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llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
Hal Finkel 5cb8ab5b5a Canonicalization for @llvm.assume 
Adds simple logical canonicalization of assumption intrinsics to instcombine,
currently:
 - invariant(a && b) -> invariant(a); invariant(b)
 - invariant(!(a || b)) -> invariant(!a); invariant(!b)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213977 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-25 21:45:17 +00:00

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//===- InstCombineCalls.cpp -----------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the visitCall and visitInvoke functions.
//
//===----------------------------------------------------------------------===//
#include "InstCombine.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
using namespace PatternMatch;
#define DEBUG_TYPE "instcombine"
STATISTIC(NumSimplified, "Number of library calls simplified");
/// getPromotedType - 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;
}
/// reduceToSingleValueType - Given an aggregate type which ultimately holds a
/// single scalar element, like {{{type}}} or [1 x type], return type.
static Type *reduceToSingleValueType(Type *T) {
while (!T->isSingleValueType()) {
if (StructType *STy = dyn_cast<StructType>(T)) {
if (STy->getNumElements() == 1)
T = STy->getElementType(0);
else
break;
} else if (ArrayType *ATy = dyn_cast<ArrayType>(T)) {
if (ATy->getNumElements() == 1)
T = ATy->getElementType();
else
break;
} else
break;
}
return T;
}
Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
unsigned DstAlign = getKnownAlignment(MI->getArgOperand(0), DL);
unsigned SrcAlign = getKnownAlignment(MI->getArgOperand(1), DL);
unsigned MinAlign = std::min(DstAlign, SrcAlign);
unsigned CopyAlign = MI->getAlignment();
if (CopyAlign < MinAlign) {
MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
MinAlign, false));
return MI;
}
// If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
// load/store.
ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getArgOperand(2));
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.
// 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);
// Memcpy forces the use of i8* for the source and destination. That means
// that if you're using memcpy to move one double around, you'll get a cast
// from double* to i8*. We'd much rather use a double load+store rather than
// an i64 load+store, here because this improves the odds that the source or
// dest address will be promotable. See if we can find a better type than the
// integer datatype.
Value *StrippedDest = MI->getArgOperand(0)->stripPointerCasts();
MDNode *CopyMD = nullptr;
if (StrippedDest != MI->getArgOperand(0)) {
Type *SrcETy = cast<PointerType>(StrippedDest->getType())
->getElementType();
if (DL && SrcETy->isSized() && DL->getTypeStoreSize(SrcETy) == Size) {
// The SrcETy might be something like {{{double}}} or [1 x double]. Rip
// down through these levels if so.
SrcETy = reduceToSingleValueType(SrcETy);
if (SrcETy->isSingleValueType()) {
NewSrcPtrTy = PointerType::get(SrcETy, SrcAddrSp);
NewDstPtrTy = PointerType::get(SrcETy, DstAddrSp);
// If the memcpy has metadata describing the members, see if we can
// get the TBAA tag describing our copy.
if (MDNode *M = MI->getMetadata(LLVMContext::MD_tbaa_struct)) {
if (M->getNumOperands() == 3 &&
M->getOperand(0) &&
isa<ConstantInt>(M->getOperand(0)) &&
cast<ConstantInt>(M->getOperand(0))->isNullValue() &&
M->getOperand(1) &&
isa<ConstantInt>(M->getOperand(1)) &&
cast<ConstantInt>(M->getOperand(1))->getValue() == Size &&
M->getOperand(2) &&
isa<MDNode>(M->getOperand(2)))
CopyMD = cast<MDNode>(M->getOperand(2));
}
}
}
}
// If the memcpy/memmove provides better alignment info than we can
// infer, use it.
SrcAlign = std::max(SrcAlign, CopyAlign);
DstAlign = std::max(DstAlign, CopyAlign);
Value *Src = Builder->CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy);
Value *Dest = Builder->CreateBitCast(MI->getArgOperand(0), NewDstPtrTy);
LoadInst *L = Builder->CreateLoad(Src, MI->isVolatile());
L->setAlignment(SrcAlign);
if (CopyMD)
L->setMetadata(LLVMContext::MD_tbaa, CopyMD);
StoreInst *S = Builder->CreateStore(L, Dest, MI->isVolatile());
S->setAlignment(DstAlign);
if (CopyMD)
S->setMetadata(LLVMContext::MD_tbaa, CopyMD);
// Set the size of the copy to 0, it will be deleted on the next iteration.
MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType()));
return MI;
}
Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) {
unsigned Alignment = getKnownAlignment(MI->getDest(), DL);
if (MI->getAlignment() < Alignment) {
MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
Alignment, false));
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;
uint64_t Len = LenC->getLimitedValue();
Alignment = MI->getAlignment();
assert(Len && "0-sized memory setting should be removed already.");
// 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);
// Alignment 0 is identity for alignment 1 for memset, but not store.
if (Alignment == 0) Alignment = 1;
// Extract the fill value and store.
uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
StoreInst *S = Builder->CreateStore(ConstantInt::get(ITy, Fill), Dest,
MI->isVolatile());
S->setAlignment(Alignment);
// 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;
}
/// visitCallInst - CallInst simplification. This mostly only handles folding
/// of intrinsic instructions. For normal calls, it allows visitCallSite to do
/// the heavy lifting.
///
Instruction *InstCombiner::visitCallInst(CallInst &CI) {
if (isFreeCall(&CI, TLI))
return visitFree(CI);
// If the caller function is nounwind, mark the call as nounwind, even if the
// callee isn't.
if (CI.getParent()->getParent()->doesNotThrow() &&
!CI.doesNotThrow()) {
CI.setDoesNotThrow();
return &CI;
}
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
if (!II) return visitCallSite(&CI);
// Intrinsics cannot occur in an invoke, so handle them here instead of in
// visitCallSite.
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) {
bool Changed = false;
// memmove/cpy/set of zero bytes is a noop.
if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) {
if (NumBytes->isNullValue())
return EraseInstFromFunction(CI);
if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes))
if (CI->getZExtValue() == 1) {
// Replace the instruction with just byte operations. We would
// transform other cases to loads/stores, but we don't know if
// alignment is sufficient.
}
}
// No other transformations apply to volatile transfers.
if (MI->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 (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) {
if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource()))
if (GVSrc->isConstant()) {
Module *M = CI.getParent()->getParent()->getParent();
Intrinsic::ID MemCpyID = 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 (MemTransferInst *MTI = dyn_cast<MemTransferInst>(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 (isa<MemTransferInst>(MI)) {
if (Instruction *I = SimplifyMemTransfer(MI))
return I;
} else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) {
if (Instruction *I = SimplifyMemSet(MSI))
return I;
}
if (Changed) return II;
}
switch (II->getIntrinsicID()) {
default: break;
case Intrinsic::objectsize: {
uint64_t Size;
if (getObjectSize(II->getArgOperand(0), Size, DL, TLI))
return ReplaceInstUsesWith(CI, ConstantInt::get(CI.getType(), Size));
return nullptr;
}
case Intrinsic::bswap: {
Value *IIOperand = II->getArgOperand(0);
Value *X = nullptr;
// bswap(bswap(x)) -> x
if (match(IIOperand, m_BSwap(m_Value(X))))
return ReplaceInstUsesWith(CI, X);
// bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) {
unsigned C = X->getType()->getPrimitiveSizeInBits() -
IIOperand->getType()->getPrimitiveSizeInBits();
Value *CV = ConstantInt::get(X->getType(), C);
Value *V = Builder->CreateLShr(X, CV);
return new TruncInst(V, IIOperand->getType());
}
break;
}
case Intrinsic::powi:
if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
// powi(x, 0) -> 1.0
if (Power->isZero())
return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0));
// powi(x, 1) -> x
if (Power->isOne())
return ReplaceInstUsesWith(CI, II->getArgOperand(0));
// powi(x, -1) -> 1/x
if (Power->isAllOnesValue())
return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0),
II->getArgOperand(0));
}
break;
case Intrinsic::cttz: {
// If all bits below the first known one are known zero,
// this value is constant.
IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType());
// FIXME: Try to simplify vectors of integers.
if (!IT) break;
uint32_t BitWidth = IT->getBitWidth();
APInt KnownZero(BitWidth, 0);
APInt KnownOne(BitWidth, 0);
computeKnownBits(II->getArgOperand(0), KnownZero, KnownOne);
unsigned TrailingZeros = KnownOne.countTrailingZeros();
APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros));
if ((Mask & KnownZero) == Mask)
return ReplaceInstUsesWith(CI, ConstantInt::get(IT,
APInt(BitWidth, TrailingZeros)));
}
break;
case Intrinsic::ctlz: {
// If all bits above the first known one are known zero,
// this value is constant.
IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType());
// FIXME: Try to simplify vectors of integers.
if (!IT) break;
uint32_t BitWidth = IT->getBitWidth();
APInt KnownZero(BitWidth, 0);
APInt KnownOne(BitWidth, 0);
computeKnownBits(II->getArgOperand(0), KnownZero, KnownOne);
unsigned LeadingZeros = KnownOne.countLeadingZeros();
APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros));
if ((Mask & KnownZero) == Mask)
return ReplaceInstUsesWith(CI, ConstantInt::get(IT,
APInt(BitWidth, LeadingZeros)));
}
break;
case Intrinsic::uadd_with_overflow: {
Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType());
uint32_t BitWidth = IT->getBitWidth();
APInt LHSKnownZero(BitWidth, 0);
APInt LHSKnownOne(BitWidth, 0);
computeKnownBits(LHS, LHSKnownZero, LHSKnownOne);
bool LHSKnownNegative = LHSKnownOne[BitWidth - 1];
bool LHSKnownPositive = LHSKnownZero[BitWidth - 1];
if (LHSKnownNegative || LHSKnownPositive) {
APInt RHSKnownZero(BitWidth, 0);
APInt RHSKnownOne(BitWidth, 0);
computeKnownBits(RHS, RHSKnownZero, RHSKnownOne);
bool RHSKnownNegative = RHSKnownOne[BitWidth - 1];
bool RHSKnownPositive = RHSKnownZero[BitWidth - 1];
if (LHSKnownNegative && RHSKnownNegative) {
// The sign bit is set in both cases: this MUST overflow.
// Create a simple add instruction, and insert it into the struct.
Value *Add = Builder->CreateAdd(LHS, RHS);
Add->takeName(&CI);
Constant *V[] = {
UndefValue::get(LHS->getType()),
ConstantInt::getTrue(II->getContext())
};
StructType *ST = cast<StructType>(II->getType());
Constant *Struct = ConstantStruct::get(ST, V);
return InsertValueInst::Create(Struct, Add, 0);
}
if (LHSKnownPositive && RHSKnownPositive) {
// The sign bit is clear in both cases: this CANNOT overflow.
// Create a simple add instruction, and insert it into the struct.
Value *Add = Builder->CreateNUWAdd(LHS, RHS);
Add->takeName(&CI);
Constant *V[] = {
UndefValue::get(LHS->getType()),
ConstantInt::getFalse(II->getContext())
};
StructType *ST = cast<StructType>(II->getType());
Constant *Struct = ConstantStruct::get(ST, V);
return InsertValueInst::Create(Struct, Add, 0);
}
}
}
// FALL THROUGH uadd into sadd
case Intrinsic::sadd_with_overflow:
// Canonicalize constants into the RHS.
if (isa<Constant>(II->getArgOperand(0)) &&
!isa<Constant>(II->getArgOperand(1))) {
Value *LHS = II->getArgOperand(0);
II->setArgOperand(0, II->getArgOperand(1));
II->setArgOperand(1, LHS);
return II;
}
// X + undef -> undef
if (isa<UndefValue>(II->getArgOperand(1)))
return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
// X + 0 -> {X, false}
if (RHS->isZero()) {
Constant *V[] = {
UndefValue::get(II->getArgOperand(0)->getType()),
ConstantInt::getFalse(II->getContext())
};
Constant *Struct =
ConstantStruct::get(cast<StructType>(II->getType()), V);
return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
}
}
// We can strength reduce reduce this signed add into a regular add if we
// can prove that it will never overflow.
if (II->getIntrinsicID() == Intrinsic::sadd_with_overflow) {
Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
if (WillNotOverflowSignedAdd(LHS, RHS)) {
Value *Add = Builder->CreateNSWAdd(LHS, RHS);
Add->takeName(&CI);
Constant *V[] = {UndefValue::get(Add->getType()), Builder->getFalse()};
StructType *ST = cast<StructType>(II->getType());
Constant *Struct = ConstantStruct::get(ST, V);
return InsertValueInst::Create(Struct, Add, 0);
}
}
break;
case Intrinsic::usub_with_overflow:
case Intrinsic::ssub_with_overflow:
// undef - X -> undef
// X - undef -> undef
if (isa<UndefValue>(II->getArgOperand(0)) ||
isa<UndefValue>(II->getArgOperand(1)))
return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
// X - 0 -> {X, false}
if (RHS->isZero()) {
Constant *V[] = {
UndefValue::get(II->getArgOperand(0)->getType()),
ConstantInt::getFalse(II->getContext())
};
Constant *Struct =
ConstantStruct::get(cast<StructType>(II->getType()), V);
return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
}
}
break;
case Intrinsic::umul_with_overflow: {
Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth();
APInt LHSKnownZero(BitWidth, 0);
APInt LHSKnownOne(BitWidth, 0);
computeKnownBits(LHS, LHSKnownZero, LHSKnownOne);
APInt RHSKnownZero(BitWidth, 0);
APInt RHSKnownOne(BitWidth, 0);
computeKnownBits(RHS, RHSKnownZero, RHSKnownOne);
// Get the largest possible values for each operand.
APInt LHSMax = ~LHSKnownZero;
APInt RHSMax = ~RHSKnownZero;
// If multiplying the maximum values does not overflow then we can turn
// this into a plain NUW mul.
bool Overflow;
LHSMax.umul_ov(RHSMax, Overflow);
if (!Overflow) {
Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow");
Constant *V[] = {
UndefValue::get(LHS->getType()),
Builder->getFalse()
};
Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V);
return InsertValueInst::Create(Struct, Mul, 0);
}
} // FALL THROUGH
case Intrinsic::smul_with_overflow:
// Canonicalize constants into the RHS.
if (isa<Constant>(II->getArgOperand(0)) &&
!isa<Constant>(II->getArgOperand(1))) {
Value *LHS = II->getArgOperand(0);
II->setArgOperand(0, II->getArgOperand(1));
II->setArgOperand(1, LHS);
return II;
}
// X * undef -> undef
if (isa<UndefValue>(II->getArgOperand(1)))
return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
// X*0 -> {0, false}
if (RHSI->isZero())
return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType()));
// X * 1 -> {X, false}
if (RHSI->equalsInt(1)) {
Constant *V[] = {
UndefValue::get(II->getArgOperand(0)->getType()),
ConstantInt::getFalse(II->getContext())
};
Constant *Struct =
ConstantStruct::get(cast<StructType>(II->getType()), V);
return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
}
}
break;
case Intrinsic::ppc_altivec_lvx:
case Intrinsic::ppc_altivec_lvxl:
// Turn PPC lvx -> load if the pointer is known aligned.
if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, DL) >= 16) {
Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0),
PointerType::getUnqual(II->getType()));
return new LoadInst(Ptr);
}
break;
case Intrinsic::ppc_altivec_stvx:
case Intrinsic::ppc_altivec_stvxl:
// Turn stvx -> store if the pointer is known aligned.
if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, DL) >= 16) {
Type *OpPtrTy =
PointerType::getUnqual(II->getArgOperand(0)->getType());
Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy);
return new StoreInst(II->getArgOperand(0), Ptr);
}
break;
case Intrinsic::x86_sse_storeu_ps:
case Intrinsic::x86_sse2_storeu_pd:
case Intrinsic::x86_sse2_storeu_dq:
// Turn X86 storeu -> store if the pointer is known aligned.
if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, DL) >= 16) {
Type *OpPtrTy =
PointerType::getUnqual(II->getArgOperand(1)->getType());
Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy);
return new StoreInst(II->getArgOperand(1), Ptr);
}
break;
case Intrinsic::x86_sse_cvtss2si:
case Intrinsic::x86_sse_cvtss2si64:
case Intrinsic::x86_sse_cvttss2si:
case Intrinsic::x86_sse_cvttss2si64:
case Intrinsic::x86_sse2_cvtsd2si:
case Intrinsic::x86_sse2_cvtsd2si64:
case Intrinsic::x86_sse2_cvttsd2si:
case Intrinsic::x86_sse2_cvttsd2si64: {
// These intrinsics only demand the 0th element of their input vectors. If
// we can simplify the input based on that, do so now.
unsigned VWidth =
cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
APInt DemandedElts(VWidth, 1);
APInt UndefElts(VWidth, 0);
if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0),
DemandedElts, UndefElts)) {
II->setArgOperand(0, V);
return II;
}
break;
}
// Constant fold <A x Bi> << Ci.
// FIXME: We don't handle _dq because it's a shift of an i128, but is
// represented in the IR as <2 x i64>. A per element shift is wrong.
case Intrinsic::x86_sse2_psll_d:
case Intrinsic::x86_sse2_psll_q:
case Intrinsic::x86_sse2_psll_w:
case Intrinsic::x86_sse2_pslli_d:
case Intrinsic::x86_sse2_pslli_q:
case Intrinsic::x86_sse2_pslli_w:
case Intrinsic::x86_avx2_psll_d:
case Intrinsic::x86_avx2_psll_q:
case Intrinsic::x86_avx2_psll_w:
case Intrinsic::x86_avx2_pslli_d:
case Intrinsic::x86_avx2_pslli_q:
case Intrinsic::x86_avx2_pslli_w:
case Intrinsic::x86_sse2_psrl_d:
case Intrinsic::x86_sse2_psrl_q:
case Intrinsic::x86_sse2_psrl_w:
case Intrinsic::x86_sse2_psrli_d:
case Intrinsic::x86_sse2_psrli_q:
case Intrinsic::x86_sse2_psrli_w:
case Intrinsic::x86_avx2_psrl_d:
case Intrinsic::x86_avx2_psrl_q:
case Intrinsic::x86_avx2_psrl_w:
case Intrinsic::x86_avx2_psrli_d:
case Intrinsic::x86_avx2_psrli_q:
case Intrinsic::x86_avx2_psrli_w: {
// Simplify if count is constant. To 0 if >= BitWidth,
// otherwise to shl/lshr.
auto CDV = dyn_cast<ConstantDataVector>(II->getArgOperand(1));
auto CInt = dyn_cast<ConstantInt>(II->getArgOperand(1));
if (!CDV && !CInt)
break;
ConstantInt *Count;
if (CDV)
Count = cast<ConstantInt>(CDV->getElementAsConstant(0));
else
Count = CInt;
auto Vec = II->getArgOperand(0);
auto VT = cast<VectorType>(Vec->getType());
if (Count->getZExtValue() >
VT->getElementType()->getPrimitiveSizeInBits() - 1)
return ReplaceInstUsesWith(
CI, ConstantAggregateZero::get(Vec->getType()));
bool isPackedShiftLeft = true;
switch (II->getIntrinsicID()) {
default : break;
case Intrinsic::x86_sse2_psrl_d:
case Intrinsic::x86_sse2_psrl_q:
case Intrinsic::x86_sse2_psrl_w:
case Intrinsic::x86_sse2_psrli_d:
case Intrinsic::x86_sse2_psrli_q:
case Intrinsic::x86_sse2_psrli_w:
case Intrinsic::x86_avx2_psrl_d:
case Intrinsic::x86_avx2_psrl_q:
case Intrinsic::x86_avx2_psrl_w:
case Intrinsic::x86_avx2_psrli_d:
case Intrinsic::x86_avx2_psrli_q:
case Intrinsic::x86_avx2_psrli_w: isPackedShiftLeft = false; break;
}
unsigned VWidth = VT->getNumElements();
// Get a constant vector of the same type as the first operand.
auto VTCI = ConstantInt::get(VT->getElementType(), Count->getZExtValue());
if (isPackedShiftLeft)
return BinaryOperator::CreateShl(Vec,
Builder->CreateVectorSplat(VWidth, VTCI));
return BinaryOperator::CreateLShr(Vec,
Builder->CreateVectorSplat(VWidth, VTCI));
}
case Intrinsic::x86_sse41_pmovsxbw:
case Intrinsic::x86_sse41_pmovsxwd:
case Intrinsic::x86_sse41_pmovsxdq:
case Intrinsic::x86_sse41_pmovzxbw:
case Intrinsic::x86_sse41_pmovzxwd:
case Intrinsic::x86_sse41_pmovzxdq: {
// pmov{s|z}x ignores the upper half of their input vectors.
unsigned VWidth =
cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
unsigned LowHalfElts = VWidth / 2;
APInt InputDemandedElts(APInt::getBitsSet(VWidth, 0, LowHalfElts));
APInt UndefElts(VWidth, 0);
if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0),
InputDemandedElts,
UndefElts)) {
II->setArgOperand(0, TmpV);
return II;
}
break;
}
case Intrinsic::x86_sse4a_insertqi: {
// insertqi x, y, 64, 0 can just copy y's lower bits and leave the top
// ones undef
// TODO: eventually we should lower this intrinsic to IR
if (auto CIWidth = dyn_cast<ConstantInt>(II->getArgOperand(2))) {
if (auto CIStart = dyn_cast<ConstantInt>(II->getArgOperand(3))) {
if (CIWidth->equalsInt(64) && CIStart->isZero()) {
Value *Vec = II->getArgOperand(1);
Value *Undef = UndefValue::get(Vec->getType());
const uint32_t Mask[] = { 0, 2 };
return ReplaceInstUsesWith(
CI,
Builder->CreateShuffleVector(
Vec, Undef, ConstantDataVector::get(
II->getContext(), ArrayRef<uint32_t>(Mask))));
} else if (auto Source =
dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
if (Source->hasOneUse() &&
Source->getArgOperand(1) == II->getArgOperand(1)) {
// If the source of the insert has only one use and it's another
// insert (and they're both inserting from the same vector), try to
// bundle both together.
auto CISourceWidth =
dyn_cast<ConstantInt>(Source->getArgOperand(2));
auto CISourceStart =
dyn_cast<ConstantInt>(Source->getArgOperand(3));
if (CISourceStart && CISourceWidth) {
unsigned Start = CIStart->getZExtValue();
unsigned Width = CIWidth->getZExtValue();
unsigned End = Start + Width;
unsigned SourceStart = CISourceStart->getZExtValue();
unsigned SourceWidth = CISourceWidth->getZExtValue();
unsigned SourceEnd = SourceStart + SourceWidth;
unsigned NewStart, NewWidth;
bool ShouldReplace = false;
if (Start <= SourceStart && SourceStart <= End) {
NewStart = Start;
NewWidth = std::max(End, SourceEnd) - NewStart;
ShouldReplace = true;
} else if (SourceStart <= Start && Start <= SourceEnd) {
NewStart = SourceStart;
NewWidth = std::max(SourceEnd, End) - NewStart;
ShouldReplace = true;
}
if (ShouldReplace) {
Constant *ConstantWidth = ConstantInt::get(
II->getArgOperand(2)->getType(), NewWidth, false);
Constant *ConstantStart = ConstantInt::get(
II->getArgOperand(3)->getType(), NewStart, false);
Value *Args[4] = { Source->getArgOperand(0),
II->getArgOperand(1), ConstantWidth,
ConstantStart };
Module *M = CI.getParent()->getParent()->getParent();
Value *F =
Intrinsic::getDeclaration(M, Intrinsic::x86_sse4a_insertqi);
return ReplaceInstUsesWith(CI, Builder->CreateCall(F, Args));
}
}
}
}
}
}
break;
}
case Intrinsic::x86_sse41_pblendvb:
case Intrinsic::x86_sse41_blendvps:
case Intrinsic::x86_sse41_blendvpd:
case Intrinsic::x86_avx_blendv_ps_256:
case Intrinsic::x86_avx_blendv_pd_256:
case Intrinsic::x86_avx2_pblendvb: {
// Convert blendv* to vector selects if the mask is constant.
// This optimization is convoluted because the intrinsic is defined as
// getting a vector of floats or doubles for the ps and pd versions.
// FIXME: That should be changed.
Value *Mask = II->getArgOperand(2);
if (auto C = dyn_cast<ConstantDataVector>(Mask)) {
auto Tyi1 = Builder->getInt1Ty();
auto SelectorType = cast<VectorType>(Mask->getType());
auto EltTy = SelectorType->getElementType();
unsigned Size = SelectorType->getNumElements();
unsigned BitWidth =
EltTy->isFloatTy()
? 32
: (EltTy->isDoubleTy() ? 64 : EltTy->getIntegerBitWidth());
assert((BitWidth == 64 || BitWidth == 32 || BitWidth == 8) &&
"Wrong arguments for variable blend intrinsic");
SmallVector<Constant *, 32> Selectors;
for (unsigned I = 0; I < Size; ++I) {
// The intrinsics only read the top bit
uint64_t Selector;
if (BitWidth == 8)
Selector = C->getElementAsInteger(I);
else
Selector = C->getElementAsAPFloat(I).bitcastToAPInt().getZExtValue();
Selectors.push_back(ConstantInt::get(Tyi1, Selector >> (BitWidth - 1)));
}
auto NewSelector = ConstantVector::get(Selectors);
return SelectInst::Create(NewSelector, II->getArgOperand(1),
II->getArgOperand(0), "blendv");
} else {
break;
}
}
case Intrinsic::x86_avx_vpermilvar_ps:
case Intrinsic::x86_avx_vpermilvar_ps_256:
case Intrinsic::x86_avx_vpermilvar_pd:
case Intrinsic::x86_avx_vpermilvar_pd_256: {
// Convert vpermil* to shufflevector if the mask is constant.
Value *V = II->getArgOperand(1);
unsigned Size = cast<VectorType>(V->getType())->getNumElements();
assert(Size == 8 || Size == 4 || Size == 2);
uint32_t Indexes[8];
if (auto C = dyn_cast<ConstantDataVector>(V)) {
// The intrinsics only read one or two bits, clear the rest.
for (unsigned I = 0; I < Size; ++I) {
uint32_t Index = C->getElementAsInteger(I) & 0x3;
if (II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd ||
II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256)
Index >>= 1;
Indexes[I] = Index;
}
} else if (isa<ConstantAggregateZero>(V)) {
for (unsigned I = 0; I < Size; ++I)
Indexes[I] = 0;
} else {
break;
}
// The _256 variants are a bit trickier since the mask bits always index
// into the corresponding 128 half. In order to convert to a generic
// shuffle, we have to make that explicit.
if (II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_ps_256 ||
II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256) {
for (unsigned I = Size / 2; I < Size; ++I)
Indexes[I] += Size / 2;
}
auto NewC =
ConstantDataVector::get(V->getContext(), makeArrayRef(Indexes, Size));
auto V1 = II->getArgOperand(0);
auto V2 = UndefValue::get(V1->getType());
auto Shuffle = Builder->CreateShuffleVector(V1, V2, NewC);
return ReplaceInstUsesWith(CI, Shuffle);
}
case Intrinsic::ppc_altivec_vperm:
// Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
// Note that ppc_altivec_vperm has a big-endian bias, so when creating
// a vectorshuffle for little endian, we must undo the transformation
// performed on vec_perm in altivec.h. That is, we must complement
// the permutation mask with respect to 31 and reverse the order of
// V1 and V2.
if (Constant *Mask = dyn_cast<Constant>(II->getArgOperand(2))) {
assert(Mask->getType()->getVectorNumElements() == 16 &&
"Bad type for intrinsic!");
// Check that all of the elements are integer constants or undefs.
bool AllEltsOk = true;
for (unsigned i = 0; i != 16; ++i) {
Constant *Elt = Mask->getAggregateElement(i);
if (!Elt || !(isa<ConstantInt>(Elt) || isa<UndefValue>(Elt))) {
AllEltsOk = false;
break;
}
}
if (AllEltsOk) {
// Cast the input vectors to byte vectors.
Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0),
Mask->getType());
Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1),
Mask->getType());
Value *Result = UndefValue::get(Op0->getType());
// Only extract each element once.
Value *ExtractedElts[32];
memset(ExtractedElts, 0, sizeof(ExtractedElts));
for (unsigned i = 0; i != 16; ++i) {
if (isa<UndefValue>(Mask->getAggregateElement(i)))
continue;
unsigned Idx =
cast<ConstantInt>(Mask->getAggregateElement(i))->getZExtValue();
Idx &= 31; // Match the hardware behavior.
if (DL && DL->isLittleEndian())
Idx = 31 - Idx;
if (!ExtractedElts[Idx]) {
Value *Op0ToUse = (DL && DL->isLittleEndian()) ? Op1 : Op0;
Value *Op1ToUse = (DL && DL->isLittleEndian()) ? Op0 : Op1;
ExtractedElts[Idx] =
Builder->CreateExtractElement(Idx < 16 ? Op0ToUse : Op1ToUse,
Builder->getInt32(Idx&15));
}
// Insert this value into the result vector.
Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx],
Builder->getInt32(i));
}
return CastInst::Create(Instruction::BitCast, Result, CI.getType());
}
}
break;
case Intrinsic::arm_neon_vld1:
case Intrinsic::arm_neon_vld2:
case Intrinsic::arm_neon_vld3:
case Intrinsic::arm_neon_vld4:
case Intrinsic::arm_neon_vld2lane:
case Intrinsic::arm_neon_vld3lane:
case Intrinsic::arm_neon_vld4lane:
case Intrinsic::arm_neon_vst1:
case Intrinsic::arm_neon_vst2:
case Intrinsic::arm_neon_vst3:
case Intrinsic::arm_neon_vst4:
case Intrinsic::arm_neon_vst2lane:
case Intrinsic::arm_neon_vst3lane:
case Intrinsic::arm_neon_vst4lane: {
unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), DL);
unsigned AlignArg = II->getNumArgOperands() - 1;
ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg));
if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) {
II->setArgOperand(AlignArg,
ConstantInt::get(Type::getInt32Ty(II->getContext()),
MemAlign, false));
return II;
}
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 = (II->getIntrinsicID() == Intrinsic::arm_neon_vmullu ||
II->getIntrinsicID() == 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::AMDGPU_rcp: {
if (const ConstantFP *C = dyn_cast<ConstantFP>(II->getArgOperand(0))) {
const APFloat &ArgVal = C->getValueAPF();
APFloat Val(ArgVal.getSemantics(), 1.0);
APFloat::opStatus Status = Val.divide(ArgVal,
APFloat::rmNearestTiesToEven);
// Only do this if it was exact and therefore not dependent on the
// rounding mode.
if (Status == APFloat::opOK)
return ReplaceInstUsesWith(CI, ConstantFP::get(II->getContext(), Val));
}
break;
}
case Intrinsic::stackrestore: {
// If the save is right next to the restore, remove the restore. This can
// happen when variable allocas are DCE'd.
if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
if (SS->getIntrinsicID() == Intrinsic::stacksave) {
BasicBlock::iterator BI = SS;
if (&*++BI == II)
return EraseInstFromFunction(CI);
}
}
// Scan down this block to see if there is another stack restore in the
// same block without an intervening call/alloca.
BasicBlock::iterator BI = II;
TerminatorInst *TI = II->getParent()->getTerminator();
bool CannotRemove = false;
for (++BI; &*BI != TI; ++BI) {
if (isa<AllocaInst>(BI)) {
CannotRemove = true;
break;
}
if (CallInst *BCI = dyn_cast<CallInst>(BI)) {
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) {
// If there is a stackrestore below this one, remove this one.
if (II->getIntrinsicID() == Intrinsic::stackrestore)
return EraseInstFromFunction(CI);
// Otherwise, ignore the intrinsic.
} else {
// If we found a non-intrinsic call, we can't remove the stack
// restore.
CannotRemove = true;
break;
}
}
}
// If the stack restore is in a return, resume, or unwind block and if there
// are no allocas or calls between the restore and the return, nuke the
// restore.
if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI)))
return EraseInstFromFunction(CI);
break;
}
case Intrinsic::assume: {
// Canonicalize assume(a && b) -> assume(a); assume(b);
Value *IIOperand = II->getArgOperand(0), *A, *B,
*AssumeIntrinsic = II->getCalledValue();
if (match(IIOperand, m_And(m_Value(A), m_Value(B)))) {
Builder->CreateCall(AssumeIntrinsic, A, II->getName());
Builder->CreateCall(AssumeIntrinsic, B, II->getName());
return EraseInstFromFunction(*II);
}
// assume(!(a || b)) -> assume(!a); assume(!b);
if (match(IIOperand, m_Not(m_Or(m_Value(A), m_Value(B))))) {
Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(A), II->getName());
Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(B), II->getName());
return EraseInstFromFunction(*II);
}
break;
}
}
return visitCallSite(II);
}
// InvokeInst simplification
//
Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) {
return visitCallSite(&II);
}
/// isSafeToEliminateVarargsCast - 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 CallSite CS,
const CastInst * const CI,
const DataLayout * const DL,
const int ix) {
if (!CI->isLosslessCast())
return false;
// The size of ByVal or InAlloca arguments is derived from the type, so we
// can't change to a type with a different size. If the size were
// passed explicitly we could avoid this check.
if (!CS.isByValOrInAllocaArgument(ix))
return true;
Type* SrcTy =
cast<PointerType>(CI->getOperand(0)->getType())->getElementType();
Type* DstTy = cast<PointerType>(CI->getType())->getElementType();
if (!SrcTy->isSized() || !DstTy->isSized())
return false;
if (!DL || DL->getTypeAllocSize(SrcTy) != DL->getTypeAllocSize(DstTy))
return false;
return true;
}
// Try to fold some different type of calls here.
// Currently we're only working with the checking functions, memcpy_chk,
// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk,
// strcat_chk and strncat_chk.
Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const DataLayout *DL) {
if (!CI->getCalledFunction()) return nullptr;
if (Value *With = Simplifier->optimizeCall(CI)) {
++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,
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;
}
// visitCallSite - Improvements for call and invoke instructions.
//
Instruction *InstCombiner::visitCallSite(CallSite CS) {
if (isAllocLikeFn(CS.getInstruction(), TLI))
return visitAllocSite(*CS.getInstruction());
bool Changed = false;
// If the callee is a pointer to a function, attempt to move any casts to the
// arguments of the call/invoke.
Value *Callee = CS.getCalledValue();
if (!isa<Function>(Callee) && transformConstExprCastCall(CS))
return nullptr;
if (Function *CalleeF = dyn_cast<Function>(Callee))
// If the call and callee calling conventions don't match, this call must
// be unreachable, as the call is undefined.
if (CalleeF->getCallingConv() != CS.getCallingConv() &&
// 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 = CS.getInstruction();
new StoreInst(ConstantInt::getTrue(Callee->getContext()),
UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
OldCall);
// If OldCall does not return void then replaceAllUsesWith undef.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!OldCall->getType()->isVoidTy())
ReplaceInstUsesWith(*OldCall, UndefValue::get(OldCall->getType()));
if (isa<CallInst>(OldCall))
return EraseInstFromFunction(*OldCall);
// We cannot remove an invoke, because it would change the CFG, just
// change the callee to a null pointer.
cast<InvokeInst>(OldCall)->setCalledFunction(
Constant::getNullValue(CalleeF->getType()));
return nullptr;
}
if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
// If CS does not return void then replaceAllUsesWith undef.
// This allows ValueHandlers and custom metadata to adjust itself.
if (!CS.getInstruction()->getType()->isVoidTy())
ReplaceInstUsesWith(*CS.getInstruction(),
UndefValue::get(CS.getInstruction()->getType()));
if (isa<InvokeInst>(CS.getInstruction())) {
// Can't remove an invoke because we cannot change the CFG.
return nullptr;
}
// This instruction is not reachable, just remove it. We insert a store to
// undef so that we know that this code is not reachable, despite the fact
// that we can't modify the CFG here.
new StoreInst(ConstantInt::getTrue(Callee->getContext()),
UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
CS.getInstruction());
return EraseInstFromFunction(*CS.getInstruction());
}
if (IntrinsicInst *II = FindInitTrampoline(Callee))
return transformCallThroughTrampoline(CS, II);
PointerType *PTy = cast<PointerType>(Callee->getType());
FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
if (FTy->isVarArg()) {
int ix = FTy->getNumParams();
// See if we can optimize any arguments passed through the varargs area of
// the call.
for (CallSite::arg_iterator I = CS.arg_begin() + FTy->getNumParams(),
E = CS.arg_end(); I != E; ++I, ++ix) {
CastInst *CI = dyn_cast<CastInst>(*I);
if (CI && isSafeToEliminateVarargsCast(CS, CI, DL, ix)) {
*I = CI->getOperand(0);
Changed = true;
}
}
}
if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) {
// Inline asm calls cannot throw - mark them 'nounwind'.
CS.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>(CS.getInstruction())) {
Instruction *I = tryOptimizeCall(CI, DL);
// If we changed something return the result, etc. Otherwise let
// the fallthrough check.
if (I) return EraseInstFromFunction(*I);
}
return Changed ? CS.getInstruction() : nullptr;
}
// transformConstExprCastCall - If the callee is a constexpr cast of a function,
// attempt to move the cast to the arguments of the call/invoke.
//
bool InstCombiner::transformConstExprCastCall(CallSite CS) {
Function *Callee =
dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts());
if (!Callee)
return false;
Instruction *Caller = CS.getInstruction();
const AttributeSet &CallerPAL = CS.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::isBitCastable(NewRetTy, OldRetTy)) {
if (Callee->isDeclaration())
return false; // Cannot transform this return value.
if (!Caller->use_empty() &&
// void -> non-void is handled specially
!NewRetTy->isVoidTy())
return false; // Cannot transform this return value.
}
if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
AttrBuilder RAttrs(CallerPAL, AttributeSet::ReturnIndex);
if (RAttrs.
hasAttributes(AttributeFuncs::
typeIncompatible(NewRetTy, AttributeSet::ReturnIndex),
AttributeSet::ReturnIndex))
return false; // Attribute not compatible with transformed value.
}
// If the callsite 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())
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller))
for (User *U : II->users())
if (PHINode *PN = dyn_cast<PHINode>(U))
if (PN->getParent() == II->getNormalDest() ||
PN->getParent() == II->getUnwindDest())
return false;
}
unsigned NumActualArgs = CS.arg_size();
unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
CallSite::arg_iterator AI = CS.arg_begin();
for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
Type *ParamTy = FT->getParamType(i);
Type *ActTy = (*AI)->getType();
if (!CastInst::isBitCastable(ActTy, ParamTy))
return false; // Cannot transform this parameter value.
if (AttrBuilder(CallerPAL.getParamAttributes(i + 1), i + 1).
hasAttributes(AttributeFuncs::
typeIncompatible(ParamTy, i + 1), i + 1))
return false; // Attribute not compatible with transformed value.
if (CS.isInAllocaArgument(i))
return false; // Cannot transform to and from inalloca.
// 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.getParamAttributes(i + 1).hasAttribute(i + 1,
Attribute::ByVal)) {
PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy);
if (!ParamPTy || !ParamPTy->getElementType()->isSized() || !DL)
return false;
Type *CurElTy = ActTy->getPointerElementType();
if (DL->getTypeAllocSize(CurElTy) !=
DL->getTypeAllocSize(ParamPTy->getElementType()))
return false;
}
}
if (Callee->isDeclaration()) {
// Do not delete arguments unless we have a function body.
if (FT->getNumParams() < NumActualArgs && !FT->isVarArg())
return false;
// If the callee is just a declaration, don't change the varargsness of the
// call. We don't want to introduce a varargs call where one doesn't
// already exist.
PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType());
if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg())
return false;
// If both the callee and the cast type are varargs, we still have to make
// sure the number of fixed parameters are the same or we have the same
// ABI issues as if we introduce a varargs call.
if (FT->isVarArg() &&
cast<FunctionType>(APTy->getElementType())->isVarArg() &&
FT->getNumParams() !=
cast<FunctionType>(APTy->getElementType())->getNumParams())
return false;
}
if (FT->getNumParams() < NumActualArgs && FT->isVarArg() &&
!CallerPAL.isEmpty())
// In this case we have more arguments than the new function type, but we
// won't be dropping them. Check that these extra arguments have attributes
// that are compatible with being a vararg call argument.
for (unsigned i = CallerPAL.getNumSlots(); i; --i) {
unsigned Index = CallerPAL.getSlotIndex(i - 1);
if (Index <= FT->getNumParams())
break;
// Check if it has an attribute that's incompatible with varargs.
AttributeSet PAttrs = CallerPAL.getSlotAttributes(i - 1);
if (PAttrs.hasAttribute(Index, Attribute::StructRet))
return false;
}
// Okay, we decided that this is a safe thing to do: go ahead and start
// inserting cast instructions as necessary.
std::vector<Value*> Args;
Args.reserve(NumActualArgs);
SmallVector<AttributeSet, 8> attrVec;
attrVec.reserve(NumCommonArgs);
// Get any return attributes.
AttrBuilder RAttrs(CallerPAL, AttributeSet::ReturnIndex);
// If the return value is not being used, the type may not be compatible
// with the existing attributes. Wipe out any problematic attributes.
RAttrs.
removeAttributes(AttributeFuncs::
typeIncompatible(NewRetTy, AttributeSet::ReturnIndex),
AttributeSet::ReturnIndex);
// Add the new return attributes.
if (RAttrs.hasAttributes())
attrVec.push_back(AttributeSet::get(Caller->getContext(),
AttributeSet::ReturnIndex, RAttrs));
AI = CS.arg_begin();
for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
Type *ParamTy = FT->getParamType(i);
if ((*AI)->getType() == ParamTy) {
Args.push_back(*AI);
} else {
Args.push_back(Builder->CreateBitCast(*AI, ParamTy));
}
// Add any parameter attributes.
AttrBuilder PAttrs(CallerPAL.getParamAttributes(i + 1), i + 1);
if (PAttrs.hasAttributes())
attrVec.push_back(AttributeSet::get(Caller->getContext(), i + 1,
PAttrs));
}
// 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)));
// 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());
if (PTy != (*AI)->getType()) {
// Must promote to pass through va_arg area!
Instruction::CastOps opcode =
CastInst::getCastOpcode(*AI, false, PTy, false);
Args.push_back(Builder->CreateCast(opcode, *AI, PTy));
} else {
Args.push_back(*AI);
}
// Add any parameter attributes.
AttrBuilder PAttrs(CallerPAL.getParamAttributes(i + 1), i + 1);
if (PAttrs.hasAttributes())
attrVec.push_back(AttributeSet::get(FT->getContext(), i + 1,
PAttrs));
}
}
}
AttributeSet FnAttrs = CallerPAL.getFnAttributes();
if (CallerPAL.hasAttributes(AttributeSet::FunctionIndex))
attrVec.push_back(AttributeSet::get(Callee->getContext(), FnAttrs));
if (NewRetTy->isVoidTy())
Caller->setName(""); // Void type should not have a name.
const AttributeSet &NewCallerPAL = AttributeSet::get(Callee->getContext(),
attrVec);
Instruction *NC;
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
NC = Builder->CreateInvoke(Callee, II->getNormalDest(),
II->getUnwindDest(), Args);
NC->takeName(II);
cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv());
cast<InvokeInst>(NC)->setAttributes(NewCallerPAL);
} else {
CallInst *CI = cast<CallInst>(Caller);
NC = Builder->CreateCall(Callee, Args);
NC->takeName(CI);
if (CI->isTailCall())
cast<CallInst>(NC)->setTailCall();
cast<CallInst>(NC)->setCallingConv(CI->getCallingConv());
cast<CallInst>(NC)->setAttributes(NewCallerPAL);
}
// Insert a cast of the return type as necessary.
Value *NV = NC;
if (OldRetTy != NV->getType() && !Caller->use_empty()) {
if (!NV->getType()->isVoidTy()) {
NV = NC = CastInst::Create(CastInst::BitCast, NC, OldRetTy);
NC->setDebugLoc(Caller->getDebugLoc());
// If this is an invoke instruction, we should insert it after the first
// non-phi, instruction in the normal successor block.
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
BasicBlock::iterator I = II->getNormalDest()->getFirstInsertionPt();
InsertNewInstBefore(NC, *I);
} else {
// Otherwise, it's a call, just insert cast right after the call.
InsertNewInstBefore(NC, *Caller);
}
Worklist.AddUsersToWorkList(*Caller);
} else {
NV = UndefValue::get(Caller->getType());
}
}
if (!Caller->use_empty())
ReplaceInstUsesWith(*Caller, NV);
else if (Caller->hasValueHandle())
ValueHandleBase::ValueIsRAUWd(Caller, NV);
EraseInstFromFunction(*Caller);
return true;
}
// transformCallThroughTrampoline - Turn a call to a function created by
// init_trampoline / adjust_trampoline intrinsic pair into a direct call to the
// underlying function.
//
Instruction *
InstCombiner::transformCallThroughTrampoline(CallSite CS,
IntrinsicInst *Tramp) {
Value *Callee = CS.getCalledValue();
PointerType *PTy = cast<PointerType>(Callee->getType());
FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
const AttributeSet &Attrs = CS.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;
assert(Tramp &&
"transformCallThroughTrampoline called with incorrect CallSite.");
Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts());
PointerType *NestFPTy = cast<PointerType>(NestF->getType());
FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType());
const AttributeSet &NestAttrs = NestF->getAttributes();
if (!NestAttrs.isEmpty()) {
unsigned NestIdx = 1;
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; ++NestIdx, ++I)
if (NestAttrs.hasAttribute(NestIdx, Attribute::Nest)) {
// Record the parameter type and any other attributes.
NestTy = *I;
NestAttr = NestAttrs.getParamAttributes(NestIdx);
break;
}
if (NestTy) {
Instruction *Caller = CS.getInstruction();
std::vector<Value*> NewArgs;
NewArgs.reserve(CS.arg_size() + 1);
SmallVector<AttributeSet, 8> NewAttrs;
NewAttrs.reserve(Attrs.getNumSlots() + 1);
// Insert the nest argument into the call argument list, which may
// mean appending it. Likewise for attributes.
// Add any result attributes.
if (Attrs.hasAttributes(AttributeSet::ReturnIndex))
NewAttrs.push_back(AttributeSet::get(Caller->getContext(),
Attrs.getRetAttributes()));
{
unsigned Idx = 1;
CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
do {
if (Idx == NestIdx) {
// 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);
NewAttrs.push_back(AttributeSet::get(Caller->getContext(),
NestAttr));
}
if (I == E)
break;
// Add the original argument and attributes.
NewArgs.push_back(*I);
AttributeSet Attr = Attrs.getParamAttributes(Idx);
if (Attr.hasAttributes(Idx)) {
AttrBuilder B(Attr, Idx);
NewAttrs.push_back(AttributeSet::get(Caller->getContext(),
Idx + (Idx >= NestIdx), B));
}
++Idx, ++I;
} while (1);
}
// Add any function attributes.
if (Attrs.hasAttributes(AttributeSet::FunctionIndex))
NewAttrs.push_back(AttributeSet::get(FTy->getContext(),
Attrs.getFnAttributes()));
// 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 Idx = 1;
FunctionType::param_iterator I = FTy->param_begin(),
E = FTy->param_end();
do {
if (Idx == NestIdx)
// Add the chain's type.
NewTypes.push_back(NestTy);
if (I == E)
break;
// Add the original type.
NewTypes.push_back(*I);
++Idx, ++I;
} while (1);
}
// 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));
const AttributeSet &NewPAL =
AttributeSet::get(FTy->getContext(), NewAttrs);
Instruction *NewCaller;
if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
NewCaller = InvokeInst::Create(NewCallee,
II->getNormalDest(), II->getUnwindDest(),
NewArgs);
cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
cast<InvokeInst>(NewCaller)->setAttributes(NewPAL);
} else {
NewCaller = CallInst::Create(NewCallee, NewArgs);
if (cast<CallInst>(Caller)->isTailCall())
cast<CallInst>(NewCaller)->setTailCall();
cast<CallInst>(NewCaller)->
setCallingConv(cast<CallInst>(Caller)->getCallingConv());
cast<CallInst>(NewCaller)->setAttributes(NewPAL);
}
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 =
NestF->getType() == PTy ? NestF :
ConstantExpr::getBitCast(NestF, PTy);
CS.setCalledFunction(NewCallee);
return CS.getInstruction();
}
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