &F);
return SI;
}
if (Instruction *crossLogicOpFold =
foldBitOrderCrossLogicOp<Intrinsic::bitreverse>(IIOperand, Builder))
return crossLogicOpFold;
break;
}
case Intrinsic::bswap: {
Value *IIOperand = II->getArgOperand(0);
// Try to canonicalize bswap-of-logical-shift-by-8-bit-multiple as
// inverse-shift-of-bswap:
// bswap (shl X, Y) --> lshr (bswap X), Y
// bswap (lshr X, Y) --> shl (bswap X), Y
Value *X, *Y;
if (match(IIOperand, m_OneUse(m_LogicalShift(m_Value(X), m_Value(Y))))) {
unsigned BitWidth = IIOperand->getType()->getScalarSizeInBits();
if (MaskedValueIsZero(Y, APInt::getLowBitsSet(BitWidth, 3))) {
Value *NewSwap = Builder.CreateUnaryIntrinsic(Intrinsic::bswap, X);
BinaryOperator::BinaryOps InverseShift =
cast<BinaryOperator>(IIOperand)->getOpcode() == Instruction::Shl
? Instruction::LShr
: Instruction::Shl;
return BinaryOperator::Create(InverseShift, NewSwap, Y);
}
}
KnownBits Known = computeKnownBits(IIOperand, II);
uint64_t LZ = alignDown(Known.countMinLeadingZeros(), 8);
uint64_t TZ = alignDown(Known.countMinTrailingZeros(), 8);
unsigned BW = Known.getBitWidth();
// bswap(x) -> shift(x) if x has exactly one "active byte"
if (BW - LZ - TZ == 8) {
assert(LZ != TZ && "active byte cannot be in the middle");
if (LZ > TZ) // -> shl(x) if the "active byte" is in the low part of x
return BinaryOperator::CreateNUWShl(
IIOperand, ConstantInt::get(IIOperand->getType(), LZ - TZ));
// -> lshr(x) if the "active byte" is in the high part of x
return BinaryOperator::CreateExactLShr(
IIOperand, ConstantInt::get(IIOperand->getType(), TZ - LZ));
}
// bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) {
unsigned C = X->getType()->getScalarSizeInBits() - BW;
Value *CV = ConstantInt::get(X->getType(), C);
Value *V = Builder.CreateLShr(X, CV);
return new TruncInst(V, IIOperand->getType());
}
if (Instruction *crossLogicOpFold =
foldBitOrderCrossLogicOp<Intrinsic::bswap>(IIOperand, Builder)) {
return crossLogicOpFold;
}
// Try to fold into bitreverse if bswap is the root of the expression tree.
if (Instruction *BitOp = matchBSwapOrBitReverse(*II, /*MatchBSwaps*/ false,
/*MatchBitReversals*/ true))
return BitOp;
break;
}
case Intrinsic::masked_load:
if (Value *SimplifiedMaskedOp = simplifyMaskedLoad(*II))
return replaceInstUsesWith(CI, SimplifiedMaskedOp);
break;
case Intrinsic::masked_store:
return simplifyMaskedStore(*II);
case Intrinsic::masked_gather:
return simplifyMaskedGather(*II);
case Intrinsic::masked_scatter:
return simplifyMaskedScatter(*II);
case Intrinsic::launder_invariant_group:
if (auto *SkippedBarrier = simplifyInvariantGroupIntrinsic(*II, *this))
return replaceInstUsesWith(*II, SkippedBarrier);
break;
case Intrinsic::powi: {
if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
// 0 and 1 are handled in instsimplify
// powi(x, -1) -> 1/x
if (Power->isMinusOne())
return BinaryOperator::CreateFDivFMF(ConstantFP::get(CI.getType(), 1.0),
II->getArgOperand(0), II);
// powi(x, 2) -> x*x
if (Power->equalsInt(2))
return BinaryOperator::CreateFMulFMF(II->getArgOperand(0),
II->getArgOperand(0), II);
if (!Power->getValue()[0]) {
Value *X;
// If power is even:
// powi(-x, p) -> powi(x, p)
// powi(fabs(x), p) -> powi(x, p)
// powi(copysign(x, y), p) -> powi(x, p)
if (match(II->getArgOperand(0), m_FNeg(m_Value(X))) ||
match(II->getArgOperand(0), m_FAbs(m_Value(X))) ||
match(II->getArgOperand(0),
m_Intrinsic<Intrinsic::copysign>(m_Value(X), m_Value())))
return CallInst::Create(II->getCalledFunction(), {X, Power});
}
}
if (ConstantFP *Base = dyn_cast<ConstantFP>(II->getArgOperand(0))) {
Value *Exp = II->getArgOperand(1);
Type *Ty = Base->getType();
// powi(2.0, p) -> ldexp(1.0, p)
if (II->hasApproxFunc() && Base->isExactlyValue(2.0)) {
ConstantFP *One = ConstantFP::get(Ty, 1.0);
if (auto *VTy = dyn_cast<VectorType>(Ty))
Exp = Builder.CreateVectorSplat(VTy->getElementCount(), Exp);
Value *Ldexp = Builder.CreateLdexp(One, Exp, II);
return replaceInstUsesWith(*II, Ldexp);
}
}
break;
}
case Intrinsic::cttz:
case Intrinsic::ctlz:
if (auto *I = foldCttzCtlz(*II, *this))
return I;
break;
case Intrinsic::ctpop:
if (auto *I = foldCtpop(*II, *this))
return I;
break;
case Intrinsic::fshl:
case Intrinsic::fshr: {
Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1);
Type *Ty = II->getType();
unsigned BitWidth = Ty->getScalarSizeInBits();
Constant *ShAmtC;
if (match(II->getArgOperand(2), m_ImmConstant(ShAmtC))) {
// Canonicalize a shift amount constant operand to modulo the bit-width.
Constant *WidthC = ConstantInt::get(Ty, BitWidth);
Constant *ModuloC =
ConstantFoldBinaryOpOperands(Instruction::URem, ShAmtC, WidthC, DL);
if (!ModuloC)
return nullptr;
if (ModuloC != ShAmtC)
return CallInst::Create(II->getCalledFunction(), {Op0, Op1, ModuloC});
assert(match(ConstantFoldCompareInstOperands(ICmpInst::ICMP_UGT, WidthC,
ShAmtC, DL),
m_One()) &&
"Shift amount expected to be modulo bitwidth");
// Canonicalize funnel shift right by constant to funnel shift left. This
// is not entirely arbitrary. For historical reasons, the backend may
// recognize rotate left patterns but miss rotate right patterns.
if (IID == Intrinsic::fshr) {
// fshr X, Y, C --> fshl X, Y, (BitWidth - C) if C is not zero.
if (!isKnownNonZero(ShAmtC, SQ.getWithInstruction(II)))
return nullptr;
Constant *LeftShiftC = ConstantExpr::getSub(WidthC, ShAmtC);
Module *Mod = II->getModule();
Function *Fshl =
Intrinsic::getOrInsertDeclaration(Mod, Intrinsic::fshl, Ty);
return CallInst::Create(Fshl, { Op0, Op1, LeftShiftC });
}
assert(IID == Intrinsic::fshl &&
"All funnel shifts by simple constants should go left");
// fshl(X, 0, C) --> shl X, C
// fshl(X, undef, C) --> shl X, C
if (match(Op1, m_ZeroInt()) || match(Op1, m_Undef()))
return BinaryOperator::CreateShl(Op0, ShAmtC);
// fshl(0, X, C) --> lshr X, (BW-C)
// fshl(undef, X, C) --> lshr X, (BW-C)
// Similar to fshr -> fshl fold above, this is only valid if C is not zero
if ((match(Op0, m_ZeroInt()) || match(Op0, m_Undef())) &&
isKnownNonZero(ShAmtC, SQ.getWithInstruction(II)))
return BinaryOperator::CreateLShr(Op1,
ConstantExpr::getSub(WidthC, ShAmtC));
// fshl i16 X, X, 8 --> bswap i16 X (reduce to more-specific form)
if (Op0 == Op1 && BitWidth == 16 && match(ShAmtC, m_SpecificInt(8))) {
Module *Mod = II->getModule();
Function *Bswap =
Intrinsic::getOrInsertDeclaration(Mod, Intrinsic::bswap, Ty);
return CallInst::Create(Bswap, { Op0 });
}
if (Instruction *BitOp =
matchBSwapOrBitReverse(*II, /*MatchBSwaps*/ true,
/*MatchBitReversals*/ true))
return BitOp;
// R = fshl(X, X, C2)
// fshl(R, R, C1) --> fshl(X, X, (C1 + C2) % bitsize)
Value *InnerOp;
const APInt *ShAmtInnerC, *ShAmtOuterC;
if (match(Op0, m_FShl(m_Value(InnerOp), m_Deferred(InnerOp),
m_APInt(ShAmtInnerC))) &&
match(ShAmtC, m_APInt(ShAmtOuterC)) && Op0 == Op1) {
APInt Sum = *ShAmtOuterC + *ShAmtInnerC;
APInt Modulo = Sum.urem(APInt(Sum.getBitWidth(), BitWidth));
if (Modulo.isZero())
return replaceInstUsesWith(*II, InnerOp);
Constant *ModuloC = ConstantInt::get(Ty, Modulo);
return CallInst::Create(cast<IntrinsicInst>(Op0)->getCalledFunction(),
{InnerOp, InnerOp, ModuloC});
}
}
// fshl(X, X, Neg(Y)) --> fshr(X, X, Y)
// fshr(X, X, Neg(Y)) --> fshl(X, X, Y)
// if BitWidth is a power-of-2
Value *Y;
if (Op0 == Op1 && isPowerOf2_32(BitWidth) &&
match(II->getArgOperand(2), m_Neg(m_Value(Y)))) {
Module *Mod = II->getModule();
Function *OppositeShift = Intrinsic::getOrInsertDeclaration(
Mod, IID == Intrinsic::fshl ? Intrinsic::fshr : Intrinsic::fshl, Ty);
return CallInst::Create(OppositeShift, {Op0, Op1, Y});
}
// fshl(X, 0, Y) --> shl(X, and(Y, BitWidth - 1)) if bitwidth is a
// power-of-2
if (IID == Intrinsic::fshl && isPowerOf2_32(BitWidth) &&
match(Op1, m_ZeroInt())) {
Value *Op2 = II->getArgOperand(2);
Value *And = Builder.CreateAnd(Op2, ConstantInt::get(Ty, BitWidth - 1));
return BinaryOperator::CreateShl(Op0, And);
}
// Left or right might be masked.
if (SimplifyDemandedInstructionBits(*II))
return &CI;
// The shift amount (operand 2) of a funnel shift is modulo the bitwidth,
// so only the low bits of the shift amount are demanded if the bitwidth is
// a power-of-2.
if (!isPowerOf2_32(BitWidth))
break;
APInt Op2Demanded = APInt::getLowBitsSet(BitWidth, Log2_32_Ceil(BitWidth));
KnownBits Op2Known(BitWidth);
if (SimplifyDemandedBits(II, 2, Op2Demanded, Op2Known))
return &CI;
break;
}
case Intrinsic::pdep: {
const APInt *MaskC;
if (match(II->getArgOperand(1), m_APInt(MaskC))) {
unsigned MaskIdx, MaskLen;
if (MaskC->isShiftedMask(MaskIdx, MaskLen)) {
// any single contiguous sequence of 1s anywhere in the mask simply
// describes a subset of the input bits shifted to the appropriate
// position. Replace with the straight forward IR.
Value *Input = II->getArgOperand(0);
Value *ShiftAmt = ConstantInt::get(II->getType(), MaskIdx);
Value *Shifted = Builder.CreateShl(Input, ShiftAmt);
Value *Masked = Builder.CreateAnd(Shifted, II->getArgOperand(1));
return replaceInstUsesWith(*II, Masked);
}
}
break;
}
case Intrinsic::pext: {
const APInt *MaskC;
if (match(II->getArgOperand(1), m_APInt(MaskC))) {
unsigned MaskIdx, MaskLen;
if (MaskC->isShiftedMask(MaskIdx, MaskLen)) {
// any single contiguous sequence of 1s anywhere in the mask simply
// describes a subset of the input bits shifted to the appropriate
// position. Replace with the straight forward IR.
Value *Input = II->getArgOperand(0);
Value *Masked = Builder.CreateAnd(Input, II->getArgOperand(1));
Value *ShiftAmt = ConstantInt::get(II->getType(), MaskIdx);
Value *Shifted = Builder.CreateLShr(Masked, ShiftAmt);
return replaceInstUsesWith(*II, Shifted);
}
}
break;
}
case Intrinsic::ptrmask: {
unsigned BitWidth = DL.getPointerTypeSizeInBits(II->getType());
KnownBits Known(BitWidth);
if (SimplifyDemandedInstructionBits(*II, Known))
return II;
Value *InnerPtr, *InnerMask;
bool Changed = false;
// Combine:
// (ptrmask (ptrmask p, A), B)
// -> (ptrmask p, (and A, B))
if (match(II->getArgOperand(0),
m_OneUse(m_Intrinsic<Intrinsic::ptrmask>(m_Value(InnerPtr),
m_Value(InnerMask))))) {
assert(II->getArgOperand(1)->getType() == InnerMask->getType() &&
"Mask types must match");
// TODO: If InnerMask == Op1, we could copy attributes from inner
// callsite -> outer callsite.
Value *NewMask = Builder.CreateAnd(II->getArgOperand(1), InnerMask);
replaceOperand(CI, 0, InnerPtr);
replaceOperand(CI, 1, NewMask);
Changed = true;
}
// See if we can deduce non-null.
if (!CI.hasRetAttr(Attribute::NonNull) &&
(Known.isNonZero() ||
isKnownNonZero(II, getSimplifyQuery().getWithInstruction(II)))) {
CI.addRetAttr(Attribute::NonNull);
Changed = true;
}
unsigned NewAlignmentLog =
std::min(Value::MaxAlignmentExponent,
std::min(BitWidth - 1, Known.countMinTrailingZeros()));
// Known bits will capture if we had alignment information associated with
// the pointer argument.
if (NewAlignmentLog > Log2(CI.getRetAlign().valueOrOne())) {
CI.addRetAttr(Attribute::getWithAlignment(
CI.getContext(), Align(uint64_t(1) << NewAlignmentLog)));
Changed = true;
}
if (Changed)
return &CI;
break;
}
case Intrinsic::uadd_with_overflow:
case Intrinsic::sadd_with_overflow: {
if (Instruction *I = foldIntrinsicWithOverflowCommon(II))
return I;
// Given 2 constant operands whose sum does not overflow:
// uaddo (X +nuw C0), C1 -> uaddo X, C0 + C1
// saddo (X +nsw C0), C1 -> saddo X, C0 + C1
Value *X;
const APInt *C0, *C1;
Value *Arg0 = II->getArgOperand(0);
Value *Arg1 = II->getArgOperand(1);
bool IsSigned = IID == Intrinsic::sadd_with_overflow;
bool HasNWAdd = IsSigned
? match(Arg0, m_NSWAddLike(m_Value(X), m_APInt(C0)))
: match(Arg0, m_NUWAddLike(m_Value(X), m_APInt(C0)));
if (HasNWAdd && match(Arg1, m_APInt(C1))) {
bool Overflow;
APInt NewC =
IsSigned ? C1->sadd_ov(*C0, Overflow) : C1->uadd_ov(*C0, Overflow);
if (!Overflow)
return replaceInstUsesWith(
*II, Builder.CreateBinaryIntrinsic(
IID, X, ConstantInt::get(Arg1->getType(), NewC)));
}
break;
}
case Intrinsic::umul_with_overflow:
case Intrinsic::smul_with_overflow:
case Intrinsic::usub_with_overflow:
if (Instruction *I = foldIntrinsicWithOverflowCommon(II))
return I;
break;
case Intrinsic::ssub_with_overflow: {
if (Instruction *I = foldIntrinsicWithOverflowCommon(II))
return I;
Constant *C;
Value *Arg0 = II->getArgOperand(0);
Value *Arg1 = II->getArgOperand(1);
// Given a constant C that is not the minimum signed value
// for an integer of a given bit width:
//
// ssubo X, C -> saddo X, -C
if (match(Arg1, m_Constant(C)) && C->isNotMinSignedValue()) {
Value *NegVal = ConstantExpr::getNeg(C);
// Build a saddo call that is equivalent to the discovered
// ssubo call.
return replaceInstUsesWith(
*II, Builder.CreateBinaryIntrinsic(Intrinsic::sadd_with_overflow,
Arg0, NegVal));
}
break;
}
case Intrinsic::uadd_sat:
case Intrinsic::sadd_sat:
case Intrinsic::usub_sat:
case Intrinsic::ssub_sat: {
SaturatingInst *SI = cast<SaturatingInst>(II);
Type *Ty = SI->getType();
Value *Arg0 = SI->getLHS();
Value *Arg1 = SI->getRHS();
// Make use of known overflow information.
OverflowResult OR = computeOverflow(SI->getBinaryOp(), SI->isSigned(),
Arg0, Arg1, SI);
switch (OR) {
case OverflowResult::MayOverflow:
break;
case OverflowResult::NeverOverflows:
if (SI->isSigned())
return BinaryOperator::CreateNSW(SI->getBinaryOp(), Arg0, Arg1);
else
return BinaryOperator::CreateNUW(SI->getBinaryOp(), Arg0, Arg1);
case OverflowResult::AlwaysOverflowsLow: {
unsigned BitWidth = Ty->getScalarSizeInBits();
APInt Min = APSInt::getMinValue(BitWidth, !SI->isSigned());
return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Min));
}
case OverflowResult::AlwaysOverflowsHigh: {
unsigned BitWidth = Ty->getScalarSizeInBits();
APInt Max = APSInt::getMaxValue(BitWidth, !SI->isSigned());
return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Max));
}
}
// usub_sat((sub nuw C, A), C1) -> usub_sat(usub_sat(C, C1), A)
// which after that:
// usub_sat((sub nuw C, A), C1) -> usub_sat(C - C1, A) if C1 u< C
// usub_sat((sub nuw C, A), C1) -> 0 otherwise
Constant *C, *C1;
Value *A;
if (IID == Intrinsic::usub_sat &&
match(Arg0, m_NUWSub(m_ImmConstant(C), m_Value(A))) &&
match(Arg1, m_ImmConstant(C1))) {
auto *NewC = Builder.CreateBinaryIntrinsic(Intrinsic::usub_sat, C, C1);
auto *NewSub =
Builder.CreateBinaryIntrinsic(Intrinsic::usub_sat, NewC, A);
return replaceInstUsesWith(*SI, NewSub);
}
// ssub.sat(X, C) -> sadd.sat(X, -C) if C != MIN
if (IID == Intrinsic::ssub_sat && match(Arg1, m_Constant(C)) &&
C->isNotMinSignedValue()) {
Value *NegVal = ConstantExpr::getNeg(C);
return replaceInstUsesWith(
*II, Builder.CreateBinaryIntrinsic(
Intrinsic::sadd_sat, Arg0, NegVal));
}
// sat(sat(X + Val2) + Val) -> sat(X + (Val+Val2))
// sat(sat(X - Val2) - Val) -> sat(X - (Val+Val2))
// if Val and Val2 have the same sign
if (auto *Other = dyn_cast<IntrinsicInst>(Arg0)) {
Value *X;
const APInt *Val, *Val2;
APInt NewVal;
bool IsUnsigned =
IID == Intrinsic::uadd_sat || IID == Intrinsic::usub_sat;
if (Other->getIntrinsicID() == IID &&
match(Arg1, m_APInt(Val)) &&
match(Other->getArgOperand(0), m_Value(X)) &&
match(Other->getArgOperand(1), m_APInt(Val2))) {
if (IsUnsigned)
NewVal = Val->uadd_sat(*Val2);
else if (Val->isNonNegative() == Val2->isNonNegative()) {
bool Overflow;
NewVal = Val->sadd_ov(*Val2, Overflow);
if (Overflow) {
// Both adds together may add more than SignedMaxValue
// without saturating the final result.
break;
}
} else {
// Cannot fold saturated addition with different signs.
break;
}
return replaceInstUsesWith(
*II, Builder.CreateBinaryIntrinsic(
IID, X, ConstantInt::get(II->getType(), NewVal)));
}
}
break;
}
case Intrinsic::minnum:
case Intrinsic::maxnum:
case Intrinsic::minimumnum:
case Intrinsic::maximumnum:
case Intrinsic::minimum:
case Intrinsic::maximum: {
Value *Arg0 = II->getArgOperand(0);
Value *Arg1 = II->getArgOperand(1);
Value *X, *Y;
if (match(Arg0, m_FNeg(m_Value(X))) && match(Arg1, m_FNeg(m_Value(Y))) &&
(Arg0->hasOneUse() || Arg1->hasOneUse())) {
// If both operands are negated, invert the call and negate the result:
// min(-X, -Y) --> -(max(X, Y))
// max(-X, -Y) --> -(min(X, Y))
Intrinsic::ID NewIID;
switch (IID) {
case Intrinsic::maxnum:
NewIID = Intrinsic::minnum;
break;
case Intrinsic::minnum:
NewIID = Intrinsic::maxnum;
break;
case Intrinsic::maximumnum:
NewIID = Intrinsic::minimumnum;
break;
case Intrinsic::minimumnum:
NewIID = Intrinsic::maximumnum;
break;
case Intrinsic::maximum:
NewIID = Intrinsic::minimum;
break;
case Intrinsic::minimum:
NewIID = Intrinsic::maximum;
break;
default:
llvm_unreachable("unexpected intrinsic ID");
}
Value *NewCall = Builder.CreateBinaryIntrinsic(NewIID, X, Y, II);
Instruction *FNeg = UnaryOperator::CreateFNeg(NewCall);
FNeg->copyIRFlags(II);
return FNeg;
}
// m(m(X, C2), C1) -> m(X, C)
const APFloat *C1, *C2;
if (auto *M = dyn_cast<IntrinsicInst>(Arg0)) {
if (M->getIntrinsicID() == IID && match(Arg1, m_APFloat(C1)) &&
((match(M->getArgOperand(0), m_Value(X)) &&
match(M->getArgOperand(1), m_APFloat(C2))) ||
(match(M->getArgOperand(1), m_Value(X)) &&
match(M->getArgOperand(0), m_APFloat(C2))))) {
APFloat Res(0.0);
switch (IID) {
case Intrinsic::maxnum:
Res = maxnum(*C1, *C2);
break;
case Intrinsic::minnum:
Res = minnum(*C1, *C2);
break;
case Intrinsic::maximumnum:
Res = maximumnum(*C1, *C2);
break;
case Intrinsic::minimumnum:
Res = minimumnum(*C1, *C2);
break;
case Intrinsic::maximum:
Res = maximum(*C1, *C2);
break;
case Intrinsic::minimum:
Res = minimum(*C1, *C2);
break;
default:
llvm_unreachable("unexpected intrinsic ID");
}
// TODO: Conservatively intersecting FMF. If Res == C2, the transform
// was a simplification (so Arg0 and its original flags could
// propagate?)
Value *V = Builder.CreateBinaryIntrinsic(
IID, X, ConstantFP::get(Arg0->getType(), Res),
FMFSource::intersect(II, M));
return replaceInstUsesWith(*II, V);
}
}
// m((fpext X), (fpext Y)) -> fpext (m(X, Y))
if (match(Arg0, m_FPExt(m_Value(X))) && match(Arg1, m_FPExt(m_Value(Y))) &&
(Arg0->hasOneUse() || Arg1->hasOneUse()) &&
X->getType() == Y->getType()) {
Value *NewCall =
Builder.CreateBinaryIntrinsic(IID, X, Y, II, II->getName());
return new FPExtInst(NewCall, II->getType());
}
// m(fpext X, C) -> fpext m(X, TruncC) if C can be losslessly truncated.
Constant *C;
if (match(Arg0, m_OneUse(m_FPExt(m_Value(X)))) &&
match(Arg1, m_ImmConstant(C))) {
if (Constant *TruncC =
getLosslessInvCast(C, X->getType(), Instruction::FPExt, DL)) {
Value *NewCall =
Builder.CreateBinaryIntrinsic(IID, X, TruncC, II, II->getName());
return new FPExtInst(NewCall, II->getType());
}
}
// max X, -X --> fabs X
// min X, -X --> -(fabs X)
// TODO: Remove one-use limitation? That is obviously better for max,
// hence why we don't check for one-use for that. However,
// it would be an extra instruction for min (fnabs), but
// that is still likely better for analysis and codegen.
auto IsMinMaxOrXNegX = [IID, &X](Value *Op0, Value *Op1) {
if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Specific(X)))
return Op0->hasOneUse() ||
(IID != Intrinsic::minimum && IID != Intrinsic::minnum &&
IID != Intrinsic::minimumnum);
return false;
};
if (IsMinMaxOrXNegX(Arg0, Arg1) || IsMinMaxOrXNegX(Arg1, Arg0)) {
Value *R = Builder.CreateFAbs(X, II);
if (IID == Intrinsic::minimum || IID == Intrinsic::minnum ||
IID == Intrinsic::minimumnum)
R = Builder.CreateFNegFMF(R, II);
return replaceInstUsesWith(*II, R);
}
break;
}
case Intrinsic::matrix_multiply: {
// Optimize negation in matrix multiplication.
// -A * -B -> A * B
Value *A, *B;
if (match(II->getArgOperand(0), m_FNeg(m_Value(A))) &&
match(II->getArgOperand(1), m_FNeg(m_Value(B)))) {
replaceOperand(*II, 0, A);
replaceOperand(*II, 1, B);
return II;
}
Value *Op0 = II->getOperand(0);
Value *Op1 = II->getOperand(1);
Value *OpNotNeg, *NegatedOp;
unsigned NegatedOpArg, OtherOpArg;
if (match(Op0, m_FNeg(m_Value(OpNotNeg)))) {
NegatedOp = Op0;
NegatedOpArg = 0;
OtherOpArg = 1;
} else if (match(Op1, m_FNeg(m_Value(OpNotNeg)))) {
NegatedOp = Op1;
NegatedOpArg = 1;
OtherOpArg = 0;
} else
// Multiplication doesn't have a negated operand.
break;
// Only optimize if the negated operand has only one use.
if (!NegatedOp->hasOneUse())
break;
Value *OtherOp = II->getOperand(OtherOpArg);
VectorType *RetTy = cast<VectorType>(II->getType());
VectorType *NegatedOpTy = cast<VectorType>(NegatedOp->getType());
VectorType *OtherOpTy = cast<VectorType>(OtherOp->getType());
ElementCount NegatedCount = NegatedOpTy->getElementCount();
ElementCount OtherCount = OtherOpTy->getElementCount();
ElementCount RetCount = RetTy->getElementCount();
// (-A) * B -> A * (-B), if it is cheaper to negate B and vice versa.
if (ElementCount::isKnownGT(NegatedCount, OtherCount) &&
ElementCount::isKnownLT(OtherCount, RetCount)) {
Value *InverseOtherOp = Builder.CreateFNeg(OtherOp);
replaceOperand(*II, NegatedOpArg, OpNotNeg);
replaceOperand(*II, OtherOpArg, InverseOtherOp);
return II;
}
// (-A) * B -> -(A * B), if it is cheaper to negate the result
if (ElementCount::isKnownGT(NegatedCount, RetCount)) {
SmallVector<Value *, 5> NewArgs(II->args());
NewArgs[NegatedOpArg] = OpNotNeg;
Value *NewMul = Builder.CreateIntrinsic(II->getType(), IID, NewArgs, II);
return replaceInstUsesWith(*II, Builder.CreateFNegFMF(NewMul, II));
}
break;
}
case Intrinsic::fmuladd: {
// Try to simplify the underlying FMul.
if (Value *V =
simplifyFMulInst(II->getArgOperand(0), II->getArgOperand(1),
II->getFastMathFlags(), SQ.getWithInstruction(II)))
return BinaryOperator::CreateFAddFMF(V, II->getArgOperand(2),
II->getFastMathFlags());
[[fallthrough]];
}
case Intrinsic::fma: {
// fma fneg(x), fneg(y), z -> fma x, y, z
Value *Src0 = II->getArgOperand(0);
Value *Src1 = II->getArgOperand(1);
Value *Src2 = II->getArgOperand(2);
Value *X, *Y;
if (match(Src0, m_FNeg(m_Value(X))) && match(Src1, m_FNeg(m_Value(Y))))
return replaceInstUsesWith(
*II, Builder.CreateIntrinsic(IID, II->getType(), {X, Y, Src2}, II));
// fma fabs(x), fabs(x), z -> fma x, x, z
if (match(Src0, m_FAbs(m_Value(X))) && match(Src1, m_FAbs(m_Specific(X))))
return replaceInstUsesWith(
*II, Builder.CreateIntrinsic(IID, II->getType(), {X, X, Src2}, II));
// Try to simplify the underlying FMul. We can only apply simplifications
// that do not require rounding.
if (Value *V = simplifyFMAFMul(Src0, Src1, II->getFastMathFlags(),
SQ.getWithInstruction(II)))
return BinaryOperator::CreateFAddFMF(V, Src2, II->getFastMathFlags());
// fma x, y, 0 -> fmul x, y
// This is always valid for -0.0, but requires nsz for +0.0 as
// -0.0 + 0.0 = 0.0, which would not be the same as the fmul on its own.
if (match(Src2, m_NegZeroFP()) ||
(match(Src2, m_PosZeroFP()) && II->getFastMathFlags().noSignedZeros()))
return BinaryOperator::CreateFMulFMF(Src0, Src1, II);
// fma x, -1.0, y -> fsub y, x
if (match(Src1, m_SpecificFP(-1.0)))
return BinaryOperator::CreateFSubFMF(Src2, Src0, II);
break;
}
case Intrinsic::copysign: {
Value *Mag = II->getArgOperand(0), *Sign = II->getArgOperand(1);
if (std::optional<bool> KnownSignBit = computeKnownFPSignBit(
Sign, getSimplifyQuery().getWithInstruction(II))) {
if (*KnownSignBit) {
// If we know that the sign argument is negative, reduce to FNABS:
// copysign Mag, -Sign --> fneg (fabs Mag)
Value *Fabs = Builder.CreateFAbs(Mag, II);
return replaceInstUsesWith(*II, Builder.CreateFNegFMF(Fabs, II));
}
// If we know that the sign argument is positive, reduce to FABS:
// copysign Mag, +Sign --> fabs Mag
Value *Fabs = Builder.CreateFAbs(Mag, II);
return replaceInstUsesWith(*II, Fabs);
}
// Propagate sign argument through nested calls:
// copysign Mag, (copysign ?, X) --> copysign Mag, X
Value *X;
if (match(Sign, m_Intrinsic<Intrinsic::copysign>(m_Value(), m_Value(X)))) {
Value *CopySign =
Builder.CreateCopySign(Mag, X, FMFSource::intersect(II, Sign));
return replaceInstUsesWith(*II, CopySign);
}
// Clear sign-bit of constant magnitude:
// copysign -MagC, X --> copysign MagC, X
// TODO: Support constant folding for fabs
const APFloat *MagC;
if (match(Mag, m_APFloat(MagC)) && MagC->isNegative()) {
APFloat PosMagC = *MagC;
PosMagC.clearSign();
return replaceInstUsesWith(
*II, Builder.CreateCopySign(ConstantFP::get(Mag->getType(), PosMagC),
Sign, II));
}
// Peek through changes of magnitude's sign-bit. This call rewrites those:
// copysign (fabs X), Sign --> copysign X, Sign
// copysign (fneg X), Sign --> copysign X, Sign
if (match(Mag, m_FAbs(m_Value(X))) || match(Mag, m_FNeg(m_Value(X))))
return replaceInstUsesWith(*II, Builder.CreateCopySign(X, Sign, II));
// copysign(floor(fabs(X)), X) --> copysign(trunc(X), X)
// copysign ignores the sign bit of its magnitude argument (implicit fabs),
// so replacing floor(fabs(X)) with trunc(X) is correct for all inputs
// including NaN without requiring nnan. The m_FAbs match also ensures
// the floor argument is non-negative, so floor == trunc.
Value *FAbsArg;
if (match(Mag, m_Intrinsic<Intrinsic::floor>(m_FAbs(m_Value(FAbsArg)))) &&
FAbsArg == Sign) {
Value *Trunc = Builder.CreateUnaryIntrinsic(Intrinsic::trunc, Sign, II);
return replaceInstUsesWith(*II, Builder.CreateCopySign(Trunc, Sign, II));
}
Type *SignEltTy = Sign->getType()->getScalarType();
Value *CastSrc;
if (match(Sign,
m_OneUse(m_ElementWiseBitCast(m_OneUse(m_Value(CastSrc))))) &&
CastSrc->getType()->isIntOrIntVectorTy() &&
APFloat::hasSignBitInMSB(SignEltTy->getFltSemantics())) {
KnownBits Known(SignEltTy->getPrimitiveSizeInBits());
if (SimplifyDemandedBits(cast<Instruction>(Sign), 0,
APInt::getSignMask(Known.getBitWidth()), Known,
SQ))
return II;
}
break;
}
case Intrinsic::fabs: {
Value *Cond, *TVal, *FVal;
Value *Arg = II->getArgOperand(0);
Value *X;
// fabs (-X) --> fabs (X)
if (match(Arg, m_FNeg(m_Value(X)))) {
Value *Fabs = Builder.CreateFAbs(X, II);
return replaceInstUsesWith(CI, Fabs);
}
if (match(Arg, m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))) {
// fabs (select Cond, TrueC, FalseC) --> select Cond, AbsT, AbsF
if (Arg->hasOneUse() ? (isa<Constant>(TVal) || isa<Constant>(FVal))
: (isa<Constant>(TVal) && isa<Constant>(FVal))) {
CallInst *AbsT = Builder.CreateCall(II->getCalledFunction(), {TVal});
CallInst *AbsF = Builder.CreateCall(II->getCalledFunction(), {FVal});
SelectInst *SI = SelectInst::Create(Cond, AbsT, AbsF);
SI->setFastMathFlags(II->getFastMathFlags() |
cast<SelectInst>(Arg)->getFastMathFlags());
// Can't copy nsz to select, as even with the nsz flag the fabs result
// always has the sign bit unset.
SI->setHasNoSignedZeros(false);
return SI;
}
// fabs (select Cond, -FVal, FVal) --> fabs FVal
if (match(TVal, m_FNeg(m_Specific(FVal))))
return replaceInstUsesWith(*II, Builder.CreateFAbs(FVal, II));
// fabs (select Cond, TVal, -TVal) --> fabs TVal
if (match(FVal, m_FNeg(m_Specific(TVal))))
return replaceInstUsesWith(*II, Builder.CreateFAbs(TVal, II));
}
Value *Magnitude, *Sign;
if (match(II->getArgOperand(0),
m_CopySign(m_Value(Magnitude), m_Value(Sign)))) {
// fabs (copysign x, y) -> (fabs x)
Value *AbsSign = Builder.CreateFAbs(Magnitude, II);
return replaceInstUsesWith(*II, AbsSign);
}
[[fallthrough]];
}
case Intrinsic::ceil:
case Intrinsic::floor:
case Intrinsic::round:
case Intrinsic::roundeven:
case Intrinsic::nearbyint:
case Intrinsic::rint:
case Intrinsic::trunc: {
Value *ExtSrc;
if (match(II->getArgOperand(0), m_OneUse(m_FPExt(m_Value(ExtSrc))))) {
// Narrow the call: intrinsic (fpext x) -> fpext (intrinsic x)
Value *NarrowII = Builder.CreateUnaryIntrinsic(IID, ExtSrc, II);
return new FPExtInst(NarrowII, II->getType());
}
break;
}
case Intrinsic::cos:
case Intrinsic::amdgcn_cos:
case Intrinsic::cosh: {
Value *X, *Sign;
Value *Src = II->getArgOperand(0);
if (match(Src, m_FNeg(m_Value(X))) || match(Src, m_FAbs(m_Value(X))) ||
match(Src, m_CopySign(m_Value(X), m_Value(Sign)))) {
// f(-x) --> f(x)
// f(fabs(x)) --> f(x)
// f(copysign(x, y)) --> f(x)
// for f in {cos, cosh}
return replaceInstUsesWith(*II, Builder.CreateUnaryIntrinsic(IID, X, II));
}
if (IID == Intrinsic::cos) {
if (Value *Result = foldSinAndCosToSinCos(II, Builder, *this))
return replaceInstUsesWith(*II, Result);
}
break;
}
case Intrinsic::sin:
case Intrinsic::amdgcn_sin:
case Intrinsic::sinh:
case Intrinsic::tan:
case Intrinsic::tanh: {
Value *X;
if (match(II->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X)))) &&
!mayFlushDenormalsToPositiveZero(II)) {
// f(-x) --> -f(x)
// for f in {sin, sinh, tan, tanh}
Value *NewFunc = Builder.CreateUnaryIntrinsic(IID, X, II);
return UnaryOperator::CreateFNegFMF(NewFunc, II);
}
if (IID == Intrinsic::sin) {
if (Value *Result = foldSinAndCosToSinCos(II, Builder, *this))
return replaceInstUsesWith(*II, Result);
}
break;
}
case Intrinsic::ldexp: {
Value *Src = II->getArgOperand(0);
Value *Exp = II->getArgOperand(1);
// ldexp(x, K) -> fmul x, 2^K
uint64_t ConstExp;
if (match(Exp, m_ConstantInt(ConstExp))) {
const fltSemantics &FPTy =
Src->getType()->getScalarType()->getFltSemantics();
APFloat Scaled = scalbn(APFloat::getOne(FPTy), static_cast<int>(ConstExp),
APFloat::rmNearestTiesToEven);
if (!Scaled.isZero() && !Scaled.isInfinity()) {
// Skip overflow and underflow cases.
Constant *FPConst = ConstantFP::get(Src->getType(), Scaled);
return BinaryOperator::CreateFMulFMF(Src, FPConst, II);
}
}
// ldexp(ldexp(x, a), b) -> ldexp(x, sadd.sat(a, b))
//
// A danger is if the first ldexp would overflow to infinity or underflow to
// zero, but the combined exponent avoids it.
//
// We ignore this with reassoc, or if we know both exponents have the same
// sign (since then we'd just double down on the over/underflow which would
// occur anyway).
//
// ldexp can take arbitrary integer types, so we also need to ensure that
// our exponent type is wide enough so that if sadd.sat(a, b) saturates,
// then ldexp at the saturated exponent saturates to inf or zero as well.
//
// TODO: Could do better if we had range tracking for the input value
// exponent. Also could broaden sign check to cover == 0 case.
Value *InnerSrc;
Value *InnerExp;
if (match(Src, m_OneUse(m_Intrinsic<Intrinsic::ldexp>(
m_Value(InnerSrc), m_Value(InnerExp)))) &&
Exp->getType() == InnerExp->getType()) {
FastMathFlags FMF = II->getFastMathFlags();
FastMathFlags InnerFlags = cast<FPMathOperator>(Src)->getFastMathFlags();
if (ldexpSaturatingAddIsSafe(II->getType(), Exp->getType()) &&
((FMF.allowReassoc() && InnerFlags.allowReassoc()) ||
signBitMustBeTheSame(Exp, InnerExp, SQ.getWithInstruction(II)))) {
Value *NewExp =
Builder.CreateBinaryIntrinsic(Intrinsic::sadd_sat, InnerExp, Exp);
return replaceInstUsesWith(
*II, Builder.CreateLdexp(InnerSrc, NewExp, FMF | InnerFlags));
}
}
// ldexp(x, zext(i1 y)) -> fmul x, (select y, 2.0, 1.0)
// ldexp(x, sext(i1 y)) -> fmul x, (select y, 0.5, 1.0)
Value *ExtSrc;
if (match(Exp, m_ZExt(m_Value(ExtSrc))) &&
ExtSrc->getType()->getScalarSizeInBits() == 1) {
Value *Select =
Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 2.0),
ConstantFP::get(II->getType(), 1.0));
return BinaryOperator::CreateFMulFMF(Src, Select, II);
}
if (match(Exp, m_SExt(m_Value(ExtSrc))) &&
ExtSrc->getType()->getScalarSizeInBits() == 1) {
Value *Select =
Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 0.5),
ConstantFP::get(II->getType(), 1.0));
return BinaryOperator::CreateFMulFMF(Src, Select, II);
}
// ldexp(x, c ? exp : 0) -> c ? ldexp(x, exp) : x
// ldexp(x, c ? 0 : exp) -> c ? x : ldexp(x, exp)
///
// TODO: If we cared, should insert a canonicalize for x
Value *SelectCond, *SelectLHS, *SelectRHS;
if (match(II->getArgOperand(1),
m_OneUse(m_Select(m_Value(SelectCond), m_Value(SelectLHS),
m_Value(SelectRHS))))) {
Value *NewLdexp = nullptr;
Value *Select = nullptr;
if (match(SelectRHS, m_ZeroInt())) {
NewLdexp = Builder.CreateLdexp(Src, SelectLHS, II);
Select = Builder.CreateSelect(SelectCond, NewLdexp, Src);
} else if (match(SelectLHS, m_ZeroInt())) {
NewLdexp = Builder.CreateLdexp(Src, SelectRHS, II);
Select = Builder.CreateSelect(SelectCond, Src, NewLdexp);
}
if (NewLdexp) {
Select->takeName(II);
return replaceInstUsesWith(*II, Select);
}
}
break;
}
case Intrinsic::ptrauth_auth:
case Intrinsic::ptrauth_resign: {
// (sign|resign) + (auth|resign) can be folded by omitting the middle
// sign+auth component if the key and discriminator match.
bool NeedSign = II->getIntrinsicID() == Intrinsic::ptrauth_resign;
Value *Ptr = II->getArgOperand(0);
Value *Key = II->getArgOperand(1);
Value *Disc = II->getArgOperand(2);
Value *DS = nullptr;
if (auto Bundle = II->getOperandBundle(LLVMContext::OB_deactivation_symbol))
DS = Bundle->Inputs[0];
// AuthKey will be the key we need to end up authenticating against in
// whatever we replace this sequence with.
Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr;
if (const auto *CI = dyn_cast<CallBase>(Ptr)) {
Value *OtherDS = nullptr;
if (auto Bundle =
CI->getOperandBundle(LLVMContext::OB_deactivation_symbol))
OtherDS = Bundle->Inputs[0];
if (DS != OtherDS)
break;
if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) {
if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc)
break;
} else if (CI->getIntrinsicID() == Intrinsic::ptrauth_resign) {
// The resign intrinsic does not support deactivation symbols.
assert(!DS);
if (CI->getArgOperand(3) != Key || CI->getArgOperand(4) != Disc)
break;
AuthKey = CI->getArgOperand(1);
AuthDisc = CI->getArgOperand(2);
} else
break;
BasePtr = CI->getArgOperand(0);
} else if (const auto *PtrToInt = dyn_cast<PtrToIntOperator>(Ptr)) {
// ptrauth constants are equivalent to a call to @llvm.ptrauth.sign for
// our purposes, so check for that too.
const auto *CPA = dyn_cast<ConstantPtrAuth>(PtrToInt->getOperand(0));
if (!CPA || DS || !CPA->isKnownCompatibleWith(Key, Disc, DL))
break;
// resign(ptrauth(p,ks,ds),ks,ds,kr,dr) -> ptrauth(p,kr,dr)
if (NeedSign && isa<ConstantInt>(II->getArgOperand(4))) {
auto *SignKey = cast<ConstantInt>(II->getArgOperand(3));
auto *SignDisc = cast<ConstantInt>(II->getArgOperand(4));
auto *Null = ConstantPointerNull::get(Builder.getPtrTy());
auto *NewCPA = ConstantPtrAuth::get(CPA->getPointer(), SignKey,
SignDisc, /*AddrDisc=*/Null,
/*DeactivationSymbol=*/Null);
replaceInstUsesWith(
*II, ConstantExpr::getPointerCast(NewCPA, II->getType()));
return eraseInstFromFunction(*II);
}
// auth(ptrauth(p,k,d),k,d) -> p
BasePtr = Builder.CreatePtrToInt(CPA->getPointer(), II->getType());
} else
break;
unsigned NewIntrin;
if (AuthKey && NeedSign) {
// resign(0,1) + resign(1,2) = resign(0, 2)
NewIntrin = Intrinsic::ptrauth_resign;
} else if (AuthKey) {
// resign(0,1) + auth(1) = auth(0)
NewIntrin = Intrinsic::ptrauth_auth;
} else if (NeedSign) {
// sign(0) + resign(0, 1) = sign(1)
NewIntrin = Intrinsic::ptrauth_sign;
} else {
// sign(0) + auth(0) = nop
replaceInstUsesWith(*II, BasePtr);
return eraseInstFromFunction(*II);
}
SmallVector<Value *, 4> CallArgs;
CallArgs.push_back(BasePtr);
if (AuthKey) {
CallArgs.push_back(AuthKey);
CallArgs.push_back(AuthDisc);
}
if (NeedSign) {
CallArgs.push_back(II->getArgOperand(3));
CallArgs.push_back(II->getArgOperand(4));
}
std::vector<OperandBundleDef> Bundles;
if (DS)
Bundles.push_back(OperandBundleDef("deactivation-symbol", DS));
Function *NewFn =
Intrinsic::getOrInsertDeclaration(II->getModule(), NewIntrin);
return CallInst::Create(NewFn, CallArgs, Bundles);
}
case Intrinsic::arm_neon_vtbl1:
case Intrinsic::arm_neon_vtbl2:
case Intrinsic::arm_neon_vtbl3:
case Intrinsic::arm_neon_vtbl4:
case Intrinsic::aarch64_neon_tbl1:
case Intrinsic::aarch64_neon_tbl2:
case Intrinsic::aarch64_neon_tbl3:
case Intrinsic::aarch64_neon_tbl4:
return simplifyNeonTbl(*II, *this, /*IsExtension=*/false);
case Intrinsic::arm_neon_vtbx1:
case Intrinsic::arm_neon_vtbx2:
case Intrinsic::arm_neon_vtbx3:
case Intrinsic::arm_neon_vtbx4:
case Intrinsic::aarch64_neon_tbx1:
case Intrinsic::aarch64_neon_tbx2:
case Intrinsic::aarch64_neon_tbx3:
case Intrinsic::aarch64_neon_tbx4:
return simplifyNeonTbl(*II, *this, /*IsExtension=*/true);
case Intrinsic::arm_neon_vmulls:
case Intrinsic::arm_neon_vmullu:
case Intrinsic::aarch64_neon_smull:
case Intrinsic::aarch64_neon_umull: {
Value *Arg0 = II->getArgOperand(0);
Value *Arg1 = II->getArgOperand(1);
// Handle mul by zero first:
if (isa<ConstantAggregateZero>(Arg0) || isa<ConstantAggregateZero>(Arg1)) {
return replaceInstUsesWith(CI, ConstantAggregateZero::get(II->getType()));
}
// Check for constant LHS & RHS - in this case we just simplify.
bool Zext = (IID == Intrinsic::arm_neon_vmullu ||
IID == Intrinsic::aarch64_neon_umull);
VectorType *NewVT = cast<VectorType>(II->getType());
if (Constant *CV0 = dyn_cast<Constant>(Arg0)) {
if (Constant *CV1 = dyn_cast<Constant>(Arg1)) {
Value *V0 = Builder.CreateIntCast(CV0, NewVT, /*isSigned=*/!Zext);
Value *V1 = Builder.CreateIntCast(CV1, NewVT, /*isSigned=*/!Zext);
return replaceInstUsesWith(CI, Builder.CreateMul(V0, V1));
}
// Couldn't simplify - canonicalize constant to the RHS.
std::swap(Arg0, Arg1);
}
// Handle mul by one:
if (Constant *CV1 = dyn_cast<Constant>(Arg1))
if (ConstantInt *Splat =
dyn_cast_or_null<ConstantInt>(CV1->getSplatValue()))
if (Splat->isOne())
return CastInst::CreateIntegerCast(Arg0, II->getType(),
/*isSigned=*/!Zext);
break;
}
case Intrinsic::arm_neon_aesd:
case Intrinsic::arm_neon_aese:
case Intrinsic::aarch64_crypto_aesd:
case Intrinsic::aarch64_crypto_aese:
case Intrinsic::aarch64_sve_aesd:
case Intrinsic::aarch64_sve_aese: {
Value *DataArg = II->getArgOperand(0);
Value *KeyArg = II->getArgOperand(1);
// Accept zero on either operand.
if (!match(KeyArg, m_ZeroInt()))
std::swap(KeyArg, DataArg);
// Try to use the builtin XOR in AESE and AESD to eliminate a prior XOR
Value *Data, *Key;
if (match(KeyArg, m_ZeroInt()) &&
match(DataArg, m_Xor(m_Value(Data), m_Value(Key)))) {
replaceOperand(*II, 0, Data);
replaceOperand(*II, 1, Key);
return II;
}
break;
}
case Intrinsic::arm_neon_vshifts:
case Intrinsic::arm_neon_vshiftu:
case Intrinsic::aarch64_neon_sshl:
case Intrinsic::aarch64_neon_ushl:
return foldNeonShift(II, *this);
case Intrinsic::hexagon_V6_vandvrt:
case Intrinsic::hexagon_V6_vandvrt_128B: {
// Simplify Q -> V -> Q conversion.
if (auto Op0 = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
Intrinsic::ID ID0 = Op0->getIntrinsicID();
if (ID0 != Intrinsic::hexagon_V6_vandqrt &&
ID0 != Intrinsic::hexagon_V6_vandqrt_128B)
break;
Value *Bytes = Op0->getArgOperand(1), *Mask = II->getArgOperand(1);
uint64_t Bytes1 = computeKnownBits(Bytes, Op0).One.getZExtValue();
uint64_t Mask1 = computeKnownBits(Mask, II).One.getZExtValue();
// Check if every byte has common bits in Bytes and Mask.
uint64_t C = Bytes1 & Mask1;
if ((C & 0xFF) && (C & 0xFF00) && (C & 0xFF0000) && (C & 0xFF000000))
return replaceInstUsesWith(*II, Op0->getArgOperand(0));
}
break;
}
case Intrinsic::stackrestore: {
enum class ClassifyResult {
None,
Alloca,
StackRestore,
CallWithSideEffects,
};
auto Classify = [](const Instruction *I) {
if (isa<AllocaInst>(I))
return ClassifyResult::Alloca;
if (auto *CI = dyn_cast<CallInst>(I)) {
if (auto *II = dyn_cast<IntrinsicInst>(CI)) {
if (II->getIntrinsicID() == Intrinsic::stackrestore)
return ClassifyResult::StackRestore;
if (II->mayHaveSideEffects())
return ClassifyResult::CallWithSideEffects;
} else {
// Consider all non-intrinsic calls to be side effects
return ClassifyResult::CallWithSideEffects;
}
}
return ClassifyResult::None;
};
// If the stacksave and the stackrestore are in the same BB, and there is
// no intervening call, alloca, or stackrestore of a different stacksave,
// remove the restore. This can happen when variable allocas are DCE'd.
if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
if (SS->getIntrinsicID() == Intrinsic::stacksave &&
SS->getParent() == II->getParent()) {
BasicBlock::iterator BI(SS);
bool CannotRemove = false;
for (++BI; &*BI != II; ++BI) {
switch (Classify(&*BI)) {
case ClassifyResult::None:
// So far so good, look at next instructions.
break;
case ClassifyResult::StackRestore:
// If we found an intervening stackrestore for a different
// stacksave, we can't remove the stackrestore. Otherwise, continue.
if (cast<IntrinsicInst>(*BI).getArgOperand(0) != SS)
CannotRemove = true;
break;
case ClassifyResult::Alloca:
case ClassifyResult::CallWithSideEffects:
// If we found an alloca, a non-intrinsic call, or an intrinsic
// call with side effects, we can't remove the stackrestore.
CannotRemove = true;
break;
}
if (CannotRemove)
break;
}
if (!CannotRemove)
return eraseInstFromFunction(CI);
}
}
// Scan down this block to see if there is another stack restore in the
// same block without an intervening call/alloca.
BasicBlock::iterator BI(II);
Instruction *TI = II->getParent()->getTerminator();
bool CannotRemove = false;
for (++BI; &*BI != TI; ++BI) {
switch (Classify(&*BI)) {
case ClassifyResult::None:
// So far so good, look at next instructions.
break;
case ClassifyResult::StackRestore:
// If there is a stackrestore below this one, remove this one.
return eraseInstFromFunction(CI);
case ClassifyResult::Alloca:
case ClassifyResult::CallWithSideEffects:
// If we found an alloca, a non-intrinsic call, or an intrinsic call
// with side effects (such as llvm.stacksave and llvm.read_register),
// we can't remove the stack restore.
CannotRemove = true;
break;
}
if (CannotRemove)
break;
}
// If the stack restore is in a return, resume, or unwind block and if there
// are no allocas or calls between the restore and the return, nuke the
// restore.
if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI)))
return eraseInstFromFunction(CI);
break;
}
case Intrinsic::lifetime_end:
// Asan needs to poison memory to detect invalid access which is possible
// even for empty lifetime range.
if (II->getFunction()->hasFnAttribute(Attribute::SanitizeAddress) ||
II->getFunction()->hasFnAttribute(Attribute::SanitizeMemory) ||
II->getFunction()->hasFnAttribute(Attribute::SanitizeHWAddress) ||
II->getFunction()->hasFnAttribute(Attribute::SanitizeMemTag))
break;
if (removeTriviallyEmptyRange(*II, *this, [](const IntrinsicInst &I) {
return I.getIntrinsicID() == Intrinsic::lifetime_start;
}))
return nullptr;
break;
case Intrinsic::assume: {
for (auto [Idx, OBU] : llvm::enumerate(II->operand_bundles())) {
auto RemoveBundle = [&, Idx = Idx]() -> Instruction * {
if (II->getNumOperandBundles() == 1)
return eraseInstFromFunction(*II);
return CallBase::removeOperandBundleAt(II, Idx);
};
switch (getBundleAttrFromOBU(OBU)) {
case BundleAttr::None:
llvm_unreachable("Unexpected Attribute");
case BundleAttr::Align: {
// Try to remove redundant alignment assumptions.
auto [Ptr, _, OffsetPtr, Alignment, Offset] = getAssumeAlignInfo(OBU);
if (!Alignment)
break;
// Remove align 1 and non-power-of-two bundles; they don't add any
// useful information.
if (*Alignment == 1 || !isPowerOf2_64(*Alignment))
return RemoveBundle();
if (auto *GEP = dyn_cast<GEPOperator>(Ptr);
GEP &&
GEP->getMaxPreservedAlignment(getDataLayout()) >= *Alignment) {
Builder.CreateAlignmentAssumption(
getDataLayout(), GEP->getPointerOperand(), *Alignment,
OffsetPtr ? const_cast<Value *>(OffsetPtr->get()) : nullptr);
return RemoveBundle();
}
if (!Offset)
break;
Value *BasePtr;
const APInt *PtrOffset;
if (match(Ptr.get(), m_PtrAdd(m_Value(BasePtr), m_APInt(PtrOffset)))) {
auto PtrOffsetVal =
PtrOffset->sextOrTrunc(DL.getIndexTypeSizeInBits(Ptr->getType()))
.trySExtValue();
if (!PtrOffsetVal)
break;
Builder.CreateAlignmentAssumption(
DL, BasePtr, *Alignment,
Builder.getInt64(*Offset - *PtrOffsetVal));
return RemoveBundle();
}
// Don't try to remove align assumptions for pointers derived from
// arguments. We might lose information if the function gets inline and
// the align argument attribute disappears.
Value *UO = getUnderlyingObject(Ptr);
if (!UO || isa<Argument>(UO))
break;
// Compute known bits for the pointer and drop the assume if the
// known alignment isn't increased by it.
auto AlignMask = (*Alignment - 1);
if (KnownBits KB = computeKnownBits(Ptr, II);
(KB.Zero & AlignMask) == (~*Offset & AlignMask) &&
(KB.One & AlignMask) == (*Offset & AlignMask))
return RemoveBundle();
break;
}
case BundleAttr::Dereferenceable: {
auto [Ptr, _, Count] = getAssumeDereferenceableInfo(OBU);
if (!Count)
break;
if (*Count == 0 ||
isDereferenceablePointer(Ptr, APInt(64, *Count),
getSimplifyQuery().getWithInstruction(II)))
return RemoveBundle();
break;
}
case BundleAttr::Ignore:
return RemoveBundle();
case BundleAttr::NonNull: {
auto [Ptr] = llvm::getAssumeNonNullInfo(OBU);
// Drop assume if we can prove nonnull without it
if (isKnownNonZero(Ptr, getSimplifyQuery().getWithInstruction(II)))
return RemoveBundle();
// Fold the assume into metadata if it's valid at the load
if (auto *LI = dyn_cast<LoadInst>(Ptr);
LI &&
isValidAssumeForContext(II, LI, &DT, /*AllowEphemerals=*/true)) {
MDNode *MD = MDNode::get(II->getContext(), {});
LI->setMetadata(LLVMContext::MD_nonnull, MD);
LI->setMetadata(LLVMContext::MD_noundef, MD);
return RemoveBundle();
}
if (auto *GEP = dyn_cast<GEPOperator>(Ptr);
GEP && GEP->isInBounds() &&
!NullPointerIsDefined(II->getFunction(),
Ptr->getType()->getPointerAddressSpace())) {
Builder.CreateNonnullAssumption(GEP->stripInBoundsOffsets());
return RemoveBundle();
}
// TODO: apply nonnull return attributes to calls and invokes
break;
}
case BundleAttr::NoUndef: {
auto [Val] = getAssumeNoUndefInfo(OBU);
if (isGuaranteedNotToBeUndefOrPoison(Val, &AC, II, &DT))
return RemoveBundle();
if (auto *LI = dyn_cast<LoadInst>(Val);
LI &&
isValidAssumeForContext(II, LI, &DT, /*AllowEphemerals=*/true)) {
LI->setMetadata(LLVMContext::MD_noundef,
MDNode::get(II->getContext(), {}));
return RemoveBundle();
}
} break;
case BundleAttr::SeparateStorage: {
auto [Ptr1, Ptr2] = getAssumeSeparateStorageInfo(OBU);
// Separate storage assumptions apply to the underlying allocations, not
// any particular pointer within them. When evaluating the hints for AA
// purposes we getUnderlyingObject them; by precomputing the answers
// here we can avoid having to do so repeatedly there.
auto MaybeSimplifyHint = [&](const Use &U) {
Value *Hint = U.get();
// Not having a limit is safe because InstCombine removes unreachable
// code.
Value *UnderlyingObject = getUnderlyingObject(Hint, /*MaxLookup*/ 0);
if (Hint != UnderlyingObject)
replaceUse(const_cast<Use &>(U), UnderlyingObject);
};
MaybeSimplifyHint(Ptr1);
MaybeSimplifyHint(Ptr2);
} break;
// TODO: Drop these assumes when they are redundant
case BundleAttr::DereferenceableOrNull:
break;
// This cannot be simplified
case BundleAttr::Cold:
break;
}
}
// If the assume has operand bundles, the folds below will never work, so
// don't bother trying.
if (II->hasOperandBundles())
break;
Value *IIOperand = II->getArgOperand(0);
// Canonicalize assume(a && b) -> assume(a); assume(b);
// Note: New assumption intrinsics created here are registered by
// the InstCombineIRInserter object.
Value *A, *B;
if (match(IIOperand, m_LogicalAnd(m_Value(A), m_Value(B)))) {
Builder.CreateAssumption(A);
Builder.CreateAssumption(B);
return eraseInstFromFunction(*II);
}
// assume(!(a || b)) -> assume(!a); assume(!b);
if (match(IIOperand, m_Not(m_LogicalOr(m_Value(A), m_Value(B))))) {
Builder.CreateAssumption(Builder.CreateNot(A));
Builder.CreateAssumption(Builder.CreateNot(B));
return eraseInstFromFunction(*II);
}
// Convert nonnull assume like:
// %A = icmp ne i32* %PTR, null
// call void @llvm.assume(i1 %A)
// into
// call void @llvm.assume(i1 true) [ "nonnull"(i32* %PTR) ]
if (match(
IIOperand,
m_CombineOr(m_SpecificICmp(ICmpInst::ICMP_NE, m_Value(A), m_Zero()),
m_Not(m_SpecificICmp(ICmpInst::ICMP_EQ, m_Value(A),
m_Zero())))) &&
A->getType()->isPointerTy()) {
Builder.CreateNonnullAssumption(A);
return eraseInstFromFunction(*II);
}
// Convert alignment assume like:
// %B = ptrtoint ptr %A to i64
// %C = and i64 %B, Constant
// %D = icmp eq i64 %C, 0
// call void @llvm.assume(i1 %D)
// into
// call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 Constant + 1)]
uint64_t AlignMask = 1;
if ((match(IIOperand, m_Not(m_Trunc(m_Value(A)))) ||
match(IIOperand,
m_SpecificICmp(ICmpInst::ICMP_EQ,
m_And(m_Value(A), m_ConstantInt(AlignMask)),
m_Zero())))) {
if (isPowerOf2_64(AlignMask + 1) &&
match(A, m_PtrToIntOrAddr(m_Value(A)))) {
Builder.CreateAlignmentAssumption(getDataLayout(), A, AlignMask + 1);
return eraseInstFromFunction(*II);
}
}
// Remove assumes on true/false
if (auto *CI = dyn_cast<ConstantInt>(IIOperand);
CI || isa<UndefValue, PoisonValue>(IIOperand)) {
if (!CI || CI->isZero())
CreateNonTerminatorUnreachable(II);
return eraseInstFromFunction(*II);
}
// Update the cache of affected values for this assumption (we might be
// here because we just simplified the condition).
AC.updateAffectedValues(cast<AssumeInst>(II));
break;
}
case Intrinsic::experimental_guard: {
// Is this guard followed by another guard? We scan forward over a small
// fixed window of instructions to handle common cases with conditions
// computed between guards.
Instruction *NextInst = II->getNextNode();
for (unsigned i = 0; i < GuardWideningWindow; i++) {
// Note: Using context-free form to avoid compile time blow up
if (!isSafeToSpeculativelyExecute(NextInst))
break;
NextInst = NextInst->getNextNode();
}
Value *NextCond = nullptr;
if (match(NextInst,
m_Intrinsic<Intrinsic::experimental_guard>(m_Value(NextCond)))) {
Value *CurrCond = II->getArgOperand(0);
// Remove a guard that it is immediately preceded by an identical guard.
// Otherwise canonicalize guard(a); guard(b) -> guard(a & b).
if (CurrCond != NextCond) {
Instruction *MoveI = II->getNextNode();
while (MoveI != NextInst) {
auto *Temp = MoveI;
MoveI = MoveI->getNextNode();
Temp->moveBefore(II->getIterator());
}
replaceOperand(*II, 0, Builder.CreateAnd(CurrCond, NextCond));
}
eraseInstFromFunction(*NextInst);
return II;
}
break;
}
case Intrinsic::vector_insert: {
Value *Vec = II->getArgOperand(0);
Value *SubVec = II->getArgOperand(1);
Value *Idx = II->getArgOperand(2);
auto *DstTy = dyn_cast<FixedVectorType>(II->getType());
auto *VecTy = dyn_cast<FixedVectorType>(Vec->getType());
auto *SubVecTy = dyn_cast<FixedVectorType>(SubVec->getType());
// Only canonicalize if the destination vector, Vec, and SubVec are all
// fixed vectors.
if (DstTy && VecTy && SubVecTy) {
unsigned DstNumElts = DstTy->getNumElements();
unsigned VecNumElts = VecTy->getNumElements();
unsigned SubVecNumElts = SubVecTy->getNumElements();
unsigned IdxN = cast<ConstantInt>(Idx)->getZExtValue();
// An insert that entirely overwrites Vec with SubVec is a nop.
if (VecNumElts == SubVecNumElts)
return replaceInstUsesWith(CI, SubVec);
// Widen SubVec into a vector of the same width as Vec, since
// shufflevector requires the two input vectors to be the same width.
// Elements beyond the bounds of SubVec within the widened vector are
// undefined.
SmallVector<int, 8> WidenMask;
unsigned i;
for (i = 0; i != SubVecNumElts; ++i)
WidenMask.push_back(i);
for (; i != VecNumElts; ++i)
WidenMask.push_back(PoisonMaskElem);
Value *WidenShuffle = Builder.CreateShuffleVector(SubVec, WidenMask);
SmallVector<int, 8> Mask;
for (unsigned i = 0; i != IdxN; ++i)
Mask.push_back(i);
for (unsigned i = DstNumElts; i != DstNumElts + SubVecNumElts; ++i)
Mask.push_back(i);
for (unsigned i = IdxN + SubVecNumElts; i != DstNumElts; ++i)
Mask.push_back(i);
Value *Shuffle = Builder.CreateShuffleVector(Vec, WidenShuffle, Mask);
return replaceInstUsesWith(CI, Shuffle);
}
break;
}
case Intrinsic::vector_extract: {
Value *Vec = II->getArgOperand(0);
Value *Idx = II->getArgOperand(1);
Type *ReturnType = II->getType();
// (extract_vector (insert_vector InsertTuple, InsertValue, InsertIdx),
// ExtractIdx)
uint64_t ExtractIdx = cast<ConstantInt>(Idx)->getZExtValue();
Value *InsertTuple, *InsertIdx, *InsertValue;
if (match(Vec, m_Intrinsic<Intrinsic::vector_insert>(m_Value(InsertTuple),
m_Value(InsertValue),
m_Value(InsertIdx))) &&
InsertValue->getType() == ReturnType) {
uint64_t Index = cast<ConstantInt>(InsertIdx)->getZExtValue();
// Case where we get the same index right after setting it.
// extract.vector(insert.vector(InsertTuple, InsertValue, Idx), Idx) -->
// InsertValue
if (ExtractIdx == Index)
return replaceInstUsesWith(CI, InsertValue);
// If we are getting a different index than what was set in the
// insert.vector intrinsic. We can just set the input tuple to the one up
// in the chain. extract.vector(insert.vector(InsertTuple, InsertValue,
// InsertIndex), ExtractIndex)
// --> extract.vector(InsertTuple, ExtractIndex)
else
return replaceOperand(CI, 0, InsertTuple);
}
ConstantInt *ALMUpperBound;
if (match(Vec, m_Intrinsic<Intrinsic::get_active_lane_mask>(
m_Value(), m_ConstantInt(ALMUpperBound)))) {
const auto &Attrs = II->getFunction()->getAttributes().getFnAttrs();
unsigned VScaleMin = Attrs.getVScaleRangeMin();
unsigned ScaleFactor =
cast<VectorType>(ReturnType)->isScalableTy() ? VScaleMin : 1;
if (ExtractIdx * ScaleFactor >= ALMUpperBound->getZExtValue())
return replaceInstUsesWith(CI,
ConstantVector::getNullValue(ReturnType));
}
auto *DstTy = dyn_cast<VectorType>(ReturnType);
auto *VecTy = dyn_cast<VectorType>(Vec->getType());
if (DstTy && VecTy) {
auto DstEltCnt = DstTy->getElementCount();
auto VecEltCnt = VecTy->getElementCount();
unsigned IdxN = cast<ConstantInt>(Idx)->getZExtValue();
// Extracting the entirety of Vec is a nop.
if (DstEltCnt == VecTy->getElementCount()) {
replaceInstUsesWith(CI, Vec);
return eraseInstFromFunction(CI);
}
// Only canonicalize to shufflevector if the destination vector and
// Vec are fixed vectors.
if (VecEltCnt.isScalable() || DstEltCnt.isScalable())
break;
SmallVector<int, 8> Mask;
for (unsigned i = 0; i != DstEltCnt.getKnownMinValue(); ++i)
Mask.push_back(IdxN + i);
Value *Shuffle = Builder.CreateShuffleVector(Vec, Mask);
return replaceInstUsesWith(CI, Shuffle);
}
break;
}
case Intrinsic::experimental_vp_reverse: {
Value *X;
Value *Vec = II->getArgOperand(0);
Value *Mask = II->getArgOperand(1);
if (!match(Mask, m_AllOnes()))
break;
Value *EVL = II->getArgOperand(2);
// TODO: Canonicalize experimental.vp.reverse after unop/binops?
// rev(unop rev(X)) --> unop X
if (match(Vec,
m_OneUse(m_UnOp(m_Intrinsic<Intrinsic::experimental_vp_reverse>(
m_Value(X), m_AllOnes(), m_Specific(EVL)))))) {
auto *OldUnOp = cast<UnaryOperator>(Vec);
auto *NewUnOp = UnaryOperator::CreateWithCopiedFlags(
OldUnOp->getOpcode(), X, OldUnOp, OldUnOp->getName(),
II->getIterator());
return replaceInstUsesWith(CI, NewUnOp);
}
break;
}
case Intrinsic::vector_reduce_or:
case Intrinsic::vector_reduce_and: {
// Canonicalize logical or/and reductions:
// Or reduction for i1 is represented as:
// %val = bitcast <ReduxWidth x i1> to iReduxWidth
// %res = cmp ne iReduxWidth %val, 0
// And reduction for i1 is represented as:
// %val = bitcast <ReduxWidth x i1> to iReduxWidth
// %res = cmp eq iReduxWidth %val, 11111
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (Value *NewOp =
simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) {
replaceUse(II->getOperandUse(0), NewOp);
return II;
}
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = Builder.CreateBitCast(
Vect, Builder.getIntNTy(FTy->getNumElements()));
if (IID == Intrinsic::vector_reduce_and) {
Res = Builder.CreateICmpEQ(
Res, ConstantInt::getAllOnesValue(Res->getType()));
} else {
assert(IID == Intrinsic::vector_reduce_or &&
"Expected or reduction.");
Res = Builder.CreateIsNotNull(Res);
}
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());
return replaceInstUsesWith(CI, Res);
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_add: {
if (IID == Intrinsic::vector_reduce_add) {
// Convert vector_reduce_add(ZExt(<n x i1>)) to
// ZExtOrTrunc(ctpop(bitcast <n x i1> to in)).
// Convert vector_reduce_add(SExt(<n x i1>)) to
// -ZExtOrTrunc(ctpop(bitcast <n x i1> to in)).
// Convert vector_reduce_add(<n x i1>) to
// Trunc(ctpop(bitcast <n x i1> to in)).
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (Value *NewOp =
simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) {
replaceUse(II->getOperandUse(0), NewOp);
return II;
}
// vector.reduce.add.vNiM(splat(%x)) -> mul(%x, N)
if (Value *Splat = getSplatValue(Arg)) {
ElementCount VecToReduceCount =
cast<VectorType>(Arg->getType())->getElementCount();
if (VecToReduceCount.isFixed()) {
unsigned VectorSize = VecToReduceCount.getFixedValue();
return BinaryOperator::CreateMul(
Splat,
ConstantInt::get(Splat->getType(), VectorSize, /*IsSigned=*/false,
/*ImplicitTrunc=*/true));
}
}
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *V = Builder.CreateBitCast(
Vect, Builder.getIntNTy(FTy->getNumElements()));
Value *Res = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, V);
Res = Builder.CreateZExtOrTrunc(Res, II->getType());
if (Arg != Vect &&
cast<Instruction>(Arg)->getOpcode() == Instruction::SExt)
Res = Builder.CreateNeg(Res);
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_xor: {
if (IID == Intrinsic::vector_reduce_xor) {
// Exclusive disjunction reduction over the vector with
// (potentially-extended) i1 element type is actually a
// (potentially-extended) arithmetic `add` reduction over the original
// non-extended value:
// vector_reduce_xor(?ext(<n x i1>))
// -->
// ?ext(vector_reduce_add(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (Value *NewOp =
simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) {
replaceUse(II->getOperandUse(0), NewOp);
return II;
}
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *VTy = dyn_cast<VectorType>(Vect->getType()))
if (VTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = Builder.CreateAddReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_mul: {
if (IID == Intrinsic::vector_reduce_mul) {
Value *Arg = II->getArgOperand(0);
if (Value *NewOp =
simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) {
replaceUse(II->getOperandUse(0), NewOp);
return II;
}
// vector_reduce_mul(zext(<n x i1>)), or
// vector_reduce_mul(sext(<n x i1>)) (if n is even) -->
// zext(vector_reduce_and(<n x i1>)).
// (The sext case doesn't work if n is odd because multiplying an odd
// number of -1's produces -1, not 1.)
Value *Vect;
bool IsZext = match(Arg, m_ZExt(m_Value(Vect))) &&
Vect->getType()->isIntOrIntVectorTy(1);
bool IsSext =
match(Arg, m_SExt(m_Value(Vect))) &&
Vect->getType()->isIntOrIntVectorTy(1) &&
cast<VectorType>(Vect->getType())->getElementCount().isKnownEven();
if (IsZext || IsSext) {
Value *Res = Builder.CreateAndReduce(Vect);
return CastInst::Create(Instruction::ZExt, Res, II->getType());
}
// vector_reduce_mul(<n x i1>) --> vector_reduce_and(<n x i1>)
if (Arg->getType()->isIntOrIntVectorTy(1))
return replaceInstUsesWith(CI, Builder.CreateAndReduce(Arg));
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_umin:
case Intrinsic::vector_reduce_umax: {
if (IID == Intrinsic::vector_reduce_umin ||
IID == Intrinsic::vector_reduce_umax) {
// UMin/UMax reduction over the vector with (potentially-extended)
// i1 element type is actually a (potentially-extended)
// logical `and`/`or` reduction over the original non-extended value:
// vector_reduce_u{min,max}(?ext(<n x i1>))
// -->
// ?ext(vector_reduce_{and,or}(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (Value *NewOp =
simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) {
replaceUse(II->getOperandUse(0), NewOp);
return II;
}
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *VTy = dyn_cast<VectorType>(Vect->getType()))
if (VTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = IID == Intrinsic::vector_reduce_umin
? Builder.CreateAndReduce(Vect)
: Builder.CreateOrReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_smin:
case Intrinsic::vector_reduce_smax: {
if (IID == Intrinsic::vector_reduce_smin ||
IID == Intrinsic::vector_reduce_smax) {
// SMin/SMax reduction over the vector with (potentially-extended)
// i1 element type is actually a (potentially-extended)
// logical `and`/`or` reduction over the original non-extended value:
// vector_reduce_s{min,max}(<n x i1>)
// -->
// vector_reduce_{or,and}(<n x i1>)
// and
// vector_reduce_s{min,max}(sext(<n x i1>))
// -->
// sext(vector_reduce_{or,and}(<n x i1>))
// and
// vector_reduce_s{min,max}(zext(<n x i1>))
// -->
// zext(vector_reduce_{and,or}(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (Value *NewOp =
simplifyReductionOperand(Arg, /*CanReorderLanes=*/true)) {
replaceUse(II->getOperandUse(0), NewOp);
return II;
}
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *VTy = dyn_cast<VectorType>(Vect->getType()))
if (VTy->getElementType() == Builder.getInt1Ty()) {
Instruction::CastOps ExtOpc = Instruction::CastOps::CastOpsEnd;
if (Arg != Vect)
ExtOpc = cast<CastInst>(Arg)->getOpcode();
Value *Res = ((IID == Intrinsic::vector_reduce_smin) ==
(ExtOpc == Instruction::CastOps::ZExt))
? Builder.CreateAndReduce(Vect)
: Builder.CreateOrReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(ExtOpc, Res, II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_fmax:
case Intrinsic::vector_reduce_fmin:
case Intrinsic::vector_reduce_fadd:
case Intrinsic::vector_reduce_fmul: {
bool CanReorderLanes = (IID != Intrinsic::vector_reduce_fadd &&
IID != Intrinsic::vector_reduce_fmul) ||
II->hasAllowReassoc();
const unsigned ArgIdx = (IID == Intrinsic::vector_reduce_fadd ||
IID == Intrinsic::vector_reduce_fmul)
? 1
: 0;
Value *Arg = II->getArgOperand(ArgIdx);
if (Value *NewOp = simplifyReductionOperand(Arg, CanReorderLanes)) {
replaceUse(II->getOperandUse(ArgIdx), NewOp);
return nullptr;
}
break;
}
case Intrinsic::is_fpclass: {
if (Instruction *I = foldIntrinsicIsFPClass(*II))
return I;
break;
}
case Intrinsic::threadlocal_address: {
Align MinAlign = getKnownAlignment(II->getArgOperand(0), DL, II, &AC, &DT);
MaybeAlign Align = II->getRetAlign();
if (MinAlign > Align.valueOrOne()) {
II->addRetAttr(Attribute::getWithAlignment(II->getContext(), MinAlign));
return II;
}
break;
}
case Intrinsic::fptoui_sat:
case Intrinsic::fptosi_sat:
if (Instruction *I = foldItoFPtoI(*II))
return I;
break;
case Intrinsic::frexp: {
// frexp(frexp(x).fract) -> { frexp(x).fract, 0 }: the fraction operand is
// already normalized, so the first result is idempotent and the second is
// zero.
if (match(II->getArgOperand(0),
m_ExtractValue<0>(m_Intrinsic<Intrinsic::frexp>(m_Value())))) {
Value *Res = Builder.CreateInsertValue(PoisonValue::get(II->getType()),
II->getArgOperand(0), 0);
Res = Builder.CreateInsertValue(
Res, Constant::getNullValue(II->getType()->getStructElementType(1)),
1);
return replaceInstUsesWith(*II, Res);
}
break;
}
case Intrinsic::get_active_lane_mask: {
const APInt *Op0, *Op1;
if (match(II->getOperand(0), m_StrictlyPositive(Op0)) &&
match(II->getOperand(1), m_APInt(Op1))) {
Type *OpTy = II->getOperand(0)->getType();
return replaceInstUsesWith(
*II, Builder.CreateIntrinsic(
II->getType(), Intrinsic::get_active_lane_mask,
{Constant::getNullValue(OpTy),
ConstantInt::get(OpTy, Op1->usub_sat(*Op0))}));
}
break;
}
case Intrinsic::experimental_get_vector_length: {
// get.vector.length(Cnt, MaxLanes) --> Cnt when Cnt <= MaxLanes
unsigned BitWidth =
std::max(II->getArgOperand(0)->getType()->getScalarSizeInBits(),
II->getType()->getScalarSizeInBits());
ConstantRange Cnt =
computeConstantRangeIncludingKnownBits(II->getArgOperand(0), false,
SQ.getWithInstruction(II))
.zextOrTrunc(BitWidth);
ConstantRange MaxLanes = cast<ConstantInt>(II->getArgOperand(1))
->getValue()
.zextOrTrunc(Cnt.getBitWidth());
if (cast<ConstantInt>(II->getArgOperand(2))->isOne())
MaxLanes = MaxLanes.multiply(
getVScaleRange(II->getFunction(), Cnt.getBitWidth()));
if (Cnt.icmp(CmpInst::ICMP_ULE, MaxLanes))
return replaceInstUsesWith(
*II, Builder.CreateZExtOrTrunc(II->getArgOperand(0), II->getType()));
return nullptr;
}
default: {
// Handle target specific intrinsics
std::optional<Instruction *> V = targetInstCombineIntrinsic(*II);
if (V)
return *V;
break;
}
}
// Try to fold intrinsic into select/phi operands. This is legal if:
// * The intrinsic is speculatable.
// * The operand is one of the following:
// - a phi.
// - a select with a scalar condition.
// - a select with a vector condition and II is not a cross lane operation.
if (isSafeToSpeculativelyExecuteWithVariableReplaced(&CI)) {
for (Value *Op : II->args()) {
if (auto *Sel = dyn_cast<SelectInst>(Op)) {
bool IsVectorCond = Sel->getCondition()->getType()->isVectorTy();
if (IsVectorCond &&
(!isNotCrossLaneOperation(II) || !II->getType()->isVectorTy()))
continue;
// Don't replace a scalar select with a more expensive vector select if
// we can't simplify both arms of the select.
bool SimplifyBothArms =
!Op->getType()->isVectorTy() && II->getType()->isVectorTy();
if (Instruction *R = FoldOpIntoSelect(
*II, Sel, /*FoldWithMultiUse=*/false, SimplifyBothArms))
return R;
}
if (auto *Phi = dyn_cast<PHINode>(Op))
if (Instruction *R = foldOpIntoPhi(*II, Phi))
return R;
}
}
if (Instruction *Shuf = foldShuffledIntrinsicOperands(II))
return Shuf;
if (Value *Reverse = foldReversedIntrinsicOperands(II))
return replaceInstUsesWith(*II, Reverse);
if (Value *Res = foldIdempotentBinaryIntrinsicRecurrence(*this, II))
return replaceInstUsesWith(*II, Res);
// Some intrinsics (like experimental_gc_statepoint) can be used in invoke
// context, so it is handled in visitCallBase and we should trigger it.
return visitCallBase(*II);
}
// Fence instruction simplification
Instruction *InstCombinerImpl::visitFenceInst(FenceInst &FI) {
auto *NFI = dyn_cast<FenceInst>(FI.getNextNode());
// This check is solely here to handle arbitrary target-dependent syncscopes.
// TODO: Can remove if does not matter in practice.
if (NFI && FI.isIdenticalTo(NFI))
return eraseInstFromFunction(FI);
// Returns true if FI1 is identical or stronger fence than FI2.
auto isIdenticalOrStrongerFence = [](FenceInst *FI1, FenceInst *FI2) {
auto FI1SyncScope = FI1->getSyncScopeID();
// Consider same scope, where scope is global or single-thread.
if (FI1SyncScope != FI2->getSyncScopeID() ||
(FI1SyncScope != SyncScope::System &&
FI1SyncScope != SyncScope::SingleThread))
return false;
return isAtLeastOrStrongerThan(FI1->getOrdering(), FI2->getOrdering());
};
if (NFI && isIdenticalOrStrongerFence(NFI, &FI))
return eraseInstFromFunction(FI);
if (auto *PFI = dyn_cast_or_null<FenceInst>(FI.getPrevNode()))
if (isIdenticalOrStrongerFence(PFI, &FI))
return eraseInstFromFunction(FI);
return nullptr;
}
// InvokeInst simplification
Instruction *InstCombinerImpl::visitInvokeInst(InvokeInst &II) {
return visitCallBase(II);
}
// CallBrInst simplification
Instruction *InstCombinerImpl::visitCallBrInst(CallBrInst &CBI) {
return visitCallBase(CBI);
}
// A simple parser for format string specifiers for the purposes of the
// modular-format attribute. In the case of malformed format strings this might
// under or over report the specifiers present, but such cases are undefined
// behavior.
static Bitset<256> parseFormatStringSpecifiers(StringRef FormatStr) {
Bitset<256> Specifiers;
for (size_t I = 0; I < FormatStr.size(); ++I) {
if (FormatStr[I] != '%')
continue;
// Check for escaped '%'.
if (I + 1 < FormatStr.size() && FormatStr[I + 1] == '%') {
++I; // Skip the second '%'.
continue;
}
// Scan past allowed prefix characters.
size_t J =
FormatStr.find_first_not_of("0123456789-+ #0$.*'hlLjztqwvI", I + 1);
if (J == StringRef::npos)
break;
Specifiers.set(static_cast<unsigned char>(FormatStr[J]));
I = J; // Resume search from after the specifier.
}
return Specifiers;
}
static bool isAspectNeeded(StringRef Aspect, CallInst *CI,
std::optional<unsigned> FirstArgIdx,
const std::optional<Bitset<256>> &Specifiers) {
if (Aspect == "float") {
if (Specifiers) {
static constexpr Bitset<256> FloatSpecifiers{'f', 'F', 'e', 'E',
'g', 'G', 'a', 'A'};
return (*Specifiers & FloatSpecifiers).any();
}
// Fallback to type-based check for dynamic format string.
if (!FirstArgIdx)
return true;
return llvm::any_of(
llvm::make_range(std::next(CI->arg_begin(), *FirstArgIdx),
CI->arg_end()),
[](Value *V) { return V->getType()->isFloatingPointTy(); });
}
if (Aspect == "fixed") {
if (Specifiers) {
static constexpr Bitset<256> FixedSpecifiers{'r', 'R', 'k', 'K'};
return (*Specifiers & FixedSpecifiers).any();
}
// Fallback for fixed-point: assume needed if format is dynamic.
return true;
}
// Unknown aspects are always considered to be needed.
return true;
}
static void referenceAspect(StringRef Aspect, StringRef ImplName, Module *M,
IRBuilderBase &B) {
SmallString<20> Name = ImplName;
Name += '_';
Name += Aspect;
LLVMContext &Ctx = M->getContext();
Function *RelocNoneFn =
Intrinsic::getOrInsertDeclaration(M, Intrinsic::reloc_none);
B.CreateCall(RelocNoneFn,
{MetadataAsValue::get(Ctx, MDString::get(Ctx, Name))});
}
static Value *optimizeModularFormat(CallInst *CI, IRBuilderBase &B) {
if (!CI->hasFnAttr("modular-format"))
return nullptr;
SmallVector<StringRef> Args(
llvm::split(CI->getFnAttr("modular-format").getValueAsString(), ','));
if (Args.size() < 5)
return nullptr;
StringRef FormatIdxStr = Args[1];
StringRef FirstArgIdxStr = Args[2];
StringRef FnName = Args[3];
StringRef ImplName = Args[4];
ArrayRef<StringRef> AllAspects = ArrayRef<StringRef>(Args).drop_front(5);
unsigned FormatIdx;
std::optional<unsigned> FirstArgIdx;
[[maybe_unused]] bool Error;
Error = FormatIdxStr.getAsInteger(10, FormatIdx);
assert(!Error && "invalid format arg index");
--FormatIdx; // 1-based to 0-based
FirstArgIdx.emplace();
Error = FirstArgIdxStr.getAsInteger(10, *FirstArgIdx);
assert(!Error && "invalid first arg index");
if (*FirstArgIdx > 0)
--*FirstArgIdx; // 1-based to 0-based
else
FirstArgIdx.reset();
if (AllAspects.empty())
return nullptr;
Value *FormatVal = CI->getArgOperand(FormatIdx);
StringRef FormatStr;
std::optional<Bitset<256>> Specifiers;
if (getConstantStringInfo(FormatVal, FormatStr))
Specifiers = parseFormatStringSpecifiers(FormatStr);
SmallVector<StringRef> NeededAspects;
for (StringRef Aspect : AllAspects)
if (isAspectNeeded(Aspect, CI, FirstArgIdx, Specifiers))
NeededAspects.push_back(Aspect);
if (NeededAspects.size() == AllAspects.size())
return nullptr;
Module *M = CI->getModule();
LLVMContext &Ctx = M->getContext();
Function *Callee = CI->getCalledFunction();
FunctionCallee ModularFn = M->getOrInsertFunction(
FnName, Callee->getFunctionType(),
Callee->getAttributes().removeFnAttribute(Ctx, "modular-format"));
CallInst *New = cast<CallInst>(CI->clone());
New->setCalledFunction(ModularFn);
New->removeFnAttr("modular-format");
B.Insert(New);
llvm::sort(NeededAspects);
for (StringRef Request : NeededAspects)
referenceAspect(Request, ImplName, M, B);
return New;
}
Instruction *InstCombinerImpl::tryOptimizeCall(CallInst *CI) {
if (!CI->getCalledFunction()) return nullptr;
// Skip optimizing notail and musttail calls so
// LibCallSimplifier::optimizeCall doesn't have to preserve those invariants.
// LibCallSimplifier::optimizeCall should try to preserve tail calls though.
if (CI->isMustTailCall() || CI->isNoTailCall())
return nullptr;
auto InstCombineRAUW = [this](Instruction *From, Value *With) {
replaceInstUsesWith(*From, With);
};
auto InstCombineErase = [this](Instruction *I) {
eraseInstFromFunction(*I);
};
LibCallSimplifier Simplifier(DL, &TLI, &DT, &DC, &AC, ORE, BFI, PSI,
InstCombineRAUW, InstCombineErase);
if (Value *With = Simplifier.optimizeCall(CI, Builder)) {
++NumSimplified;
return CI->use_empty() ? CI : replaceInstUsesWith(*CI, With);
}
if (Value *With = optimizeModularFormat(CI, Builder)) {
++NumSimplified;
return CI->use_empty() ? CI : replaceInstUsesWith(*CI, With);
}
return nullptr;
}
static IntrinsicInst *findInitTrampolineFromAlloca(Value *TrampMem) {
// Strip off at most one level of pointer casts, looking for an alloca. This
// is good enough in practice and simpler than handling any number of casts.
Value *Underlying = TrampMem->stripPointerCasts();
if (Underlying != TrampMem &&
(!Underlying->hasOneUse() || Underlying->user_back() != TrampMem))
return nullptr;
if (!isa<AllocaInst>(Underlying))
return nullptr;
IntrinsicInst *InitTrampoline = nullptr;
for (User *U : TrampMem->users()) {
IntrinsicInst *II = dyn_cast<IntrinsicInst>(U);
if (!II)
return nullptr;
if (II->getIntrinsicID() == Intrinsic::init_trampoline) {
if (InitTrampoline)
// More than one init_trampoline writes to this value. Give up.
return nullptr;
InitTrampoline = II;
continue;
}
if (II->getIntrinsicID() == Intrinsic::adjust_trampoline)
// Allow any number of calls to adjust.trampoline.
continue;
return nullptr;
}
// No call to init.trampoline found.
if (!InitTrampoline)
return nullptr;
// Check that the alloca is being used in the expected way.
if (InitTrampoline->getOperand(0) != TrampMem)
return nullptr;
return InitTrampoline;
}
static IntrinsicInst *findInitTrampolineFromBB(IntrinsicInst *AdjustTramp,
Value *TrampMem) {
// Visit all the previous instructions in the basic block, and try to find a
// init.trampoline which has a direct path to the adjust.trampoline.
for (BasicBlock::iterator I = AdjustTramp->getIterator(),
E = AdjustTramp->getParent()->begin();
I != E;) {
Instruction *Inst = &*--I;
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
if (II->getIntrinsicID() == Intrinsic::init_trampoline &&
II->getOperand(0) == TrampMem)
return II;
if (Inst->mayWriteToMemory())
return nullptr;
}
return nullptr;
}
// Given a call to llvm.adjust.trampoline, find and return the corresponding
// call to llvm.init.trampoline if the call to the trampoline can be optimized
// to a direct call to a function. Otherwise return NULL.
static IntrinsicInst *findInitTrampoline(Value *Callee) {
Callee = Callee->stripPointerCasts();
IntrinsicInst *AdjustTramp = dyn_cast<IntrinsicInst>(Callee);
if (!AdjustTramp ||
AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline)
return nullptr;
Value *TrampMem = AdjustTramp->getOperand(0);
if (IntrinsicInst *IT = findInitTrampolineFromAlloca(TrampMem))
return IT;
if (IntrinsicInst *IT = findInitTrampolineFromBB(AdjustTramp, TrampMem))
return IT;
return nullptr;
}
Instruction *InstCombinerImpl::foldPtrAuthIntrinsicCallee(CallBase &Call) {
const Value *Callee = Call.getCalledOperand();
const auto *IPC = dyn_cast<IntToPtrInst>(Callee);
if (!IPC || !IPC->isNoopCast(DL))
return nullptr;
const auto *II = dyn_cast<IntrinsicInst>(IPC->getOperand(0));
if (!II)
return nullptr;
Intrinsic::ID IIID = II->getIntrinsicID();
if (IIID != Intrinsic::ptrauth_resign && IIID != Intrinsic::ptrauth_sign)
return nullptr;
// Isolate the ptrauth bundle from the others.
std::optional<OperandBundleUse> PtrAuthBundleOrNone;
SmallVector<OperandBundleDef, 2> NewBundles;
for (unsigned BI = 0, BE = Call.getNumOperandBundles(); BI != BE; ++BI) {
OperandBundleUse Bundle = Call.getOperandBundleAt(BI);
if (Bundle.getTagID() == LLVMContext::OB_ptrauth)
PtrAuthBundleOrNone = Bundle;
else
NewBundles.emplace_back(Bundle);
}
if (!PtrAuthBundleOrNone)
return nullptr;
Value *NewCallee = nullptr;
switch (IIID) {
// call(ptrauth.resign(p)), ["ptrauth"()] -> call p, ["ptrauth"()]
// assuming the call bundle and the sign operands match.
case Intrinsic::ptrauth_resign: {
// Resign result key should match bundle.
if (II->getOperand(3) != PtrAuthBundleOrNone->Inputs[0])
return nullptr;
// Resign result discriminator should match bundle.
if (II->getOperand(4) != PtrAuthBundleOrNone->Inputs[1])
return nullptr;
// Resign input (auth) key should also match: we can't change the key on
// the new call we're generating, because we don't know what keys are valid.
if (II->getOperand(1) != PtrAuthBundleOrNone->Inputs[0])
return nullptr;
Value *NewBundleOps[] = {II->getOperand(1), II->getOperand(2)};
NewBundles.emplace_back("ptrauth", NewBundleOps);
NewCallee = II->getOperand(0);
break;
}
// call(ptrauth.sign(p)), ["ptrauth"()] -> call p
// assuming the call bundle and the sign operands match.
// Non-ptrauth indirect calls are undesirable, but so is ptrauth.sign.
case Intrinsic::ptrauth_sign: {
// Sign key should match bundle.
if (II->getOperand(1) != PtrAuthBundleOrNone->Inputs[0])
return nullptr;
// Sign discriminator should match bundle.
if (II->getOperand(2) != PtrAuthBundleOrNone->Inputs[1])
return nullptr;
NewCallee = II->getOperand(0);
break;
}
default:
llvm_unreachable("unexpected intrinsic ID");
}
if (!NewCallee)
return nullptr;
NewCallee = Builder.CreateBitOrPointerCast(NewCallee, Callee->getType());
CallBase *NewCall = CallBase::Create(&Call, NewBundles);
NewCall->setCalledOperand(NewCallee);
return NewCall;
}
Instruction *InstCombinerImpl::foldPtrAuthConstantCallee(CallBase &Call) {
auto *CPA = dyn_cast<ConstantPtrAuth>(Call.getCalledOperand());
if (!CPA)
return nullptr;
auto *CalleeF = dyn_cast<Function>(CPA->getPointer());
// If the ptrauth constant isn't based on a function pointer, bail out.
if (!CalleeF)
return nullptr;
// Inspect the call ptrauth bundle to check it matches the ptrauth constant.
auto PAB = Call.getOperandBundle(LLVMContext::OB_ptrauth);
if (!PAB)
return nullptr;
auto *Key = cast<ConstantInt>(PAB->Inputs[0]);
Value *Discriminator = PAB->Inputs[1];
// If the bundle doesn't match, this is probably going to fail to auth.
if (!CPA->isKnownCompatibleWith(Key, Discriminator, DL))
return nullptr;
// If the bundle matches the constant, proceed in making this a direct call.
auto *NewCall = CallBase::removeOperandBundle(&Call, LLVMContext::OB_ptrauth);
NewCall->setCalledOperand(CalleeF);
return NewCall;
}
bool InstCombinerImpl::annotateAnyAllocSite(CallBase &Call,
const TargetLibraryInfo *TLI) {
// Note: We only handle cases which can't be driven from generic attributes
// here. So, for example, nonnull and noalias (which are common properties
// of some allocation functions) are expected to be handled via annotation
// of the respective allocator declaration with generic attributes.
bool Changed = false;
if (!Call.getType()->isPointerTy())
return Changed;
std::optional<APInt> Size = getAllocSize(&Call, TLI);
if (Size && *Size != 0) {
// TODO: We really should just emit deref_or_null here and then
// let the generic inference code combine that with nonnull.
if (Call.hasRetAttr(Attribute::NonNull)) {
Changed = !Call.hasRetAttr(Attribute::Dereferenceable);
Call.addRetAttr(Attribute::getWithDereferenceableBytes(
Call.getContext(), Size->getLimitedValue()));
} else {
Changed = !Call.hasRetAttr(Attribute::DereferenceableOrNull);
Call.addRetAttr(Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Size->getLimitedValue()));
}
}
// Add alignment attribute if alignment is a power of two constant.
Value *Alignment = getAllocAlignment(&Call, TLI);
if (!Alignment)
return Changed;
ConstantInt *AlignOpC = dyn_cast<ConstantInt>(Alignment);
if (AlignOpC && AlignOpC->getValue().ult(llvm::Value::MaximumAlignment)) {
uint64_t AlignmentVal = AlignOpC->getZExtValue();
if (llvm::isPowerOf2_64(AlignmentVal)) {
Align ExistingAlign = Call.getRetAlign().valueOrOne();
Align NewAlign = Align(AlignmentVal);
if (NewAlign > ExistingAlign) {
Call.addRetAttr(
Attribute::getWithAlignment(Call.getContext(), NewAlign));
Changed = true;
}
}
}
return Changed;
}
/// Improvements for call, callbr and invoke instructions.
Instruction *InstCombinerImpl::visitCallBase(CallBase &Call) {
bool Changed = annotateAnyAllocSite(Call, &TLI);
// Mark any parameters that are known to be non-null with the nonnull
// attribute. This is helpful for inlining calls to functions with null
// checks on their arguments.
SmallVector<unsigned, 4> ArgNos;
unsigned ArgNo = 0;
for (Value *V : Call.args()) {
if (V->getType()->isPointerTy()) {
// Simplify the nonnull operand if the parameter is known to be nonnull.
// Otherwise, try to infer nonnull for it.
bool HasDereferenceable = Call.getParamDereferenceableBytes(ArgNo) > 0;
if (Call.paramHasAttr(ArgNo, Attribute::NonNull) ||
(HasDereferenceable &&
!NullPointerIsDefined(Call.getFunction(),
V->getType()->getPointerAddressSpace()))) {
if (Value *Res = simplifyNonNullOperand(V, HasDereferenceable)) {
replaceOperand(Call, ArgNo, Res);
Changed = true;
}
} else if (isKnownNonZero(V,
getSimplifyQuery().getWithInstruction(&Call))) {
ArgNos.push_back(ArgNo);
}
}
ArgNo++;
}
assert(ArgNo == Call.arg_size() && "Call arguments not processed correctly.");
if (!ArgNos.empty()) {
AttributeList AS = Call.getAttributes();
LLVMContext &Ctx = Call.getContext();
AS = AS.addParamAttribute(Ctx, ArgNos,
Attribute::get(Ctx, Attribute::NonNull));
Call.setAttributes(AS);
Changed = true;
}
// If the callee is a pointer to a function, attempt to move any casts to the
// arguments of the call/callbr/invoke.
Value *Callee = Call.getCalledOperand();
Function *CalleeF = dyn_cast<Function>(Callee);
if ((!CalleeF || CalleeF->getFunctionType() != Call.getFunctionType()) &&
transformConstExprCastCall(Call))
return nullptr;
if (CalleeF) {
// Remove the convergent attr on calls when the callee is not convergent.
if (Call.isConvergent() && !CalleeF->isConvergent() &&
!CalleeF->isIntrinsic()) {
LLVM_DEBUG(dbgs() << "Removing convergent attr from instr " << Call
<< "\n");
Call.setNotConvergent();
return &Call;
}
// If the call and callee calling conventions don't match, and neither one
// of the calling conventions is compatible with C calling convention
// this call must be unreachable, as the call is undefined.
if ((CalleeF->getCallingConv() != Call.getCallingConv() &&
!(CalleeF->getCallingConv() == llvm::CallingConv::C &&
TargetLibraryInfoImpl::isCallingConvCCompatible(&Call)) &&
!(Call.getCallingConv() == llvm::CallingConv::C &&
TargetLibraryInfoImpl::isCallingConvCCompatible(CalleeF))) &&
// Only do this for calls to a function with a body. A prototype may
// not actually end up matching the implementation's calling conv for a
// variety of reasons (e.g. it may be written in assembly).
!CalleeF->isDeclaration()) {
Instruction *OldCall = &Call;
CreateNonTerminatorUnreachable(OldCall);
// If OldCall does not return void then replaceInstUsesWith poison.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!OldCall->getType()->isVoidTy())
replaceInstUsesWith(*OldCall, PoisonValue::get(OldCall->getType()));
if (isa<CallInst>(OldCall))
return eraseInstFromFunction(*OldCall);
// We cannot remove an invoke or a callbr, because it would change thexi
// CFG, just change the callee to a null pointer.
cast<CallBase>(OldCall)->setCalledFunction(
CalleeF->getFunctionType(),
Constant::getNullValue(CalleeF->getType()));
return nullptr;
}
}
// Calling a null function pointer is undefined if a null address isn't
// dereferenceable.
if ((isa<ConstantPointerNull>(Callee) &&
!NullPointerIsDefined(Call.getFunction())) ||
isa<UndefValue>(Callee)) {
// If Call does not return void then replaceInstUsesWith poison.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!Call.getType()->isVoidTy())
replaceInstUsesWith(Call, PoisonValue::get(Call.getType()));
if (Call.isTerminator()) {
// Can't remove an invoke or callbr because we cannot change the CFG.
return nullptr;
}
// This instruction is not reachable, just remove it.
CreateNonTerminatorUnreachable(&Call);
return eraseInstFromFunction(Call);
}
if (IntrinsicInst *II = findInitTrampoline(Callee))
return transformCallThroughTrampoline(Call, *II);
// Combine calls involving pointer authentication intrinsics.
if (Instruction *NewCall = foldPtrAuthIntrinsicCallee(Call))
return NewCall;
// Combine calls to ptrauth constants.
if (Instruction *NewCall = foldPtrAuthConstantCallee(Call))
return NewCall;
if (isa<InlineAsm>(Callee) && !Call.doesNotThrow()) {
InlineAsm *IA = cast<InlineAsm>(Callee);
if (!IA->canThrow()) {
// Normal inline asm calls cannot throw - mark them
// 'nounwind'.
Call.setDoesNotThrow();
Changed = true;
}
}
// Try to optimize the call if possible, we require DataLayout for most of
// this. None of these calls are seen as possibly dead so go ahead and
// delete the instruction now.
if (CallInst *CI = dyn_cast<CallInst>(&Call)) {
Instruction *I = tryOptimizeCall(CI);
// If we changed something return the result, etc. Otherwise let
// the fallthrough check.
if (I) return eraseInstFromFunction(*I);
}
if (!Call.use_empty() && !Call.isMustTailCall())
if (Value *ReturnedArg = Call.getReturnedArgOperand()) {
Type *CallTy = Call.getType();
Type *RetArgTy = ReturnedArg->getType();
if (RetArgTy->canLosslesslyBitCastTo(CallTy))
return replaceInstUsesWith(
Call, Builder.CreateBitOrPointerCast(ReturnedArg, CallTy));
}
// Drop unnecessary callee_type metadata from calls that were converted
// into direct calls.
if (Call.getMetadata(LLVMContext::MD_callee_type) && !Call.isIndirectCall()) {
Call.setMetadata(LLVMContext::MD_callee_type, nullptr);
Changed = true;
}
// Drop unnecessary kcfi operand bundles from calls that were converted
// into direct calls.
auto Bundle = Call.getOperandBundle(LLVMContext::OB_kcfi);
if (Bundle && !Call.isIndirectCall()) {
DEBUG_WITH_TYPE(DEBUG_TYPE "-kcfi", {
if (CalleeF) {
ConstantInt *FunctionType = nullptr;
ConstantInt *ExpectedType = cast<ConstantInt>(Bundle->Inputs[0]);
if (MDNode *MD = CalleeF->getMetadata(LLVMContext::MD_kcfi_type))
FunctionType = mdconst::extract<ConstantInt>(MD->getOperand(0));
if (FunctionType &&
FunctionType->getZExtValue() != ExpectedType->getZExtValue())
dbgs() << Call.getModule()->getName()
<< ": warning: kcfi: " << Call.getCaller()->getName()
<< ": call to " << CalleeF->getName()
<< " using a mismatching function pointer type\n";
}
});
return CallBase::removeOperandBundle(&Call, LLVMContext::OB_kcfi);
}
if (isRemovableAlloc(&Call, &TLI))
return visitAllocSite(Call);
// Handle intrinsics which can be used in both call and invoke context.
switch (Call.getIntrinsicID()) {
case Intrinsic::experimental_gc_statepoint: {
GCStatepointInst &GCSP = *cast<GCStatepointInst>(&Call);
SmallPtrSet<Value *, 32> LiveGcValues;
for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) {
GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc);
// Remove the relocation if unused.
if (GCR.use_empty()) {
eraseInstFromFunction(GCR);
continue;
}
Value *DerivedPtr = GCR.getDerivedPtr();
Value *BasePtr = GCR.getBasePtr();
// Undef is undef, even after relocation.
if (isa<UndefValue>(DerivedPtr) || isa<UndefValue>(BasePtr)) {
replaceInstUsesWith(GCR, UndefValue::get(GCR.getType()));
eraseInstFromFunction(GCR);
continue;
}
if (auto *PT = dyn_cast<PointerType>(GCR.getType())) {
// The relocation of null will be null for most any collector.
// TODO: provide a hook for this in GCStrategy. There might be some
// weird collector this property does not hold for.
if (isa<ConstantPointerNull>(DerivedPtr)) {
// Use null-pointer of gc_relocate's type to replace it.
replaceInstUsesWith(GCR, ConstantPointerNull::get(PT));
eraseInstFromFunction(GCR);
continue;
}
// isKnownNonNull -> nonnull attribute
if (!GCR.hasRetAttr(Attribute::NonNull) &&
isKnownNonZero(DerivedPtr,
getSimplifyQuery().getWithInstruction(&Call))) {
GCR.addRetAttr(Attribute::NonNull);
// We discovered new fact, re-check users.
Worklist.pushUsersToWorkList(GCR);
}
}
// If we have two copies of the same pointer in the statepoint argument
// list, canonicalize to one. This may let us common gc.relocates.
if (GCR.getBasePtr() == GCR.getDerivedPtr() &&
GCR.getBasePtrIndex() != GCR.getDerivedPtrIndex()) {
auto *OpIntTy = GCR.getOperand(2)->getType();
GCR.setOperand(2, ConstantInt::get(OpIntTy, GCR.getBasePtrIndex()));
}
// TODO: bitcast(relocate(p)) -> relocate(bitcast(p))
// Canonicalize on the type from the uses to the defs
// TODO: relocate((gep p, C, C2, ...)) -> gep(relocate(p), C, C2, ...)
LiveGcValues.insert(BasePtr);
LiveGcValues.insert(DerivedPtr);
}
std::optional<OperandBundleUse> Bundle =
GCSP.getOperandBundle(LLVMContext::OB_gc_live);
unsigned NumOfGCLives = LiveGcValues.size();
if (!Bundle || NumOfGCLives == Bundle->Inputs.size())
break;
// We can reduce the size of gc live bundle.
DenseMap<Value *, unsigned> Val2Idx;
std::vector<Value *> NewLiveGc;
for (Value *V : Bundle->Inputs) {
auto [It, Inserted] = Val2Idx.try_emplace(V);
if (!Inserted)
continue;
if (LiveGcValues.count(V)) {
It->second = NewLiveGc.size();
NewLiveGc.push_back(V);
} else
It->second = NumOfGCLives;
}
// Update all gc.relocates
for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) {
GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc);
Value *BasePtr = GCR.getBasePtr();
assert(Val2Idx.count(BasePtr) && Val2Idx[BasePtr] != NumOfGCLives &&
"Missed live gc for base pointer");
auto *OpIntTy1 = GCR.getOperand(1)->getType();
GCR.setOperand(1, ConstantInt::get(OpIntTy1, Val2Idx[BasePtr]));
Value *DerivedPtr = GCR.getDerivedPtr();
assert(Val2Idx.count(DerivedPtr) && Val2Idx[DerivedPtr] != NumOfGCLives &&
"Missed live gc for derived pointer");
auto *OpIntTy2 = GCR.getOperand(2)->getType();
GCR.setOperand(2, ConstantInt::get(OpIntTy2, Val2Idx[DerivedPtr]));
}
// Create new statepoint instruction.
OperandBundleDef NewBundle("gc-live", std::move(NewLiveGc));
return CallBase::Create(&Call, NewBundle);
}
default: { break; }
}
return Changed ? &Call : nullptr;
}
/// If the callee is a constexpr cast of a function, attempt to move the cast to
/// the arguments of the call/invoke.
/// CallBrInst is not supported.
bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) {
auto *Callee =
dyn_cast<Function>(Call.getCalledOperand()->stripPointerCasts());
if (!Callee)
return false;
assert(!isa<CallBrInst>(Call) &&
"CallBr's don't have a single point after a def to insert at");
// Don't perform the transform for declarations, which may not be fully
// accurate. For example, void @foo() is commonly used as a placeholder for
// unknown prototypes.
if (Callee->isDeclaration())
return false;
// If this is a call to a thunk function, don't remove the cast. Thunks are
// used to transparently forward all incoming parameters and outgoing return
// values, so it's important to leave the cast in place.
if (Callee->hasFnAttribute("thunk"))
return false;
// If this is a call to a naked function, the assembly might be
// using an argument, or otherwise rely on the frame layout,
// the function prototype will mismatch.
if (Callee->hasFnAttribute(Attribute::Naked))
return false;
// If this is a musttail call, the callee's prototype must match the caller's
// prototype with the exception of pointee types. The code below doesn't
// implement that, so we can't do this transform.
// TODO: Do the transform if it only requires adding pointer casts.
if (Call.isMustTailCall())
return false;
Instruction *Caller = &Call;
const AttributeList &CallerPAL = Call.getAttributes();
// Okay, this is a cast from a function to a different type. Unless doing so
// would cause a type conversion of one of our arguments, change this call to
// be a direct call with arguments casted to the appropriate types.
FunctionType *FT = Callee->getFunctionType();
Type *OldRetTy = Caller->getType();
Type *NewRetTy = FT->getReturnType();
// Check to see if we are changing the return type...
if (OldRetTy != NewRetTy) {
if (NewRetTy->isStructTy())
return false; // TODO: Handle multiple return values.
if (!CastInst::isBitOrNoopPointerCastable(NewRetTy, OldRetTy, DL)) {
if (!Caller->use_empty())
return false; // Cannot transform this return value.
}
if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs());
if (RAttrs.overlaps(AttributeFuncs::typeIncompatible(
NewRetTy, CallerPAL.getRetAttrs())))
return false; // Attribute not compatible with transformed value.
}
// If the callbase is an invoke instruction, and the return value is
// used by a PHI node in a successor, we cannot change the return type of
// the call because there is no place to put the cast instruction (without
// breaking the critical edge). Bail out in this case.
if (!Caller->use_empty()) {
BasicBlock *PhisNotSupportedBlock = nullptr;
if (auto *II = dyn_cast<InvokeInst>(Caller))
PhisNotSupportedBlock = II->getNormalDest();
if (PhisNotSupportedBlock)
for (User *U : Caller->users())
if (PHINode *PN = dyn_cast<PHINode>(U))
if (PN->getParent() == PhisNotSupportedBlock)
return false;
}
}
unsigned NumActualArgs = Call.arg_size();
unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
// Prevent us turning:
// declare void @takes_i32_inalloca(i32* inalloca)
// call void bitcast (void (i32*)* @takes_i32_inalloca to void (i32)*)(i32 0)
//
// into:
// call void @takes_i32_inalloca(i32* null)
//
// Similarly, avoid folding away bitcasts of byval calls.
if (Callee->getAttributes().hasAttrSomewhere(Attribute::InAlloca) ||
Callee->getAttributes().hasAttrSomewhere(Attribute::Preallocated))
return false;
auto AI = Call.arg_begin();
for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
Type *ParamTy = FT->getParamType(i);
Type *ActTy = (*AI)->getType();
if (!CastInst::isBitOrNoopPointerCastable(ActTy, ParamTy, DL))
return false; // Cannot transform this parameter value.
// Check if there are any incompatible attributes we cannot drop safely.
if (AttrBuilder(FT->getContext(), CallerPAL.getParamAttrs(i))
.overlaps(AttributeFuncs::typeIncompatible(
ParamTy, CallerPAL.getParamAttrs(i),
AttributeFuncs::ASK_UNSAFE_TO_DROP)))
return false; // Attribute not compatible with transformed value.
if (Call.isInAllocaArgument(i) ||
CallerPAL.hasParamAttr(i, Attribute::Preallocated))
return false; // Cannot transform to and from inalloca/preallocated.
if (CallerPAL.hasParamAttr(i, Attribute::SwiftError))
return false;
if (CallerPAL.hasParamAttr(i, Attribute::ByVal) !=
Callee->getAttributes().hasParamAttr(i, Attribute::ByVal))
return false; // Cannot transform to or from byval.
}
if (FT->getNumParams() < NumActualArgs && FT->isVarArg() &&
!CallerPAL.isEmpty()) {
// In this case we have more arguments than the new function type, but we
// won't be dropping them. Check that these extra arguments have attributes
// that are compatible with being a vararg call argument.
unsigned SRetIdx;
if (CallerPAL.hasAttrSomewhere(Attribute::StructRet, &SRetIdx) &&
SRetIdx - AttributeList::FirstArgIndex >= FT->getNumParams())
return false;
}
// Okay, we decided that this is a safe thing to do: go ahead and start
// inserting cast instructions as necessary.
SmallVector<Value *, 8> Args;
SmallVector<AttributeSet, 8> ArgAttrs;
Args.reserve(NumActualArgs);
ArgAttrs.reserve(NumActualArgs);
// Get any return attributes.
AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs());
// If the return value is not being used, the type may not be compatible
// with the existing attributes. Wipe out any problematic attributes.
RAttrs.remove(
AttributeFuncs::typeIncompatible(NewRetTy, CallerPAL.getRetAttrs()));
LLVMContext &Ctx = Call.getContext();
AI = Call.arg_begin();
for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
Type *ParamTy = FT->getParamType(i);
Value *NewArg = *AI;
if ((*AI)->getType() != ParamTy)
NewArg = Builder.CreateBitOrPointerCast(*AI, ParamTy);
Args.push_back(NewArg);
// Add any parameter attributes except the ones incompatible with the new
// type. Note that we made sure all incompatible ones are safe to drop.
AttributeMask IncompatibleAttrs = AttributeFuncs::typeIncompatible(
ParamTy, CallerPAL.getParamAttrs(i), AttributeFuncs::ASK_SAFE_TO_DROP);
ArgAttrs.push_back(
CallerPAL.getParamAttrs(i).removeAttributes(Ctx, IncompatibleAttrs));
}
// If the function takes more arguments than the call was taking, add them
// now.
for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) {
Args.push_back(Constant::getNullValue(FT->getParamType(i)));
ArgAttrs.push_back(AttributeSet());
}
// If we are removing arguments to the function, emit an obnoxious warning.
if (FT->getNumParams() < NumActualArgs) {
// TODO: if (!FT->isVarArg()) this call may be unreachable. PR14722
if (FT->isVarArg()) {
// Add all of the arguments in their promoted form to the arg list.
for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) {
Type *PTy = getPromotedType((*AI)->getType());
Value *NewArg = *AI;
if (PTy != (*AI)->getType()) {
// Must promote to pass through va_arg area!
Instruction::CastOps opcode =
CastInst::getCastOpcode(*AI, false, PTy, false);
NewArg = Builder.CreateCast(opcode, *AI, PTy);
}
Args.push_back(NewArg);
// Add any parameter attributes.
ArgAttrs.push_back(CallerPAL.getParamAttrs(i));
}
}
}
AttributeSet FnAttrs = CallerPAL.getFnAttrs();
if (NewRetTy->isVoidTy())
Caller->setName(""); // Void type should not have a name.
assert((ArgAttrs.size() == FT->getNumParams() || FT->isVarArg()) &&
"missing argument attributes");
AttributeList NewCallerPAL = AttributeList::get(
Ctx, FnAttrs, AttributeSet::get(Ctx, RAttrs), ArgAttrs);
SmallVector<OperandBundleDef, 1> OpBundles;
Call.getOperandBundlesAsDefs(OpBundles);
CallBase *NewCall;
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
NewCall = Builder.CreateInvoke(Callee, II->getNormalDest(),
II->getUnwindDest(), Args, OpBundles);
} else {
NewCall = Builder.CreateCall(Callee, Args, OpBundles);
cast<CallInst>(NewCall)->setTailCallKind(
cast<CallInst>(Caller)->getTailCallKind());
}
NewCall->takeName(Caller);
NewCall->setCallingConv(Call.getCallingConv());
NewCall->setAttributes(NewCallerPAL);
// Preserve prof metadata if any.
NewCall->copyMetadata(*Caller, {LLVMContext::MD_prof});
// Insert a cast of the return type as necessary.
Instruction *NC = NewCall;
Value *NV = NC;
if (OldRetTy != NV->getType() && !Caller->use_empty()) {
assert(!NV->getType()->isVoidTy());
NV = NC = CastInst::CreateBitOrPointerCast(NC, OldRetTy);
NC->setDebugLoc(Caller->getDebugLoc());
auto OptInsertPt = NewCall->getInsertionPointAfterDef();
assert(OptInsertPt && "No place to insert cast");
InsertNewInstBefore(NC, *OptInsertPt);
Worklist.pushUsersToWorkList(*Caller);
}
if (!Caller->use_empty())
replaceInstUsesWith(*Caller, NV);
else if (Caller->hasValueHandle()) {
if (OldRetTy == NV->getType())
ValueHandleBase::ValueIsRAUWd(Caller, NV);
else
// We cannot call ValueIsRAUWd with a different type, and the
// actual tracked value will disappear.
ValueHandleBase::ValueIsDeleted(Caller);
}
eraseInstFromFunction(*Caller);
return true;
}
/// Turn a call to a function created by init_trampoline / adjust_trampoline
/// intrinsic pair into a direct call to the underlying function.
Instruction *
InstCombinerImpl::transformCallThroughTrampoline(CallBase &Call,
IntrinsicInst &Tramp) {
FunctionType *FTy = Call.getFunctionType();
AttributeList Attrs = Call.getAttributes();
// If the call already has the 'nest' attribute somewhere then give up -
// otherwise 'nest' would occur twice after splicing in the chain.
if (Attrs.hasAttrSomewhere(Attribute::Nest))
return nullptr;
Function *NestF = cast<Function>(Tramp.getArgOperand(1)->stripPointerCasts());
FunctionType *NestFTy = NestF->getFunctionType();
AttributeList NestAttrs = NestF->getAttributes();
if (!NestAttrs.isEmpty()) {
unsigned NestArgNo = 0;
Type *NestTy = nullptr;
AttributeSet NestAttr;
// Look for a parameter marked with the 'nest' attribute.
for (FunctionType::param_iterator I = NestFTy->param_begin(),
E = NestFTy->param_end();
I != E; ++NestArgNo, ++I) {
AttributeSet AS = NestAttrs.getParamAttrs(NestArgNo);
if (AS.hasAttribute(Attribute::Nest)) {
// Record the parameter type and any other attributes.
NestTy = *I;
NestAttr = AS;
break;
}
}
if (NestTy) {
std::vector<Value*> NewArgs;
std::vector<AttributeSet> NewArgAttrs;
NewArgs.reserve(Call.arg_size() + 1);
NewArgAttrs.reserve(Call.arg_size());
// Insert the nest argument into the call argument list, which may
// mean appending it. Likewise for attributes.
{
unsigned ArgNo = 0;
auto I = Call.arg_begin(), E = Call.arg_end();
do {
if (ArgNo == NestArgNo) {
// Add the chain argument and attributes.
Value *NestVal = Tramp.getArgOperand(2);
if (NestVal->getType() != NestTy)
NestVal = Builder.CreateBitCast(NestVal, NestTy, "nest");
NewArgs.push_back(NestVal);
NewArgAttrs.push_back(NestAttr);
}
if (I == E)
break;
// Add the original argument and attributes.
NewArgs.push_back(*I);
NewArgAttrs.push_back(Attrs.getParamAttrs(ArgNo));
++ArgNo;
++I;
} while (true);
}
// The trampoline may have been bitcast to a bogus type (FTy).
// Handle this by synthesizing a new function type, equal to FTy
// with the chain parameter inserted.
std::vector<Type*> NewTypes;
NewTypes.reserve(FTy->getNumParams()+1);
// Insert the chain's type into the list of parameter types, which may
// mean appending it.
{
unsigned ArgNo = 0;
FunctionType::param_iterator I = FTy->param_begin(),
E = FTy->param_end();
do {
if (ArgNo == NestArgNo)
// Add the chain's type.
NewTypes.push_back(NestTy);
if (I == E)
break;
// Add the original type.
NewTypes.push_back(*I);
++ArgNo;
++I;
} while (true);
}
// Replace the trampoline call with a direct call. Let the generic
// code sort out any function type mismatches.
FunctionType *NewFTy =
FunctionType::get(FTy->getReturnType(), NewTypes, FTy->isVarArg());
AttributeList NewPAL =
AttributeList::get(FTy->getContext(), Attrs.getFnAttrs(),
Attrs.getRetAttrs(), NewArgAttrs);
SmallVector<OperandBundleDef, 1> OpBundles;
Call.getOperandBundlesAsDefs(OpBundles);
Instruction *NewCaller;
if (InvokeInst *II = dyn_cast<InvokeInst>(&Call)) {
NewCaller = InvokeInst::Create(NewFTy, NestF, II->getNormalDest(),
II->getUnwindDest(), NewArgs, OpBundles);
cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
cast<InvokeInst>(NewCaller)->setAttributes(NewPAL);
} else if (CallBrInst *CBI = dyn_cast<CallBrInst>(&Call)) {
NewCaller =
CallBrInst::Create(NewFTy, NestF, CBI->getDefaultDest(),
CBI->getIndirectDests(), NewArgs, OpBundles);
cast<CallBrInst>(NewCaller)->setCallingConv(CBI->getCallingConv());
cast<CallBrInst>(NewCaller)->setAttributes(NewPAL);
} else {
NewCaller = CallInst::Create(NewFTy, NestF, NewArgs, OpBundles);
cast<CallInst>(NewCaller)->setTailCallKind(
cast<CallInst>(Call).getTailCallKind());
cast<CallInst>(NewCaller)->setCallingConv(
cast<CallInst>(Call).getCallingConv());
cast<CallInst>(NewCaller)->setAttributes(NewPAL);
}
NewCaller->setDebugLoc(Call.getDebugLoc());
return NewCaller;
}
}
// Replace the trampoline call with a direct call. Since there is no 'nest'
// parameter, there is no need to adjust the argument list. Let the generic
// code sort out any function type mismatches.
Call.setCalledFunction(FTy, NestF);
return &Call;
}