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llvm-project/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
Matt Arsenault ec2234a21a InstCombine: Fold is.fpclass for single infinity to fcmp 
llvm.is.fpclass(x, fcPosInf) -> fcmp oeq x, +inf
llvm.is.fpclass(x, fcNegInf) -> fcmp oeq x, -inf
llvm.is.fpclass(x, ~fcPosInf) -> fcmp one x, +inf
llvm.is.fpclass(x, ~fcNegInf) -> fcmp one x, -inf

llvm.is.fpclass(x, fcPosInf|fcNan) -> fcmp ueq x, +inf
llvm.is.fpclass(x, fcNegInf|fcNan) -> fcmp ueq, -inf
llvm.is.fpclass(x, ~fcPosInf & ~fcNan) -> fcmp one, x, +inf
llvm.is.fpclass(x, ~fcNegInf & ~fcNan) -> fcmp one, x, -inf

This regresses some of the logic of fcmp tests. These should be restored
in a future patch to better handle combining logic of fcmp and class.
2023-03-17 11:52:16 -04:00

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//===- 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/STLFunctionalExtras.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumeBundleQueries.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/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/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsAArch64.h"
#include "llvm/IR/IntrinsicsAMDGPU.h"
#include "llvm/IR/IntrinsicsARM.h"
#include "llvm/IR/IntrinsicsHexagon.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/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/InstCombiner.h"
#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <optional>
#include <utility>
#include <vector>
#define DEBUG_TYPE "instcombine"
#include "llvm/Transforms/Utils/InstructionWorklist.h"
using namespace llvm;
using namespace PatternMatch;
STATISTIC(NumSimplified, "Number of library calls simplified");
static cl::opt<unsigned> GuardWideningWindow(
"instcombine-guard-widening-window",
cl::init(3),
cl::desc("How wide an instruction window to bypass looking for "
"another guard"));
namespace llvm {
/// enable preservation of attributes in assume like:
/// call void @llvm.assume(i1 true) [ "nonnull"(i32* %PTR) ]
extern cl::opt<bool> EnableKnowledgeRetention;
} // namespace llvm
/// Return the specified type promoted as it would be to pass though a va_arg
/// area.
static Type *getPromotedType(Type *Ty) {
if (IntegerType* ITy = dyn_cast<IntegerType>(Ty)) {
if (ITy->getBitWidth() < 32)
return Type::getInt32Ty(Ty->getContext());
}
return Ty;
}
/// Recognize a memcpy/memmove from a trivially otherwise unused alloca.
/// TODO: This should probably be integrated with visitAllocSites, but that
/// requires a deeper change to allow either unread or unwritten objects.
static bool hasUndefSource(AnyMemTransferInst *MI) {
auto *Src = MI->getRawSource();
while (isa<GetElementPtrInst>(Src) || isa<BitCastInst>(Src)) {
if (!Src->hasOneUse())
return false;
Src = cast<Instruction>(Src)->getOperand(0);
}
return isa<AllocaInst>(Src) && Src->hasOneUse();
}
Instruction *InstCombinerImpl::SimplifyAnyMemTransfer(AnyMemTransferInst *MI) {
Align DstAlign = getKnownAlignment(MI->getRawDest(), DL, MI, &AC, &DT);
MaybeAlign CopyDstAlign = MI->getDestAlign();
if (!CopyDstAlign || *CopyDstAlign < DstAlign) {
MI->setDestAlignment(DstAlign);
return MI;
}
Align SrcAlign = getKnownAlignment(MI->getRawSource(), DL, MI, &AC, &DT);
MaybeAlign CopySrcAlign = MI->getSourceAlign();
if (!CopySrcAlign || *CopySrcAlign < SrcAlign) {
MI->setSourceAlignment(SrcAlign);
return MI;
}
// If we have a store to a location which is known constant, we can conclude
// that the store must be storing the constant value (else the memory
// wouldn't be constant), and this must be a noop.
if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength(Constant::getNullValue(MI->getLength()->getType()));
return MI;
}
// If the source is provably undef, the memcpy/memmove doesn't do anything
// (unless the transfer is volatile).
if (hasUndefSource(MI) && !MI->isVolatile()) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength(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);
S->copyMetadata(*MI, LLVMContext::MD_DIAssignID);
if (auto *MT = dyn_cast<MemTransferInst>(MI)) {
// non-atomics can be volatile
L->setVolatile(MT->isVolatile());
S->setVolatile(MT->isVolatile());
}
if (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 (!isModSet(AA->getModRefInfoMask(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;
}
// Remove memset with an undef value.
// FIXME: This is technically incorrect because it might overwrite a poison
// value. Change to PoisonValue once #52930 is resolved.
if (isa<UndefValue>(MI->getValue())) {
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setLength(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 = MI->getDestAlign().valueOrOne();
// If it is an atomic and alignment is less than the size then we will
// introduce the unaligned memory access which will be later transformed
// into libcall in CodeGen. This is not evident performance gain so disable
// it now.
if (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.
const uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
Constant *FillVal = ConstantInt::get(ITy, Fill);
StoreInst *S = Builder.CreateStore(FillVal, Dest, MI->isVolatile());
S->copyMetadata(*MI, LLVMContext::MD_DIAssignID);
for (auto *DAI : at::getAssignmentMarkers(S)) {
if (any_of(DAI->location_ops(), [&](Value *V) { return V == FillC; }))
DAI->replaceVariableLocationOp(FillC, FillVal);
}
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))) {
LoadInst *L = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment,
"unmaskedload");
L->copyMetadata(II);
return L;
}
// If we can unconditionally load from this address, replace with a
// load/select idiom. TODO: use DT for context sensitive query
if (isDereferenceablePointer(LoadPtr, II.getType(),
II.getModule()->getDataLayout(), &II, &AC)) {
LoadInst *LI = Builder.CreateAlignedLoad(II.getType(), LoadPtr, Alignment,
"unmaskedload");
LI->copyMetadata(II);
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();
StoreInst *S =
new StoreInst(II.getArgOperand(0), StorePtr, false, Alignment);
S->copyMetadata(II);
return S;
}
if (isa<ScalableVectorType>(ConstMask->getType()))
return nullptr;
// Use masked off lanes to simplify operands via SimplifyDemandedVectorElts
APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask);
APInt 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 incrementing address -> vector masked load
Instruction *InstCombinerImpl::simplifyMaskedGather(IntrinsicInst &II) {
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(2));
if (!ConstMask)
return nullptr;
// Vector splat address w/known mask -> scalar load
// Fold the gather to load the source vector first lane
// because it is reloading the same value each time
if (ConstMask->isAllOnesValue())
if (auto *SplatPtr = getSplatValue(II.getArgOperand(0))) {
auto *VecTy = cast<VectorType>(II.getType());
const Align Alignment =
cast<ConstantInt>(II.getArgOperand(1))->getAlignValue();
LoadInst *L = Builder.CreateAlignedLoad(VecTy->getElementType(), SplatPtr,
Alignment, "load.scalar");
Value *Shuf =
Builder.CreateVectorSplat(VecTy->getElementCount(), L, "broadcast");
return replaceInstUsesWith(II, cast<Instruction>(Shuf));
}
return nullptr;
}
// TODO, Obvious Missing Transforms:
// * Single constant active lane -> store
// * Adjacent vector addresses -> masked.store
// * Narrow store width by halfs excluding zero/undef lanes
// * Vector incrementing address -> vector masked store
Instruction *InstCombinerImpl::simplifyMaskedScatter(IntrinsicInst &II) {
auto *ConstMask = dyn_cast<Constant>(II.getArgOperand(3));
if (!ConstMask)
return nullptr;
// If the mask is all zeros, a scatter does nothing.
if (ConstMask->isNullValue())
return eraseInstFromFunction(II);
// Vector splat address -> scalar store
if (auto *SplatPtr = getSplatValue(II.getArgOperand(1))) {
// scatter(splat(value), splat(ptr), non-zero-mask) -> store value, ptr
if (auto *SplatValue = getSplatValue(II.getArgOperand(0))) {
Align Alignment = cast<ConstantInt>(II.getArgOperand(2))->getAlignValue();
StoreInst *S =
new StoreInst(SplatValue, SplatPtr, /*IsVolatile=*/false, Alignment);
S->copyMetadata(II);
return S;
}
// scatter(vector, splat(ptr), splat(true)) -> store extract(vector,
// lastlane), ptr
if (ConstMask->isAllOnesValue()) {
Align Alignment = cast<ConstantInt>(II.getArgOperand(2))->getAlignValue();
VectorType *WideLoadTy = cast<VectorType>(II.getArgOperand(1)->getType());
ElementCount VF = WideLoadTy->getElementCount();
Value *RunTimeVF = Builder.CreateElementCount(Builder.getInt32Ty(), VF);
Value *LastLane = Builder.CreateSub(RunTimeVF, Builder.getInt32(1));
Value *Extract =
Builder.CreateExtractElement(II.getArgOperand(0), LastLane);
StoreInst *S =
new StoreInst(Extract, SplatPtr, /*IsVolatile=*/false, Alignment);
S->copyMetadata(II);
return S;
}
}
if (isa<ScalableVectorType>(ConstMask->getType()))
return nullptr;
// Use masked off lanes to simplify operands via SimplifyDemandedVectorElts
APInt DemandedElts = possiblyDemandedEltsInMask(ConstMask);
APInt 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 *Op1 = II.getArgOperand(1);
Value *X;
// ctlz(bitreverse(x)) -> cttz(x)
// cttz(bitreverse(x)) -> ctlz(x)
if (match(Op0, m_BitReverse(m_Value(X)))) {
Intrinsic::ID ID = IsTZ ? Intrinsic::ctlz : Intrinsic::cttz;
Function *F = Intrinsic::getDeclaration(II.getModule(), ID, II.getType());
return CallInst::Create(F, {X, II.getArgOperand(1)});
}
if (II.getType()->isIntOrIntVectorTy(1)) {
// ctlz/cttz i1 Op0 --> not Op0
if (match(Op1, m_Zero()))
return BinaryOperator::CreateNot(Op0);
// If zero is poison, then the input can be assumed to be "true", so the
// instruction simplifies to "false".
assert(match(Op1, m_One()) && "Expected ctlz/cttz operand to be 0 or 1");
return IC.replaceInstUsesWith(II, ConstantInt::getNullValue(II.getType()));
}
// If the operand is a select with constant arm(s), try to hoist ctlz/cttz.
if (auto *Sel = dyn_cast<SelectInst>(Op0))
if (Instruction *R = IC.FoldOpIntoSelect(II, Sel))
return R;
if (IsTZ) {
// cttz(-x) -> cttz(x)
if (match(Op0, m_Neg(m_Value(X))))
return IC.replaceOperand(II, 0, X);
// cttz(sext(x)) -> cttz(zext(x))
if (match(Op0, m_OneUse(m_SExt(m_Value(X))))) {
auto *Zext = IC.Builder.CreateZExt(X, II.getType());
auto *CttzZext =
IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, Zext, Op1);
return IC.replaceInstUsesWith(II, CttzZext);
}
// Zext doesn't change the number of trailing zeros, so narrow:
// cttz(zext(x)) -> zext(cttz(x)) if the 'ZeroIsPoison' parameter is 'true'.
if (match(Op0, m_OneUse(m_ZExt(m_Value(X)))) && match(Op1, m_One())) {
auto *Cttz = IC.Builder.CreateBinaryIntrinsic(Intrinsic::cttz, X,
IC.Builder.getTrue());
auto *ZextCttz = IC.Builder.CreateZExt(Cttz, II.getType());
return IC.replaceInstUsesWith(II, ZextCttz);
}
// cttz(abs(x)) -> cttz(x)
// cttz(nabs(x)) -> cttz(x)
Value *Y;
SelectPatternFlavor SPF = matchSelectPattern(Op0, X, Y).Flavor;
if (SPF == SPF_ABS || SPF == SPF_NABS)
return 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 'ZeroIsPoison' parameter to 'true'
// because we know the zero behavior can't affect the result.
if (!Known.One.isZero() ||
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.
auto *IT = cast<IntegerType>(Op0->getType()->getScalarType());
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, *Y;
// ctpop(bitreverse(x)) -> ctpop(x)
// ctpop(bswap(x)) -> ctpop(x)
if (match(Op0, m_BitReverse(m_Value(X))) || match(Op0, m_BSwap(m_Value(X))))
return IC.replaceOperand(II, 0, X);
// ctpop(rot(x)) -> ctpop(x)
if ((match(Op0, m_FShl(m_Value(X), m_Value(Y), m_Value())) ||
match(Op0, m_FShr(m_Value(X), m_Value(Y), m_Value()))) &&
X == Y)
return 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()});
}
// Zext doesn't change the number of set bits, so narrow:
// ctpop (zext X) --> zext (ctpop X)
if (match(Op0, m_OneUse(m_ZExt(m_Value(X))))) {
Value *NarrowPop = IC.Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, X);
return CastInst::Create(Instruction::ZExt, NarrowPop, Ty);
}
// If the operand is a select with constant arm(s), try to hoist ctpop.
if (auto *Sel = dyn_cast<SelectInst>(Op0))
if (Instruction *R = IC.FoldOpIntoSelect(II, Sel))
return R;
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
// TODO: Investigate removing this as its likely unnecessary given the below
// `isKnownToBeAPowerOfTwo` check.
if ((~Known.Zero).isPowerOf2())
return BinaryOperator::CreateLShr(
Op0, ConstantInt::get(Ty, (~Known.Zero).exactLogBase2()));
// More generally we can also handle non-constant power of 2 patterns such as
// shl/shr(Pow2, X), (X & -X), etc... by transforming:
// ctpop(Pow2OrZero) --> icmp ne X, 0
if (IC.isKnownToBeAPowerOfTwo(Op0, /* OrZero */ true))
return CastInst::Create(Instruction::ZExt,
IC.Builder.CreateICmp(ICmpInst::ICMP_NE, Op0,
Constant::getNullValue(Ty)),
Ty);
// Add range metadata since known bits can't completely reflect what we know.
auto *IT = cast<IntegerType>(Ty->getScalarType());
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, ArrayRef(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.arg_size() >= NumOperands && "Not enough operands");
assert(E.arg_size() >= NumOperands && "Not enough operands");
for (unsigned i = 0; i < NumOperands; i++)
if (I.getArgOperand(i) != E.getArgOperand(i))
return false;
return true;
}
// Remove trivially empty start/end intrinsic ranges, i.e. a start
// immediately followed by an end (ignoring debuginfo or other
// start/end intrinsics in between). As this handles only the most trivial
// cases, tracking the nesting level is not needed:
//
// call @llvm.foo.start(i1 0)
// call @llvm.foo.start(i1 0) ; This one won't be skipped: it will be removed
// call @llvm.foo.end(i1 0)
// call @llvm.foo.end(i1 0) ; &I
static bool
removeTriviallyEmptyRange(IntrinsicInst &EndI, InstCombinerImpl &IC,
std::function<bool(const IntrinsicInst &)> IsStart) {
// We start from the end intrinsic and scan backwards, so that InstCombine
// has already processed (and potentially removed) all the instructions
// before the end intrinsic.
BasicBlock::reverse_iterator BI(EndI), BE(EndI.getParent()->rend());
for (; BI != BE; ++BI) {
if (auto *I = dyn_cast<IntrinsicInst>(&*BI)) {
if (I->isDebugOrPseudoInst() ||
I->getIntrinsicID() == EndI.getIntrinsicID())
continue;
if (IsStart(*I)) {
if (haveSameOperands(EndI, *I, EndI.arg_size())) {
IC.eraseInstFromFunction(*I);
IC.eraseInstFromFunction(EndI);
return true;
}
// Skip start intrinsics that don't pair with this end intrinsic.
continue;
}
}
break;
}
return false;
}
Instruction *InstCombinerImpl::visitVAEndInst(VAEndInst &I) {
removeTriviallyEmptyRange(I, *this, [](const IntrinsicInst &I) {
return I.getIntrinsicID() == Intrinsic::vastart ||
I.getIntrinsicID() == Intrinsic::vacopy;
});
return nullptr;
}
static CallInst *canonicalizeConstantArg0ToArg1(CallInst &Call) {
assert(Call.arg_size() > 1 && "Need at least 2 args to swap");
Value *Arg0 = Call.getArgOperand(0), *Arg1 = Call.getArgOperand(1);
if (isa<Constant>(Arg0) && !isa<Constant>(Arg1)) {
Call.setArgOperand(0, Arg1);
Call.setArgOperand(1, Arg0);
return &Call;
}
return nullptr;
}
/// Creates a result tuple for an overflow intrinsic \p II with a given
/// \p Result and a constant \p Overflow value.
static Instruction *createOverflowTuple(IntrinsicInst *II, Value *Result,
Constant *Overflow) {
Constant *V[] = {PoisonValue::get(Result->getType()), Overflow};
StructType *ST = cast<StructType>(II->getType());
Constant *Struct = ConstantStruct::get(ST, V);
return InsertValueInst::Create(Struct, Result, 0);
}
Instruction *
InstCombinerImpl::foldIntrinsicWithOverflowCommon(IntrinsicInst *II) {
WithOverflowInst *WO = cast<WithOverflowInst>(II);
Value *OperationResult = nullptr;
Constant *OverflowResult = nullptr;
if (OptimizeOverflowCheck(WO->getBinaryOp(), WO->isSigned(), WO->getLHS(),
WO->getRHS(), *WO, OperationResult, OverflowResult))
return createOverflowTuple(WO, OperationResult, OverflowResult);
return nullptr;
}
/// \returns true if the test performed by llvm.is.fpclass(x, \p Mask) is
/// equivalent to fcmp oeq x, 0.0 with the floating-point environment assumed
/// for \p F for type \p Ty
static bool fpclassTestIsFCmp0(FPClassTest Mask, const Function &F, Type *Ty) {
if (Mask == fcZero)
return F.getDenormalMode(Ty->getScalarType()->getFltSemantics()).Input ==
DenormalMode::IEEE;
if (Mask == (fcZero | fcSubnormal)) {
DenormalMode::DenormalModeKind InputMode =
F.getDenormalMode(Ty->getScalarType()->getFltSemantics()).Input;
return InputMode == DenormalMode::PreserveSign ||
InputMode == DenormalMode::PositiveZero;
}
return false;
}
Instruction *InstCombinerImpl::foldIntrinsicIsFPClass(IntrinsicInst &II) {
Value *Src0 = II.getArgOperand(0);
Value *Src1 = II.getArgOperand(1);
const ConstantInt *CMask = cast<ConstantInt>(Src1);
FPClassTest Mask = static_cast<FPClassTest>(CMask->getZExtValue());
const bool IsUnordered = (Mask & fcNan) == fcNan;
const bool IsOrdered = (Mask & fcNan) == fcNone;
const FPClassTest OrderedMask = Mask & ~fcNan;
const FPClassTest OrderedInvertedMask = ~OrderedMask & ~fcNan;
const bool IsStrict = II.isStrictFP();
Value *FNegSrc;
if (match(Src0, m_FNeg(m_Value(FNegSrc)))) {
// is.fpclass (fneg x), mask -> is.fpclass x, (fneg mask)
II.setArgOperand(1, ConstantInt::get(Src1->getType(), fneg(Mask)));
return replaceOperand(II, 0, FNegSrc);
}
Value *FAbsSrc;
if (match(Src0, m_FAbs(m_Value(FAbsSrc)))) {
II.setArgOperand(1, ConstantInt::get(Src1->getType(), fabs(Mask)));
return replaceOperand(II, 0, FAbsSrc);
}
// TODO: is.fpclass(x, fcInf) -> fabs(x) == inf
if ((OrderedMask == fcPosInf || OrderedMask == fcNegInf) &&
(IsOrdered || IsUnordered) && !IsStrict) {
// is.fpclass(x, fcPosInf) -> fcmp oeq x, +inf
// is.fpclass(x, fcNegInf) -> fcmp oeq x, -inf
// is.fpclass(x, fcPosInf|fcNan) -> fcmp ueq x, +inf
// is.fpclass(x, fcNegInf|fcNan) -> fcmp ueq x, -inf
Constant *Inf =
ConstantFP::getInfinity(Src0->getType(), OrderedMask == fcNegInf);
Value *EqInf = IsUnordered ? Builder.CreateFCmpUEQ(Src0, Inf)
: Builder.CreateFCmpOEQ(Src0, Inf);
EqInf->takeName(&II);
return replaceInstUsesWith(II, EqInf);
}
if ((OrderedInvertedMask == fcPosInf || OrderedInvertedMask == fcNegInf) &&
(IsOrdered || IsUnordered) && !IsStrict) {
// is.fpclass(x, ~fcPosInf) -> fcmp one x, +inf
// is.fpclass(x, ~fcNegInf) -> fcmp one x, -inf
// is.fpclass(x, ~fcPosInf|fcNan) -> fcmp une x, +inf
// is.fpclass(x, ~fcNegInf|fcNan) -> fcmp une x, -inf
Constant *Inf = ConstantFP::getInfinity(Src0->getType(),
OrderedInvertedMask == fcNegInf);
Value *NeInf = IsUnordered ? Builder.CreateFCmpUNE(Src0, Inf)
: Builder.CreateFCmpONE(Src0, Inf);
NeInf->takeName(&II);
return replaceInstUsesWith(II, NeInf);
}
if (Mask == fcNan && !IsStrict) {
// Equivalent of isnan. Replace with standard fcmp if we don't care about FP
// exceptions.
Value *IsNan =
Builder.CreateFCmpUNO(Src0, ConstantFP::getZero(Src0->getType()));
IsNan->takeName(&II);
return replaceInstUsesWith(II, IsNan);
}
if (Mask == (~fcNan & fcAllFlags) && !IsStrict) {
// Equivalent of !isnan. Replace with standard fcmp.
Value *FCmp =
Builder.CreateFCmpORD(Src0, ConstantFP::getZero(Src0->getType()));
FCmp->takeName(&II);
return replaceInstUsesWith(II, FCmp);
}
if (!IsStrict && (IsOrdered || IsUnordered) &&
fpclassTestIsFCmp0(OrderedMask, *II.getFunction(), Src0->getType())) {
Constant *Zero = ConstantFP::getZero(Src0->getType());
// Equivalent of == 0.
Value *FCmp = IsUnordered ? Builder.CreateFCmpUEQ(Src0, Zero)
: Builder.CreateFCmpOEQ(Src0, Zero);
FCmp->takeName(&II);
return replaceInstUsesWith(II, FCmp);
}
if (!IsStrict && (IsOrdered || IsUnordered) &&
fpclassTestIsFCmp0(OrderedInvertedMask, *II.getFunction(),
Src0->getType())) {
Constant *Zero = ConstantFP::getZero(Src0->getType());
// Equivalent of !(x == 0).
Value *FCmp = IsUnordered ? Builder.CreateFCmpUNE(Src0, Zero)
: Builder.CreateFCmpONE(Src0, Zero);
FCmp->takeName(&II);
return replaceInstUsesWith(II, FCmp);
}
// fp_class (nnan x), qnan|snan|other -> fp_class (nnan x), other
if ((Mask & fcNan) && isKnownNeverNaN(Src0, &getTargetLibraryInfo())) {
II.setArgOperand(1, ConstantInt::get(Src1->getType(), Mask & ~fcNan));
return &II;
}
// fp_class (nnan x), ~(qnan|snan) -> true
if (Mask == (~fcNan & fcAllFlags) &&
isKnownNeverNaN(Src0, &getTargetLibraryInfo())) {
return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true));
}
// fp_class (ninf x), ninf|pinf|other -> fp_class (ninf x), other
if ((Mask & fcInf) && isKnownNeverInfinity(Src0, &getTargetLibraryInfo())) {
II.setArgOperand(1, ConstantInt::get(Src1->getType(), Mask & ~fcInf));
return &II;
}
// fp_class (ninf x), ~(ninf|pinf) -> true
if (Mask == (~fcInf & fcAllFlags) &&
isKnownNeverInfinity(Src0, &getTargetLibraryInfo())) {
return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true));
}
return nullptr;
}
static std::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;
Value *X, *Y;
if (match(Op, m_NSWSub(m_Value(X), m_Value(Y))))
return isImpliedByDomCondition(ICmpInst::ICMP_SLT, X, Y, CxtI, DL);
return isImpliedByDomCondition(
ICmpInst::ICMP_SLT, Op, Constant::getNullValue(Op->getType()), CxtI, DL);
}
/// Try to canonicalize min/max(X + C0, C1) as min/max(X, C1 - C0) + C0. This
/// can trigger other combines.
static Instruction *moveAddAfterMinMax(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
Intrinsic::ID MinMaxID = II->getIntrinsicID();
assert((MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin ||
MinMaxID == Intrinsic::umax || MinMaxID == Intrinsic::umin) &&
"Expected a min or max intrinsic");
// TODO: Match vectors with undef elements, but undef may not propagate.
Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1);
Value *X;
const APInt *C0, *C1;
if (!match(Op0, m_OneUse(m_Add(m_Value(X), m_APInt(C0)))) ||
!match(Op1, m_APInt(C1)))
return nullptr;
// Check for necessary no-wrap and overflow constraints.
bool IsSigned = MinMaxID == Intrinsic::smax || MinMaxID == Intrinsic::smin;
auto *Add = cast<BinaryOperator>(Op0);
if ((IsSigned && !Add->hasNoSignedWrap()) ||
(!IsSigned && !Add->hasNoUnsignedWrap()))
return nullptr;
// If the constant difference overflows, then instsimplify should reduce the
// min/max to the add or C1.
bool Overflow;
APInt CDiff =
IsSigned ? C1->ssub_ov(*C0, Overflow) : C1->usub_ov(*C0, Overflow);
assert(!Overflow && "Expected simplify of min/max");
// min/max (add X, C0), C1 --> add (min/max X, C1 - C0), C0
// Note: the "mismatched" no-overflow setting does not propagate.
Constant *NewMinMaxC = ConstantInt::get(II->getType(), CDiff);
Value *NewMinMax = Builder.CreateBinaryIntrinsic(MinMaxID, X, NewMinMaxC);
return IsSigned ? BinaryOperator::CreateNSWAdd(NewMinMax, Add->getOperand(1))
: BinaryOperator::CreateNUWAdd(NewMinMax, Add->getOperand(1));
}
/// Match a sadd_sat or ssub_sat which is using min/max to clamp the value.
Instruction *InstCombinerImpl::matchSAddSubSat(IntrinsicInst &MinMax1) {
Type *Ty = MinMax1.getType();
// We are looking for a tree of:
// max(INT_MIN, min(INT_MAX, add(sext(A), sext(B))))
// Where the min and max could be reversed
Instruction *MinMax2;
BinaryOperator *AddSub;
const APInt *MinValue, *MaxValue;
if (match(&MinMax1, m_SMin(m_Instruction(MinMax2), m_APInt(MaxValue)))) {
if (!match(MinMax2, m_SMax(m_BinOp(AddSub), m_APInt(MinValue))))
return nullptr;
} else if (match(&MinMax1,
m_SMax(m_Instruction(MinMax2), m_APInt(MinValue)))) {
if (!match(MinMax2, m_SMin(m_BinOp(AddSub), m_APInt(MaxValue))))
return nullptr;
} else
return nullptr;
// Check that the constants clamp a saturate, and that the new type would be
// sensible to convert to.
if (!(*MaxValue + 1).isPowerOf2() || -*MinValue != *MaxValue + 1)
return nullptr;
// In what bitwidth can this be treated as saturating arithmetics?
unsigned NewBitWidth = (*MaxValue + 1).logBase2() + 1;
// FIXME: This isn't quite right for vectors, but using the scalar type is a
// good first approximation for what should be done there.
if (!shouldChangeType(Ty->getScalarType()->getIntegerBitWidth(), NewBitWidth))
return nullptr;
// Also make sure that the inner min/max and the add/sub have one use.
if (!MinMax2->hasOneUse() || !AddSub->hasOneUse())
return nullptr;
// Create the new type (which can be a vector type)
Type *NewTy = Ty->getWithNewBitWidth(NewBitWidth);
Intrinsic::ID IntrinsicID;
if (AddSub->getOpcode() == Instruction::Add)
IntrinsicID = Intrinsic::sadd_sat;
else if (AddSub->getOpcode() == Instruction::Sub)
IntrinsicID = Intrinsic::ssub_sat;
else
return nullptr;
// The two operands of the add/sub must be nsw-truncatable to the NewTy. This
// is usually achieved via a sext from a smaller type.
if (ComputeMaxSignificantBits(AddSub->getOperand(0), 0, AddSub) >
NewBitWidth ||
ComputeMaxSignificantBits(AddSub->getOperand(1), 0, AddSub) > NewBitWidth)
return nullptr;
// Finally create and return the sat intrinsic, truncated to the new type
Function *F = Intrinsic::getDeclaration(MinMax1.getModule(), IntrinsicID, NewTy);
Value *AT = Builder.CreateTrunc(AddSub->getOperand(0), NewTy);
Value *BT = Builder.CreateTrunc(AddSub->getOperand(1), NewTy);
Value *Sat = Builder.CreateCall(F, {AT, BT});
return CastInst::Create(Instruction::SExt, Sat, Ty);
}
/// If we have a clamp pattern like max (min X, 42), 41 -- where the output
/// can only be one of two possible constant values -- turn that into a select
/// of constants.
static Instruction *foldClampRangeOfTwo(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
Value *X;
const APInt *C0, *C1;
if (!match(I1, m_APInt(C1)) || !I0->hasOneUse())
return nullptr;
CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE;
switch (II->getIntrinsicID()) {
case Intrinsic::smax:
if (match(I0, m_SMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1)
Pred = ICmpInst::ICMP_SGT;
break;
case Intrinsic::smin:
if (match(I0, m_SMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1)
Pred = ICmpInst::ICMP_SLT;
break;
case Intrinsic::umax:
if (match(I0, m_UMin(m_Value(X), m_APInt(C0))) && *C0 == *C1 + 1)
Pred = ICmpInst::ICMP_UGT;
break;
case Intrinsic::umin:
if (match(I0, m_UMax(m_Value(X), m_APInt(C0))) && *C1 == *C0 + 1)
Pred = ICmpInst::ICMP_ULT;
break;
default:
llvm_unreachable("Expected min/max intrinsic");
}
if (Pred == CmpInst::BAD_ICMP_PREDICATE)
return nullptr;
// max (min X, 42), 41 --> X > 41 ? 42 : 41
// min (max X, 42), 43 --> X < 43 ? 42 : 43
Value *Cmp = Builder.CreateICmp(Pred, X, I1);
return SelectInst::Create(Cmp, ConstantInt::get(II->getType(), *C0), I1);
}
/// If this min/max has a constant operand and an operand that is a matching
/// min/max with a constant operand, constant-fold the 2 constant operands.
static Value *reassociateMinMaxWithConstants(IntrinsicInst *II,
IRBuilderBase &Builder) {
Intrinsic::ID MinMaxID = II->getIntrinsicID();
auto *LHS = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
if (!LHS || LHS->getIntrinsicID() != MinMaxID)
return nullptr;
Constant *C0, *C1;
if (!match(LHS->getArgOperand(1), m_ImmConstant(C0)) ||
!match(II->getArgOperand(1), m_ImmConstant(C1)))
return nullptr;
// max (max X, C0), C1 --> max X, (max C0, C1) --> max X, NewC
ICmpInst::Predicate Pred = MinMaxIntrinsic::getPredicate(MinMaxID);
Value *CondC = Builder.CreateICmp(Pred, C0, C1);
Value *NewC = Builder.CreateSelect(CondC, C0, C1);
return Builder.CreateIntrinsic(MinMaxID, II->getType(),
{LHS->getArgOperand(0), NewC});
}
/// If this min/max has a matching min/max operand with a constant, try to push
/// the constant operand into this instruction. This can enable more folds.
static Instruction *
reassociateMinMaxWithConstantInOperand(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
// Match and capture a min/max operand candidate.
Value *X, *Y;
Constant *C;
Instruction *Inner;
if (!match(II, m_c_MaxOrMin(m_OneUse(m_CombineAnd(
m_Instruction(Inner),
m_MaxOrMin(m_Value(X), m_ImmConstant(C)))),
m_Value(Y))))
return nullptr;
// The inner op must match. Check for constants to avoid infinite loops.
Intrinsic::ID MinMaxID = II->getIntrinsicID();
auto *InnerMM = dyn_cast<IntrinsicInst>(Inner);
if (!InnerMM || InnerMM->getIntrinsicID() != MinMaxID ||
match(X, m_ImmConstant()) || match(Y, m_ImmConstant()))
return nullptr;
// max (max X, C), Y --> max (max X, Y), C
Function *MinMax =
Intrinsic::getDeclaration(II->getModule(), MinMaxID, II->getType());
Value *NewInner = Builder.CreateBinaryIntrinsic(MinMaxID, X, Y);
NewInner->takeName(Inner);
return CallInst::Create(MinMax, {NewInner, C});
}
/// Reduce a sequence of min/max intrinsics with a common operand.
static Instruction *factorizeMinMaxTree(IntrinsicInst *II) {
// Match 3 of the same min/max ops. Example: umin(umin(), umin()).
auto *LHS = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
auto *RHS = dyn_cast<IntrinsicInst>(II->getArgOperand(1));
Intrinsic::ID MinMaxID = II->getIntrinsicID();
if (!LHS || !RHS || LHS->getIntrinsicID() != MinMaxID ||
RHS->getIntrinsicID() != MinMaxID ||
(!LHS->hasOneUse() && !RHS->hasOneUse()))
return nullptr;
Value *A = LHS->getArgOperand(0);
Value *B = LHS->getArgOperand(1);
Value *C = RHS->getArgOperand(0);
Value *D = RHS->getArgOperand(1);
// Look for a common operand.
Value *MinMaxOp = nullptr;
Value *ThirdOp = nullptr;
if (LHS->hasOneUse()) {
// If the LHS is only used in this chain and the RHS is used outside of it,
// reuse the RHS min/max because that will eliminate the LHS.
if (D == A || C == A) {
// min(min(a, b), min(c, a)) --> min(min(c, a), b)
// min(min(a, b), min(a, d)) --> min(min(a, d), b)
MinMaxOp = RHS;
ThirdOp = B;
} else if (D == B || C == B) {
// min(min(a, b), min(c, b)) --> min(min(c, b), a)
// min(min(a, b), min(b, d)) --> min(min(b, d), a)
MinMaxOp = RHS;
ThirdOp = A;
}
} else {
assert(RHS->hasOneUse() && "Expected one-use operand");
// Reuse the LHS. This will eliminate the RHS.
if (D == A || D == B) {
// min(min(a, b), min(c, a)) --> min(min(a, b), c)
// min(min(a, b), min(c, b)) --> min(min(a, b), c)
MinMaxOp = LHS;
ThirdOp = C;
} else if (C == A || C == B) {
// min(min(a, b), min(b, d)) --> min(min(a, b), d)
// min(min(a, b), min(c, b)) --> min(min(a, b), d)
MinMaxOp = LHS;
ThirdOp = D;
}
}
if (!MinMaxOp || !ThirdOp)
return nullptr;
Module *Mod = II->getModule();
Function *MinMax = Intrinsic::getDeclaration(Mod, MinMaxID, II->getType());
return CallInst::Create(MinMax, { MinMaxOp, ThirdOp });
}
/// If all arguments of the intrinsic are unary shuffles with the same mask,
/// try to shuffle after the intrinsic.
static Instruction *
foldShuffledIntrinsicOperands(IntrinsicInst *II,
InstCombiner::BuilderTy &Builder) {
// TODO: This should be extended to handle other intrinsics like fshl, ctpop,
// etc. Use llvm::isTriviallyVectorizable() and related to determine
// which intrinsics are safe to shuffle?
switch (II->getIntrinsicID()) {
case Intrinsic::smax:
case Intrinsic::smin:
case Intrinsic::umax:
case Intrinsic::umin:
case Intrinsic::fma:
case Intrinsic::fshl:
case Intrinsic::fshr:
break;
default:
return nullptr;
}
Value *X;
ArrayRef<int> Mask;
if (!match(II->getArgOperand(0),
m_Shuffle(m_Value(X), m_Undef(), m_Mask(Mask))))
return nullptr;
// At least 1 operand must have 1 use because we are creating 2 instructions.
if (none_of(II->args(), [](Value *V) { return V->hasOneUse(); }))
return nullptr;
// See if all arguments are shuffled with the same mask.
SmallVector<Value *, 4> NewArgs(II->arg_size());
NewArgs[0] = X;
Type *SrcTy = X->getType();
for (unsigned i = 1, e = II->arg_size(); i != e; ++i) {
if (!match(II->getArgOperand(i),
m_Shuffle(m_Value(X), m_Undef(), m_SpecificMask(Mask))) ||
X->getType() != SrcTy)
return nullptr;
NewArgs[i] = X;
}
// intrinsic (shuf X, M), (shuf Y, M), ... --> shuf (intrinsic X, Y, ...), M
Instruction *FPI = isa<FPMathOperator>(II) ? II : nullptr;
Value *NewIntrinsic =
Builder.CreateIntrinsic(II->getIntrinsicID(), SrcTy, NewArgs, FPI);
return new ShuffleVectorInst(NewIntrinsic, Mask);
}
/// 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 (Value *FreedOp = getFreedOperand(&CI, &TLI))
return visitFree(CI, FreedOp);
// If the caller function (i.e. us, the function that contains this CallInst)
// is nounwind, mark the call as nounwind, even if the callee isn't.
if (CI.getFunction()->doesNotThrow() && !CI.doesNotThrow()) {
CI.setDoesNotThrow();
return &CI;
}
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
if (!II) return visitCallBase(CI);
// 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);
}
// 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::getAllOnes(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;
}
// Unused constrained FP intrinsic calls may have declared side effect, which
// prevents it from being removed. In some cases however the side effect is
// actually absent. To detect this case, call SimplifyConstrainedFPCall. If it
// returns a replacement, the call may be removed.
if (CI.use_empty() && isa<ConstrainedFPIntrinsic>(CI)) {
if (simplifyConstrainedFPCall(&CI, SQ.getWithInstruction(&CI)))
return eraseInstFromFunction(CI);
}
Intrinsic::ID IID = II->getIntrinsicID();
switch (IID) {
case Intrinsic::objectsize:
if (Value *V = lowerObjectSizeCall(II, DL, &TLI, AA, /*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 (std::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::umin: {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
// umin(x, 1) == zext(x != 0)
if (match(I1, m_One())) {
assert(II->getType()->getScalarSizeInBits() != 1 &&
"Expected simplify of umin with max constant");
Value *Zero = Constant::getNullValue(I0->getType());
Value *Cmp = Builder.CreateICmpNE(I0, Zero);
return CastInst::Create(Instruction::ZExt, Cmp, II->getType());
}
[[fallthrough]];
}
case Intrinsic::umax: {
Value *I0 = II->getArgOperand(0), *I1 = II->getArgOperand(1);
Value *X, *Y;
if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_ZExt(m_Value(Y))) &&
(I0->hasOneUse() || I1->hasOneUse()) && X->getType() == Y->getType()) {
Value *NarrowMaxMin = Builder.CreateBinaryIntrinsic(IID, X, Y);
return CastInst::Create(Instruction::ZExt, NarrowMaxMin, II->getType());
}
Constant *C;
if (match(I0, m_ZExt(m_Value(X))) && match(I1, m_Constant(C)) &&
I0->hasOneUse()) {
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.
[[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 (IID == Intrinsic::smax || IID == Intrinsic::smin) {
// smax (neg nsw X), (neg nsw Y) --> neg nsw (smin X, Y)
// smin (neg nsw X), (neg nsw Y) --> neg nsw (smax X, Y)
// TODO: Canonicalize neg after min/max if I1 is constant.
if (match(I0, m_NSWNeg(m_Value(X))) && match(I1, m_NSWNeg(m_Value(Y))) &&
(I0->hasOneUse() || I1->hasOneUse())) {
Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID);
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, Y);
return BinaryOperator::CreateNSWNeg(InvMaxMin);
}
}
// (umax X, (xor X, Pow2))
// -> (or X, Pow2)
// (umin X, (xor X, Pow2))
// -> (and X, ~Pow2)
// (smax X, (xor X, Pos_Pow2))
// -> (or X, Pos_Pow2)
// (smin X, (xor X, Pos_Pow2))
// -> (and X, ~Pos_Pow2)
// (smax X, (xor X, Neg_Pow2))
// -> (and X, ~Neg_Pow2)
// (smin X, (xor X, Neg_Pow2))
// -> (or X, Neg_Pow2)
if ((match(I0, m_c_Xor(m_Specific(I1), m_Value(X))) ||
match(I1, m_c_Xor(m_Specific(I0), m_Value(X)))) &&
isKnownToBeAPowerOfTwo(X, /* OrZero */ true)) {
bool UseOr = IID == Intrinsic::smax || IID == Intrinsic::umax;
bool UseAndN = IID == Intrinsic::smin || IID == Intrinsic::umin;
if (IID == Intrinsic::smax || IID == Intrinsic::smin) {
auto KnownSign = getKnownSign(X, II, DL, &AC, &DT);
if (KnownSign == std::nullopt) {
UseOr = false;
UseAndN = false;
} else if (*KnownSign /* true is Signed. */) {
UseOr ^= true;
UseAndN ^= true;
Type *Ty = I0->getType();
// Negative power of 2 must be IntMin. It's possible to be able to
// prove negative / power of 2 without actually having known bits, so
// just get the value by hand.
X = Constant::getIntegerValue(
Ty, APInt::getSignedMinValue(Ty->getScalarSizeInBits()));
}
}
if (UseOr)
return BinaryOperator::CreateOr(I0, X);
else if (UseAndN)
return BinaryOperator::CreateAnd(I0, Builder.CreateNot(X));
}
// If we can eliminate ~A and Y is free to invert:
// max ~A, Y --> ~(min A, ~Y)
//
// Examples:
// max ~A, ~Y --> ~(min A, Y)
// max ~A, C --> ~(min A, ~C)
// max ~A, (max ~Y, ~Z) --> ~min( A, (min Y, Z))
auto moveNotAfterMinMax = [&](Value *X, Value *Y) -> Instruction * {
Value *A;
if (match(X, m_OneUse(m_Not(m_Value(A)))) &&
!isFreeToInvert(A, A->hasOneUse()) &&
isFreeToInvert(Y, Y->hasOneUse())) {
Value *NotY = Builder.CreateNot(Y);
Intrinsic::ID InvID = getInverseMinMaxIntrinsic(IID);
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, A, NotY);
return BinaryOperator::CreateNot(InvMaxMin);
}
return nullptr;
};
if (Instruction *I = moveNotAfterMinMax(I0, I1))
return I;
if (Instruction *I = moveNotAfterMinMax(I1, I0))
return I;
if (Instruction *I = moveAddAfterMinMax(II, Builder))
return I;
// 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);
}
if (Instruction *Sel = foldClampRangeOfTwo(II, Builder))
return Sel;
if (Instruction *SAdd = matchSAddSubSat(*II))
return SAdd;
if (match(I1, m_ImmConstant()))
if (auto *Sel = dyn_cast<SelectInst>(I0))
if (Instruction *R = FoldOpIntoSelect(*II, Sel))
return R;
if (Value *NewMinMax = reassociateMinMaxWithConstants(II, Builder))
return replaceInstUsesWith(*II, NewMinMax);
if (Instruction *R = reassociateMinMaxWithConstantInOperand(II, Builder))
return R;
if (Instruction *NewMinMax = factorizeMinMaxTree(II))
return NewMinMax;
break;
}
case Intrinsic::bitreverse: {
// bitrev (zext i1 X to ?) --> X ? SignBitC : 0
Value *X;
if (match(II->getArgOperand(0), m_ZExt(m_Value(X))) &&
X->getType()->isIntOrIntVectorTy(1)) {
Type *Ty = II->getType();
APInt SignBit = APInt::getSignMask(Ty->getScalarSizeInBits());
return SelectInst::Create(X, ConstantInt::get(Ty, SignBit),
ConstantInt::getNullValue(Ty));
}
break;
}
case Intrinsic::bswap: {
Value *IIOperand = II->getArgOperand(0);
// Try to canonicalize bswap-of-logical-shift-by-8-bit-multiple as
// inverse-shift-of-bswap:
// bswap (shl X, Y) --> lshr (bswap X), Y
// bswap (lshr X, Y) --> shl (bswap X), Y
Value *X, *Y;
if (match(IIOperand, m_OneUse(m_LogicalShift(m_Value(X), m_Value(Y))))) {
// The transform allows undef vector elements, so try a constant match
// first. If knownbits can handle that case, that clause could be removed.
unsigned BitWidth = IIOperand->getType()->getScalarSizeInBits();
const APInt *C;
if ((match(Y, m_APIntAllowUndef(C)) && (*C & 7) == 0) ||
MaskedValueIsZero(Y, APInt::getLowBitsSet(BitWidth, 3))) {
Value *NewSwap = Builder.CreateUnaryIntrinsic(Intrinsic::bswap, X);
BinaryOperator::BinaryOps InverseShift =
cast<BinaryOperator>(IIOperand)->getOpcode() == Instruction::Shl
? Instruction::LShr
: Instruction::Shl;
return BinaryOperator::Create(InverseShift, NewSwap, Y);
}
}
KnownBits Known = computeKnownBits(IIOperand, 0, II);
uint64_t LZ = alignDown(Known.countMinLeadingZeros(), 8);
uint64_t TZ = alignDown(Known.countMinTrailingZeros(), 8);
unsigned BW = Known.getBitWidth();
// bswap(x) -> shift(x) if x has exactly one "active byte"
if (BW - LZ - TZ == 8) {
assert(LZ != TZ && "active byte cannot be in the middle");
if (LZ > TZ) // -> shl(x) if the "active byte" is in the low part of x
return BinaryOperator::CreateNUWShl(
IIOperand, ConstantInt::get(IIOperand->getType(), LZ - TZ));
// -> lshr(x) if the "active byte" is in the high part of x
return BinaryOperator::CreateExactLShr(
IIOperand, ConstantInt::get(IIOperand->getType(), TZ - LZ));
}
// bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) {
unsigned C = X->getType()->getScalarSizeInBits() - BW;
Value *CV = ConstantInt::get(X->getType(), C);
Value *V = Builder.CreateLShr(X, CV);
return new TruncInst(V, IIOperand->getType());
}
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);
if (!Power->getValue()[0]) {
Value *X;
// If power is even:
// powi(-x, p) -> powi(x, p)
// powi(fabs(x), p) -> powi(x, p)
// powi(copysign(x, y), p) -> powi(x, p)
if (match(II->getArgOperand(0), m_FNeg(m_Value(X))) ||
match(II->getArgOperand(0), m_FAbs(m_Value(X))) ||
match(II->getArgOperand(0),
m_Intrinsic<Intrinsic::copysign>(m_Value(X), m_Value())))
return replaceOperand(*II, 0, X);
}
}
break;
case Intrinsic::cttz:
case Intrinsic::ctlz:
if (auto *I = foldCttzCtlz(*II, *this))
return I;
break;
case Intrinsic::ctpop:
if (auto *I = foldCtpop(*II, *this))
return I;
break;
case Intrinsic::fshl:
case Intrinsic::fshr: {
Value *Op0 = II->getArgOperand(0), *Op1 = II->getArgOperand(1);
Type *Ty = II->getType();
unsigned BitWidth = Ty->getScalarSizeInBits();
Constant *ShAmtC;
if (match(II->getArgOperand(2), m_ImmConstant(ShAmtC))) {
// Canonicalize a shift amount constant operand to modulo the bit-width.
Constant *WidthC = ConstantInt::get(Ty, BitWidth);
Constant *ModuloC =
ConstantFoldBinaryOpOperands(Instruction::URem, ShAmtC, WidthC, DL);
if (!ModuloC)
return nullptr;
if (ModuloC != ShAmtC)
return 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);
}
}
// m((fpext X), (fpext Y)) -> fpext (m(X, Y))
if (match(Arg0, m_OneUse(m_FPExt(m_Value(X)))) &&
match(Arg1, m_OneUse(m_FPExt(m_Value(Y)))) &&
X->getType() == Y->getType()) {
Value *NewCall =
Builder.CreateBinaryIntrinsic(IID, X, Y, II, II->getName());
return new FPExtInst(NewCall, II->getType());
}
// max X, -X --> fabs X
// min X, -X --> -(fabs X)
// TODO: Remove one-use limitation? That is obviously better for max.
// It would be an extra instruction for min (fnabs), but that is
// still likely better for analysis and codegen.
if ((match(Arg0, m_OneUse(m_FNeg(m_Value(X)))) && Arg1 == X) ||
(match(Arg1, m_OneUse(m_FNeg(m_Value(X)))) && Arg0 == X)) {
Value *R = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, II);
if (IID == Intrinsic::minimum || IID == Intrinsic::minnum)
R = Builder.CreateFNegFMF(R, II);
return replaceInstUsesWith(*II, R);
}
break;
}
case Intrinsic::matrix_multiply: {
// Optimize negation in matrix multiplication.
// -A * -B -> A * B
Value *A, *B;
if (match(II->getArgOperand(0), m_FNeg(m_Value(A))) &&
match(II->getArgOperand(1), m_FNeg(m_Value(B)))) {
replaceOperand(*II, 0, A);
replaceOperand(*II, 1, B);
return II;
}
Value *Op0 = II->getOperand(0);
Value *Op1 = II->getOperand(1);
Value *OpNotNeg, *NegatedOp;
unsigned NegatedOpArg, OtherOpArg;
if (match(Op0, m_FNeg(m_Value(OpNotNeg)))) {
NegatedOp = Op0;
NegatedOpArg = 0;
OtherOpArg = 1;
} else if (match(Op1, m_FNeg(m_Value(OpNotNeg)))) {
NegatedOp = Op1;
NegatedOpArg = 1;
OtherOpArg = 0;
} else
// Multiplication doesn't have a negated operand.
break;
// Only optimize if the negated operand has only one use.
if (!NegatedOp->hasOneUse())
break;
Value *OtherOp = II->getOperand(OtherOpArg);
VectorType *RetTy = cast<VectorType>(II->getType());
VectorType *NegatedOpTy = cast<VectorType>(NegatedOp->getType());
VectorType *OtherOpTy = cast<VectorType>(OtherOp->getType());
ElementCount NegatedCount = NegatedOpTy->getElementCount();
ElementCount OtherCount = OtherOpTy->getElementCount();
ElementCount RetCount = RetTy->getElementCount();
// (-A) * B -> A * (-B), if it is cheaper to negate B and vice versa.
if (ElementCount::isKnownGT(NegatedCount, OtherCount) &&
ElementCount::isKnownLT(OtherCount, RetCount)) {
Value *InverseOtherOp = Builder.CreateFNeg(OtherOp);
replaceOperand(*II, NegatedOpArg, OpNotNeg);
replaceOperand(*II, OtherOpArg, InverseOtherOp);
return II;
}
// (-A) * B -> -(A * B), if it is cheaper to negate the result
if (ElementCount::isKnownGT(NegatedCount, RetCount)) {
SmallVector<Value *, 5> NewArgs(II->args());
NewArgs[NegatedOpArg] = OpNotNeg;
Instruction *NewMul =
Builder.CreateIntrinsic(II->getType(), IID, NewArgs, II);
return replaceInstUsesWith(*II, Builder.CreateFNegFMF(NewMul, II));
}
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;
}
[[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);
}
Value *Magnitude, *Sign;
if (match(II->getArgOperand(0),
m_CopySign(m_Value(Magnitude), m_Value(Sign)))) {
// fabs (copysign x, y) -> (fabs x)
CallInst *AbsSign =
Builder.CreateCall(II->getCalledFunction(), {Magnitude});
AbsSign->copyFastMathFlags(II);
return replaceInstUsesWith(*II, AbsSign);
}
[[fallthrough]];
}
case Intrinsic::ceil:
case Intrinsic::floor:
case Intrinsic::round:
case Intrinsic::roundeven:
case Intrinsic::nearbyint:
case Intrinsic::rint:
case Intrinsic::trunc: {
Value *ExtSrc;
if (match(II->getArgOperand(0), m_OneUse(m_FPExt(m_Value(ExtSrc))))) {
// Narrow the call: intrinsic (fpext x) -> fpext (intrinsic x)
Value *NarrowII = Builder.CreateUnaryIntrinsic(IID, ExtSrc, II);
return new FPExtInst(NarrowII, II->getType());
}
break;
}
case Intrinsic::cos:
case Intrinsic::amdgcn_cos: {
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::ptrauth_auth:
case Intrinsic::ptrauth_resign: {
// (sign|resign) + (auth|resign) can be folded by omitting the middle
// sign+auth component if the key and discriminator match.
bool NeedSign = II->getIntrinsicID() == Intrinsic::ptrauth_resign;
Value *Key = II->getArgOperand(1);
Value *Disc = II->getArgOperand(2);
// AuthKey will be the key we need to end up authenticating against in
// whatever we replace this sequence with.
Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr;
if (auto CI = dyn_cast<CallBase>(II->getArgOperand(0))) {
BasePtr = CI->getArgOperand(0);
if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) {
if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc)
break;
} else if (CI->getIntrinsicID() == Intrinsic::ptrauth_resign) {
if (CI->getArgOperand(3) != Key || CI->getArgOperand(4) != Disc)
break;
AuthKey = CI->getArgOperand(1);
AuthDisc = CI->getArgOperand(2);
} else
break;
} else
break;
unsigned NewIntrin;
if (AuthKey && NeedSign) {
// resign(0,1) + resign(1,2) = resign(0, 2)
NewIntrin = Intrinsic::ptrauth_resign;
} else if (AuthKey) {
// resign(0,1) + auth(1) = auth(0)
NewIntrin = Intrinsic::ptrauth_auth;
} else if (NeedSign) {
// sign(0) + resign(0, 1) = sign(1)
NewIntrin = Intrinsic::ptrauth_sign;
} else {
// sign(0) + auth(0) = nop
replaceInstUsesWith(*II, BasePtr);
eraseInstFromFunction(*II);
return nullptr;
}
SmallVector<Value *, 4> CallArgs;
CallArgs.push_back(BasePtr);
if (AuthKey) {
CallArgs.push_back(AuthKey);
CallArgs.push_back(AuthDisc);
}
if (NeedSign) {
CallArgs.push_back(II->getArgOperand(3));
CallArgs.push_back(II->getArgOperand(4));
}
Function *NewFn = Intrinsic::getDeclaration(II->getModule(), NewIntrin);
return CallInst::Create(NewFn, CallArgs);
}
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: {
enum class ClassifyResult {
None,
Alloca,
StackRestore,
CallWithSideEffects,
};
auto Classify = [](const Instruction *I) {
if (isa<AllocaInst>(I))
return ClassifyResult::Alloca;
if (auto *CI = dyn_cast<CallInst>(I)) {
if (auto *II = dyn_cast<IntrinsicInst>(CI)) {
if (II->getIntrinsicID() == Intrinsic::stackrestore)
return ClassifyResult::StackRestore;
if (II->mayHaveSideEffects())
return ClassifyResult::CallWithSideEffects;
} else {
// Consider all non-intrinsic calls to be side effects
return ClassifyResult::CallWithSideEffects;
}
}
return ClassifyResult::None;
};
// If the stacksave and the stackrestore are in the same BB, and there is
// no intervening call, alloca, or stackrestore of a different stacksave,
// remove the restore. This can happen when variable allocas are DCE'd.
if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
if (SS->getIntrinsicID() == Intrinsic::stacksave &&
SS->getParent() == II->getParent()) {
BasicBlock::iterator BI(SS);
bool CannotRemove = false;
for (++BI; &*BI != II; ++BI) {
switch (Classify(&*BI)) {
case ClassifyResult::None:
// So far so good, look at next instructions.
break;
case ClassifyResult::StackRestore:
// If we found an intervening stackrestore for a different
// stacksave, we can't remove the stackrestore. Otherwise, continue.
if (cast<IntrinsicInst>(*BI).getArgOperand(0) != SS)
CannotRemove = true;
break;
case ClassifyResult::Alloca:
case ClassifyResult::CallWithSideEffects:
// If we found an alloca, a non-intrinsic call, or an intrinsic
// call with side effects, we can't remove the stackrestore.
CannotRemove = true;
break;
}
if (CannotRemove)
break;
}
if (!CannotRemove)
return eraseInstFromFunction(CI);
}
}
// Scan down this block to see if there is another stack restore in the
// same block without an intervening call/alloca.
BasicBlock::iterator BI(II);
Instruction *TI = II->getParent()->getTerminator();
bool CannotRemove = false;
for (++BI; &*BI != TI; ++BI) {
switch (Classify(&*BI)) {
case ClassifyResult::None:
// So far so good, look at next instructions.
break;
case ClassifyResult::StackRestore:
// If there is a stackrestore below this one, remove this one.
return eraseInstFromFunction(CI);
case ClassifyResult::Alloca:
case ClassifyResult::CallWithSideEffects:
// If we found an alloca, a non-intrinsic call, or an intrinsic call
// with side effects (such as llvm.stacksave and llvm.read_register),
// we can't remove the stack restore.
CannotRemove = true;
break;
}
if (CannotRemove)
break;
}
// If the stack restore is in a return, resume, or unwind block and if there
// are no allocas or calls between the restore and the return, nuke the
// restore.
if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI)))
return eraseInstFromFunction(CI);
break;
}
case Intrinsic::lifetime_end:
// Asan needs to poison memory to detect invalid access which is possible
// even for empty lifetime range.
if (II->getFunction()->hasFnAttribute(Attribute::SanitizeAddress) ||
II->getFunction()->hasFnAttribute(Attribute::SanitizeMemory) ||
II->getFunction()->hasFnAttribute(Attribute::SanitizeHWAddress))
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(), std::nullopt);
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?
}
// Separate storage assumptions apply to the underlying allocations, not any
// particular pointer within them. When evaluating the hints for AA purposes
// we getUnderlyingObject them; by precomputing the answers here we can
// avoid having to do so repeatedly there.
for (unsigned Idx = 0; Idx < II->getNumOperandBundles(); Idx++) {
OperandBundleUse OBU = II->getOperandBundleAt(Idx);
if (OBU.getTagName() == "separate_storage") {
assert(OBU.Inputs.size() == 2);
auto MaybeSimplifyHint = [&](const Use &U) {
Value *Hint = U.get();
// Not having a limit is safe because InstCombine removes unreachable
// code.
Value *UnderlyingObject = getUnderlyingObject(Hint, /*MaxLookup*/ 0);
if (Hint != UnderlyingObject)
replaceUse(const_cast<Use &>(U), UnderlyingObject);
};
MaybeSimplifyHint(OBU.Inputs[0]);
MaybeSimplifyHint(OBU.Inputs[1]);
}
}
// 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 from 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::vector_insert: {
Value *Vec = II->getArgOperand(0);
Value *SubVec = II->getArgOperand(1);
Value *Idx = II->getArgOperand(2);
auto *DstTy = dyn_cast<FixedVectorType>(II->getType());
auto *VecTy = dyn_cast<FixedVectorType>(Vec->getType());
auto *SubVecTy = dyn_cast<FixedVectorType>(SubVec->getType());
// Only canonicalize if the destination vector, Vec, and SubVec are all
// fixed vectors.
if (DstTy && VecTy && SubVecTy) {
unsigned DstNumElts = DstTy->getNumElements();
unsigned VecNumElts = VecTy->getNumElements();
unsigned SubVecNumElts = SubVecTy->getNumElements();
unsigned IdxN = cast<ConstantInt>(Idx)->getZExtValue();
// An insert that entirely overwrites Vec with SubVec is a nop.
if (VecNumElts == SubVecNumElts)
return replaceInstUsesWith(CI, SubVec);
// Widen SubVec into a vector of the same width as Vec, since
// shufflevector requires the two input vectors to be the same width.
// Elements beyond the bounds of SubVec within the widened vector are
// undefined.
SmallVector<int, 8> WidenMask;
unsigned i;
for (i = 0; i != SubVecNumElts; ++i)
WidenMask.push_back(i);
for (; i != VecNumElts; ++i)
WidenMask.push_back(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);
return replaceInstUsesWith(CI, Shuffle);
}
break;
}
case Intrinsic::vector_extract: {
Value *Vec = II->getArgOperand(0);
Value *Idx = II->getArgOperand(1);
Type *ReturnType = II->getType();
// (extract_vector (insert_vector InsertTuple, InsertValue, InsertIdx),
// ExtractIdx)
unsigned ExtractIdx = cast<ConstantInt>(Idx)->getZExtValue();
Value *InsertTuple, *InsertIdx, *InsertValue;
if (match(Vec, m_Intrinsic<Intrinsic::vector_insert>(m_Value(InsertTuple),
m_Value(InsertValue),
m_Value(InsertIdx))) &&
InsertValue->getType() == ReturnType) {
unsigned Index = cast<ConstantInt>(InsertIdx)->getZExtValue();
// Case where we get the same index right after setting it.
// extract.vector(insert.vector(InsertTuple, InsertValue, Idx), Idx) -->
// InsertValue
if (ExtractIdx == Index)
return replaceInstUsesWith(CI, InsertValue);
// If we are getting a different index than what was set in the
// insert.vector intrinsic. We can just set the input tuple to the one up
// in the chain. extract.vector(insert.vector(InsertTuple, InsertValue,
// InsertIndex), ExtractIndex)
// --> extract.vector(InsertTuple, ExtractIndex)
else
return replaceOperand(CI, 0, InsertTuple);
}
auto *DstTy = dyn_cast<FixedVectorType>(ReturnType);
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();
// 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, Mask);
return replaceInstUsesWith(CI, Shuffle);
}
break;
}
case Intrinsic::experimental_vector_reverse: {
Value *BO0, *BO1, *X, *Y;
Value *Vec = II->getArgOperand(0);
if (match(Vec, m_OneUse(m_BinOp(m_Value(BO0), m_Value(BO1))))) {
auto *OldBinOp = cast<BinaryOperator>(Vec);
if (match(BO0, m_VecReverse(m_Value(X)))) {
// rev(binop rev(X), rev(Y)) --> binop X, Y
if (match(BO1, m_VecReverse(m_Value(Y))))
return replaceInstUsesWith(CI,
BinaryOperator::CreateWithCopiedFlags(
OldBinOp->getOpcode(), X, Y, OldBinOp,
OldBinOp->getName(), II));
// rev(binop rev(X), BO1Splat) --> binop X, BO1Splat
if (isSplatValue(BO1))
return replaceInstUsesWith(CI,
BinaryOperator::CreateWithCopiedFlags(
OldBinOp->getOpcode(), X, BO1,
OldBinOp, OldBinOp->getName(), II));
}
// rev(binop BO0Splat, rev(Y)) --> binop BO0Splat, Y
if (match(BO1, m_VecReverse(m_Value(Y))) && isSplatValue(BO0))
return replaceInstUsesWith(CI, BinaryOperator::CreateWithCopiedFlags(
OldBinOp->getOpcode(), BO0, Y,
OldBinOp, OldBinOp->getName(), II));
}
// rev(unop rev(X)) --> unop X
if (match(Vec, m_OneUse(m_UnOp(m_VecReverse(m_Value(X)))))) {
auto *OldUnOp = cast<UnaryOperator>(Vec);
auto *NewUnOp = UnaryOperator::CreateWithCopiedFlags(
OldUnOp->getOpcode(), X, OldUnOp, OldUnOp->getName(), II);
return replaceInstUsesWith(CI, NewUnOp);
}
break;
}
case Intrinsic::vector_reduce_or:
case Intrinsic::vector_reduce_and: {
// Canonicalize logical or/and reductions:
// Or reduction for i1 is represented as:
// %val = bitcast <ReduxWidth x i1> to iReduxWidth
// %res = cmp ne iReduxWidth %val, 0
// And reduction for i1 is represented as:
// %val = bitcast <ReduxWidth x i1> to iReduxWidth
// %res = cmp eq iReduxWidth %val, 11111
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = Builder.CreateBitCast(
Vect, Builder.getIntNTy(FTy->getNumElements()));
if (IID == Intrinsic::vector_reduce_and) {
Res = Builder.CreateICmpEQ(
Res, ConstantInt::getAllOnesValue(Res->getType()));
} else {
assert(IID == Intrinsic::vector_reduce_or &&
"Expected or reduction.");
Res = Builder.CreateIsNotNull(Res);
}
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());
return replaceInstUsesWith(CI, Res);
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_add: {
if (IID == Intrinsic::vector_reduce_add) {
// Convert vector_reduce_add(ZExt(<n x i1>)) to
// ZExtOrTrunc(ctpop(bitcast <n x i1> to in)).
// Convert vector_reduce_add(SExt(<n x i1>)) to
// -ZExtOrTrunc(ctpop(bitcast <n x i1> to in)).
// Convert vector_reduce_add(<n x i1>) to
// Trunc(ctpop(bitcast <n x i1> to in)).
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *V = Builder.CreateBitCast(
Vect, Builder.getIntNTy(FTy->getNumElements()));
Value *Res = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, V);
if (Res->getType() != II->getType())
Res = Builder.CreateZExtOrTrunc(Res, II->getType());
if (Arg != Vect &&
cast<Instruction>(Arg)->getOpcode() == Instruction::SExt)
Res = Builder.CreateNeg(Res);
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_xor: {
if (IID == Intrinsic::vector_reduce_xor) {
// Exclusive disjunction reduction over the vector with
// (potentially-extended) i1 element type is actually a
// (potentially-extended) arithmetic `add` reduction over the original
// non-extended value:
// vector_reduce_xor(?ext(<n x i1>))
// -->
// ?ext(vector_reduce_add(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = Builder.CreateAddReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_mul: {
if (IID == Intrinsic::vector_reduce_mul) {
// Multiplicative reduction over the vector with (potentially-extended)
// i1 element type is actually a (potentially zero-extended)
// logical `and` reduction over the original non-extended value:
// vector_reduce_mul(?ext(<n x i1>))
// -->
// zext(vector_reduce_and(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = Builder.CreateAndReduce(Vect);
if (Res->getType() != II->getType())
Res = Builder.CreateZExt(Res, II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_umin:
case Intrinsic::vector_reduce_umax: {
if (IID == Intrinsic::vector_reduce_umin ||
IID == Intrinsic::vector_reduce_umax) {
// UMin/UMax reduction over the vector with (potentially-extended)
// i1 element type is actually a (potentially-extended)
// logical `and`/`or` reduction over the original non-extended value:
// vector_reduce_u{min,max}(?ext(<n x i1>))
// -->
// ?ext(vector_reduce_{and,or}(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *Res = IID == Intrinsic::vector_reduce_umin
? Builder.CreateAndReduce(Vect)
: Builder.CreateOrReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_smin:
case Intrinsic::vector_reduce_smax: {
if (IID == Intrinsic::vector_reduce_smin ||
IID == Intrinsic::vector_reduce_smax) {
// SMin/SMax reduction over the vector with (potentially-extended)
// i1 element type is actually a (potentially-extended)
// logical `and`/`or` reduction over the original non-extended value:
// vector_reduce_s{min,max}(<n x i1>)
// -->
// vector_reduce_{or,and}(<n x i1>)
// and
// vector_reduce_s{min,max}(sext(<n x i1>))
// -->
// sext(vector_reduce_{or,and}(<n x i1>))
// and
// vector_reduce_s{min,max}(zext(<n x i1>))
// -->
// zext(vector_reduce_{and,or}(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Instruction::CastOps ExtOpc = Instruction::CastOps::CastOpsEnd;
if (Arg != Vect)
ExtOpc = cast<CastInst>(Arg)->getOpcode();
Value *Res = ((IID == Intrinsic::vector_reduce_smin) ==
(ExtOpc == Instruction::CastOps::ZExt))
? Builder.CreateAndReduce(Vect)
: Builder.CreateOrReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(ExtOpc, Res, II->getType());
return replaceInstUsesWith(CI, Res);
}
}
}
[[fallthrough]];
}
case Intrinsic::vector_reduce_fmax:
case Intrinsic::vector_reduce_fmin:
case Intrinsic::vector_reduce_fadd:
case Intrinsic::vector_reduce_fmul: {
bool CanBeReassociated = (IID != Intrinsic::vector_reduce_fadd &&
IID != Intrinsic::vector_reduce_fmul) ||
II->hasAllowReassoc();
const unsigned ArgIdx = (IID == Intrinsic::vector_reduce_fadd ||
IID == Intrinsic::vector_reduce_fmul)
? 1
: 0;
Value *Arg = II->getArgOperand(ArgIdx);
Value *V;
ArrayRef<int> Mask;
if (!isa<FixedVectorType>(Arg->getType()) || !CanBeReassociated ||
!match(Arg, m_Shuffle(m_Value(V), m_Undef(), m_Mask(Mask))) ||
!cast<ShuffleVectorInst>(Arg)->isSingleSource())
break;
int Sz = Mask.size();
SmallBitVector UsedIndices(Sz);
for (int Idx : Mask) {
if (Idx == UndefMaskElem || UsedIndices.test(Idx))
break;
UsedIndices.set(Idx);
}
// Can remove shuffle iff just shuffled elements, no repeats, undefs, or
// other changes.
if (UsedIndices.all()) {
replaceUse(II->getOperandUse(ArgIdx), V);
return nullptr;
}
break;
}
case Intrinsic::is_fpclass: {
if (Instruction *I = foldIntrinsicIsFPClass(*II))
return I;
break;
}
default: {
// Handle target specific intrinsics
std::optional<Instruction *> V = targetInstCombineIntrinsic(*II);
if (V)
return *V;
break;
}
}
if (Instruction *Shuf = foldShuffledIntrinsicOperands(II, Builder))
return Shuf;
// Some intrinsics (like experimental_gc_statepoint) can be used in invoke
// context, so it is handled in visitCallBase and we should trigger it.
return visitCallBase(*II);
}
// Fence instruction simplification
Instruction *InstCombinerImpl::visitFenceInst(FenceInst &FI) {
auto *NFI = dyn_cast<FenceInst>(FI.getNextNonDebugInstruction());
// This check is solely here to handle arbitrary target-dependent syncscopes.
// TODO: Can remove if does not matter in practice.
if (NFI && FI.isIdenticalTo(NFI))
return eraseInstFromFunction(FI);
// Returns true if FI1 is identical or stronger fence than FI2.
auto isIdenticalOrStrongerFence = [](FenceInst *FI1, FenceInst *FI2) {
auto FI1SyncScope = FI1->getSyncScopeID();
// Consider same scope, where scope is global or single-thread.
if (FI1SyncScope != FI2->getSyncScopeID() ||
(FI1SyncScope != SyncScope::System &&
FI1SyncScope != SyncScope::SingleThread))
return false;
return isAtLeastOrStrongerThan(FI1->getOrdering(), FI2->getOrdering());
};
if (NFI && isIdenticalOrStrongerFence(NFI, &FI))
return eraseInstFromFunction(FI);
if (auto *PFI = dyn_cast_or_null<FenceInst>(FI.getPrevNonDebugInstruction()))
if (isIdenticalOrStrongerFence(PFI, &FI))
return eraseInstFromFunction(FI);
return nullptr;
}
// InvokeInst simplification
Instruction *InstCombinerImpl::visitInvokeInst(InvokeInst &II) {
return visitCallBase(II);
}
// CallBrInst simplification
Instruction *InstCombinerImpl::visitCallBrInst(CallBrInst &CBI) {
return visitCallBase(CBI);
}
/// 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;
// Opaque pointers are compatible with any byval types.
PointerType *SrcTy = cast<PointerType>(CI->getOperand(0)->getType());
if (SrcTy->isOpaque())
return true;
// 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;
// The transform currently only handles type replacement for byval, not other
// type-carrying attributes.
if (!Call.isByValArgument(ix))
return false;
Type *SrcElemTy = SrcTy->getNonOpaquePointerElementType();
Type *DstElemTy = Call.getParamByValType(ix);
if (!SrcElemTy->isSized() || !DstElemTy->isSized())
return false;
if (DL.getTypeAllocSize(SrcElemTy) != DL.getTypeAllocSize(DstElemTy))
return false;
return true;
}
Instruction *InstCombinerImpl::tryOptimizeCall(CallInst *CI) {
if (!CI->getCalledFunction()) return nullptr;
// Skip optimizing notail and musttail calls so
// LibCallSimplifier::optimizeCall doesn't have to preserve those invariants.
// LibCallSimplifier::optimizeCall should try to preseve tail calls though.
if (CI->isMustTailCall() || CI->isNoTailCall())
return nullptr;
auto InstCombineRAUW = [this](Instruction *From, Value *With) {
replaceInstUsesWith(*From, With);
};
auto InstCombineErase = [this](Instruction *I) {
eraseInstFromFunction(*I);
};
LibCallSimplifier Simplifier(DL, &TLI, 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;
}
bool InstCombinerImpl::annotateAnyAllocSite(CallBase &Call,
const TargetLibraryInfo *TLI) {
// Note: We only handle cases which can't be driven from generic attributes
// here. So, for example, nonnull and noalias (which are common properties
// of some allocation functions) are expected to be handled via annotation
// of the respective allocator declaration with generic attributes.
bool Changed = false;
if (!Call.getType()->isPointerTy())
return Changed;
std::optional<APInt> Size = getAllocSize(&Call, TLI);
if (Size && *Size != 0) {
// TODO: We really should just emit deref_or_null here and then
// let the generic inference code combine that with nonnull.
if (Call.hasRetAttr(Attribute::NonNull)) {
Changed = !Call.hasRetAttr(Attribute::Dereferenceable);
Call.addRetAttr(Attribute::getWithDereferenceableBytes(
Call.getContext(), Size->getLimitedValue()));
} else {
Changed = !Call.hasRetAttr(Attribute::DereferenceableOrNull);
Call.addRetAttr(Attribute::getWithDereferenceableOrNullBytes(
Call.getContext(), Size->getLimitedValue()));
}
}
// Add alignment attribute if alignment is a power of two constant.
Value *Alignment = getAllocAlignment(&Call, TLI);
if (!Alignment)
return Changed;
ConstantInt *AlignOpC = dyn_cast<ConstantInt>(Alignment);
if (AlignOpC && AlignOpC->getValue().ult(llvm::Value::MaximumAlignment)) {
uint64_t AlignmentVal = AlignOpC->getZExtValue();
if (llvm::isPowerOf2_64(AlignmentVal)) {
Align ExistingAlign = Call.getRetAlign().valueOrOne();
Align NewAlign = Align(AlignmentVal);
if (NewAlign > ExistingAlign) {
Call.addRetAttr(
Attribute::getWithAlignment(Call.getContext(), NewAlign));
Changed = true;
}
}
}
return Changed;
}
/// Improvements for call, callbr and invoke instructions.
Instruction *InstCombinerImpl::visitCallBase(CallBase &Call) {
bool Changed = annotateAnyAllocSite(Call, &TLI);
// Mark any parameters that are known to be non-null with the nonnull
// attribute. This is helpful for inlining calls to functions with null
// checks on their arguments.
SmallVector<unsigned, 4> ArgNos;
unsigned ArgNo = 0;
for (Value *V : Call.args()) {
if (V->getType()->isPointerTy() &&
!Call.paramHasAttr(ArgNo, Attribute::NonNull) &&
isKnownNonZero(V, DL, 0, &AC, &Call, &DT))
ArgNos.push_back(ArgNo);
ArgNo++;
}
assert(ArgNo == Call.arg_size() && "Call arguments not processed correctly.");
if (!ArgNos.empty()) {
AttributeList AS = Call.getAttributes();
LLVMContext &Ctx = Call.getContext();
AS = AS.addParamAttribute(Ctx, ArgNos,
Attribute::get(Ctx, Attribute::NonNull));
Call.setAttributes(AS);
Changed = true;
}
// If the callee is a pointer to a function, attempt to move any casts to the
// arguments of the call/callbr/invoke.
Value *Callee = Call.getCalledOperand();
Function *CalleeF = dyn_cast<Function>(Callee);
if ((!CalleeF || CalleeF->getFunctionType() != Call.getFunctionType()) &&
transformConstExprCastCall(Call))
return nullptr;
if (CalleeF) {
// Remove the convergent attr on calls when the callee is not convergent.
if (Call.isConvergent() && !CalleeF->isConvergent() &&
!CalleeF->isIntrinsic()) {
LLVM_DEBUG(dbgs() << "Removing convergent attr from instr " << Call
<< "\n");
Call.setNotConvergent();
return &Call;
}
// If the call and callee calling conventions don't match, and neither one
// of the calling conventions is compatible with C calling convention
// this call must be unreachable, as the call is undefined.
if ((CalleeF->getCallingConv() != Call.getCallingConv() &&
!(CalleeF->getCallingConv() == llvm::CallingConv::C &&
TargetLibraryInfoImpl::isCallingConvCCompatible(&Call)) &&
!(Call.getCallingConv() == llvm::CallingConv::C &&
TargetLibraryInfoImpl::isCallingConvCCompatible(CalleeF))) &&
// Only do this for calls to a function with a body. A prototype may
// not actually end up matching the implementation's calling conv for a
// variety of reasons (e.g. it may be written in assembly).
!CalleeF->isDeclaration()) {
Instruction *OldCall = &Call;
CreateNonTerminatorUnreachable(OldCall);
// If OldCall does not return void then replaceInstUsesWith poison.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!OldCall->getType()->isVoidTy())
replaceInstUsesWith(*OldCall, PoisonValue::get(OldCall->getType()));
if (isa<CallInst>(OldCall))
return eraseInstFromFunction(*OldCall);
// We cannot remove an invoke or a callbr, because it would change thexi
// CFG, just change the callee to a null pointer.
cast<CallBase>(OldCall)->setCalledFunction(
CalleeF->getFunctionType(),
Constant::getNullValue(CalleeF->getType()));
return nullptr;
}
}
// Calling a null function pointer is undefined if a null address isn't
// dereferenceable.
if ((isa<ConstantPointerNull>(Callee) &&
!NullPointerIsDefined(Call.getFunction())) ||
isa<UndefValue>(Callee)) {
// If Call does not return void then replaceInstUsesWith poison.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!Call.getType()->isVoidTy())
replaceInstUsesWith(Call, PoisonValue::get(Call.getType()));
if (Call.isTerminator()) {
// Can't remove an invoke or callbr because we cannot change the CFG.
return nullptr;
}
// This instruction is not reachable, just remove it.
CreateNonTerminatorUnreachable(&Call);
return eraseInstFromFunction(Call);
}
if (IntrinsicInst *II = findInitTrampoline(Callee))
return transformCallThroughTrampoline(Call, *II);
// TODO: Drop this transform once opaque pointer transition is done.
FunctionType *FTy = Call.getFunctionType();
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 pointer type.
// Not necessary for opaque pointers.
PointerType *NewTy = cast<PointerType>(CI->getOperand(0)->getType());
if (!NewTy->isOpaque() && Call.isByValArgument(ix)) {
Call.removeParamAttr(ix, Attribute::ByVal);
Call.addParamAttr(ix, Attribute::getWithByValType(
Call.getContext(),
NewTy->getNonOpaquePointerElementType()));
}
Changed = true;
}
}
}
if (isa<InlineAsm>(Callee) && !Call.doesNotThrow()) {
InlineAsm *IA = cast<InlineAsm>(Callee);
if (!IA->canThrow()) {
// Normal inline asm calls cannot throw - mark them
// 'nounwind'.
Call.setDoesNotThrow();
Changed = true;
}
}
// Try to optimize the call if possible, we require DataLayout for most of
// this. None of these calls are seen as possibly dead so go ahead and
// delete the instruction now.
if (CallInst *CI = dyn_cast<CallInst>(&Call)) {
Instruction *I = tryOptimizeCall(CI);
// If we changed something return the result, etc. Otherwise let
// the fallthrough check.
if (I) return eraseInstFromFunction(*I);
}
if (!Call.use_empty() && !Call.isMustTailCall())
if (Value *ReturnedArg = Call.getReturnedArgOperand()) {
Type *CallTy = Call.getType();
Type *RetArgTy = ReturnedArg->getType();
if (RetArgTy->canLosslesslyBitCastTo(CallTy))
return replaceInstUsesWith(
Call, Builder.CreateBitOrPointerCast(ReturnedArg, CallTy));
}
// Drop unnecessary kcfi operand bundles from calls that were converted
// into direct calls.
auto Bundle = Call.getOperandBundle(LLVMContext::OB_kcfi);
if (Bundle && !Call.isIndirectCall()) {
DEBUG_WITH_TYPE(DEBUG_TYPE "-kcfi", {
if (CalleeF) {
ConstantInt *FunctionType = nullptr;
ConstantInt *ExpectedType = cast<ConstantInt>(Bundle->Inputs[0]);
if (MDNode *MD = CalleeF->getMetadata(LLVMContext::MD_kcfi_type))
FunctionType = mdconst::extract<ConstantInt>(MD->getOperand(0));
if (FunctionType &&
FunctionType->getZExtValue() != ExpectedType->getZExtValue())
dbgs() << Call.getModule()->getName()
<< ": warning: kcfi: " << Call.getCaller()->getName()
<< ": call to " << CalleeF->getName()
<< " using a mismatching function pointer type\n";
}
});
return CallBase::removeOperandBundle(&Call, LLVMContext::OB_kcfi);
}
if (isRemovableAlloc(&Call, &TLI))
return visitAllocSite(Call);
// Handle intrinsics which can be used in both call and invoke context.
switch (Call.getIntrinsicID()) {
case Intrinsic::experimental_gc_statepoint: {
GCStatepointInst &GCSP = *cast<GCStatepointInst>(&Call);
SmallPtrSet<Value *, 32> LiveGcValues;
for (const GCRelocateInst *Reloc : GCSP.getGCRelocates()) {
GCRelocateInst &GCR = *const_cast<GCRelocateInst *>(Reloc);
// Remove the relocation if unused.
if (GCR.use_empty()) {
eraseInstFromFunction(GCR);
continue;
}
Value *DerivedPtr = GCR.getDerivedPtr();
Value *BasePtr = GCR.getBasePtr();
// Undef is undef, even after relocation.
if (isa<UndefValue>(DerivedPtr) || isa<UndefValue>(BasePtr)) {
replaceInstUsesWith(GCR, UndefValue::get(GCR.getType()));
eraseInstFromFunction(GCR);
continue;
}
if (auto *PT = dyn_cast<PointerType>(GCR.getType())) {
// The relocation of null will be null for most any collector.
// TODO: provide a hook for this in GCStrategy. There might be some
// weird collector this property does not hold for.
if (isa<ConstantPointerNull>(DerivedPtr)) {
// Use null-pointer of gc_relocate's type to replace it.
replaceInstUsesWith(GCR, ConstantPointerNull::get(PT));
eraseInstFromFunction(GCR);
continue;
}
// isKnownNonNull -> nonnull attribute
if (!GCR.hasRetAttr(Attribute::NonNull) &&
isKnownNonZero(DerivedPtr, DL, 0, &AC, &Call, &DT)) {
GCR.addRetAttr(Attribute::NonNull);
// We discovered new fact, re-check users.
Worklist.pushUsersToWorkList(GCR);
}
}
// If we have two copies of the same pointer in the statepoint argument
// list, canonicalize to one. This may let us common gc.relocates.
if (GCR.getBasePtr() == GCR.getDerivedPtr() &&
GCR.getBasePtrIndex() != GCR.getDerivedPtrIndex()) {
auto *OpIntTy = GCR.getOperand(2)->getType();
GCR.setOperand(2, ConstantInt::get(OpIntTy, GCR.getBasePtrIndex()));
}
// TODO: bitcast(relocate(p)) -> relocate(bitcast(p))
// Canonicalize on the type from the uses to the defs
// TODO: relocate((gep p, C, C2, ...)) -> gep(relocate(p), C, C2, ...)
LiveGcValues.insert(BasePtr);
LiveGcValues.insert(DerivedPtr);
}
std::optional<OperandBundleUse> Bundle =
GCSP.getOperandBundle(LLVMContext::OB_gc_live);
unsigned NumOfGCLives = LiveGcValues.size();
if (!Bundle || NumOfGCLives == Bundle->Inputs.size())
break;
// We can reduce the size of gc live bundle.
DenseMap<Value *, unsigned> Val2Idx;
std::vector<Value *> NewLiveGc;
for (Value *V : Bundle->Inputs) {
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/invoke.
/// CallBrInst is not supported.
bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) {
auto *Callee =
dyn_cast<Function>(Call.getCalledOperand()->stripPointerCasts());
if (!Callee)
return false;
assert(!isa<CallBrInst>(Call) &&
"CallBr's don't have a single point after a def to insert at");
// 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(FT->getContext(), CallerPAL.getRetAttrs());
if (RAttrs.overlaps(AttributeFuncs::typeIncompatible(NewRetTy)))
return false; // Attribute not compatible with transformed value.
}
// If the callbase is an invoke instruction, and the return value is
// used by a PHI node in a successor, we cannot change the return type of
// the call because there is no place to put the cast instruction (without
// breaking the critical edge). Bail out in this case.
if (!Caller->use_empty()) {
BasicBlock *PhisNotSupportedBlock = nullptr;
if (auto *II = dyn_cast<InvokeInst>(Caller))
PhisNotSupportedBlock = II->getNormalDest();
if (PhisNotSupportedBlock)
for (User *U : Caller->users())
if (PHINode *PN = dyn_cast<PHINode>(U))
if (PN->getParent() == PhisNotSupportedBlock)
return false;
}
}
unsigned NumActualArgs = Call.arg_size();
unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
// Prevent us turning:
// declare void @takes_i32_inalloca(i32* inalloca)
// call void bitcast (void (i32*)* @takes_i32_inalloca to void (i32)*)(i32 0)
//
// into:
// call void @takes_i32_inalloca(i32* null)
//
// Similarly, avoid folding away bitcasts of byval calls.
if (Callee->getAttributes().hasAttrSomewhere(Attribute::InAlloca) ||
Callee->getAttributes().hasAttrSomewhere(Attribute::Preallocated))
return false;
auto AI = Call.arg_begin();
for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
Type *ParamTy = FT->getParamType(i);
Type *ActTy = (*AI)->getType();
if (!CastInst::isBitOrNoopPointerCastable(ActTy, ParamTy, DL))
return false; // Cannot transform this parameter value.
// Check if there are any incompatible attributes we cannot drop safely.
if (AttrBuilder(FT->getContext(), CallerPAL.getParamAttrs(i))
.overlaps(AttributeFuncs::typeIncompatible(
ParamTy, AttributeFuncs::ASK_UNSAFE_TO_DROP)))
return false; // Attribute not compatible with transformed value.
if (Call.isInAllocaArgument(i) ||
CallerPAL.hasParamAttr(i, Attribute::Preallocated))
return false; // Cannot transform to and from inalloca/preallocated.
if (CallerPAL.hasParamAttr(i, Attribute::SwiftError))
return false;
if (CallerPAL.hasParamAttr(i, Attribute::ByVal) !=
Callee->getAttributes().hasParamAttr(i, Attribute::ByVal))
return false; // Cannot transform to or from byval.
// If 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.hasParamAttr(i, Attribute::ByVal)) {
PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy);
if (!ParamPTy)
return false;
if (!ParamPTy->isOpaque()) {
Type *ParamElTy = ParamPTy->getNonOpaquePointerElementType();
if (!ParamElTy->isSized())
return false;
Type *CurElTy = Call.getParamByValType(i);
if (DL.getTypeAllocSize(CurElTy) != DL.getTypeAllocSize(ParamElTy))
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.
if (FT->isVarArg() != Call.getFunctionType()->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() && Call.getFunctionType()->isVarArg() &&
FT->getNumParams() != Call.getFunctionType()->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 - AttributeList::FirstArgIndex >= FT->getNumParams())
return false;
}
// Okay, we decided that this is a safe thing to do: go ahead and start
// inserting cast instructions as necessary.
SmallVector<Value *, 8> Args;
SmallVector<AttributeSet, 8> ArgAttrs;
Args.reserve(NumActualArgs);
ArgAttrs.reserve(NumActualArgs);
// Get any return attributes.
AttrBuilder RAttrs(FT->getContext(), CallerPAL.getRetAttrs());
// If the return value is not being used, the type may not be compatible
// with the existing attributes. Wipe out any problematic attributes.
RAttrs.remove(AttributeFuncs::typeIncompatible(NewRetTy));
LLVMContext &Ctx = Call.getContext();
AI = Call.arg_begin();
for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
Type *ParamTy = FT->getParamType(i);
Value *NewArg = *AI;
if ((*AI)->getType() != ParamTy)
NewArg = Builder.CreateBitOrPointerCast(*AI, ParamTy);
Args.push_back(NewArg);
// Add any parameter attributes except the ones incompatible with the new
// type. Note that we made sure all incompatible ones are safe to drop.
AttributeMask IncompatibleAttrs = AttributeFuncs::typeIncompatible(
ParamTy, AttributeFuncs::ASK_SAFE_TO_DROP);
if (CallerPAL.hasParamAttr(i, Attribute::ByVal) &&
!ParamTy->isOpaquePointerTy()) {
AttrBuilder AB(Ctx, CallerPAL.getParamAttrs(i).removeAttributes(
Ctx, IncompatibleAttrs));
AB.addByValAttr(ParamTy->getNonOpaquePointerElementType());
ArgAttrs.push_back(AttributeSet::get(Ctx, AB));
} else {
ArgAttrs.push_back(
CallerPAL.getParamAttrs(i).removeAttributes(Ctx, IncompatibleAttrs));
}
}
// If the function takes more arguments than the call was taking, add them
// now.
for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) {
Args.push_back(Constant::getNullValue(FT->getParamType(i)));
ArgAttrs.push_back(AttributeSet());
}
// If we are removing arguments to the function, emit an obnoxious warning.
if (FT->getNumParams() < NumActualArgs) {
// TODO: if (!FT->isVarArg()) this call may be unreachable. PR14722
if (FT->isVarArg()) {
// Add all of the arguments in their promoted form to the arg list.
for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) {
Type *PTy = getPromotedType((*AI)->getType());
Value *NewArg = *AI;
if (PTy != (*AI)->getType()) {
// Must promote to pass through va_arg area!
Instruction::CastOps opcode =
CastInst::getCastOpcode(*AI, false, PTy, false);
NewArg = Builder.CreateCast(opcode, *AI, PTy);
}
Args.push_back(NewArg);
// Add any parameter attributes.
ArgAttrs.push_back(CallerPAL.getParamAttrs(i));
}
}
}
AttributeSet FnAttrs = CallerPAL.getFnAttrs();
if (NewRetTy->isVoidTy())
Caller->setName(""); // Void type should not have a name.
assert((ArgAttrs.size() == FT->getNumParams() || FT->isVarArg()) &&
"missing argument attributes");
AttributeList NewCallerPAL = AttributeList::get(
Ctx, FnAttrs, AttributeSet::get(Ctx, RAttrs), ArgAttrs);
SmallVector<OperandBundleDef, 1> OpBundles;
Call.getOperandBundlesAsDefs(OpBundles);
CallBase *NewCall;
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
NewCall = Builder.CreateInvoke(Callee, II->getNormalDest(),
II->getUnwindDest(), Args, OpBundles);
} else {
NewCall = Builder.CreateCall(Callee, Args, OpBundles);
cast<CallInst>(NewCall)->setTailCallKind(
cast<CallInst>(Caller)->getTailCallKind());
}
NewCall->takeName(Caller);
NewCall->setCallingConv(Call.getCallingConv());
NewCall->setAttributes(NewCallerPAL);
// Preserve prof metadata if any.
NewCall->copyMetadata(*Caller, {LLVMContext::MD_prof});
// Insert a cast of the return type as necessary.
Instruction *NC = NewCall;
Value *NV = NC;
if (OldRetTy != NV->getType() && !Caller->use_empty()) {
if (!NV->getType()->isVoidTy()) {
NV = NC = CastInst::CreateBitOrPointerCast(NC, OldRetTy);
NC->setDebugLoc(Caller->getDebugLoc());
Instruction *InsertPt = NewCall->getInsertionPointAfterDef();
assert(InsertPt && "No place to insert cast");
InsertNewInstBefore(NC, *InsertPt);
Worklist.pushUsersToWorkList(*Caller);
} else {
NV = PoisonValue::get(Caller->getType());
}
}
if (!Caller->use_empty())
replaceInstUsesWith(*Caller, NV);
else if (Caller->hasValueHandle()) {
if (OldRetTy == NV->getType())
ValueHandleBase::ValueIsRAUWd(Caller, NV);
else
// We cannot call ValueIsRAUWd with a different type, and the
// actual tracked value will disappear.
ValueHandleBase::ValueIsDeleted(Caller);
}
eraseInstFromFunction(*Caller);
return true;
}
/// Turn a call to a function created by init_trampoline / adjust_trampoline
/// intrinsic pair into a direct call to the underlying function.
Instruction *
InstCombinerImpl::transformCallThroughTrampoline(CallBase &Call,
IntrinsicInst &Tramp) {
Value *Callee = Call.getCalledOperand();
Type *CalleeTy = Callee->getType();
FunctionType *FTy = Call.getFunctionType();
AttributeList Attrs = Call.getAttributes();
// If the call already has the 'nest' attribute somewhere then give up -
// otherwise 'nest' would occur twice after splicing in the chain.
if (Attrs.hasAttrSomewhere(Attribute::Nest))
return nullptr;
Function *NestF = cast<Function>(Tramp.getArgOperand(1)->stripPointerCasts());
FunctionType *NestFTy = NestF->getFunctionType();
AttributeList NestAttrs = NestF->getAttributes();
if (!NestAttrs.isEmpty()) {
unsigned NestArgNo = 0;
Type *NestTy = nullptr;
AttributeSet NestAttr;
// Look for a parameter marked with the 'nest' attribute.
for (FunctionType::param_iterator I = NestFTy->param_begin(),
E = NestFTy->param_end();
I != E; ++NestArgNo, ++I) {
AttributeSet AS = NestAttrs.getParamAttrs(NestArgNo);
if (AS.hasAttribute(Attribute::Nest)) {
// Record the parameter type and any other attributes.
NestTy = *I;
NestAttr = AS;
break;
}
}
if (NestTy) {
std::vector<Value*> NewArgs;
std::vector<AttributeSet> NewArgAttrs;
NewArgs.reserve(Call.arg_size() + 1);
NewArgAttrs.reserve(Call.arg_size());
// Insert the nest argument into the call argument list, which may
// mean appending it. Likewise for attributes.
{
unsigned ArgNo = 0;
auto I = Call.arg_begin(), E = Call.arg_end();
do {
if (ArgNo == NestArgNo) {
// Add the chain argument and attributes.
Value *NestVal = Tramp.getArgOperand(2);
if (NestVal->getType() != NestTy)
NestVal = Builder.CreateBitCast(NestVal, NestTy, "nest");
NewArgs.push_back(NestVal);
NewArgAttrs.push_back(NestAttr);
}
if (I == E)
break;
// Add the original argument and attributes.
NewArgs.push_back(*I);
NewArgAttrs.push_back(Attrs.getParamAttrs(ArgNo));
++ArgNo;
++I;
} while (true);
}
// The trampoline may have been bitcast to a bogus type (FTy).
// Handle this by synthesizing a new function type, equal to FTy
// with the chain parameter inserted.
std::vector<Type*> NewTypes;
NewTypes.reserve(FTy->getNumParams()+1);
// Insert the chain's type into the list of parameter types, which may
// mean appending it.
{
unsigned ArgNo = 0;
FunctionType::param_iterator I = FTy->param_begin(),
E = FTy->param_end();
do {
if (ArgNo == NestArgNo)
// Add the chain's type.
NewTypes.push_back(NestTy);
if (I == E)
break;
// Add the original type.
NewTypes.push_back(*I);
++ArgNo;
++I;
} while (true);
}
// Replace the trampoline call with a direct call. Let the generic
// code sort out any function type mismatches.
FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes,
FTy->isVarArg());
Constant *NewCallee =
NestF->getType() == PointerType::getUnqual(NewFTy) ?
NestF : ConstantExpr::getBitCast(NestF,
PointerType::getUnqual(NewFTy));
AttributeList NewPAL =
AttributeList::get(FTy->getContext(), Attrs.getFnAttrs(),
Attrs.getRetAttrs(), NewArgAttrs);
SmallVector<OperandBundleDef, 1> OpBundles;
Call.getOperandBundlesAsDefs(OpBundles);
Instruction *NewCaller;
if (InvokeInst *II = dyn_cast<InvokeInst>(&Call)) {
NewCaller = InvokeInst::Create(NewFTy, NewCallee,
II->getNormalDest(), II->getUnwindDest(),
NewArgs, OpBundles);
cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
cast<InvokeInst>(NewCaller)->setAttributes(NewPAL);
} else if (CallBrInst *CBI = dyn_cast<CallBrInst>(&Call)) {
NewCaller =
CallBrInst::Create(NewFTy, NewCallee, CBI->getDefaultDest(),
CBI->getIndirectDests(), NewArgs, OpBundles);
cast<CallBrInst>(NewCaller)->setCallingConv(CBI->getCallingConv());
cast<CallBrInst>(NewCaller)->setAttributes(NewPAL);
} else {
NewCaller = CallInst::Create(NewFTy, NewCallee, NewArgs, OpBundles);
cast<CallInst>(NewCaller)->setTailCallKind(
cast<CallInst>(Call).getTailCallKind());
cast<CallInst>(NewCaller)->setCallingConv(
cast<CallInst>(Call).getCallingConv());
cast<CallInst>(NewCaller)->setAttributes(NewPAL);
}
NewCaller->setDebugLoc(Call.getDebugLoc());
return NewCaller;
}
}
// Replace the trampoline call with a direct call. Since there is no 'nest'
// parameter, there is no need to adjust the argument list. Let the generic
// code sort out any function type mismatches.
Constant *NewCallee = ConstantExpr::getBitCast(NestF, CalleeTy);
Call.setCalledFunction(FTy, NewCallee);
return &Call;
}
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