Google Git
Sign in
llvm / llvm-project / llvm / 49a8cd29ed54c64b3b1fd80612508262a4a7b519 / . / lib / Transforms / InstCombine / InstCombineCalls.cpp
blob: 615f10e1de7f308fe99ce07b1773d4bc24eb026c [file] [log] [blame]
//===- 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/FloatingPointMode.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Twine.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/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.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/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/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/InstCombine/InstCombineWorklist.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 <cstring>
#include <utility>
#include <vector>
using namespace llvm;
using namespace PatternMatch;
#define DEBUG_TYPE "instcombine"
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"));
/// enable preservation of attributes in assume like:
/// call void @llvm.assume(i1 true) [ "nonnull"(i32* %PTR) ]
extern cl::opt<bool> EnableKnowledgeRetention;
/// 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;
}
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 (AA->pointsToConstantMemory(MI->getDest())) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength(Constant::getNullValue(MI->getLength()->getType()));
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 (isa<AtomicMemTransferInst>(MI))
if (*CopyDstAlign < Size || *CopySrcAlign < Size)
return nullptr;
// Use an integer load+store unless we can find something better.
unsigned SrcAddrSp =
cast<PointerType>(MI->getArgOperand(1)->getType())->getAddressSpace();
unsigned DstAddrSp =
cast<PointerType>(MI->getArgOperand(0)->getType())->getAddressSpace();
IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3);
Type *NewSrcPtrTy = PointerType::get(IntType, SrcAddrSp);
Type *NewDstPtrTy = PointerType::get(IntType, DstAddrSp);
// If the memcpy has metadata describing the members, see if we can get the
// TBAA tag describing our copy.
MDNode *CopyMD = nullptr;
if (MDNode *M = MI->getMetadata(LLVMContext::MD_tbaa)) {
CopyMD = M;
} else if (MDNode *M = MI->getMetadata(LLVMContext::MD_tbaa_struct)) {
if (M->getNumOperands() == 3 && M->getOperand(0) &&
mdconst::hasa<ConstantInt>(M->getOperand(0)) &&
mdconst::extract<ConstantInt>(M->getOperand(0))->isZero() &&
M->getOperand(1) &&
mdconst::hasa<ConstantInt>(M->getOperand(1)) &&
mdconst::extract<ConstantInt>(M->getOperand(1))->getValue() ==
Size &&
M->getOperand(2) && isa<MDNode>(M->getOperand(2)))
CopyMD = cast<MDNode>(M->getOperand(2));
}
Value *Src = Builder.CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy);
Value *Dest = Builder.CreateBitCast(MI->getArgOperand(0), NewDstPtrTy);
LoadInst *L = Builder.CreateLoad(IntType, Src);
// Alignment from the mem intrinsic will be better, so use it.
L->setAlignment(*CopySrcAlign);
if (CopyMD)
L->setMetadata(LLVMContext::MD_tbaa, CopyMD);
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);
if (CopyMD)
S->setMetadata(LLVMContext::MD_tbaa, CopyMD);
if (LoopMemParallelMD)
S->setMetadata(LLVMContext::MD_mem_parallel_loop_access, LoopMemParallelMD);
if (AccessGroupMD)
S->setMetadata(LLVMContext::MD_access_group, AccessGroupMD);
if (auto *MT = dyn_cast<MemTransferInst>(MI)) {
// non-atomics can be volatile
L->setVolatile(MT->isVolatile());
S->setVolatile(MT->isVolatile());
}
if (isa<AtomicMemTransferInst>(MI)) {
// 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(Constant::getNullValue(MemOpLength->getType()));
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 (AA->pointsToConstantMemory(MI->getDest())) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength(Constant::getNullValue(MI->getLength()->getType()));
return MI;
}
// Extract the length and alignment and fill if they are constant.
ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength());
ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue());
if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8))
return nullptr;
const uint64_t Len = LenC->getLimitedValue();
assert(Len && "0-sized memory setting should be removed already.");
const Align Alignment = assumeAligned(MI->getDestAlignment());
// 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 (isa<AtomicMemSetInst>(MI))
if (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)) {
Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8.
Value *Dest = MI->getDest();
unsigned DstAddrSp = cast<PointerType>(Dest->getType())->getAddressSpace();
Type *NewDstPtrTy = PointerType::get(ITy, DstAddrSp);
Dest = Builder.CreateBitCast(Dest, NewDstPtrTy);
// Extract the fill value and store.
uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
StoreInst *S = Builder.CreateStore(ConstantInt::get(ITy, Fill), Dest,
MI->isVolatile());
S->setAlignment(Alignment);
if (isa<AtomicMemSetInst>(MI))
S->setOrdering(AtomicOrdering::Unordered);
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength(Constant::getNullValue(LenC->getType()));
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 =
cast<ConstantInt>(II.getArgOperand(1))->getAlignValue();
// If the mask is all ones or undefs, this is a plain vector load of the 1st
// argument.
if (maskIsAllOneOrUndef(II.getArgOperand(2)))
return Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment,
"unmaskedload");
// If we can unconditionally load from this address, replace with a
// load/select idiom. TODO: use DT for context sensitive query
if (isDereferenceablePointer(LoadPtr, II.getType(),
II.getModule()->getDataLayout(), &II, nullptr)) {
Value *LI = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment,
"unmaskedload");
return Builder.CreateSelect(II.getArgOperand(2), LI, II.getArgOperand(3));
}
return nullptr;
}
// TODO, Obvious Missing Transforms:
// * Single constant active lane -> store
// * Narrow width by halfs excluding zero/undef lanes
Instruction *InstCombinerImpl::simplifyMaskedStore(IntrinsicInst &II) {
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(3));
if (!ConstMask)
return nullptr;
// If the mask is all zeros, this instruction does nothing.
if (ConstMask->isNullValue())
return eraseInstFromFunction(II);
// If the mask is all ones, this is a plain vector store of the 1st argument.
if (ConstMask->isAllOnesValue()) {
Value *StorePtr = II.getArgOperand(1);
Align Alignment = cast<ConstantInt>(II.getArgOperand(2))->getAlignValue();
return new StoreInst(II.getArgOperand(0), StorePtr, false, Alignment);
}
if (isa<ScalableVectorType>(ConstMask->getType()))
return nullptr;
// Use masked off lanes to simplify operands via SimplifyDemandedVectorElts
APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask);
APInt UndefElts(DemandedElts.getBitWidth(), 0);
if (Value *V =
SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts, UndefElts))
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 splat address w/known mask -> scalar load
// * Vector incrementing address -> vector masked load
Instruction *InstCombinerImpl::simplifyMaskedGather(IntrinsicInst &II) {
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 splat address w/known mask -> scalar store
// * Vector incrementing address -> vector masked store
Instruction *InstCombinerImpl::simplifyMaskedScatter(IntrinsicInst &II) {
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(3));
if (!ConstMask)
return nullptr;
// If the mask is all zeros, a scatter does nothing.
if (ConstMask->isNullValue())
return eraseInstFromFunction(II);
if (isa<ScalableVectorType>(ConstMask->getType()))
return nullptr;
// Use masked off lanes to simplify operands via SimplifyDemandedVectorElts
APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask);
APInt UndefElts(DemandedElts.getBitWidth(), 0);
if (Value *V =
SimplifyDemandedVectorElts(II.getOperand(0), DemandedElts, UndefElts))
return replaceOperand(II, 0, V);
if (Value *V =
SimplifyDemandedVectorElts(II.getOperand(1), DemandedElts, UndefElts))
return replaceOperand(II, 1, V);
return nullptr;
}
/// This function transforms launder.invariant.group and strip.invariant.group
/// like:
/// launder(launder(%x)) -> launder(%x) (the result is not the argument)
/// launder(strip(%x)) -> launder(%x)
/// strip(strip(%x)) -> strip(%x) (the result is not the argument)
/// strip(launder(%x)) -> strip(%x)
/// 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 &&
Intr->getIntrinsicID() != Intrinsic::strip_invariant_group)
break;
StrippedInvariantGroupsArg = Intr->getArgOperand(0)->stripPointerCasts();
}
if (StrippedArg == StrippedInvariantGroupsArg)
return nullptr; // No launders/strips to remove.
Value *Result = nullptr;
if (II.getIntrinsicID() == Intrinsic::launder_invariant_group)
Result = IC.Builder.CreateLaunderInvariantGroup(StrippedInvariantGroupsArg);
else if (II.getIntrinsicID() == Intrinsic::strip_invariant_group)
Result = IC.Builder.CreateStripInvariantGroup(StrippedInvariantGroupsArg);
else
llvm_unreachable(
"simplifyInvariantGroupIntrinsic only handles launder and strip");
if (Result->getType()->getPointerAddressSpace() !=
II.getType()->getPointerAddressSpace())
Result = IC.Builder.CreateAddrSpaceCast(Result, II.getType());
if (Result->getType() != II.getType())
Result = IC.Builder.CreateBitCast(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 *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::getDeclaration(II.getModule(), ID, II.getType());
return CallInst::Create(F, {X, II.getArgOperand(1)});
}
if (IsTZ) {
// cttz(-x) -> cttz(x)
if (match(Op0, m_Neg(m_Value(X))))
return IC.replaceOperand(II, 0, X);
// 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 IC.replaceOperand(II, 0, X);
if (match(Op0, m_Intrinsic<Intrinsic::abs>(m_Value(X))))
return IC.replaceOperand(II, 0, X);
}
KnownBits Known = IC.computeKnownBits(Op0, 0, &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 'ZeroIsUndef' parameter to 'true'
// because we know the zero behavior can't affect the result.
if (!Known.One.isNullValue() ||
isKnownNonZero(Op0, IC.getDataLayout(), 0, &IC.getAssumptionCache(), &II,
&IC.getDominatorTree())) {
if (!match(II.getArgOperand(1), m_One()))
return IC.replaceOperand(II, 1, IC.Builder.getTrue());
}
// Add range metadata since known bits can't completely reflect what we know.
// TODO: Handle splat vectors.
auto *IT = dyn_cast<IntegerType>(Op0->getType());
if (IT && IT->getBitWidth() != 1 && !II.getMetadata(LLVMContext::MD_range)) {
Metadata *LowAndHigh[] = {
ConstantAsMetadata::get(ConstantInt::get(IT, DefiniteZeros)),
ConstantAsMetadata::get(ConstantInt::get(IT, PossibleZeros + 1))};
II.setMetadata(LLVMContext::MD_range,
MDNode::get(II.getContext(), LowAndHigh));
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;
// 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 IC.replaceOperand(II, 0, X);
// ctpop(x | -x) -> bitwidth - cttz(x, false)
if (Op0->hasOneUse() &&
match(Op0, m_c_Or(m_Value(X), m_Neg(m_Deferred(X))))) {
Function *F =
Intrinsic::getDeclaration(II.getModule(), Intrinsic::cttz, Ty);
auto *Cttz = IC.Builder.CreateCall(F, {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::getDeclaration(II.getModule(), Intrinsic::cttz, Ty);
return CallInst::Create(F, {X, IC.Builder.getFalse()});
}
KnownBits Known(BitWidth);
IC.computeKnownBits(Op0, Known, 0, &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
if ((~Known.Zero).isPowerOf2())
return BinaryOperator::CreateLShr(
Op0, ConstantInt::get(Ty, (~Known.Zero).exactLogBase2()));
// FIXME: Try to simplify vectors of integers.
auto *IT = dyn_cast<IntegerType>(Ty);
if (!IT)
return nullptr;
// Add range metadata since known bits can't completely reflect what we know.
unsigned MinCount = Known.countMinPopulation();
unsigned MaxCount = Known.countMaxPopulation();
if (IT->getBitWidth() != 1 && !II.getMetadata(LLVMContext::MD_range)) {
Metadata *LowAndHigh[] = {
ConstantAsMetadata::get(ConstantInt::get(IT, MinCount)),
ConstantAsMetadata::get(ConstantInt::get(IT, MaxCount + 1))};
II.setMetadata(LLVMContext::MD_range,
MDNode::get(II.getContext(), LowAndHigh));
return &II;
}
return nullptr;
}
/// Convert a table lookup to shufflevector if the mask is constant.
/// This could benefit tbl1 if the mask is { 7,6,5,4,3,2,1,0 }, in
/// which case we could lower the shufflevector with rev64 instructions
/// as it's actually a byte reverse.
static Value *simplifyNeonTbl1(const IntrinsicInst &II,
InstCombiner::BuilderTy &Builder) {
// Bail out if the mask is not a constant.
auto *C = dyn_cast<Constant>(II.getArgOperand(1));
if (!C)
return nullptr;
auto *VecTy = cast<FixedVectorType>(II.getType());
unsigned NumElts = VecTy->getNumElements();
// Only perform this transformation for <8 x i8> vector types.
if (!VecTy->getElementType()->isIntegerTy(8) || NumElts != 8)
return nullptr;
int Indexes[8];
for (unsigned I = 0; I < NumElts; ++I) {
Constant *COp = C->getAggregateElement(I);
if (!COp || !isa<ConstantInt>(COp))
return nullptr;
Indexes[I] = cast<ConstantInt>(COp)->getLimitedValue();
// Make sure the mask indices are in range.
if ((unsigned)Indexes[I] >= NumElts)
return nullptr;
}
auto *V1 = II.getArgOperand(0);
auto *V2 = Constant::getNullValue(V1->getType());
return Builder.CreateShuffleVector(V1, V2, makeArrayRef(Indexes));
}
// 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.getNumArgOperands() >= NumOperands && "Not enough operands");
assert(E.getNumArgOperands() >= 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 (isa<DbgInfoIntrinsic>(I) ||
I->getIntrinsicID() == EndI.getIntrinsicID())
continue;
if (IsStart(*I)) {
if (haveSameOperands(EndI, *I, EndI.getNumArgOperands())) {
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, [](const IntrinsicInst &I) {
return I.getIntrinsicID() == Intrinsic::vastart ||
I.getIntrinsicID() == Intrinsic::vacopy;
});
return nullptr;
}
static CallInst *canonicalizeConstantArg0ToArg1(CallInst &Call) {
assert(Call.getNumArgOperands() > 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);
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[] = {UndefValue::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);
return nullptr;
}
static Optional<bool> getKnownSign(Value *Op, Instruction *CxtI,
const DataLayout &DL, AssumptionCache *AC,
DominatorTree *DT) {
KnownBits Known = computeKnownBits(Op, DL, 0, AC, CxtI, DT);
if (Known.isNonNegative())
return false;
if (Known.isNegative())
return true;
return isImpliedByDomCondition(
ICmpInst::ICMP_SLT, Op, Constant::getNullValue(Op->getType()), CxtI, DL);
}
/// 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())
if (Value *V = SimplifyCall(&CI, SQ.getWithInstruction(&CI)))
return replaceInstUsesWith(CI, V);
if (isFreeCall(&CI, &TLI))
return visitFree(CI);
// If the caller function 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);
// For atomic unordered mem intrinsics if len is not a positive or
// not a multiple of element size then behavior is undefined.
if (auto *AMI = dyn_cast<AtomicMemIntrinsic>(II))
if (ConstantInt *NumBytes = dyn_cast<ConstantInt>(AMI->getLength()))
if (NumBytes->getSExtValue() < 0 ||
(NumBytes->getZExtValue() % AMI->getElementSizeInBytes() != 0)) {
CreateNonTerminatorUnreachable(AMI);
assert(AMI->getType()->isVoidTy() &&
"non void atomic unordered mem intrinsic");
return eraseInstFromFunction(*AMI);
}
// Intrinsics cannot occur in an invoke or a callbr, so handle them here
// instead of in visitCallBase.
if (auto *MI = dyn_cast<AnyMemIntrinsic>(II)) {
bool Changed = false;
// memmove/cpy/set of zero bytes is a noop.
if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) {
if (NumBytes->isNullValue())
return eraseInstFromFunction(CI);
if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes))
if (CI->getZExtValue() == 1) {
// Replace the instruction with just byte operations. We would
// transform other cases to loads/stores, but we don't know if
// alignment is sufficient.
}
}
// No other transformations apply to volatile transfers.
if (auto *M = dyn_cast<MemIntrinsic>(MI))
if (M->isVolatile())
return nullptr;
// 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 =
isa<AtomicMemMoveInst>(MMI)
? 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::getDeclaration(M, MemCpyID, Tys));
Changed = true;
}
}
if (AnyMemTransferInst *MTI = dyn_cast<AnyMemTransferInst>(MI)) {
// memmove(x,x,size) -> noop.
if (MTI->getSource() == MTI->getDest())
return eraseInstFromFunction(CI);
}
// 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;
} else if (auto *MSI = dyn_cast<AnyMemSetInst>(MI)) {
if (Instruction *I = SimplifyAnyMemSet(MSI))
return I;
}
if (Changed) 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 UndefElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
if (Value *V = SimplifyDemandedVectorElts(II, AllOnesEltMask, UndefElts)) {
if (V != II)
return replaceInstUsesWith(*II, V);
return II;
}
}
if (II->isCommutative()) {
if (CallInst *NewCall = canonicalizeConstantArg0ToArg1(CI))
return NewCall;
}
Intrinsic::ID IID = II->getIntrinsicID();
switch (IID) {
case Intrinsic::objectsize:
if (Value *V = lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/false))
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)
// TODO: Copy nsw if it was present on the neg?
Value *X;
if (match(IIOperand, m_Neg(m_Value(X))))
return replaceOperand(*II, 0, X);
if (match(IIOperand, m_Select(m_Value(), m_Value(X), m_Neg(m_Deferred(X)))))
return replaceOperand(*II, 0, X);
if (match(IIOperand, m_Select(m_Value(), m_Neg(m_Value(X)), m_Deferred(X))))
return replaceOperand(*II, 0, X);
if (Optional<bool> Sign = getKnownSign(IIOperand, II, DL, &AC, &DT)) {
// abs(x) -> x if x >= 0
if (!*Sign)
return replaceInstUsesWith(*II, IIOperand);
// abs(x) -> -x if x < 0
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::umax:
case Intrinsic::umin: {
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()) {
Constant *NarrowC = ConstantExpr::getTrunc(C, X->getType());
if (ConstantExpr::getZExt(NarrowC, II->getType()) == C) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC);
return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType());
}
}
// If both operands of unsigned min/max are sign-extended, it is still ok
// to narrow the operation.
LLVM_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()) {
Constant *NarrowC = ConstantExpr::getTrunc(C, X->getType());
if (ConstantExpr::getSExt(NarrowC, II->getType()) == C) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, NarrowC);
return CastInst::Create(Instruction::SExt, NarrowMaxMin, II->getType());
}
}
if (match(I0, m_Not(m_Value(X)))) {
// max (not X), (not Y) --> not (min X, Y)
Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID);
if (match(I1, m_Not(m_Value(Y))) &&
(I0->hasOneUse() || I1->hasOneUse())) {
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, Y);
return BinaryOperator::CreateNot(InvMaxMin);
}
// max (not X), C --> not(min X, ~C)
if (match(I1, m_Constant(C)) && I0->hasOneUse()) {
Constant *NotC = ConstantExpr::getNot(C);
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, NotC);
return BinaryOperator::CreateNot(InvMaxMin);
}
}
// 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", /* NUW */ false, IntMinIsPoison);
return replaceInstUsesWith(CI, Abs);
}
break;
}
case Intrinsic::bswap: {
Value *IIOperand = II->getArgOperand(0);
Value *X = nullptr;
// bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) {
unsigned C = X->getType()->getScalarSizeInBits() -
IIOperand->getType()->getScalarSizeInBits();
Value *CV = ConstantInt::get(X->getType(), C);
Value *V = Builder.CreateLShr(X, CV);
return new TruncInst(V, IIOperand->getType());
}
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:
case Intrinsic::strip_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);
}
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)) &&
!ShAmtC->containsConstantExpression()) {
// Canonicalize a shift amount constant operand to modulo the bit-width.
Constant *WidthC = ConstantInt::get(Ty, BitWidth);
Constant *ModuloC = ConstantExpr::getURem(ShAmtC, WidthC);
if (ModuloC != ShAmtC)
return replaceOperand(*II, 2, ModuloC);
assert(ConstantExpr::getICmp(ICmpInst::ICMP_UGT, WidthC, ShAmtC) ==
ConstantInt::getTrue(CmpInst::makeCmpResultType(Ty)) &&
"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)
Constant *LeftShiftC = ConstantExpr::getSub(WidthC, ShAmtC);
Module *Mod = II->getModule();
Function *Fshl = Intrinsic::getDeclaration(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)
if (match(Op0, m_ZeroInt()) || match(Op0, m_Undef()))
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::getDeclaration(Mod, Intrinsic::bswap, Ty);
return CallInst::Create(Bswap, { Op0 });
}
}
// 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::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_NSWAdd(m_Value(X), m_APInt(C0)))
: match(Arg0, m_NUWAdd(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));
}
}
// ssub.sat(X, C) -> sadd.sat(X, -C) if C != MIN
Constant *C;
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::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::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::maximum:
Res = maximum(*C1, *C2);
break;
case Intrinsic::minimum:
Res = minimum(*C1, *C2);
break;
default:
llvm_unreachable("unexpected intrinsic ID");
}
Instruction *NewCall = Builder.CreateBinaryIntrinsic(
IID, X, ConstantFP::get(Arg0->getType(), Res), II);
// TODO: Conservatively intersecting FMF. If Res == C2, the transform
// was a simplification (so Arg0 and its original flags could
// propagate?)
NewCall->andIRFlags(M);
return replaceInstUsesWith(*II, NewCall);
}
}
Value *ExtSrc0;
Value *ExtSrc1;
// minnum (fpext x), (fpext y) -> minnum x, y
// maxnum (fpext x), (fpext y) -> maxnum x, y
if (match(II->getArgOperand(0), m_OneUse(m_FPExt(m_Value(ExtSrc0)))) &&
match(II->getArgOperand(1), m_OneUse(m_FPExt(m_Value(ExtSrc1)))) &&
ExtSrc0->getType() == ExtSrc1->getType()) {
Function *F = Intrinsic::getDeclaration(
II->getModule(), II->getIntrinsicID(), {ExtSrc0->getType()});
CallInst *NewCall = Builder.CreateCall(F, { ExtSrc0, ExtSrc1 });
NewCall->copyFastMathFlags(II);
NewCall->takeName(II);
return new FPExtInst(NewCall, II->getType());
}
break;
}
case Intrinsic::fmuladd: {
// Canonicalize fast fmuladd to the separate fmul + fadd.
if (II->isFast()) {
BuilderTy::FastMathFlagGuard Guard(Builder);
Builder.setFastMathFlags(II->getFastMathFlags());
Value *Mul = Builder.CreateFMul(II->getArgOperand(0),
II->getArgOperand(1));
Value *Add = Builder.CreateFAdd(Mul, II->getArgOperand(2));
Add->takeName(II);
return replaceInstUsesWith(*II, Add);
}
// Try to simplify the underlying FMul.
if (Value *V = SimplifyFMulInst(II->getArgOperand(0), II->getArgOperand(1),
II->getFastMathFlags(),
SQ.getWithInstruction(II))) {
auto *FAdd = BinaryOperator::CreateFAdd(V, II->getArgOperand(2));
FAdd->copyFastMathFlags(II);
return FAdd;
}
LLVM_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 *X, *Y;
if (match(Src0, m_FNeg(m_Value(X))) && match(Src1, m_FNeg(m_Value(Y)))) {
replaceOperand(*II, 0, X);
replaceOperand(*II, 1, Y);
return 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)))) {
replaceOperand(*II, 0, X);
replaceOperand(*II, 1, X);
return II;
}
// Try to simplify the underlying FMul. We can only apply simplifications
// that do not require rounding.
if (Value *V = SimplifyFMAFMul(II->getArgOperand(0), II->getArgOperand(1),
II->getFastMathFlags(),
SQ.getWithInstruction(II))) {
auto *FAdd = BinaryOperator::CreateFAdd(V, II->getArgOperand(2));
FAdd->copyFastMathFlags(II);
return FAdd;
}
// 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(II->getArgOperand(2), m_NegZeroFP()) ||
(match(II->getArgOperand(2), m_PosZeroFP()) &&
II->getFastMathFlags().noSignedZeros()))
return BinaryOperator::CreateFMulFMF(Src0, Src1, II);
break;
}
case Intrinsic::copysign: {
Value *Mag = II->getArgOperand(0), *Sign = II->getArgOperand(1);
if (SignBitMustBeZero(Sign, &TLI)) {
// If we know that the sign argument is positive, reduce to FABS:
// copysign Mag, +Sign --> fabs Mag
Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Mag, II);
return replaceInstUsesWith(*II, Fabs);
}
// TODO: There should be a ValueTracking sibling like SignBitMustBeOne.
const APFloat *C;
if (match(Sign, m_APFloat(C)) && C->isNegative()) {
// If we know that the sign argument is negative, reduce to FNABS:
// copysign Mag, -Sign --> fneg (fabs Mag)
Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, Mag, II);
return replaceInstUsesWith(*II, Builder.CreateFNegFMF(Fabs, II));
}
// 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))))
return replaceOperand(*II, 1, X);
// 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 replaceOperand(*II, 0, X);
break;
}
case Intrinsic::fabs: {
Value *Cond, *TVal, *FVal;
if (match(II->getArgOperand(0),
m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))) {
// fabs (select Cond, TrueC, FalseC) --> select Cond, AbsT, AbsF
if (isa<Constant>(TVal) && isa<Constant>(FVal)) {
CallInst *AbsT = Builder.CreateCall(II->getCalledFunction(), {TVal});
CallInst *AbsF = Builder.CreateCall(II->getCalledFunction(), {FVal});
return SelectInst::Create(Cond, AbsT, AbsF);
}
// fabs (select Cond, -FVal, FVal) --> fabs FVal
if (match(TVal, m_FNeg(m_Specific(FVal))))
return replaceOperand(*II, 0, FVal);
// fabs (select Cond, TVal, -TVal) --> fabs TVal
if (match(FVal, m_FNeg(m_Specific(TVal))))
return replaceOperand(*II, 0, TVal);
}
LLVM_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: {
Value *X;
Value *Src = II->getArgOperand(0);
if (match(Src, m_FNeg(m_Value(X))) || match(Src, m_FAbs(m_Value(X)))) {
// cos(-x) -> cos(x)
// cos(fabs(x)) -> cos(x)
return replaceOperand(*II, 0, X);
}
break;
}
case Intrinsic::sin: {
Value *X;
if (match(II->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X))))) {
// sin(-x) --> -sin(x)
Value *NewSin = Builder.CreateUnaryIntrinsic(Intrinsic::sin, X, II);
Instruction *FNeg = UnaryOperator::CreateFNeg(NewSin);
FNeg->copyFastMathFlags(II);
return FNeg;
}
break;
}
case Intrinsic::arm_neon_vtbl1:
case Intrinsic::aarch64_neon_tbl1:
if (Value *V = simplifyNeonTbl1(*II, Builder))
return replaceInstUsesWith(*II, V);
break;
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)) {
CV0 = ConstantExpr::getIntegerCast(CV0, NewVT, /*isSigned=*/!Zext);
CV1 = ConstantExpr::getIntegerCast(CV1, NewVT, /*isSigned=*/!Zext);
return replaceInstUsesWith(CI, ConstantExpr::getMul(CV0, CV1));
}
// 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: {
Value *DataArg = II->getArgOperand(0);
Value *KeyArg = II->getArgOperand(1);
// 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::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, 0, Op0).One.getZExtValue();
uint64_t Mask1 = computeKnownBits(Mask, 0, 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: {
// If the save is right next to the restore, 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) {
// Skip over debug info.
if (SS->getNextNonDebugInstruction() == II) {
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) {
if (isa<AllocaInst>(BI)) {
CannotRemove = true;
break;
}
if (CallInst *BCI = dyn_cast<CallInst>(BI)) {
if (auto *II2 = dyn_cast<IntrinsicInst>(BCI)) {
// If there is a stackrestore below this one, remove this one.
if (II2->getIntrinsicID() == Intrinsic::stackrestore)
return eraseInstFromFunction(CI);
// Bail if we cross over an intrinsic with side effects, such as
// llvm.stacksave, or llvm.read_register.
if (II2->mayHaveSideEffects()) {
CannotRemove = true;
break;
}
} else {
// If we found a non-intrinsic call, we can't remove the stack
// restore.
CannotRemove = true;
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))
break;
if (removeTriviallyEmptyRange(*II, *this, [](const IntrinsicInst &I) {
return I.getIntrinsicID() == Intrinsic::lifetime_start;
}))
return nullptr;
break;
case Intrinsic::assume: {
Value *IIOperand = II->getArgOperand(0);
SmallVector<OperandBundleDef, 4> OpBundles;
II->getOperandBundlesAsDefs(OpBundles);
/// This will remove the boolean Condition from the assume given as
/// argument and remove the assume if it becomes useless.
/// always returns nullptr for use as a return values.
auto RemoveConditionFromAssume = [&](Instruction *Assume) -> Instruction * {
assert(isa<AssumeInst>(Assume));
if (isAssumeWithEmptyBundle(*cast<AssumeInst>(II)))
return eraseInstFromFunction(CI);
replaceUse(II->getOperandUse(0), ConstantInt::getTrue(II->getContext()));
return nullptr;
};
// Remove an assume if it is followed by an identical assume.
// TODO: Do we need this? Unless there are conflicting assumptions, the
// computeKnownBits(IIOperand) below here eliminates redundant assumes.
Instruction *Next = II->getNextNonDebugInstruction();
if (match(Next, m_Intrinsic<Intrinsic::assume>(m_Specific(IIOperand))))
return RemoveConditionFromAssume(Next);
// Canonicalize assume(a && b) -> assume(a); assume(b);
// Note: New assumption intrinsics created here are registered by
// the InstCombineIRInserter object.
FunctionType *AssumeIntrinsicTy = II->getFunctionType();
Value *AssumeIntrinsic = II->getCalledOperand();
Value *A, *B;
if (match(IIOperand, m_LogicalAnd(m_Value(A), m_Value(B)))) {
Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, A, OpBundles,
II->getName());
Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic, B, II->getName());
return eraseInstFromFunction(*II);
}
// assume(!(a || b)) -> assume(!a); assume(!b);
if (match(IIOperand, m_Not(m_LogicalOr(m_Value(A), m_Value(B))))) {
Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic,
Builder.CreateNot(A), OpBundles, II->getName());
Builder.CreateCall(AssumeIntrinsicTy, AssumeIntrinsic,
Builder.CreateNot(B), II->getName());
return eraseInstFromFunction(*II);
}
// assume( (load addr) != null ) -> add 'nonnull' metadata to load
// (if assume is valid at the load)
CmpInst::Predicate Pred;
Instruction *LHS;
if (match(IIOperand, m_ICmp(Pred, m_Instruction(LHS), m_Zero())) &&
Pred == ICmpInst::ICMP_NE && LHS->getOpcode() == Instruction::Load &&
LHS->getType()->isPointerTy() &&
isValidAssumeForContext(II, LHS, &DT)) {
MDNode *MD = MDNode::get(II->getContext(), None);
LHS->setMetadata(LLVMContext::MD_nonnull, MD);
return RemoveConditionFromAssume(II);
// TODO: apply nonnull return attributes to calls and invokes
// TODO: apply range metadata for range check patterns?
}
// 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 (EnableKnowledgeRetention &&
match(IIOperand, m_Cmp(Pred, m_Value(A), m_Zero())) &&
Pred == CmpInst::ICMP_NE && A->getType()->isPointerTy()) {
if (auto *Replacement = buildAssumeFromKnowledge(
{RetainedKnowledge{Attribute::NonNull, 0, A}}, Next, &AC, &DT)) {
Replacement->insertBefore(Next);
AC.registerAssumption(Replacement);
return RemoveConditionFromAssume(II);
}
}
// Convert alignment assume like:
// %B = ptrtoint i32* %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"(i32* [[A]], i64 Constant + 1)]
uint64_t AlignMask;
if (EnableKnowledgeRetention &&
match(IIOperand,
m_Cmp(Pred, m_And(m_Value(A), m_ConstantInt(AlignMask)),
m_Zero())) &&
Pred == CmpInst::ICMP_EQ) {
if (isPowerOf2_64(AlignMask + 1)) {
uint64_t Offset = 0;
match(A, m_Add(m_Value(A), m_ConstantInt(Offset)));
if (match(A, m_PtrToInt(m_Value(A)))) {
/// Note: this doesn't preserve the offset information but merges
/// offset and alignment.
/// TODO: we can generate a GEP instead of merging the alignment with
/// the offset.
RetainedKnowledge RK{Attribute::Alignment,
(unsigned)MinAlign(Offset, AlignMask + 1), A};
if (auto *Replacement =
buildAssumeFromKnowledge(RK, Next, &AC, &DT)) {
Replacement->insertAfter(II);
AC.registerAssumption(Replacement);
}
return RemoveConditionFromAssume(II);
}
}
}
/// Canonicalize Knowledge in operand bundles.
if (EnableKnowledgeRetention && II->hasOperandBundles()) {
for (unsigned Idx = 0; Idx < II->getNumOperandBundles(); Idx++) {
auto &BOI = II->bundle_op_info_begin()[Idx];
RetainedKnowledge RK =
llvm::getKnowledgeFromBundle(cast<AssumeInst>(*II), BOI);
if (BOI.End - BOI.Begin > 2)
continue; // Prevent reducing knowledge in an align with offset since
// extracting a RetainedKnowledge form them looses offset
// information
RetainedKnowledge CanonRK =
llvm::simplifyRetainedKnowledge(cast<AssumeInst>(II), RK,
&getAssumptionCache(),
&getDominatorTree());
if (CanonRK == RK)
continue;
if (!CanonRK) {
if (BOI.End - BOI.Begin > 0) {
Worklist.pushValue(II->op_begin()[BOI.Begin]);
Value::dropDroppableUse(II->op_begin()[BOI.Begin]);
}
continue;
}
assert(RK.AttrKind == CanonRK.AttrKind);
if (BOI.End - BOI.Begin > 0)
II->op_begin()[BOI.Begin].set(CanonRK.WasOn);
if (BOI.End - BOI.Begin > 1)
II->op_begin()[BOI.Begin + 1].set(ConstantInt::get(
Type::getInt64Ty(II->getContext()), CanonRK.ArgValue));
if (RK.WasOn)
Worklist.pushValue(RK.WasOn);
return II;
}
}
// If there is a dominating assume with the same condition as this one,
// then this one is redundant, and should be removed.
KnownBits Known(1);
computeKnownBits(IIOperand, Known, 0, II);
if (Known.isAllOnes() && isAssumeWithEmptyBundle(cast<AssumeInst>(*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->getNextNonDebugInstruction();
for (unsigned i = 0; i < GuardWideningWindow; i++) {
// Note: Using context-free form to avoid compile time blow up
if (!isSafeToSpeculativelyExecute(NextInst))
break;
NextInst = NextInst->getNextNonDebugInstruction();
}
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->getNextNonDebugInstruction();
while (MoveI != NextInst) {
auto *Temp = MoveI;
MoveI = MoveI->getNextNonDebugInstruction();
Temp->moveBefore(II);
}
replaceOperand(*II, 0, Builder.CreateAnd(CurrCond, NextCond));
}
eraseInstFromFunction(*NextInst);
return II;
}
break;
}
case Intrinsic::experimental_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();
// The result of this call is undefined if IdxN is not a constant multiple
// of the SubVec's minimum vector length OR the insertion overruns Vec.
if (IdxN % SubVecNumElts != 0 || IdxN + SubVecNumElts > VecNumElts) {
replaceInstUsesWith(CI, UndefValue::get(CI.getType()));
return eraseInstFromFunction(CI);
}
// An insert that entirely overwrites Vec with SubVec is a nop.
if (VecNumElts == SubVecNumElts) {
replaceInstUsesWith(CI, SubVec);
return eraseInstFromFunction(CI);
}
// 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(UndefMaskElem);
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);
replaceInstUsesWith(CI, Shuffle);
return eraseInstFromFunction(CI);
}
break;
}
case Intrinsic::experimental_vector_extract: {
Value *Vec = II->getArgOperand(0);
Value *Idx = II->getArgOperand(1);
auto *DstTy = dyn_cast<FixedVectorType>(II->getType());
auto *VecTy = dyn_cast<FixedVectorType>(Vec->getType());
// Only canonicalize if the the destination vector and Vec are fixed
// vectors.
if (DstTy && VecTy) {
unsigned DstNumElts = DstTy->getNumElements();
unsigned VecNumElts = VecTy->getNumElements();
unsigned IdxN = cast<ConstantInt>(Idx)->getZExtValue();
// The result of this call is undefined if IdxN is not a constant multiple
// of the result type's minimum vector length OR the extraction overruns
// Vec.
if (IdxN % DstNumElts != 0 || IdxN + DstNumElts > VecNumElts) {
replaceInstUsesWith(CI, UndefValue::get(CI.getType()));
return eraseInstFromFunction(CI);
}
// Extracting the entirety of Vec is a nop.
if (VecNumElts == DstNumElts) {
replaceInstUsesWith(CI, Vec);
return eraseInstFromFunction(CI);
}
SmallVector<int, 8> Mask;
for (unsigned i = 0; i != DstNumElts; ++i)
Mask.push_back(IdxN + i);
Value *Shuffle =
Builder.CreateShuffleVector(Vec, UndefValue::get(VecTy), Mask);
replaceInstUsesWith(CI, Shuffle);
return eraseInstFromFunction(CI);
}
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);
Type *RetTy = II->getType();
if (RetTy == Builder.getInt1Ty())
if (auto *FVTy = dyn_cast<FixedVectorType>(Arg->getType())) {
Value *Res = Builder.CreateBitCast(
Arg, Builder.getIntNTy(FVTy->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);
}
replaceInstUsesWith(CI, Res);
return eraseInstFromFunction(CI);
}
break;
}
default: {
// Handle target specific intrinsics
Optional<Instruction *> V = targetInstCombineIntrinsic(*II);
if (V.hasValue())
return V.getValue();
break;
}
}
// 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) {
// Remove identical consecutive fences.
Instruction *Next = FI.getNextNonDebugInstruction();
if (auto *NFI = dyn_cast<FenceInst>(Next))
if (FI.isIdenticalTo(NFI))
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);
}
/// If this cast does not affect the value passed through the varargs area, we
/// can eliminate the use of the cast.
static bool isSafeToEliminateVarargsCast(const CallBase &Call,
const DataLayout &DL,
const CastInst *const CI,
const int ix) {
if (!CI->isLosslessCast())
return false;
// If this is a GC intrinsic, avoid munging types. We need types for
// statepoint reconstruction in SelectionDAG.
// TODO: This is probably something which should be expanded to all
// intrinsics since the entire point of intrinsics is that
// they are understandable by the optimizer.
if (isa<GCStatepointInst>(Call) || isa<GCRelocateInst>(Call) ||
isa<GCResultInst>(Call))
return false;
// The size of ByVal or InAlloca arguments is derived from the type, so we
// can't change to a type with a different size. If the size were
// passed explicitly we could avoid this check.
if (!Call.isPassPointeeByValueArgument(ix))
return true;
Type* SrcTy =
cast<PointerType>(CI->getOperand(0)->getType())->getElementType();
Type *DstTy = Call.isByValArgument(ix)
? Call.getParamByValType(ix)
: cast<PointerType>(CI->getType())->getElementType();
if (!SrcTy->isSized() || !DstTy->isSized())
return false;
if (DL.getTypeAllocSize(SrcTy) != DL.getTypeAllocSize(DstTy))
return false;
return true;
}
Instruction *InstCombinerImpl::tryOptimizeCall(CallInst *CI) {
if (!CI->getCalledFunction()) return nullptr;
auto InstCombineRAUW = [this](Instruction *From, Value *With) {
replaceInstUsesWith(*From, With);
};
auto InstCombineErase = [this](Instruction *I) {
eraseInstFromFunction(*I);
};
LibCallSimplifier Simplifier(DL, &TLI, ORE, BFI, PSI, InstCombineRAUW,
InstCombineErase);
if (Value *With = Simplifier.optimizeCall(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;
}
static void annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI) {
unsigned NumArgs = Call.getNumArgOperands();
ConstantInt *Op0C = dyn_cast<ConstantInt>(Call.getOperand(0));
ConstantInt *Op1C =
(NumArgs == 1) ? nullptr : dyn_cast<ConstantInt>(Call.getOperand(1));
// Bail out if the allocation size is zero (or an invalid alignment of zero
// with aligned_alloc).
if ((Op0C && Op0C->isNullValue()) || (Op1C && Op1C->isNullValue()))
return;
if (isMallocLikeFn(&Call, TLI) && Op0C) {
if (isOpNewLikeFn(&Call, TLI))
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithDereferenceableBytes(
Call.getContext(), Op0C->getZExtValue()));
else
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Op0C->getZExtValue()));
} else if (isAlignedAllocLikeFn(&Call, TLI) && Op1C) {
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Op1C->getZExtValue()));
// Add alignment attribute if alignment is a power of two constant.
if (Op0C && Op0C->getValue().ult(llvm::Value::MaximumAlignment)) {
uint64_t AlignmentVal = Op0C->getZExtValue();
if (llvm::isPowerOf2_64(AlignmentVal))
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithAlignment(Call.getContext(),
Align(AlignmentVal)));
}
} else if (isReallocLikeFn(&Call, TLI) && Op1C) {
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Op1C->getZExtValue()));
} else if (isCallocLikeFn(&Call, TLI) && Op0C && Op1C) {
bool Overflow;
const APInt &N = Op0C->getValue();
APInt Size = N.umul_ov(Op1C->getValue(), Overflow);
if (!Overflow)
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Size.getZExtValue()));
} else if (isStrdupLikeFn(&Call, TLI)) {
uint64_t Len = GetStringLength(Call.getOperand(0));
if (Len) {
// strdup
if (NumArgs == 1)
Call.addAttribute(AttributeList::ReturnIndex,
Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Len));
// strndup
else if (NumArgs == 2 && Op1C)
Call.addAttribute(
AttributeList::ReturnIndex,
Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), std::min(Len, Op1C->getZExtValue() + 1)));
}
}
}
/// Improvements for call, callbr and invoke instructions.
Instruction *InstCombinerImpl::visitCallBase(CallBase &Call) {
if (isAllocationFn(&Call, &TLI))
annotateAnyAllocSite(Call, &TLI);
bool Changed = false;
// 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() &&
!Call.paramHasAttr(ArgNo, Attribute::NonNull) &&
isKnownNonZero(V, DL, 0, &AC, &Call, &DT))
ArgNos.push_back(ArgNo);
ArgNo++;
}
assert(ArgNo == Call.arg_size() && "sanity check");
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();
if (!isa<Function>(Callee) && transformConstExprCastCall(Call))
return nullptr;
if (Function *CalleeF = dyn_cast<Function>(Callee)) {
// 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 undef.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!OldCall->getType()->isVoidTy())
replaceInstUsesWith(*OldCall, UndefValue::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;
}
}
if ((isa<ConstantPointerNull>(Callee) &&
!NullPointerIsDefined(Call.getFunction())) ||
isa<UndefValue>(Callee)) {
// If Call does not return void then replaceInstUsesWith undef.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!Call.getType()->isVoidTy())
replaceInstUsesWith(Call, UndefValue::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);
PointerType *PTy = cast<PointerType>(Callee->getType());
FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
if (FTy->isVarArg()) {
int ix = FTy->getNumParams();
// See if we can optimize any arguments passed through the varargs area of
// the call.
for (auto I = Call.arg_begin() + FTy->getNumParams(), E = Call.arg_end();
I != E; ++I, ++ix) {
CastInst *CI = dyn_cast<CastInst>(*I);
if (CI && isSafeToEliminateVarargsCast(Call, DL, CI, ix)) {
replaceUse(*I, CI->getOperand(0));
// Update the byval type to match the argument type.
if (Call.isByValArgument(ix)) {
Call.removeParamAttr(ix, Attribute::ByVal);
Call.addParamAttr(
ix, Attribute::getWithByValType(
Call.getContext(),
CI->getOperand(0)->getType()->getPointerElementType()));
}
Changed = true;
}
}
}
if (isa<InlineAsm>(Callee) && !Call.doesNotThrow()) {
// 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));
}
if (isAllocLikeFn(&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, DL, 0, &AC, &Call, &DT)) {
GCR.addAttribute(AttributeList::ReturnIndex, 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);
}
Optional<OperandBundleUse> Bundle =
GCSP.getOperandBundle(LLVMContext::OB_gc_live);
unsigned NumOfGCLives = LiveGcValues.size();
if (!Bundle.hasValue() || NumOfGCLives == Bundle->Inputs.size())
break;
// We can reduce the size of gc live bundle.
DenseMap<Value *, unsigned> Val2Idx;
std::vector<Value *> NewLiveGc;
for (unsigned I = 0, E = Bundle->Inputs.size(); I < E; ++I) {
Value *V = Bundle->Inputs[I];
if (Val2Idx.count(V))
continue;
if (LiveGcValues.count(V)) {
Val2Idx[V] = NewLiveGc.size();
NewLiveGc.push_back(V);
} else
Val2Idx[V] = 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", 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/callbr/invoke.
bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) {
auto *Callee =
dyn_cast<Function>(Call.getCalledOperand()->stripPointerCasts());
if (!Callee)
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 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 (Callee->isDeclaration())
return false; // Cannot transform this return value.
if (!Caller->use_empty() &&
// void -> non-void is handled specially
!NewRetTy->isVoidTy())
return false; // Cannot transform this return value.
}
if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
AttrBuilder RAttrs(CallerPAL, AttributeList::ReturnIndex);
if (RAttrs.overlaps(AttributeFuncs::typeIncompatible(NewRetTy)))
return false; // Attribute not compatible with transformed value.
}
// If the callbase is an invoke/callbr 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()) {
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller))
for (User *U : II->users())
if (PHINode *PN = dyn_cast<PHINode>(U))
if (PN->getParent() == II->getNormalDest() ||
PN->getParent() == II->getUnwindDest())
return false;
// FIXME: Be conservative for callbr to avoid a quadratic search.
if (isa<CallBrInst>(Caller))
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) ||
Callee->getAttributes().hasAttrSomewhere(Attribute::ByVal))
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.
if (AttrBuilder(CallerPAL.getParamAttributes(i))
.overlaps(AttributeFuncs::typeIncompatible(ParamTy)))
return false; // Attribute not compatible with transformed value.
if (Call.isInAllocaArgument(i))
return false; // Cannot transform to and from inalloca.
if (CallerPAL.hasParamAttribute(i, Attribute::SwiftError))
return false;
// If the parameter is passed as a byval argument, then we have to have a
// sized type and the sized type has to have the same size as the old type.
if (ParamTy != ActTy && CallerPAL.hasParamAttribute(i, Attribute::ByVal)) {
PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy);
if (!ParamPTy || !ParamPTy->getElementType()->isSized())
return false;
Type *CurElTy = Call.getParamByValType(i);
if (DL.getTypeAllocSize(CurElTy) !=
DL.getTypeAllocSize(ParamPTy->getElementType()))
return false;
}
}
if (Callee->isDeclaration()) {
// Do not delete arguments unless we have a function body.
if (FT->getNumParams() < NumActualArgs && !FT->isVarArg())
return false;
// If the callee is just a declaration, don't change the varargsness of the
// call. We don't want to introduce a varargs call where one doesn't
// already exist.
PointerType *APTy = cast<PointerType>(Call.getCalledOperand()->getType());
if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg())
return false;
// If both the callee and the cast type are varargs, we still have to make
// sure the number of fixed parameters are the same or we have the same
// ABI issues as if we introduce a varargs call.
if (FT->isVarArg() &&
cast<FunctionType>(APTy->getElementType())->isVarArg() &&
FT->getNumParams() !=
cast<FunctionType>(APTy->getElementType())->getNumParams())
return false;
}
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 > 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(CallerPAL, AttributeList::ReturnIndex);
// 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));
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.
if (CallerPAL.hasParamAttribute(i, Attribute::ByVal)) {
AttrBuilder AB(CallerPAL.getParamAttributes(i));
AB.addByValAttr(NewArg->getType()->getPointerElementType());
ArgAttrs.push_back(AttributeSet::get(Ctx, AB));
} else
ArgAttrs.push_back(CallerPAL.getParamAttributes(i));
}
// If the function takes more arguments than the call was taking, add them