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//===- llvm/CodeGen/GlobalISel/IRTranslator.cpp - IRTranslator ---*- C++ -*-==//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
/// \file
/// This file implements the IRTranslator class.
#include "llvm/CodeGen/GlobalISel/IRTranslator.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/GlobalISel/CSEInfo.h"
#include "llvm/CodeGen/GlobalISel/CSEMIRBuilder.h"
#include "llvm/CodeGen/GlobalISel/CallLowering.h"
#include "llvm/CodeGen/GlobalISel/GISelChangeObserver.h"
#include "llvm/CodeGen/GlobalISel/InlineAsmLowering.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/LowLevelType.h"
#include "llvm/CodeGen/LowLevelTypeUtils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RuntimeLibcalls.h"
#include "llvm/CodeGen/StackProtector.h"
#include "llvm/CodeGen/SwitchLoweringUtils.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.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/InitializePasses.h"
#include "llvm/MC/MCContext.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetIntrinsicInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/MemoryOpRemark.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <optional>
#include <string>
#include <utility>
#include <vector>
#define DEBUG_TYPE "irtranslator"
using namespace llvm;
static cl::opt<bool>
cl::desc("Should enable CSE in irtranslator"),
cl::Optional, cl::init(false));
char IRTranslator::ID = 0;
false, false)
false, false)
static void reportTranslationError(MachineFunction &MF,
const TargetPassConfig &TPC,
OptimizationRemarkEmitter &ORE,
OptimizationRemarkMissed &R) {
// Print the function name explicitly if we don't have a debug location (which
// makes the diagnostic less useful) or if we're going to emit a raw error.
if (!R.getLocation().isValid() || TPC.isGlobalISelAbortEnabled())
R << (" (in function: " + MF.getName() + ")").str();
if (TPC.isGlobalISelAbortEnabled())
IRTranslator::IRTranslator(CodeGenOpt::Level optlevel)
: MachineFunctionPass(ID), OptLevel(optlevel) {}
#ifndef NDEBUG
namespace {
/// Verify that every instruction created has the same DILocation as the
/// instruction being translated.
class DILocationVerifier : public GISelChangeObserver {
const Instruction *CurrInst = nullptr;
DILocationVerifier() = default;
~DILocationVerifier() = default;
const Instruction *getCurrentInst() const { return CurrInst; }
void setCurrentInst(const Instruction *Inst) { CurrInst = Inst; }
void erasingInstr(MachineInstr &MI) override {}
void changingInstr(MachineInstr &MI) override {}
void changedInstr(MachineInstr &MI) override {}
void createdInstr(MachineInstr &MI) override {
assert(getCurrentInst() && "Inserted instruction without a current MI");
// Only print the check message if we're actually checking it.
#ifndef NDEBUG
LLVM_DEBUG(dbgs() << "Checking DILocation from " << *CurrInst
<< " was copied to " << MI);
// We allow insts in the entry block to have no debug loc because
// they could have originated from constants, and we don't want a jumpy
// debug experience.
assert((CurrInst->getDebugLoc() == MI.getDebugLoc() ||
(MI.getParent()->isEntryBlock() && !MI.getDebugLoc())) &&
"Line info was not transferred to all instructions");
} // namespace
#endif // ifndef NDEBUG
void IRTranslator::getAnalysisUsage(AnalysisUsage &AU) const {
if (OptLevel != CodeGenOpt::None) {
IRTranslator::ValueToVRegInfo::VRegListT &
IRTranslator::allocateVRegs(const Value &Val) {
auto VRegsIt = VMap.findVRegs(Val);
if (VRegsIt != VMap.vregs_end())
return *VRegsIt->second;
auto *Regs = VMap.getVRegs(Val);
auto *Offsets = VMap.getOffsets(Val);
SmallVector<LLT, 4> SplitTys;
computeValueLLTs(*DL, *Val.getType(), SplitTys,
Offsets->empty() ? Offsets : nullptr);
for (unsigned i = 0; i < SplitTys.size(); ++i)
return *Regs;
ArrayRef<Register> IRTranslator::getOrCreateVRegs(const Value &Val) {
auto VRegsIt = VMap.findVRegs(Val);
if (VRegsIt != VMap.vregs_end())
return *VRegsIt->second;
if (Val.getType()->isVoidTy())
return *VMap.getVRegs(Val);
// Create entry for this type.
auto *VRegs = VMap.getVRegs(Val);
auto *Offsets = VMap.getOffsets(Val);
assert(Val.getType()->isSized() &&
"Don't know how to create an empty vreg");
SmallVector<LLT, 4> SplitTys;
computeValueLLTs(*DL, *Val.getType(), SplitTys,
Offsets->empty() ? Offsets : nullptr);
if (!isa<Constant>(Val)) {
for (auto Ty : SplitTys)
return *VRegs;
if (Val.getType()->isAggregateType()) {
// UndefValue, ConstantAggregateZero
auto &C = cast<Constant>(Val);
unsigned Idx = 0;
while (auto Elt = C.getAggregateElement(Idx++)) {
auto EltRegs = getOrCreateVRegs(*Elt);
llvm::copy(EltRegs, std::back_inserter(*VRegs));
} else {
assert(SplitTys.size() == 1 && "unexpectedly split LLT");
bool Success = translate(cast<Constant>(Val), VRegs->front());
if (!Success) {
OptimizationRemarkMissed R("gisel-irtranslator", "GISelFailure",
R << "unable to translate constant: " << ore::NV("Type", Val.getType());
reportTranslationError(*MF, *TPC, *ORE, R);
return *VRegs;
return *VRegs;
int IRTranslator::getOrCreateFrameIndex(const AllocaInst &AI) {
auto MapEntry = FrameIndices.find(&AI);
if (MapEntry != FrameIndices.end())
return MapEntry->second;
uint64_t ElementSize = DL->getTypeAllocSize(AI.getAllocatedType());
uint64_t Size =
ElementSize * cast<ConstantInt>(AI.getArraySize())->getZExtValue();
// Always allocate at least one byte.
Size = std::max<uint64_t>(Size, 1u);
int &FI = FrameIndices[&AI];
FI = MF->getFrameInfo().CreateStackObject(Size, AI.getAlign(), false, &AI);
return FI;
Align IRTranslator::getMemOpAlign(const Instruction &I) {
if (const StoreInst *SI = dyn_cast<StoreInst>(&I))
return SI->getAlign();
if (const LoadInst *LI = dyn_cast<LoadInst>(&I))
return LI->getAlign();
if (const AtomicCmpXchgInst *AI = dyn_cast<AtomicCmpXchgInst>(&I))
return AI->getAlign();
if (const AtomicRMWInst *AI = dyn_cast<AtomicRMWInst>(&I))
return AI->getAlign();
OptimizationRemarkMissed R("gisel-irtranslator", "", &I);
R << "unable to translate memop: " << ore::NV("Opcode", &I);
reportTranslationError(*MF, *TPC, *ORE, R);
return Align(1);
MachineBasicBlock &IRTranslator::getMBB(const BasicBlock &BB) {
MachineBasicBlock *&MBB = BBToMBB[&BB];
assert(MBB && "BasicBlock was not encountered before");
return *MBB;
void IRTranslator::addMachineCFGPred(CFGEdge Edge, MachineBasicBlock *NewPred) {
assert(NewPred && "new predecessor must be a real MachineBasicBlock");
bool IRTranslator::translateBinaryOp(unsigned Opcode, const User &U,
MachineIRBuilder &MIRBuilder) {
// Get or create a virtual register for each value.
// Unless the value is a Constant => loadimm cst?
// or inline constant each time?
// Creation of a virtual register needs to have a size.
Register Op0 = getOrCreateVReg(*U.getOperand(0));
Register Op1 = getOrCreateVReg(*U.getOperand(1));
Register Res = getOrCreateVReg(U);
uint32_t Flags = 0;
if (isa<Instruction>(U)) {
const Instruction &I = cast<Instruction>(U);
Flags = MachineInstr::copyFlagsFromInstruction(I);
MIRBuilder.buildInstr(Opcode, {Res}, {Op0, Op1}, Flags);
return true;
bool IRTranslator::translateUnaryOp(unsigned Opcode, const User &U,
MachineIRBuilder &MIRBuilder) {
Register Op0 = getOrCreateVReg(*U.getOperand(0));
Register Res = getOrCreateVReg(U);
uint32_t Flags = 0;
if (isa<Instruction>(U)) {
const Instruction &I = cast<Instruction>(U);
Flags = MachineInstr::copyFlagsFromInstruction(I);
MIRBuilder.buildInstr(Opcode, {Res}, {Op0}, Flags);
return true;
bool IRTranslator::translateFNeg(const User &U, MachineIRBuilder &MIRBuilder) {
return translateUnaryOp(TargetOpcode::G_FNEG, U, MIRBuilder);
bool IRTranslator::translateCompare(const User &U,
MachineIRBuilder &MIRBuilder) {
auto *CI = dyn_cast<CmpInst>(&U);
Register Op0 = getOrCreateVReg(*U.getOperand(0));
Register Op1 = getOrCreateVReg(*U.getOperand(1));
Register Res = getOrCreateVReg(U);
CmpInst::Predicate Pred =
CI ? CI->getPredicate() : static_cast<CmpInst::Predicate>(
if (CmpInst::isIntPredicate(Pred))
MIRBuilder.buildICmp(Pred, Res, Op0, Op1);
else if (Pred == CmpInst::FCMP_FALSE)
Res, getOrCreateVReg(*Constant::getNullValue(U.getType())));
else if (Pred == CmpInst::FCMP_TRUE)
Res, getOrCreateVReg(*Constant::getAllOnesValue(U.getType())));
else {
uint32_t Flags = 0;
if (CI)
Flags = MachineInstr::copyFlagsFromInstruction(*CI);
MIRBuilder.buildFCmp(Pred, Res, Op0, Op1, Flags);
return true;
bool IRTranslator::translateRet(const User &U, MachineIRBuilder &MIRBuilder) {
const ReturnInst &RI = cast<ReturnInst>(U);
const Value *Ret = RI.getReturnValue();
if (Ret && DL->getTypeStoreSize(Ret->getType()) == 0)
Ret = nullptr;
ArrayRef<Register> VRegs;
if (Ret)
VRegs = getOrCreateVRegs(*Ret);
Register SwiftErrorVReg = 0;
if (CLI->supportSwiftError() && SwiftError.getFunctionArg()) {
SwiftErrorVReg = SwiftError.getOrCreateVRegUseAt(
&RI, &MIRBuilder.getMBB(), SwiftError.getFunctionArg());
// The target may mess up with the insertion point, but
// this is not important as a return is the last instruction
// of the block anyway.
return CLI->lowerReturn(MIRBuilder, Ret, VRegs, FuncInfo, SwiftErrorVReg);
void IRTranslator::emitBranchForMergedCondition(
const Value *Cond, MachineBasicBlock *TBB, MachineBasicBlock *FBB,
MachineBasicBlock *CurBB, MachineBasicBlock *SwitchBB,
BranchProbability TProb, BranchProbability FProb, bool InvertCond) {
// If the leaf of the tree is a comparison, merge the condition into
// the caseblock.
if (const CmpInst *BOp = dyn_cast<CmpInst>(Cond)) {
CmpInst::Predicate Condition;
if (const ICmpInst *IC = dyn_cast<ICmpInst>(Cond)) {
Condition = InvertCond ? IC->getInversePredicate() : IC->getPredicate();
} else {
const FCmpInst *FC = cast<FCmpInst>(Cond);
Condition = InvertCond ? FC->getInversePredicate() : FC->getPredicate();
SwitchCG::CaseBlock CB(Condition, false, BOp->getOperand(0),
BOp->getOperand(1), nullptr, TBB, FBB, CurBB,
CurBuilder->getDebugLoc(), TProb, FProb);
// Create a CaseBlock record representing this branch.
CmpInst::Predicate Pred = InvertCond ? CmpInst::ICMP_NE : CmpInst::ICMP_EQ;
SwitchCG::CaseBlock CB(
Pred, false, Cond, ConstantInt::getTrue(MF->getFunction().getContext()),
nullptr, TBB, FBB, CurBB, CurBuilder->getDebugLoc(), TProb, FProb);
static bool isValInBlock(const Value *V, const BasicBlock *BB) {
if (const Instruction *I = dyn_cast<Instruction>(V))
return I->getParent() == BB;
return true;
void IRTranslator::findMergedConditions(
const Value *Cond, MachineBasicBlock *TBB, MachineBasicBlock *FBB,
MachineBasicBlock *CurBB, MachineBasicBlock *SwitchBB,
Instruction::BinaryOps Opc, BranchProbability TProb,
BranchProbability FProb, bool InvertCond) {
using namespace PatternMatch;
assert((Opc == Instruction::And || Opc == Instruction::Or) &&
"Expected Opc to be AND/OR");
// Skip over not part of the tree and remember to invert op and operands at
// next level.
Value *NotCond;
if (match(Cond, m_OneUse(m_Not(m_Value(NotCond)))) &&
isValInBlock(NotCond, CurBB->getBasicBlock())) {
findMergedConditions(NotCond, TBB, FBB, CurBB, SwitchBB, Opc, TProb, FProb,
const Instruction *BOp = dyn_cast<Instruction>(Cond);
const Value *BOpOp0, *BOpOp1;
// Compute the effective opcode for Cond, taking into account whether it needs
// to be inverted, e.g.
// and (not (or A, B)), C
// gets lowered as
// and (and (not A, not B), C)
Instruction::BinaryOps BOpc = (Instruction::BinaryOps)0;
if (BOp) {
BOpc = match(BOp, m_LogicalAnd(m_Value(BOpOp0), m_Value(BOpOp1)))
? Instruction::And
: (match(BOp, m_LogicalOr(m_Value(BOpOp0), m_Value(BOpOp1)))
? Instruction::Or
: (Instruction::BinaryOps)0);
if (InvertCond) {
if (BOpc == Instruction::And)
BOpc = Instruction::Or;
else if (BOpc == Instruction::Or)
BOpc = Instruction::And;
// If this node is not part of the or/and tree, emit it as a branch.
// Note that all nodes in the tree should have same opcode.
bool BOpIsInOrAndTree = BOpc && BOpc == Opc && BOp->hasOneUse();
if (!BOpIsInOrAndTree || BOp->getParent() != CurBB->getBasicBlock() ||
!isValInBlock(BOpOp0, CurBB->getBasicBlock()) ||
!isValInBlock(BOpOp1, CurBB->getBasicBlock())) {
emitBranchForMergedCondition(Cond, TBB, FBB, CurBB, SwitchBB, TProb, FProb,
// Create TmpBB after CurBB.
MachineFunction::iterator BBI(CurBB);
MachineBasicBlock *TmpBB =
CurBB->getParent()->insert(++BBI, TmpBB);
if (Opc == Instruction::Or) {
// Codegen X | Y as:
// BB1:
// jmp_if_X TBB
// jmp TmpBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
// We have flexibility in setting Prob for BB1 and Prob for TmpBB.
// The requirement is that
// TrueProb for BB1 + (FalseProb for BB1 * TrueProb for TmpBB)
// = TrueProb for original BB.
// Assuming the original probabilities are A and B, one choice is to set
// BB1's probabilities to A/2 and A/2+B, and set TmpBB's probabilities to
// A/(1+B) and 2B/(1+B). This choice assumes that
// TrueProb for BB1 == FalseProb for BB1 * TrueProb for TmpBB.
// Another choice is to assume TrueProb for BB1 equals to TrueProb for
// TmpBB, but the math is more complicated.
auto NewTrueProb = TProb / 2;
auto NewFalseProb = TProb / 2 + FProb;
// Emit the LHS condition.
findMergedConditions(BOpOp0, TBB, TmpBB, CurBB, SwitchBB, Opc, NewTrueProb,
NewFalseProb, InvertCond);
// Normalize A/2 and B to get A/(1+B) and 2B/(1+B).
SmallVector<BranchProbability, 2> Probs{TProb / 2, FProb};
BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end());
// Emit the RHS condition into TmpBB.
findMergedConditions(BOpOp1, TBB, FBB, TmpBB, SwitchBB, Opc, Probs[0],
Probs[1], InvertCond);
} else {
assert(Opc == Instruction::And && "Unknown merge op!");
// Codegen X & Y as:
// BB1:
// jmp_if_X TmpBB
// jmp FBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
// This requires creation of TmpBB after CurBB.
// We have flexibility in setting Prob for BB1 and Prob for TmpBB.
// The requirement is that
// FalseProb for BB1 + (TrueProb for BB1 * FalseProb for TmpBB)
// = FalseProb for original BB.
// Assuming the original probabilities are A and B, one choice is to set
// BB1's probabilities to A+B/2 and B/2, and set TmpBB's probabilities to
// 2A/(1+A) and B/(1+A). This choice assumes that FalseProb for BB1 ==
// TrueProb for BB1 * FalseProb for TmpBB.
auto NewTrueProb = TProb + FProb / 2;
auto NewFalseProb = FProb / 2;
// Emit the LHS condition.
findMergedConditions(BOpOp0, TmpBB, FBB, CurBB, SwitchBB, Opc, NewTrueProb,
NewFalseProb, InvertCond);
// Normalize A and B/2 to get 2A/(1+A) and B/(1+A).
SmallVector<BranchProbability, 2> Probs{TProb, FProb / 2};
BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end());
// Emit the RHS condition into TmpBB.
findMergedConditions(BOpOp1, TBB, FBB, TmpBB, SwitchBB, Opc, Probs[0],
Probs[1], InvertCond);
bool IRTranslator::shouldEmitAsBranches(
const std::vector<SwitchCG::CaseBlock> &Cases) {
// For multiple cases, it's better to emit as branches.
if (Cases.size() != 2)
return true;
// If this is two comparisons of the same values or'd or and'd together, they
// will get folded into a single comparison, so don't emit two blocks.
if ((Cases[0].CmpLHS == Cases[1].CmpLHS &&
Cases[0].CmpRHS == Cases[1].CmpRHS) ||
(Cases[0].CmpRHS == Cases[1].CmpLHS &&
Cases[0].CmpLHS == Cases[1].CmpRHS)) {
return false;
// Handle: (X != null) | (Y != null) --> (X|Y) != 0
// Handle: (X == null) & (Y == null) --> (X|Y) == 0
if (Cases[0].CmpRHS == Cases[1].CmpRHS &&
Cases[0].PredInfo.Pred == Cases[1].PredInfo.Pred &&
isa<Constant>(Cases[0].CmpRHS) &&
cast<Constant>(Cases[0].CmpRHS)->isNullValue()) {
if (Cases[0].PredInfo.Pred == CmpInst::ICMP_EQ &&
Cases[0].TrueBB == Cases[1].ThisBB)
return false;
if (Cases[0].PredInfo.Pred == CmpInst::ICMP_NE &&
Cases[0].FalseBB == Cases[1].ThisBB)
return false;
return true;
bool IRTranslator::translateBr(const User &U, MachineIRBuilder &MIRBuilder) {
const BranchInst &BrInst = cast<BranchInst>(U);
auto &CurMBB = MIRBuilder.getMBB();
auto *Succ0MBB = &getMBB(*BrInst.getSuccessor(0));
if (BrInst.isUnconditional()) {
// If the unconditional target is the layout successor, fallthrough.
if (OptLevel == CodeGenOpt::None || !CurMBB.isLayoutSuccessor(Succ0MBB))
// Link successors.
for (const BasicBlock *Succ : successors(&BrInst))
return true;
// If this condition is one of the special cases we handle, do special stuff
// now.
const Value *CondVal = BrInst.getCondition();
MachineBasicBlock *Succ1MBB = &getMBB(*BrInst.getSuccessor(1));
const auto &TLI = *MF->getSubtarget().getTargetLowering();
// If this is a series of conditions that are or'd or and'd together, emit
// this as a sequence of branches instead of setcc's with and/or operations.
// As long as jumps are not expensive (exceptions for multi-use logic ops,
// unpredictable branches, and vector extracts because those jumps are likely
// expensive for any target), this should improve performance.
// For example, instead of something like:
// cmp A, B
// C = seteq
// cmp D, E
// F = setle
// or C, F
// jnz foo
// Emit:
// cmp A, B
// je foo
// cmp D, E
// jle foo
using namespace PatternMatch;
const Instruction *CondI = dyn_cast<Instruction>(CondVal);
if (!TLI.isJumpExpensive() && CondI && CondI->hasOneUse() &&
!BrInst.hasMetadata(LLVMContext::MD_unpredictable)) {
Instruction::BinaryOps Opcode = (Instruction::BinaryOps)0;
Value *Vec;
const Value *BOp0, *BOp1;
if (match(CondI, m_LogicalAnd(m_Value(BOp0), m_Value(BOp1))))
Opcode = Instruction::And;
else if (match(CondI, m_LogicalOr(m_Value(BOp0), m_Value(BOp1))))
Opcode = Instruction::Or;
if (Opcode && !(match(BOp0, m_ExtractElt(m_Value(Vec), m_Value())) &&
match(BOp1, m_ExtractElt(m_Specific(Vec), m_Value())))) {
findMergedConditions(CondI, Succ0MBB, Succ1MBB, &CurMBB, &CurMBB, Opcode,
getEdgeProbability(&CurMBB, Succ0MBB),
getEdgeProbability(&CurMBB, Succ1MBB),
assert(SL->SwitchCases[0].ThisBB == &CurMBB && "Unexpected lowering!");
// Allow some cases to be rejected.
if (shouldEmitAsBranches(SL->SwitchCases)) {
// Emit the branch for this block.
emitSwitchCase(SL->SwitchCases[0], &CurMBB, *CurBuilder);
return true;
// Okay, we decided not to do this, remove any inserted MBB's and clear
// SwitchCases.
for (unsigned I = 1, E = SL->SwitchCases.size(); I != E; ++I)
// Create a CaseBlock record representing this branch.
SwitchCG::CaseBlock CB(CmpInst::ICMP_EQ, false, CondVal,
nullptr, Succ0MBB, Succ1MBB, &CurMBB,
// Use emitSwitchCase to actually insert the fast branch sequence for this
// cond branch.
emitSwitchCase(CB, &CurMBB, *CurBuilder);
return true;
void IRTranslator::addSuccessorWithProb(MachineBasicBlock *Src,
MachineBasicBlock *Dst,
BranchProbability Prob) {
if (!FuncInfo.BPI) {
if (Prob.isUnknown())
Prob = getEdgeProbability(Src, Dst);
Src->addSuccessor(Dst, Prob);
IRTranslator::getEdgeProbability(const MachineBasicBlock *Src,
const MachineBasicBlock *Dst) const {
const BasicBlock *SrcBB = Src->getBasicBlock();
const BasicBlock *DstBB = Dst->getBasicBlock();
if (!FuncInfo.BPI) {
// If BPI is not available, set the default probability as 1 / N, where N is
// the number of successors.
auto SuccSize = std::max<uint32_t>(succ_size(SrcBB), 1);
return BranchProbability(1, SuccSize);
return FuncInfo.BPI->getEdgeProbability(SrcBB, DstBB);
bool IRTranslator::translateSwitch(const User &U, MachineIRBuilder &MIB) {
using namespace SwitchCG;
// Extract cases from the switch.
const SwitchInst &SI = cast<SwitchInst>(U);
BranchProbabilityInfo *BPI = FuncInfo.BPI;
CaseClusterVector Clusters;
for (const auto &I : SI.cases()) {
MachineBasicBlock *Succ = &getMBB(*I.getCaseSuccessor());
assert(Succ && "Could not find successor mbb in mapping");
const ConstantInt *CaseVal = I.getCaseValue();
BranchProbability Prob =
BPI ? BPI->getEdgeProbability(SI.getParent(), I.getSuccessorIndex())
: BranchProbability(1, SI.getNumCases() + 1);
Clusters.push_back(CaseCluster::range(CaseVal, CaseVal, Succ, Prob));
MachineBasicBlock *DefaultMBB = &getMBB(*SI.getDefaultDest());
// Cluster adjacent cases with the same destination. We do this at all
// optimization levels because it's cheap to do and will make codegen faster
// if there are many clusters.
MachineBasicBlock *SwitchMBB = &getMBB(*SI.getParent());
// If there is only the default destination, jump there directly.
if (Clusters.empty()) {
if (DefaultMBB != SwitchMBB->getNextNode())
return true;
SL->findJumpTables(Clusters, &SI, DefaultMBB, nullptr, nullptr);
SL->findBitTestClusters(Clusters, &SI);
dbgs() << "Case clusters: ";
for (const CaseCluster &C : Clusters) {
if (C.Kind == CC_JumpTable)
dbgs() << "JT:";
if (C.Kind == CC_BitTests)
dbgs() << "BT:";
C.Low->getValue().print(dbgs(), true);
if (C.Low != C.High) {
dbgs() << '-';
C.High->getValue().print(dbgs(), true);
dbgs() << ' ';
dbgs() << '\n';
SwitchWorkList WorkList;
CaseClusterIt First = Clusters.begin();
CaseClusterIt Last = Clusters.end() - 1;
auto DefaultProb = getEdgeProbability(SwitchMBB, DefaultMBB);
WorkList.push_back({SwitchMBB, First, Last, nullptr, nullptr, DefaultProb});
// FIXME: At the moment we don't do any splitting optimizations here like
// SelectionDAG does, so this worklist only has one entry.
while (!WorkList.empty()) {
SwitchWorkListItem W = WorkList.pop_back_val();
if (!lowerSwitchWorkItem(W, SI.getCondition(), SwitchMBB, DefaultMBB, MIB))
return false;
return true;
void IRTranslator::emitJumpTable(SwitchCG::JumpTable &JT,
MachineBasicBlock *MBB) {
// Emit the code for the jump table
assert(JT.Reg != -1U && "Should lower JT Header first!");
MachineIRBuilder MIB(*MBB->getParent());
Type *PtrIRTy = Type::getInt8PtrTy(MF->getFunction().getContext());
const LLT PtrTy = getLLTForType(*PtrIRTy, *DL);
auto Table = MIB.buildJumpTable(PtrTy, JT.JTI);
MIB.buildBrJT(Table.getReg(0), JT.JTI, JT.Reg);
bool IRTranslator::emitJumpTableHeader(SwitchCG::JumpTable &JT,
SwitchCG::JumpTableHeader &JTH,
MachineBasicBlock *HeaderBB) {
MachineIRBuilder MIB(*HeaderBB->getParent());
const Value &SValue = *JTH.SValue;
// Subtract the lowest switch case value from the value being switched on.
const LLT SwitchTy = getLLTForType(*SValue.getType(), *DL);
Register SwitchOpReg = getOrCreateVReg(SValue);
auto FirstCst = MIB.buildConstant(SwitchTy, JTH.First);
auto Sub = MIB.buildSub({SwitchTy}, SwitchOpReg, FirstCst);
// This value may be smaller or larger than the target's pointer type, and
// therefore require extension or truncating.
Type *PtrIRTy = SValue.getType()->getPointerTo();
const LLT PtrScalarTy = LLT::scalar(DL->getTypeSizeInBits(PtrIRTy));
Sub = MIB.buildZExtOrTrunc(PtrScalarTy, Sub);
JT.Reg = Sub.getReg(0);
if (JTH.FallthroughUnreachable) {
if (JT.MBB != HeaderBB->getNextNode())
return true;
// Emit the range check for the jump table, and branch to the default block
// for the switch statement if the value being switched on exceeds the
// largest case in the switch.
auto Cst = getOrCreateVReg(
*ConstantInt::get(SValue.getType(), JTH.Last - JTH.First));
Cst = MIB.buildZExtOrTrunc(PtrScalarTy, Cst).getReg(0);
auto Cmp = MIB.buildICmp(CmpInst::ICMP_UGT, LLT::scalar(1), Sub, Cst);
auto BrCond = MIB.buildBrCond(Cmp.getReg(0), *JT.Default);
// Avoid emitting unnecessary branches to the next block.
if (JT.MBB != HeaderBB->getNextNode())
BrCond = MIB.buildBr(*JT.MBB);
return true;
void IRTranslator::emitSwitchCase(SwitchCG::CaseBlock &CB,
MachineBasicBlock *SwitchBB,
MachineIRBuilder &MIB) {
Register CondLHS = getOrCreateVReg(*CB.CmpLHS);
Register Cond;
DebugLoc OldDbgLoc = MIB.getDebugLoc();
if (CB.PredInfo.NoCmp) {
// Branch or fall through to TrueBB.
addSuccessorWithProb(CB.ThisBB, CB.TrueBB, CB.TrueProb);
addMachineCFGPred({SwitchBB->getBasicBlock(), CB.TrueBB->getBasicBlock()},
if (CB.TrueBB != CB.ThisBB->getNextNode())
const LLT i1Ty = LLT::scalar(1);
// Build the compare.
if (!CB.CmpMHS) {
const auto *CI = dyn_cast<ConstantInt>(CB.CmpRHS);
// For conditional branch lowering, we might try to do something silly like
// emit an G_ICMP to compare an existing G_ICMP i1 result with true. If so,
// just re-use the existing condition vreg.
if (MRI->getType(CondLHS).getSizeInBits() == 1 && CI && CI->isOne() &&
CB.PredInfo.Pred == CmpInst::ICMP_EQ) {
Cond = CondLHS;
} else {
Register CondRHS = getOrCreateVReg(*CB.CmpRHS);
if (CmpInst::isFPPredicate(CB.PredInfo.Pred))
Cond =
MIB.buildFCmp(CB.PredInfo.Pred, i1Ty, CondLHS, CondRHS).getReg(0);
Cond =
MIB.buildICmp(CB.PredInfo.Pred, i1Ty, CondLHS, CondRHS).getReg(0);
} else {
assert(CB.PredInfo.Pred == CmpInst::ICMP_SLE &&
"Can only handle SLE ranges");
const APInt& Low = cast<ConstantInt>(CB.CmpLHS)->getValue();
const APInt& High = cast<ConstantInt>(CB.CmpRHS)->getValue();
Register CmpOpReg = getOrCreateVReg(*CB.CmpMHS);
if (cast<ConstantInt>(CB.CmpLHS)->isMinValue(true)) {
Register CondRHS = getOrCreateVReg(*CB.CmpRHS);
Cond =
MIB.buildICmp(CmpInst::ICMP_SLE, i1Ty, CmpOpReg, CondRHS).getReg(0);
} else {
const LLT CmpTy = MRI->getType(CmpOpReg);
auto Sub = MIB.buildSub({CmpTy}, CmpOpReg, CondLHS);
auto Diff = MIB.buildConstant(CmpTy, High - Low);
Cond = MIB.buildICmp(CmpInst::ICMP_ULE, i1Ty, Sub, Diff).getReg(0);
// Update successor info
addSuccessorWithProb(CB.ThisBB, CB.TrueBB, CB.TrueProb);
addMachineCFGPred({SwitchBB->getBasicBlock(), CB.TrueBB->getBasicBlock()},
// TrueBB and FalseBB are always different unless the incoming IR is
// degenerate. This only happens when running llc on weird IR.
if (CB.TrueBB != CB.FalseBB)
addSuccessorWithProb(CB.ThisBB, CB.FalseBB, CB.FalseProb);
addMachineCFGPred({SwitchBB->getBasicBlock(), CB.FalseBB->getBasicBlock()},
MIB.buildBrCond(Cond, *CB.TrueBB);
bool IRTranslator::lowerJumpTableWorkItem(SwitchCG::SwitchWorkListItem W,
MachineBasicBlock *SwitchMBB,
MachineBasicBlock *CurMBB,
MachineBasicBlock *DefaultMBB,
MachineIRBuilder &MIB,
MachineFunction::iterator BBI,
BranchProbability UnhandledProbs,
SwitchCG::CaseClusterIt I,
MachineBasicBlock *Fallthrough,
bool FallthroughUnreachable) {
using namespace SwitchCG;
MachineFunction *CurMF = SwitchMBB->getParent();
// FIXME: Optimize away range check based on pivot comparisons.
JumpTableHeader *JTH = &SL->JTCases[I->JTCasesIndex].first;
SwitchCG::JumpTable *JT = &SL->JTCases[I->JTCasesIndex].second;
BranchProbability DefaultProb = W.DefaultProb;
// The jump block hasn't been inserted yet; insert it here.
MachineBasicBlock *JumpMBB = JT->MBB;
CurMF->insert(BBI, JumpMBB);
// Since the jump table block is separate from the switch block, we need
// to keep track of it as a machine predecessor to the default block,
// otherwise we lose the phi edges.
addMachineCFGPred({SwitchMBB->getBasicBlock(), DefaultMBB->getBasicBlock()},
addMachineCFGPred({SwitchMBB->getBasicBlock(), DefaultMBB->getBasicBlock()},
auto JumpProb = I->Prob;
auto FallthroughProb = UnhandledProbs;
// If the default statement is a target of the jump table, we evenly
// distribute the default probability to successors of CurMBB. Also
// update the probability on the edge from JumpMBB to Fallthrough.
for (MachineBasicBlock::succ_iterator SI = JumpMBB->succ_begin(),
SE = JumpMBB->succ_end();
SI != SE; ++SI) {
if (*SI == DefaultMBB) {
JumpProb += DefaultProb / 2;
FallthroughProb -= DefaultProb / 2;
JumpMBB->setSuccProbability(SI, DefaultProb / 2);
} else {
// Also record edges from the jump table block to it's successors.
addMachineCFGPred({SwitchMBB->getBasicBlock(), (*SI)->getBasicBlock()},
if (FallthroughUnreachable)
JTH->FallthroughUnreachable = true;
if (!JTH->FallthroughUnreachable)
addSuccessorWithProb(CurMBB, Fallthrough, FallthroughProb);
addSuccessorWithProb(CurMBB, JumpMBB, JumpProb);
// The jump table header will be inserted in our current block, do the
// range check, and fall through to our fallthrough block.
JTH->HeaderBB = CurMBB;
JT->Default = Fallthrough; // FIXME: Move Default to JumpTableHeader.
// If we're in the right place, emit the jump table header right now.
if (CurMBB == SwitchMBB) {
if (!emitJumpTableHeader(*JT, *JTH, CurMBB))
return false;
JTH->Emitted = true;
return true;
bool IRTranslator::lowerSwitchRangeWorkItem(SwitchCG::CaseClusterIt I,
Value *Cond,
MachineBasicBlock *Fallthrough,
bool FallthroughUnreachable,
BranchProbability UnhandledProbs,
MachineBasicBlock *CurMBB,
MachineIRBuilder &MIB,
MachineBasicBlock *SwitchMBB) {
using namespace SwitchCG;
const Value *RHS, *LHS, *MHS;
CmpInst::Predicate Pred;
if (I->Low == I->High) {
// Check Cond == I->Low.
Pred = CmpInst::ICMP_EQ;
LHS = Cond;
RHS = I->Low;
MHS = nullptr;
} else {
// Check I->Low <= Cond <= I->High.
Pred = CmpInst::ICMP_SLE;
LHS = I->Low;
MHS = Cond;
RHS = I->High;
// If Fallthrough is unreachable, fold away the comparison.
// The false probability is the sum of all unhandled cases.
CaseBlock CB(Pred, FallthroughUnreachable, LHS, RHS, MHS, I->MBB, Fallthrough,
CurMBB, MIB.getDebugLoc(), I->Prob, UnhandledProbs);
emitSwitchCase(CB, SwitchMBB, MIB);
return true;
void IRTranslator::emitBitTestHeader(SwitchCG::BitTestBlock &B,
MachineBasicBlock *SwitchBB) {
MachineIRBuilder &MIB = *CurBuilder;
// Subtract the minimum value.
Register SwitchOpReg = getOrCreateVReg(*B.SValue);
LLT SwitchOpTy = MRI->getType(SwitchOpReg);
Register MinValReg = MIB.buildConstant(SwitchOpTy, B.First).getReg(0);
auto RangeSub = MIB.buildSub(SwitchOpTy, SwitchOpReg, MinValReg);
Type *PtrIRTy = Type::getInt8PtrTy(MF->getFunction().getContext());
const LLT PtrTy = getLLTForType(*PtrIRTy, *DL);
LLT MaskTy = SwitchOpTy;
if (MaskTy.getSizeInBits() > PtrTy.getSizeInBits() ||
MaskTy = LLT::scalar(PtrTy.getSizeInBits());
else {
// Ensure that the type will fit the mask value.
for (unsigned I = 0, E = B.Cases.size(); I != E; ++I) {
if (!isUIntN(SwitchOpTy.getSizeInBits(), B.Cases[I].Mask)) {
// Switch table case range are encoded into series of masks.
// Just use pointer type, it's guaranteed to fit.
MaskTy = LLT::scalar(PtrTy.getSizeInBits());
Register SubReg = RangeSub.getReg(0);
if (SwitchOpTy != MaskTy)
SubReg = MIB.buildZExtOrTrunc(MaskTy, SubReg).getReg(0);
B.RegVT = getMVTForLLT(MaskTy);
B.Reg = SubReg;
MachineBasicBlock *MBB = B.Cases[0].ThisBB;
if (!B.FallthroughUnreachable)
addSuccessorWithProb(SwitchBB, B.Default, B.DefaultProb);
addSuccessorWithProb(SwitchBB, MBB, B.Prob);
if (!B.FallthroughUnreachable) {
// Conditional branch to the default block.
auto RangeCst = MIB.buildConstant(SwitchOpTy, B.Range);
auto RangeCmp = MIB.buildICmp(CmpInst::Predicate::ICMP_UGT, LLT::scalar(1),
RangeSub, RangeCst);
MIB.buildBrCond(RangeCmp, *B.Default);
// Avoid emitting unnecessary branches to the next block.
if (MBB != SwitchBB->getNextNode())
void IRTranslator::emitBitTestCase(SwitchCG::BitTestBlock &BB,
MachineBasicBlock *NextMBB,
BranchProbability BranchProbToNext,
Register Reg, SwitchCG::BitTestCase &B,
MachineBasicBlock *SwitchBB) {
MachineIRBuilder &MIB = *CurBuilder;
LLT SwitchTy = getLLTForMVT(BB.RegVT);
Register Cmp;
unsigned PopCount = llvm::popcount(B.Mask);
if (PopCount == 1) {
// Testing for a single bit; just compare the shift count with what it
// would need to be to shift a 1 bit in that position.
auto MaskTrailingZeros =
MIB.buildConstant(SwitchTy, llvm::countr_zero(B.Mask));
Cmp =
MIB.buildICmp(ICmpInst::ICMP_EQ, LLT::scalar(1), Reg, MaskTrailingZeros)
} else if (PopCount == BB.Range) {
// There is only one zero bit in the range, test for it directly.
auto MaskTrailingOnes =
MIB.buildConstant(SwitchTy, llvm::countr_one(B.Mask));
Cmp = MIB.buildICmp(CmpInst::ICMP_NE, LLT::scalar(1), Reg, MaskTrailingOnes)
} else {
// Make desired shift.
auto CstOne = MIB.buildConstant(SwitchTy, 1);
auto SwitchVal = MIB.buildShl(SwitchTy, CstOne, Reg);
// Emit bit tests and jumps.
auto CstMask = MIB.buildConstant(SwitchTy, B.Mask);
auto AndOp = MIB.buildAnd(SwitchTy, SwitchVal, CstMask);
auto CstZero = MIB.buildConstant(SwitchTy, 0);
Cmp = MIB.buildICmp(CmpInst::ICMP_NE, LLT::scalar(1), AndOp, CstZero)
// The branch probability from SwitchBB to B.TargetBB is B.ExtraProb.
addSuccessorWithProb(SwitchBB, B.TargetBB, B.ExtraProb);
// The branch probability from SwitchBB to NextMBB is BranchProbToNext.
addSuccessorWithProb(SwitchBB, NextMBB, BranchProbToNext);
// It is not guaranteed that the sum of B.ExtraProb and BranchProbToNext is
// one as they are relative probabilities (and thus work more like weights),
// and hence we need to normalize them to let the sum of them become one.
// Record the fact that the IR edge from the header to the bit test target
// will go through our new block. Neeeded for PHIs to have nodes added.
addMachineCFGPred({BB.Parent->getBasicBlock(), B.TargetBB->getBasicBlock()},
MIB.buildBrCond(Cmp, *B.TargetBB);
// Avoid emitting unnecessary branches to the next block.
if (NextMBB != SwitchBB->getNextNode())
bool IRTranslator::lowerBitTestWorkItem(
SwitchCG::SwitchWorkListItem W, MachineBasicBlock *SwitchMBB,
MachineBasicBlock *CurMBB, MachineBasicBlock *DefaultMBB,
MachineIRBuilder &MIB, MachineFunction::iterator BBI,
BranchProbability DefaultProb, BranchProbability UnhandledProbs,
SwitchCG::CaseClusterIt I, MachineBasicBlock *Fallthrough,
bool FallthroughUnreachable) {
using namespace SwitchCG;
MachineFunction *CurMF = SwitchMBB->getParent();
// FIXME: Optimize away range check based on pivot comparisons.
BitTestBlock *BTB = &SL->BitTestCases[I->BTCasesIndex];
// The bit test blocks haven't been inserted yet; insert them here.
for (BitTestCase &BTC : BTB->Cases)
CurMF->insert(BBI, BTC.ThisBB);
// Fill in fields of the BitTestBlock.
BTB->Parent = CurMBB;
BTB->Default = Fallthrough;
BTB->DefaultProb = UnhandledProbs;
// If the cases in bit test don't form a contiguous range, we evenly
// distribute the probability on the edge to Fallthrough to two
// successors of CurMBB.
if (!BTB->ContiguousRange) {
BTB->Prob += DefaultProb / 2;
BTB->DefaultProb -= DefaultProb / 2;
if (FallthroughUnreachable)
BTB->FallthroughUnreachable = true;
// If we're in the right place, emit the bit test header right now.
if (CurMBB == SwitchMBB) {
emitBitTestHeader(*BTB, SwitchMBB);
BTB->Emitted = true;
return true;
bool IRTranslator::lowerSwitchWorkItem(SwitchCG::SwitchWorkListItem W,
Value *Cond,
MachineBasicBlock *SwitchMBB,
MachineBasicBlock *DefaultMBB,
MachineIRBuilder &MIB) {
using namespace SwitchCG;
MachineFunction *CurMF = FuncInfo.MF;
MachineBasicBlock *NextMBB = nullptr;
MachineFunction::iterator BBI(W.MBB);
if (++BBI != FuncInfo.MF->end())
NextMBB = &*BBI;
if (EnableOpts) {
// Here, we order cases by probability so the most likely case will be
// checked first. However, two clusters can have the same probability in
// which case their relative ordering is non-deterministic. So we use Low
// as a tie-breaker as clusters are guaranteed to never overlap.
llvm::sort(W.FirstCluster, W.LastCluster + 1,
[](const CaseCluster &a, const CaseCluster &b) {
return a.Prob != b.Prob
? a.Prob > b.Prob
: a.Low->getValue().slt(b.Low->getValue());
// Rearrange the case blocks so that the last one falls through if possible
// without changing the order of probabilities.
for (CaseClusterIt I = W.LastCluster; I > W.FirstCluster;) {
if (I->Prob > W.LastCluster->Prob)
if (I->Kind == CC_Range && I->MBB == NextMBB) {
std::swap(*I, *W.LastCluster);
// Compute total probability.
BranchProbability DefaultProb = W.DefaultProb;
BranchProbability UnhandledProbs = DefaultProb;
for (CaseClusterIt I = W.FirstCluster; I <= W.LastCluster; ++I)
UnhandledProbs += I->Prob;
MachineBasicBlock *CurMBB = W.MBB;
for (CaseClusterIt I = W.FirstCluster, E = W.LastCluster; I <= E; ++I) {
bool FallthroughUnreachable = false;
MachineBasicBlock *Fallthrough;
if (I == W.LastCluster) {
// For the last cluster, fall through to the default destination.
Fallthrough = DefaultMBB;
FallthroughUnreachable = isa<UnreachableInst>(
} else {
Fallthrough = CurMF->CreateMachineBasicBlock(CurMBB->getBasicBlock());
CurMF->insert(BBI, Fallthrough);
UnhandledProbs -= I->Prob;
switch (I->Kind) {
case CC_BitTests: {
if (!lowerBitTestWorkItem(W, SwitchMBB, CurMBB, DefaultMBB, MIB, BBI,
DefaultProb, UnhandledProbs, I, Fallthrough,
FallthroughUnreachable)) {
LLVM_DEBUG(dbgs() << "Failed to lower bit test for switch");
return false;
case CC_JumpTable: {
if (!lowerJumpTableWorkItem(W, SwitchMBB, CurMBB, DefaultMBB, MIB, BBI,
UnhandledProbs, I, Fallthrough,
FallthroughUnreachable)) {
LLVM_DEBUG(dbgs() << "Failed to lower jump table");
return false;
case CC_Range: {
if (!lowerSwitchRangeWorkItem(I, Cond, Fallthrough,
FallthroughUnreachable, UnhandledProbs,
CurMBB, MIB, SwitchMBB)) {
LLVM_DEBUG(dbgs() << "Failed to lower switch range");
return false;
CurMBB = Fallthrough;
return true;
bool IRTranslator::translateIndirectBr(const User &U,
MachineIRBuilder &MIRBuilder) {
const IndirectBrInst &BrInst = cast<IndirectBrInst>(U);
const Register Tgt = getOrCreateVReg(*BrInst.getAddress());
// Link successors.
SmallPtrSet<const BasicBlock *, 32> AddedSuccessors;
MachineBasicBlock &CurBB = MIRBuilder.getMBB();
for (const BasicBlock *Succ : successors(&BrInst)) {
// It's legal for indirectbr instructions to have duplicate blocks in the
// destination list. We don't allow this in MIR. Skip anything that's
// already a successor.
if (!AddedSuccessors.insert(Succ).second)
return true;
static bool isSwiftError(const Value *V) {
if (auto Arg = dyn_cast<Argument>(V))
return Arg->hasSwiftErrorAttr();
if (auto AI = dyn_cast<AllocaInst>(V))
return AI->isSwiftError();
return false;
bool IRTranslator::translateLoad(const User &U, MachineIRBuilder &MIRBuilder) {
const LoadInst &LI = cast<LoadInst>(U);
unsigned StoreSize = DL->getTypeStoreSize(LI.getType());
if (StoreSize == 0)
return true;
ArrayRef<Register> Regs = getOrCreateVRegs(LI);
ArrayRef<uint64_t> Offsets = *VMap.getOffsets(LI);
Register Base = getOrCreateVReg(*LI.getPointerOperand());
AAMDNodes AAInfo = LI.getAAMetadata();
const Value *Ptr = LI.getPointerOperand();
Type *OffsetIRTy = DL->getIndexType(Ptr->getType());
LLT OffsetTy = getLLTForType(*OffsetIRTy, *DL);
if (CLI->supportSwiftError() && isSwiftError(Ptr)) {
assert(Regs.size() == 1 && "swifterror should be single pointer");
Register VReg =
SwiftError.getOrCreateVRegUseAt(&LI, &MIRBuilder.getMBB(), Ptr);
MIRBuilder.buildCopy(Regs[0], VReg);
return true;
auto &TLI = *MF->getSubtarget().getTargetLowering();
MachineMemOperand::Flags Flags =
TLI.getLoadMemOperandFlags(LI, *DL, AC, LibInfo);
if (AA && !(Flags & MachineMemOperand::MOInvariant)) {
if (AA->pointsToConstantMemory(
MemoryLocation(Ptr, LocationSize::precise(StoreSize), AAInfo))) {
Flags |= MachineMemOperand::MOInvariant;
const MDNode *Ranges =
Regs.size() == 1 ? LI.getMetadata(LLVMContext::MD_range) : nullptr;
for (unsigned i = 0; i < Regs.size(); ++i) {
Register Addr;
MIRBuilder.materializePtrAdd(Addr, Base, OffsetTy, Offsets[i] / 8);
MachinePointerInfo Ptr(LI.getPointerOperand(), Offsets[i] / 8);
Align BaseAlign = getMemOpAlign(LI);
auto MMO = MF->getMachineMemOperand(
Ptr, Flags, MRI->getType(Regs[i]),
commonAlignment(BaseAlign, Offsets[i] / 8), AAInfo, Ranges,
LI.getSyncScopeID(), LI.getOrdering());
MIRBuilder.buildLoad(Regs[i], Addr, *MMO);
return true;
bool IRTranslator::translateStore(const User &U, MachineIRBuilder &MIRBuilder) {
const StoreInst &SI = cast<StoreInst>(U);
if (DL->getTypeStoreSize(SI.getValueOperand()->getType()) == 0)
return true;
ArrayRef<Register> Vals = getOrCreateVRegs(*SI.getValueOperand());
ArrayRef<uint64_t> Offsets = *VMap.getOffsets(*SI.getValueOperand());
Register Base = getOrCreateVReg(*SI.getPointerOperand());
Type *OffsetIRTy = DL->getIndexType(SI.getPointerOperandType());
LLT OffsetTy = getLLTForType(*OffsetIRTy, *DL);
if (CLI->supportSwiftError() && isSwiftError(SI.getPointerOperand())) {
assert(Vals.size() == 1 && "swifterror should be single pointer");
Register VReg = SwiftError.getOrCreateVRegDefAt(&SI, &MIRBuilder.getMBB(),
MIRBuilder.buildCopy(VReg, Vals[0]);
return true;
auto &TLI = *MF->getSubtarget().getTargetLowering();
MachineMemOperand::Flags Flags = TLI.getStoreMemOperandFlags(SI, *DL);
for (unsigned i = 0; i < Vals.size(); ++i) {
Register Addr;
MIRBuilder.materializePtrAdd(Addr, Base, OffsetTy, Offsets[i] / 8);
MachinePointerInfo Ptr(SI.getPointerOperand(), Offsets[i] / 8);
Align BaseAlign = getMemOpAlign(SI);
auto MMO = MF->getMachineMemOperand(
Ptr, Flags, MRI->getType(Vals[i]),
commonAlignment(BaseAlign, Offsets[i] / 8), SI.getAAMetadata(), nullptr,
SI.getSyncScopeID(), SI.getOrdering());
MIRBuilder.buildStore(Vals[i], Addr, *MMO);
return true;
static uint64_t getOffsetFromIndices(const User &U, const DataLayout &DL) {
const Value *Src = U.getOperand(0);
Type *Int32Ty = Type::getInt32Ty(U.getContext());
// getIndexedOffsetInType is designed for GEPs, so the first index is the
// usual array element rather than looking into the actual aggregate.
SmallVector<Value *, 1> Indices;
Indices.push_back(ConstantInt::get(Int32Ty, 0));
if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(&U)) {
for (auto Idx : EVI->indices())
Indices.push_back(ConstantInt::get(Int32Ty, Idx));
} else if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(&U)) {
for (auto Idx : IVI->indices())
Indices.push_back(ConstantInt::get(Int32Ty, Idx));
} else {
for (unsigned i = 1; i < U.getNumOperands(); ++i)
return 8 * static_cast<uint64_t>(
DL.getIndexedOffsetInType(Src->getType(), Indices));
bool IRTranslator::translateExtractValue(const User &U,
MachineIRBuilder &MIRBuilder) {
const Value *Src = U.getOperand(0);
uint64_t Offset = getOffsetFromIndices(U, *DL);
ArrayRef<Register> SrcRegs = getOrCreateVRegs(*Src);
ArrayRef<uint64_t> Offsets = *VMap.getOffsets(*Src);
unsigned Idx = llvm::lower_bound(Offsets, Offset) - Offsets.begin();
auto &DstRegs = allocateVRegs(U);
for (unsigned i = 0; i < DstRegs.size(); ++i)
DstRegs[i] = SrcRegs[Idx++];
return true;
bool IRTranslator::translateInsertValue(const User &U,
MachineIRBuilder &MIRBuilder) {
const Value *Src = U.getOperand(0);
uint64_t Offset = getOffsetFromIndices(U, *DL);
auto &DstRegs = allocateVRegs(U);
ArrayRef<uint64_t> DstOffsets = *VMap.getOffsets(U);
ArrayRef<Register> SrcRegs = getOrCreateVRegs(*Src);
ArrayRef<Register> InsertedRegs = getOrCreateVRegs(*U.getOperand(1));
auto *InsertedIt = InsertedRegs.begin();
for (unsigned i = 0; i < DstRegs.size(); ++i) {
if (DstOffsets[i] >= Offset && InsertedIt != InsertedRegs.end())
DstRegs[i] = *InsertedIt++;
DstRegs[i] = SrcRegs[i];
return true;
bool IRTranslator::translateSelect(const User &U,
MachineIRBuilder &MIRBuilder) {
Register Tst = getOrCreateVReg(*U.getOperand(0));
ArrayRef<Register> ResRegs = getOrCreateVRegs(U);
ArrayRef<Register> Op0Regs = getOrCreateVRegs(*U.getOperand(1));
ArrayRef<Register> Op1Regs = getOrCreateVRegs(*U.getOperand(2));
uint32_t Flags = 0;
if (const SelectInst *SI = dyn_cast<SelectInst>(&U))
Flags = MachineInstr::copyFlagsFromInstruction(*SI);
for (unsigned i = 0; i < ResRegs.size(); ++i) {
MIRBuilder.buildSelect(ResRegs[i], Tst, Op0Regs[i], Op1Regs[i], Flags);
return true;
bool IRTranslator::translateCopy(const User &U, const Value &V,
MachineIRBuilder &MIRBuilder) {
Register Src = getOrCreateVReg(V);
auto &Regs = *VMap.getVRegs(U);
if (Regs.empty()) {
} else {
// If we already assigned a vreg for this instruction, we can't change that.
// Emit a copy to satisfy the users we already emitted.
MIRBuilder.buildCopy(Regs[0], Src);
return true;
bool IRTranslator::translateBitCast(const User &U,
MachineIRBuilder &MIRBuilder) {
// If we're bitcasting to the source type, we can reuse the source vreg.
if (getLLTForType(*U.getOperand(0)->getType(), *DL) ==
getLLTForType(*U.getType(), *DL))
return translateCopy(U, *U.getOperand(0), MIRBuilder);
return translateCast(TargetOpcode::G_BITCAST, U, MIRBuilder);
bool IRTranslator::translateCast(unsigned Opcode, const User &U,
MachineIRBuilder &MIRBuilder) {
Register Op = getOrCreateVReg(*U.getOperand(0));
Register Res = getOrCreateVReg(U);
MIRBuilder.buildInstr(Opcode, {Res}, {Op});
return true;
bool IRTranslator::translateGetElementPtr(const User &U,
MachineIRBuilder &MIRBuilder) {
Value &Op0 = *U.getOperand(0);
Register BaseReg = getOrCreateVReg(Op0);
Type *PtrIRTy = Op0.getType();
LLT PtrTy = getLLTForType(*PtrIRTy, *DL);
Type *OffsetIRTy = DL->getIndexType(PtrIRTy);
LLT OffsetTy = getLLTForType(*OffsetIRTy, *DL);
// Normalize Vector GEP - all scalar operands should be converted to the
// splat vector.
unsigned VectorWidth = 0;
// True if we should use a splat vector; using VectorWidth alone is not
// sufficient.
bool WantSplatVector = false;
if (auto *VT = dyn_cast<VectorType>(U.getType())) {
VectorWidth = cast<FixedVectorType>(VT)->getNumElements();
// We don't produce 1 x N vectors; those are treated as scalars.
WantSplatVector = VectorWidth > 1;
// We might need to splat the base pointer into a vector if the offsets
// are vectors.
if (WantSplatVector && !PtrTy.isVector()) {
BaseReg =
.buildSplatVector(LLT::fixed_vector(VectorWidth, PtrTy), BaseReg)
PtrIRTy = FixedVectorType::get(PtrIRTy, VectorWidth);
PtrTy = getLLTForType(*PtrIRTy, *DL);
OffsetIRTy = DL->getIndexType(PtrIRTy);
OffsetTy = getLLTForType(*OffsetIRTy, *DL);
int64_t Offset = 0;
for (gep_type_iterator GTI = gep_type_begin(&U), E = gep_type_end(&U);
GTI != E; ++GTI) {
const Value *Idx = GTI.getOperand();
if (StructType *StTy = GTI.getStructTypeOrNull()) {
unsigned Field = cast<Constant>(Idx)->getUniqueInteger().getZExtValue();
Offset += DL->getStructLayout(StTy)->getElementOffset(Field);
} else {
uint64_t ElementSize = DL->getTypeAllocSize(GTI.getIndexedType());
// If this is a scalar constant or a splat vector of constants,
// handle it quickly.
if (const auto *CI = dyn_cast<ConstantInt>(Idx)) {
Offset += ElementSize * CI->getSExtValue();
if (Offset != 0) {
auto OffsetMIB = MIRBuilder.buildConstant({OffsetTy}, Offset);
BaseReg = MIRBuilder.buildPtrAdd(PtrTy, BaseReg, OffsetMIB.getReg(0))
Offset = 0;
Register IdxReg = getOrCreateVReg(*Idx);
LLT IdxTy = MRI->getType(IdxReg);
if (IdxTy != OffsetTy) {
if (!IdxTy.isVector() && WantSplatVector) {
IdxReg = MIRBuilder.buildSplatVector(
OffsetTy.changeElementType(IdxTy), IdxReg).getReg(0);
IdxReg = MIRBuilder.buildSExtOrTrunc(OffsetTy, IdxReg).getReg(0);
// N = N + Idx * ElementSize;
// Avoid doing it for ElementSize of 1.
Register GepOffsetReg;
if (ElementSize != 1) {
auto ElementSizeMIB = MIRBuilder.buildConstant(
getLLTForType(*OffsetIRTy, *DL), ElementSize);
GepOffsetReg =
MIRBuilder.buildMul(OffsetTy, IdxReg, ElementSizeMIB).getReg(0);
} else
GepOffsetReg = IdxReg;
BaseReg = MIRBuilder.buildPtrAdd(PtrTy, BaseReg, GepOffsetReg).getReg(0);
if (Offset != 0) {
auto OffsetMIB =
MIRBuilder.buildConstant(OffsetTy, Offset);
MIRBuilder.buildPtrAdd(getOrCreateVReg(U), BaseReg, OffsetMIB.getReg(0));
return true;
MIRBuilder.buildCopy(getOrCreateVReg(U), BaseReg);
return true;
bool IRTranslator::translateMemFunc(const CallInst &CI,
MachineIRBuilder &MIRBuilder,
unsigned Opcode) {
const Value *SrcPtr = CI.getArgOperand(1);
// If the source is undef, then just emit a nop.
if (isa<UndefValue>(SrcPtr))
return true;
SmallVector<Register, 3> SrcRegs;
unsigned MinPtrSize = UINT_MAX;
for (auto AI = CI.arg_begin(), AE = CI.arg_end(); std::next(AI) != AE; ++AI) {
Register SrcReg = getOrCreateVReg(**AI);
LLT SrcTy = MRI->getType(SrcReg);
if (SrcTy.isPointer())
MinPtrSize = std::min<unsigned>(SrcTy.getSizeInBits(), MinPtrSize);
LLT SizeTy = LLT::scalar(MinPtrSize);
// The size operand should be the minimum of the pointer sizes.
Register &SizeOpReg = SrcRegs[SrcRegs.size() - 1];
if (MRI->getType(SizeOpReg) != SizeTy)
SizeOpReg = MIRBuilder.buildZExtOrTrunc(SizeTy, SizeOpReg).getReg(0);
auto ICall = MIRBuilder.buildInstr(Opcode);
for (Register SrcReg : SrcRegs)
Align DstAlign;
Align SrcAlign;
unsigned IsVol =
cast<ConstantInt>(CI.getArgOperand(CI.arg_size() - 1))->getZExtValue();
ConstantInt *CopySize = nullptr;
if (auto *MCI = dyn_cast<MemCpyInst>(&CI)) {
DstAlign = MCI->getDestAlign().valueOrOne();
SrcAlign = MCI->getSourceAlign().valueOrOne();
CopySize = dyn_cast<ConstantInt>(MCI->getArgOperand(2));
} else if (auto *MCI = dyn_cast<MemCpyInlineInst>(&CI)) {
DstAlign = MCI->getDestAlign().valueOrOne();
SrcAlign = MCI->getSourceAlign().valueOrOne();
CopySize = dyn_cast<ConstantInt>(MCI->getArgOperand(2));
} else if (auto *MMI = dyn_cast<MemMoveInst>(&CI)) {
DstAlign = MMI->getDestAlign().valueOrOne();
SrcAlign = MMI->getSourceAlign().valueOrOne();
CopySize = dyn_cast<ConstantInt>(MMI->getArgOperand(2));
} else {
auto *MSI = cast<MemSetInst>(&CI);
DstAlign = MSI->getDestAlign().valueOrOne();
if (Opcode != TargetOpcode::G_MEMCPY_INLINE) {
// We need to propagate the tail call flag from the IR inst as an argument.
// Otherwise, we have to pessimize and assume later that we cannot tail call
// any memory intrinsics.
ICall.addImm(CI.isTailCall() ? 1 : 0);
// Create mem operands to store the alignment and volatile info.
MachineMemOperand::Flags LoadFlags = MachineMemOperand::MOLoad;
MachineMemOperand::Flags StoreFlags = MachineMemOperand::MOStore;
if (IsVol) {
LoadFlags |= MachineMemOperand::MOVolatile;
StoreFlags |= MachineMemOperand::MOVolatile;
AAMDNodes AAInfo = CI.getAAMetadata();
if (AA && CopySize &&
SrcPtr, LocationSize::precise(CopySize->getZExtValue()), AAInfo))) {
LoadFlags |= MachineMemOperand::MOInvariant;
// FIXME: pointsToConstantMemory probably does not imply dereferenceable,
// but the previous usage implied it did. Probably should check
// isDereferenceableAndAlignedPointer.
LoadFlags |= MachineMemOperand::MODereferenceable;
StoreFlags, 1, DstAlign, AAInfo));
if (Opcode != TargetOpcode::G_MEMSET)
MachinePointerInfo(SrcPtr), LoadFlags, 1, SrcAlign, AAInfo));
return true;
void IRTranslator::getStackGuard(Register DstReg,
MachineIRBuilder &MIRBuilder) {
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
MRI->setRegClass(DstReg, TRI->getPointerRegClass(*MF));
auto MIB =
MIRBuilder.buildInstr(TargetOpcode::LOAD_STACK_GUARD, {DstReg}, {});
auto &TLI = *MF->getSubtarget().getTargetLowering();
Value *Global = TLI.getSDagStackGuard(*MF->getFunction().getParent());
if (!Global)
unsigned AddrSpace = Global->getType()->getPointerAddressSpace();
LLT PtrTy = LLT::pointer(AddrSpace, DL->getPointerSizeInBits(AddrSpace));
MachinePointerInfo MPInfo(Global);
auto Flags = MachineMemOperand::MOLoad | MachineMemOperand::MOInvariant |
MachineMemOperand *MemRef = MF->getMachineMemOperand(
MPInfo, Flags, PtrTy, DL->getPointerABIAlignment(AddrSpace));
bool IRTranslator::translateOverflowIntrinsic(const CallInst &CI, unsigned Op,
MachineIRBuilder &MIRBuilder) {
ArrayRef<Register> ResRegs = getOrCreateVRegs(CI);
Op, {ResRegs[0], ResRegs[1]},
{getOrCreateVReg(*CI.getOperand(0)), getOrCreateVReg(*CI.getOperand(1))});
return true;
bool IRTranslator::translateFixedPointIntrinsic(unsigned Op, const CallInst &CI,
MachineIRBuilder &MIRBuilder) {
Register Dst = getOrCreateVReg(CI);
Register Src0 = getOrCreateVReg(*CI.getOperand(0));
Register Src1 = getOrCreateVReg(*CI.getOperand(1));
uint64_t Scale = cast<ConstantInt>(CI.getOperand(2))->getZExtValue();
MIRBuilder.buildInstr(Op, {Dst}, { Src0, Src1, Scale });
return true;
unsigned IRTranslator::getSimpleIntrinsicOpcode(Intrinsic::ID ID) {
switch (ID) {
case Intrinsic::bswap:
return TargetOpcode::G_BSWAP;
case Intrinsic::bitreverse:
return TargetOpcode::G_BITREVERSE;
case Intrinsic::fshl:
return TargetOpcode::G_FSHL;
case Intrinsic::fshr:
return TargetOpcode::G_FSHR;
case Intrinsic::ceil:
return TargetOpcode::G_FCEIL;
case Intrinsic::cos:
return TargetOpcode::G_FCOS;
case Intrinsic::ctpop:
return TargetOpcode::G_CTPOP;
case Intrinsic::exp:
return TargetOpcode::G_FEXP;
case Intrinsic::exp2:
return TargetOpcode::G_FEXP2;
case Intrinsic::fabs:
return TargetOpcode::G_FABS;
case Intrinsic::copysign:
return TargetOpcode::G_FCOPYSIGN;
case Intrinsic::minnum:
return TargetOpcode::G_FMINNUM;
case Intrinsic::maxnum:
return TargetOpcode::G_FMAXNUM;
case Intrinsic::minimum:
return TargetOpcode::G_FMINIMUM;
case Intrinsic::maximum:
return TargetOpcode::G_FMAXIMUM;
case Intrinsic::canonicalize:
return TargetOpcode::G_FCANONICALIZE;
case Intrinsic::floor:
return TargetOpcode::G_FFLOOR;
case Intrinsic::fma:
return TargetOpcode::G_FMA;
case Intrinsic::log:
return TargetOpcode::G_FLOG;
case Intrinsic::log2:
return TargetOpcode::G_FLOG2;
case Intrinsic::log10:
return TargetOpcode::G_FLOG10;
case Intrinsic::nearbyint:
return TargetOpcode::G_FNEARBYINT;
case Intrinsic::pow:
return TargetOpcode::G_FPOW;
case Intrinsic::powi:
return TargetOpcode::G_FPOWI;
case Intrinsic::rint:
return TargetOpcode::G_FRINT;
case Intrinsic::round:
return TargetOpcode::G_INTRINSIC_ROUND;
case Intrinsic::roundeven:
return TargetOpcode::G_INTRINSIC_ROUNDEVEN;
case Intrinsic::sin:
return TargetOpcode::G_FSIN;
case Intrinsic::sqrt:
return TargetOpcode::G_FSQRT;
case Intrinsic::trunc:
return TargetOpcode::G_INTRINSIC_TRUNC;
case Intrinsic::readcyclecounter:
return TargetOpcode::G_READCYCLECOUNTER;
case Intrinsic::ptrmask:
return TargetOpcode::G_PTRMASK;
case Intrinsic::lrint:
return TargetOpcode::G_INTRINSIC_LRINT;
// FADD/FMUL require checking the FMF, so are handled elsewhere.
case Intrinsic::vector_reduce_fmin:
return TargetOpcode::G_VECREDUCE_FMIN;
case Intrinsic::vector_reduce_fmax:
return TargetOpcode::G_VECREDUCE_FMAX;
case Intrinsic::vector_reduce_add:
return TargetOpcode::G_VECREDUCE_ADD;
case Intrinsic::vector_reduce_mul:
return TargetOpcode::G_VECREDUCE_MUL;
case Intrinsic::vector_reduce_and:
return TargetOpcode::G_VECREDUCE_AND;
case Intrinsic::vector_reduce_or:
return TargetOpcode::G_VECREDUCE_OR;
case Intrinsic::vector_reduce_xor:
return TargetOpcode::G_VECREDUCE_XOR;
case Intrinsic::vector_reduce_smax:
return TargetOpcode::G_VECREDUCE_SMAX;
case Intrinsic::vector_reduce_smin:
return TargetOpcode::G_VECREDUCE_SMIN;
case Intrinsic::vector_reduce_umax:
return TargetOpcode::G_VECREDUCE_UMAX;
case Intrinsic::vector_reduce_umin:
return TargetOpcode::G_VECREDUCE_UMIN;
case Intrinsic::lround:
return TargetOpcode::G_LROUND;
case Intrinsic::llround:
return TargetOpcode::G_LLROUND;
return Intrinsic::not_intrinsic;
bool IRTranslator::translateSimpleIntrinsic(const CallInst &CI,
Intrinsic::ID ID,
MachineIRBuilder &MIRBuilder) {
unsigned Op = getSimpleIntrinsicOpcode(ID);
// Is this a simple intrinsic?
if (Op == Intrinsic::not_intrinsic)
return false;
// Yes. Let's translate it.
SmallVector<llvm::SrcOp, 4> VRegs;
for (const auto &Arg : CI.args())
MIRBuilder.buildInstr(Op, {getOrCreateVReg(CI)}, VRegs,
return true;
// TODO: Include ConstainedOps.def when all strict instructions are defined.
static unsigned getConstrainedOpcode(Intrinsic::ID ID) {
switch (ID) {
case Intrinsic::experimental_constrained_fadd:
return TargetOpcode::G_STRICT_FADD;
case Intrinsic::experimental_constrained_fsub:
return TargetOpcode::G_STRICT_FSUB;
case Intrinsic::experimental_constrained_fmul:
return TargetOpcode::G_STRICT_FMUL;
case Intrinsic::experimental_constrained_fdiv:
return TargetOpcode::G_STRICT_FDIV;
case Intrinsic::experimental_constrained_frem:
return TargetOpcode::G_STRICT_FREM;
case Intrinsic::experimental_constrained_fma:
return TargetOpcode::G_STRICT_FMA;
case Intrinsic::experimental_constrained_sqrt:
return TargetOpcode::G_STRICT_FSQRT;
return 0;
bool IRTranslator::translateConstrainedFPIntrinsic(
const ConstrainedFPIntrinsic &FPI, MachineIRBuilder &MIRBuilder) {
fp::ExceptionBehavior EB = *FPI.getExceptionBehavior();
unsigned Opcode = getConstrainedOpcode(FPI.getIntrinsicID());
if (!Opcode)
return false;
uint32_t Flags = MachineInstr::copyFlagsFromInstruction(FPI);
if (EB == fp::ExceptionBehavior::ebIgnore)
Flags |= MachineInstr::NoFPExcept;
SmallVector<llvm::SrcOp, 4> VRegs;
if (!FPI.isUnaryOp())
if (FPI.isTernaryOp())
MIRBuilder.buildInstr(Opcode, {getOrCreateVReg(FPI)}, VRegs, Flags);
return true;
std::optional<MCRegister> IRTranslator::getArgPhysReg(Argument &Arg) {
auto VRegs = getOrCreateVRegs(Arg);
if (VRegs.size() != 1)
return std::nullopt;
// Arguments are lowered as a copy of a livein physical register.
auto *VRegDef = MF->getRegInfo().getVRegDef(VRegs[0]);
if (!VRegDef || !VRegDef->isCopy())
return std::nullopt;
return VRegDef->getOperand(1).getReg().asMCReg();
bool IRTranslator::translateIfEntryValueArgument(const DbgValueInst &DebugInst,
MachineIRBuilder &MIRBuilder) {
auto *Arg = dyn_cast<Argument>(DebugInst.getValue());
if (!Arg)
return false;
const DIExpression *Expr = DebugInst.getExpression();
if (!Expr->isEntryValue())
return false;
std::optional<MCRegister> PhysReg = getArgPhysReg(*Arg);
if (!PhysReg) {
LLVM_DEBUG(dbgs() << "Dropping dbg.value: expression is entry_value but "
"couldn't find a physical register\n"
<< DebugInst << "\n");
return true;
MIRBuilder.buildDirectDbgValue(*PhysReg, DebugInst.getVariable(),
return true;
bool IRTranslator::translateIfEntryValueArgument(
const DbgDeclareInst &DebugInst) {
auto *Arg = dyn_cast<Argument>(DebugInst.getAddress());
if (!Arg)
return false;
const DIExpression *Expr = DebugInst.getExpression();
if (!Expr->isEntryValue())
return false;
std::optional<MCRegister> PhysReg = getArgPhysReg(*Arg);
if (!PhysReg)
return false;
MF->setVariableDbgInfo(DebugInst.getVariable(), Expr, *PhysReg,
return true;
bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
MachineIRBuilder &MIRBuilder) {
if (auto *MI = dyn_cast<AnyMemIntrinsic>(&CI)) {
if (ORE->enabled()) {
if (MemoryOpRemark::canHandle(MI, *LibInfo)) {
MemoryOpRemark R(*ORE, "gisel-irtranslator-memsize", *DL, *LibInfo);
// If this is a simple intrinsic (that is, we just need to add a def of
// a vreg, and uses for each arg operand, then translate it.
if (translateSimpleIntrinsic(CI, ID, MIRBuilder))
return true;
switch (ID) {
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end: {
// No stack colouring in O0, discard region information.
if (MF->getTarget().getOptLevel() == CodeGenOpt::None)
return true;
unsigned Op = ID == Intrinsic::lifetime_start ? TargetOpcode::LIFETIME_START
: TargetOpcode::LIFETIME_END;
// Get the underlying objects for the location passed on the lifetime
// marker.
SmallVector<const Value *, 4> Allocas;
getUnderlyingObjects(CI.getArgOperand(1), Allocas);
// Iterate over each underlying object, creating lifetime markers for each
// static alloca. Quit if we find a non-static alloca.
for (const Value *V : Allocas) {
const AllocaInst *AI = dyn_cast<AllocaInst>(V);
if (!AI)
if (!AI->isStaticAlloca())
return true;
return true;
case Intrinsic::dbg_declare: {
const DbgDeclareInst &DI = cast<DbgDeclareInst>(CI);
assert(DI.getVariable() && "Missing variable");
const Value *Address = DI.getAddress();
if (!Address || isa<UndefValue>(Address)) {
LLVM_DEBUG(dbgs() << "Dropping debug info for " << DI << "\n");
return true;
MIRBuilder.getDebugLoc()) &&
"Expected inlined-at fields to agree");
auto AI = dyn_cast<AllocaInst>(Address);
if (AI && AI->isStaticAlloca()) {
// Static allocas are tracked at the MF level, no need for DBG_VALUE
// instructions (in fact, they get ignored if they *do* exist).
MF->setVariableDbgInfo(DI.getVariable(), DI.getExpression(),
getOrCreateFrameIndex(*AI), DI.getDebugLoc());
return true;
if (translateIfEntryValueArgument(DI))
return true;
// A dbg.declare describes the address of a source variable, so lower it
// into an indirect DBG_VALUE.
DI.getVariable(), DI.getExpression());
return true;
case Intrinsic::dbg_label: {
const DbgLabelInst &DI = cast<DbgLabelInst>(CI);
assert(DI.getLabel() && "Missing label");
MIRBuilder.getDebugLoc()) &&
"Expected inlined-at fields to agree");
return true;
case Intrinsic::vaend:
// No target I know of cares about va_end. Certainly no in-tree target
// does. Simplest intrinsic ever!
return true;
case Intrinsic::vastart: {
auto &TLI = *MF->getSubtarget().getTargetLowering();
Value *Ptr = CI.getArgOperand(0);
unsigned ListSize = TLI.getVaListSizeInBits(*DL) / 8;
// FIXME: Get alignment
MIRBuilder.buildInstr(TargetOpcode::G_VASTART, {}, {getOrCreateVReg(*Ptr)})
ListSize, Align(1)));
return true;
case Intrinsic::dbg_value: {
// This form of DBG_VALUE is target-independent.
const DbgValueInst &DI = cast<DbgValueInst>(CI);
const Value *V = DI.getValue();
MIRBuilder.getDebugLoc()) &&
"Expected inlined-at fields to agree");
if (!V || DI.hasArgList()) {
// DI cannot produce a valid DBG_VALUE, so produce an undef DBG_VALUE to
// terminate any prior location.
MIRBuilder.buildIndirectDbgValue(0, DI.getVariable(), DI.getExpression());
return true;
if (const auto *CI = dyn_cast<Constant>(V)) {
MIRBuilder.buildConstDbgValue(*CI, DI.getVariable(), DI.getExpression());
return true;
if (auto *AI = dyn_cast<AllocaInst>(V);
AI && AI->isStaticAlloca() && DI.getExpression()->startsWithDeref()) {
// If the value is an alloca and the expression starts with a
// dereference, track a stack slot instead of a register, as registers
// may be clobbered.
auto ExprOperands = DI.getExpression()->getElements();
auto *ExprDerefRemoved =
DIExpression::get(AI->getContext(), ExprOperands.drop_front());
MIRBuilder.buildFIDbgValue(getOrCreateFrameIndex(*AI), DI.getVariable(),
return true;
if (translateIfEntryValueArgument(DI, MIRBuilder))
return true;
for (Register Reg : getOrCreateVRegs(*V)) {
// FIXME: This does not handle register-indirect values at offset 0. The
// direct/indirect thing shouldn't really be handled by something as
// implicit as reg+noreg vs reg+imm in the first place, but it seems
// pretty baked in right now.
MIRBuilder.buildDirectDbgValue(Reg, DI.getVariable(), DI.getExpression());
return true;
case Intrinsic::uadd_with_overflow:
return translateOverflowIntrinsic(CI, TargetOpcode::G_UADDO, MIRBuilder);
case Intrinsic::sadd_with_overflow:
return translateOverflowIntrinsic(CI, TargetOpcode::G_SADDO, MIRBuilder);
case Intrinsic::usub_with_overflow:
return translateOverflowIntrinsic(CI, TargetOpcode::G_USUBO, MIRBuilder);
case Intrinsic::ssub_with_overflow:
return translateOverflowIntrinsic(CI, TargetOpcode::G_SSUBO, MIRBuilder);
case Intrinsic::umul_with_overflow:
return translateOverflowIntrinsic(CI, TargetOpcode::G_UMULO, MIRBuilder);
case Intrinsic::smul_with_overflow:
return translateOverflowIntrinsic(CI, TargetOpcode::G_SMULO, MIRBuilder);
case Intrinsic::uadd_sat:
return translateBinaryOp(TargetOpcode::G_UADDSAT, CI, MIRBuilder);
case Intrinsic::sadd_sat:
return translateBinaryOp(TargetOpcode::G_SADDSAT, CI, MIRBuilder);
case Intrinsic::usub_sat:
return translateBinaryOp(TargetOpcode::G_USUBSAT, CI, MIRBuilder);
case Intrinsic::ssub_sat:
return translateBinaryOp(TargetOpcode::G_SSUBSAT, CI, MIRBuilder);
case Intrinsic::ushl_sat:
return translateBinaryOp(TargetOpcode::G_USHLSAT, CI, MIRBuilder);
case Intrinsic::sshl_sat:
return translateBinaryOp(TargetOpcode::G_SSHLSAT, CI, MIRBuilder);
case Intrinsic::umin:
return translateBinaryOp(TargetOpcode::G_UMIN, CI, MIRBuilder);
case Intrinsic::umax:
return translateBinaryOp(TargetOpcode::G_UMAX, CI, MIRBuilder);
case Intrinsic::smin:
return translateBinaryOp(TargetOpcode::G_SMIN, CI, MIRBuilder);
case Intrinsic::smax:
return translateBinaryOp(TargetOpcode::G_SMAX, CI, MIRBuilder);
case Intrinsic::abs:
// TODO: Preserve "int min is poison" arg in GMIR?
return translateUnaryOp(TargetOpcode::G_ABS, CI, MIRBuilder);
case Intrinsic::smul_fix:
return translateFixedPointIntrinsic(TargetOpcode::G_SMULFIX, CI, MIRBuilder);
case Intrinsic::umul_fix:
return translateFixedPointIntrinsic(TargetOpcode::G_UMULFIX, CI, MIRBuilder);
case Intrinsic::smul_fix_sat:
return translateFixedPointIntrinsic(TargetOpcode::G_SMULFIXSAT, CI, MIRBuilder);
case Intrinsic::umul_fix_sat:
return translateFixedPointIntrinsic(TargetOpcode::G_UMULFIXSAT, CI, MIRBuilder);
case Intrinsic::sdiv_fix:
return translateFixedPointIntrinsic(TargetOpcode::G_SDIVFIX, CI, MIRBuilder);
case Intrinsic::udiv_fix:
return translateFixedPointIntrinsic(TargetOpcode::G_UDIVFIX, CI, MIRBuilder);
case Intrinsic::sdiv_fix_sat:
return translateFixedPointIntrinsic(TargetOpcode::G_SDIVFIXSAT, CI, MIRBuilder);
case Intrinsic::udiv_fix_sat:
return translateFixedPointIntrinsic(TargetOpcode::G_UDIVFIXSAT, CI, MIRBuilder);
case Intrinsic::fmuladd: {
const TargetMachine &TM = MF->getTarget();
const TargetLowering &TLI = *MF->getSubtarget().getTargetLowering();
Register Dst = getOrCreateVReg(CI);
Register Op0 = getOrCreateVReg(*CI.getArgOperand(0));
Register Op1 = getOrCreateVReg(*CI.getArgOperand(1));
Register Op2 = getOrCreateVReg(*CI.getArgOperand(2));
if (TM.Options.AllowFPOpFusion != FPOpFusion::Strict &&
TLI.getValueType(*DL, CI.getType()))) {
// TODO: Revisit this to see if we should move this part of the
// lowering to the combiner.
MIRBuilder.buildFMA(Dst, Op0, Op1, Op2,
} else {
LLT Ty = getLLTForType(*CI.getType(), *DL);
auto FMul = MIRBuilder.buildFMul(
Ty, Op0, Op1, MachineInstr::copyFlagsFromInstruction(CI));
MIRBuilder.buildFAdd(Dst, FMul, Op2,
return true;
case Intrinsic::convert_from_fp16:
// FIXME: This intrinsic should probably be removed from the IR.
return true;
case Intrinsic::convert_to_fp16:
// FIXME: This intrinsic should probably be removed from the IR.
return true;
case Intrinsic::memcpy_inline:
return translateMemFunc(CI, MIRBuilder, TargetOpcode::G_MEMCPY_INLINE);
case Intrinsic::memcpy:
return translateMemFunc(CI, MIRBuilder, TargetOpcode::G_MEMCPY);
case Intrinsic::memmove:
return translateMemFunc(CI, MIRBuilder, TargetOpcode::G_MEMMOVE);
case Intrinsic::memset:
return translateMemFunc(CI, MIRBuilder, TargetOpcode::G_MEMSET);
case Intrinsic::eh_typeid_for: {
GlobalValue *GV = ExtractTypeInfo(CI.getArgOperand(0));
Register Reg = getOrCreateVReg(CI);
unsigned TypeID = MF->getTypeIDFor(GV);
MIRBuilder.buildConstant(Reg, TypeID);
return true;
case Intrinsic::objectsize:
llvm_unreachable("llvm.objectsize.* should have been lowered already");
case Intrinsic::is_constant:
llvm_unreachable("* should have been lowered already");
case Intrinsic::stackguard:
getStackGuard(getOrCreateVReg(CI), MIRBuilder);
return true;
case Intrinsic::stackprotector: {
const TargetLowering &TLI = *MF->getSubtarget().getTargetLowering();
LLT PtrTy = getLLTForType(*CI.getArgOperand(0)->getType(), *DL);
Register GuardVal;
if (TLI.useLoadStackGuardNode()) {
GuardVal = MRI->createGenericVirtualRegister(PtrTy);
getStackGuard(GuardVal, MIRBuilder);
} else
GuardVal = getOrCreateVReg(*CI.getArgOperand(0)); // The guard's value.
AllocaInst *Slot = cast<AllocaInst>(CI.getArgOperand(1));
int FI = getOrCreateFrameIndex(*Slot);
GuardVal, getOrCreateVReg(*Slot),
*MF->getMachineMemOperand(MachinePointerInfo::getFixedStack(*MF, FI),
MachineMemOperand::MOStore |
PtrTy, Align(8)));
return true;
case Intrinsic::stacksave: {
// Save the stack pointer to the location provided by the intrinsic.
Register Reg = getOrCreateVReg(CI);
Register StackPtr = MF->getSubtarget()
// If the target doesn't specify a stack pointer, then fall back.
if (!StackPtr)
return false;
MIRBuilder.buildCopy(Reg, StackPtr);
return true;
case Intrinsic::stackrestore: {
// Restore the stack pointer from the location provided by the intrinsic.
Register Reg = getOrCreateVReg(*CI.getArgOperand(0));
Register StackPtr = MF->getSubtarget()
// If the target doesn't specify a stack pointer, then fall back.
if (!StackPtr)
return false;
MIRBuilder.buildCopy(StackPtr, Reg);
return true;
case Intrinsic::cttz:
case Intrinsic::ctlz: {
ConstantInt *Cst = cast<ConstantInt>(CI.getArgOperand(1));
bool isTrailing = ID == Intrinsic::cttz;
unsigned Opcode = isTrailing
? Cst->isZero() ? TargetOpcode::G_CTTZ
: TargetOpcode::G_CTTZ_ZERO_UNDEF
: Cst->isZero() ? TargetOpcode::G_CTLZ
: TargetOpcode::G_CTLZ_ZERO_UNDEF;
MIRBuilder.buildInstr(Opcode, {getOrCreateVReg(CI)},
return true;
case Intrinsic::invariant_start: {
LLT PtrTy = getLLTForType(*CI.getArgOperand(0)->getType(), *DL);
Register Undef = MRI->createGenericVirtualRegister(PtrTy);
return true;
case Intrinsic::invariant_end:
return true;
case Intrinsic::expect:
case Intrinsic::annotation:
case Intrinsic::ptr_annotation:
case Intrinsic::launder_invariant_group:
case Intrinsic::strip_invariant_group: {
// Drop the intrinsic, but forward the value.
return true;
case Intrinsic::assume:
case Intrinsic::experimental_noalias_scope_decl:
case Intrinsic::var_annotation:
case Intrinsic::sideeffect:
// Discard annotate attributes, assumptions, and artificial side-effects.
return true;
case Intrinsic::read_volatile_register:
case Intrinsic::read_register: {
Value *Arg = CI.getArgOperand(0);
.buildInstr(TargetOpcode::G_READ_REGISTER, {getOrCreateVReg(CI)}, {})
return true;
case Intrinsic::write_register: {
Value *Arg = CI.getArgOperand(0);
return true;
case Intrinsic::localescape: {
MachineBasicBlock &EntryMBB = MF->front();
StringRef EscapedName = GlobalValue::dropLLVMManglingEscape(MF->getName());
// Directly emit some LOCAL_ESCAPE machine instrs. Label assignment emission
// is the same on all targets.
for (unsigned Idx = 0, E = CI.arg_size(); Idx < E; ++Idx) {
Value *Arg = CI.getArgOperand(Idx)->stripPointerCasts();
if (isa<ConstantPointerNull>(Arg))
continue; // Skip null pointers. They represent a hole in index space.
int FI = getOrCreateFrameIndex(*cast<AllocaInst>(Arg));
MCSymbol *FrameAllocSym =
// This should be inserted at the start of the entry block.
auto LocalEscape =
EntryMBB.insert(EntryMBB.begin(), LocalEscape);
return true;
case Intrinsic::vector_reduce_fadd:
case Intrinsic::vector_reduce_fmul: {
// Need to check for the reassoc flag to decide whether we want a
// sequential reduction opcode or not.
Register Dst = getOrCreateVReg(CI);
Register ScalarSrc = getOrCreateVReg(*CI.getArgOperand(0));
Register VecSrc = getOrCreateVReg(*CI.getArgOperand(1));
unsigned Opc = 0;
if (!CI.hasAllowReassoc()) {
// The sequential ordering case.
Opc = ID == Intrinsic::vector_reduce_fadd
MIRBuilder.buildInstr(Opc, {Dst}, {ScalarSrc, VecSrc},
return true;
// We split the operation into a separate G_FADD/G_FMUL + the reduce,
// since the associativity doesn't matter.
unsigned ScalarOpc;
if (ID == Intrinsic::vector_reduce_fadd) {
Opc = TargetOpcode::G_VECREDUCE_FADD;
ScalarOpc = TargetOpcode::G_FADD;
} else {
Opc = TargetOpcode::G_VECREDUCE_FMUL;
ScalarOpc = TargetOpcode::G_FMUL;
LLT DstTy = MRI->getType(Dst);
auto Rdx = MIRBuilder.buildInstr(
Opc, {DstTy}, {VecSrc}, MachineInstr::copyFlagsFromInstruction(CI));
MIRBuilder.buildInstr(ScalarOpc, {Dst}, {ScalarSrc, Rdx},
return true;
case Intrinsic::trap:
case Intrinsic::debugtrap:
case Intrinsic::ubsantrap: {
StringRef TrapFuncName =
if (TrapFuncName.empty())
break; // Use the default handling.
CallLowering::CallLoweringInfo Info;
if (ID == Intrinsic::ubsantrap) {
CI.getArgOperand(0)->getType(), 0});
Info.Callee = MachineOperand::CreateES(;
Info.CB = &CI;
Info.OrigRet = {Register(), Type::getVoidTy(CI.getContext()), 0};
return CLI->lowerCall(MIRBuilder, Info);
case Intrinsic::fptrunc_round: {
uint32_t Flags = MachineInstr::copyFlagsFromInstruction(CI);
// Convert the metadata argument to a constant integer
Metadata *MD = cast<MetadataAsValue>(CI.getArgOperand(1))->getMetadata();
std::optional<RoundingMode> RoundMode =
// Add the Rounding mode as an integer
{getOrCreateVReg(*CI.getArgOperand(0))}, Flags)
return true;
case Intrinsic::is_fpclass: {
Value *FpValue = CI.getOperand(0);
ConstantInt *TestMaskValue = cast<ConstantInt>(CI.getOperand(1));
.buildInstr(TargetOpcode::G_IS_FPCLASS, {getOrCreateVReg(CI)},
return true;
case Intrinsic::INTRINSIC:
#include "llvm/IR/ConstrainedOps.def"
return translateConstrainedFPIntrinsic(cast<ConstrainedFPIntrinsic>(CI),
return false;
bool IRTranslator::translateInlineAsm(const CallBase &CB,
MachineIRBuilder &MIRBuilder) {
const InlineAsmLowering *ALI = MF->getSubtarget().getInlineAsmLowering();
if (!ALI) {
dbgs() << "Inline asm lowering is not supported for this target yet\n");
return false;
return ALI->lowerInlineAsm(
MIRBuilder, CB, [&](const Value &Val) { return getOrCreateVRegs(Val); });
bool IRTranslator::translateCallBase(const CallBase &CB,
MachineIRBuilder &MIRBuilder) {
ArrayRef<Register> Res = getOrCreateVRegs(CB);
SmallVector<ArrayRef<Register>, 8> Args;
Register SwiftInVReg = 0;
Register SwiftErrorVReg = 0;
for (const auto &Arg : CB.args()) {
if (CLI->supportSwiftError() && isSwiftError(Arg)) {
assert(SwiftInVReg == 0 && "Expected only one swift error argument");
LLT Ty = getLLTForType(*Arg->getType(), *DL);
SwiftInVReg = MRI->createGenericVirtualRegister(Ty);
MIRBuilder.buildCopy(SwiftInVReg, SwiftError.getOrCreateVRegUseAt(
&CB, &MIRBuilder.getMBB(), Arg));
SwiftErrorVReg =
SwiftError.getOrCreateVRegDefAt(&CB, &MIRBuilder.getMBB(), Arg);
if (auto *CI = dyn_cast<CallInst>(&CB)) {
if (ORE->enabled()) {
if (MemoryOpRemark::canHandle(CI, *LibInfo)) {
MemoryOpRemark R(*ORE, "gisel-irtranslator-memsize", *DL, *LibInfo);
// We don't set HasCalls on MFI here yet because call lowering may decide to
// optimize into tail calls. Instead, we defer that to selection where a final
// scan is done to check if any instructions are calls.
bool Success =
CLI->lowerCall(MIRBuilder, CB, Res, Args, SwiftErrorVReg,
[&]() { return getOrCreateVReg(*CB.getCalledOperand()); });
// Check if we just inserted a tail call.
if (Success) {
assert(!HasTailCall && "Can't tail call return twice from block?");
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
HasTailCall = TII->isTailCall(*std::prev(MIRBuilder.getInsertPt()));
return Success;
bool IRTranslator::translateCall(const User &U, MachineIRBuilder &MIRBuilder) {
const CallInst &CI = cast<CallInst>(U);
auto TII = MF->getTarget().getIntrinsicInfo();
const Function *F = CI.getCalledFunction();
// FIXME: support Windows dllimport function calls.
if (F && (F->hasDLLImportStorageClass() ||
(MF->getTarget().getTargetTriple().isOSWindows() &&
return false;
// FIXME: support control flow guard targets.
if (CI.countOperandBundlesOfType(LLVMContext::OB_cfguardtarget))
return false;
// FIXME: support statepoints and related.
if (isa<GCStatepointInst, GCRelocateInst, GCResultInst>(U))
return false;
if (CI.isInlineAsm())
return translateInlineAsm(CI, MIRBuilder);
Intrinsic::ID ID = Intrinsic::not_intrinsic;
if (F && F->isIntrinsic()) {
ID = F->getIntrinsicID();
if (TII && ID == Intrinsic::not_intrinsic)
ID = static_cast<Intrinsic::ID>(TII->getIntrinsicID(F));
if (!F || !F->isIntrinsic() || ID == Intrinsic::not_intrinsic)
return translateCallBase(CI, MIRBuilder);
assert(ID != Intrinsic::not_intrinsic && "unknown intrinsic");
if (translateKnownIntrinsic(CI, ID, MIRBuilder))
return true;
ArrayRef<Register> ResultRegs;
if (!CI.getType()->isVoidTy())
ResultRegs = getOrCreateVRegs(CI);
// Ignore the callsite attributes. Backend code is most likely not expecting
// an intrinsic to sometimes have side effects and sometimes not.
MachineInstrBuilder MIB =
MIRBuilder.buildIntrinsic(ID, ResultRegs, !F->doesNotAccessMemory());
if (isa<FPMathOperator>(CI))
for (const auto &Arg : enumerate(CI.args())) {
// If this is required to be an immediate, don't materialize it in a
// register.
if (CI.paramHasAttr(Arg.index(), Attribute::ImmArg)) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(Arg.value())) {
// imm arguments are more convenient than cimm (and realistically
// probably sufficient), so use them.
assert(CI->getBitWidth() <= 64 &&
"large intrinsic immediates not handled");
} else {