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Constants.cpp
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//===-- Constants.cpp - Implement Constant nodes --------------------------===//
//
// 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 Constant* classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Constants.h"
#include "ConstantFold.h"
#include "LLVMContextImpl.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
using namespace PatternMatch;
//===----------------------------------------------------------------------===//
// Constant Class
//===----------------------------------------------------------------------===//
bool Constant::isNegativeZeroValue() const {
// Floating point values have an explicit -0.0 value.
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return CFP->isZero() && CFP->isNegative();
// Equivalent for a vector of -0.0's.
if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
if (CV->getElementType()->isFloatingPointTy() && CV->isSplat())
if (CV->getElementAsAPFloat(0).isNegZero())
return true;
if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
if (ConstantFP *SplatCFP = dyn_cast_or_null<ConstantFP>(CV->getSplatValue()))
if (SplatCFP && SplatCFP->isZero() && SplatCFP->isNegative())
return true;
// We've already handled true FP case; any other FP vectors can't represent -0.0.
if (getType()->isFPOrFPVectorTy())
return false;
// Otherwise, just use +0.0.
return isNullValue();
}
// Return true iff this constant is positive zero (floating point), negative
// zero (floating point), or a null value.
bool Constant::isZeroValue() const {
// Floating point values have an explicit -0.0 value.
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return CFP->isZero();
// Equivalent for a vector of -0.0's.
if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
if (CV->getElementType()->isFloatingPointTy() && CV->isSplat())
if (CV->getElementAsAPFloat(0).isZero())
return true;
if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
if (ConstantFP *SplatCFP = dyn_cast_or_null<ConstantFP>(CV->getSplatValue()))
if (SplatCFP && SplatCFP->isZero())
return true;
// Otherwise, just use +0.0.
return isNullValue();
}
bool Constant::isNullValue() const {
// 0 is null.
if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
return CI->isZero();
// +0.0 is null.
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return CFP->isZero() && !CFP->isNegative();
// constant zero is zero for aggregates, cpnull is null for pointers, none for
// tokens.
return isa<ConstantAggregateZero>(this) || isa<ConstantPointerNull>(this) ||
isa<ConstantTokenNone>(this);
}
bool Constant::isAllOnesValue() const {
// Check for -1 integers
if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
return CI->isMinusOne();
// Check for FP which are bitcasted from -1 integers
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return CFP->getValueAPF().bitcastToAPInt().isAllOnesValue();
// Check for constant vectors which are splats of -1 values.
if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
if (Constant *Splat = CV->getSplatValue())
return Splat->isAllOnesValue();
// Check for constant vectors which are splats of -1 values.
if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this)) {
if (CV->isSplat()) {
if (CV->getElementType()->isFloatingPointTy())
return CV->getElementAsAPFloat(0).bitcastToAPInt().isAllOnesValue();
return CV->getElementAsAPInt(0).isAllOnesValue();
}
}
return false;
}
bool Constant::isOneValue() const {
// Check for 1 integers
if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
return CI->isOne();
// Check for FP which are bitcasted from 1 integers
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return CFP->getValueAPF().bitcastToAPInt().isOneValue();
// Check for constant vectors which are splats of 1 values.
if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
if (Constant *Splat = CV->getSplatValue())
return Splat->isOneValue();
// Check for constant vectors which are splats of 1 values.
if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this)) {
if (CV->isSplat()) {
if (CV->getElementType()->isFloatingPointTy())
return CV->getElementAsAPFloat(0).bitcastToAPInt().isOneValue();
return CV->getElementAsAPInt(0).isOneValue();
}
}
return false;
}
bool Constant::isNotOneValue() const {
// Check for 1 integers
if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
return !CI->isOneValue();
// Check for FP which are bitcasted from 1 integers
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return !CFP->getValueAPF().bitcastToAPInt().isOneValue();
// Check that vectors don't contain 1
if (auto *VTy = dyn_cast<VectorType>(this->getType())) {
unsigned NumElts = cast<FixedVectorType>(VTy)->getNumElements();
for (unsigned i = 0; i != NumElts; ++i) {
Constant *Elt = this->getAggregateElement(i);
if (!Elt || !Elt->isNotOneValue())
return false;
}
return true;
}
// It *may* contain 1, we can't tell.
return false;
}
bool Constant::isMinSignedValue() const {
// Check for INT_MIN integers
if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
return CI->isMinValue(/*isSigned=*/true);
// Check for FP which are bitcasted from INT_MIN integers
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
// Check for constant vectors which are splats of INT_MIN values.
if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
if (Constant *Splat = CV->getSplatValue())
return Splat->isMinSignedValue();
// Check for constant vectors which are splats of INT_MIN values.
if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this)) {
if (CV->isSplat()) {
if (CV->getElementType()->isFloatingPointTy())
return CV->getElementAsAPFloat(0).bitcastToAPInt().isMinSignedValue();
return CV->getElementAsAPInt(0).isMinSignedValue();
}
}
return false;
}
bool Constant::isNotMinSignedValue() const {
// Check for INT_MIN integers
if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
return !CI->isMinValue(/*isSigned=*/true);
// Check for FP which are bitcasted from INT_MIN integers
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
return !CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
// Check that vectors don't contain INT_MIN
if (auto *VTy = dyn_cast<VectorType>(this->getType())) {
unsigned NumElts = cast<FixedVectorType>(VTy)->getNumElements();
for (unsigned i = 0; i != NumElts; ++i) {
Constant *Elt = this->getAggregateElement(i);
if (!Elt || !Elt->isNotMinSignedValue())
return false;
}
return true;
}
// It *may* contain INT_MIN, we can't tell.
return false;
}
bool Constant::isFiniteNonZeroFP() const {
if (auto *CFP = dyn_cast<ConstantFP>(this))
return CFP->getValueAPF().isFiniteNonZero();
auto *VTy = dyn_cast<FixedVectorType>(getType());
if (!VTy)
return false;
for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
if (!CFP || !CFP->getValueAPF().isFiniteNonZero())
return false;
}
return true;
}
bool Constant::isNormalFP() const {
if (auto *CFP = dyn_cast<ConstantFP>(this))
return CFP->getValueAPF().isNormal();
auto *VTy = dyn_cast<FixedVectorType>(getType());
if (!VTy)
return false;
for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
if (!CFP || !CFP->getValueAPF().isNormal())
return false;
}
return true;
}
bool Constant::hasExactInverseFP() const {
if (auto *CFP = dyn_cast<ConstantFP>(this))
return CFP->getValueAPF().getExactInverse(nullptr);
auto *VTy = dyn_cast<FixedVectorType>(getType());
if (!VTy)
return false;
for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
if (!CFP || !CFP->getValueAPF().getExactInverse(nullptr))
return false;
}
return true;
}
bool Constant::isNaN() const {
if (auto *CFP = dyn_cast<ConstantFP>(this))
return CFP->isNaN();
auto *VTy = dyn_cast<FixedVectorType>(getType());
if (!VTy)
return false;
for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
if (!CFP || !CFP->isNaN())
return false;
}
return true;
}
bool Constant::isElementWiseEqual(Value *Y) const {
// Are they fully identical?
if (this == Y)
return true;
// The input value must be a vector constant with the same type.
auto *VTy = dyn_cast<VectorType>(getType());
if (!isa<Constant>(Y) || !VTy || VTy != Y->getType())
return false;
// TODO: Compare pointer constants?
if (!(VTy->getElementType()->isIntegerTy() ||
VTy->getElementType()->isFloatingPointTy()))
return false;
// They may still be identical element-wise (if they have `undef`s).
// Bitcast to integer to allow exact bitwise comparison for all types.
Type *IntTy = VectorType::getInteger(VTy);
Constant *C0 = ConstantExpr::getBitCast(const_cast<Constant *>(this), IntTy);
Constant *C1 = ConstantExpr::getBitCast(cast<Constant>(Y), IntTy);
Constant *CmpEq = ConstantExpr::getICmp(ICmpInst::ICMP_EQ, C0, C1);
return isa<UndefValue>(CmpEq) || match(CmpEq, m_One());
}
static bool
containsUndefinedElement(const Constant *C,
function_ref<bool(const Constant *)> HasFn) {
if (auto *VTy = dyn_cast<VectorType>(C->getType())) {
if (HasFn(C))
return true;
if (isa<ConstantAggregateZero>(C))
return false;
if (isa<ScalableVectorType>(C->getType()))
return false;
for (unsigned i = 0, e = cast<FixedVectorType>(VTy)->getNumElements();
i != e; ++i)
if (HasFn(C->getAggregateElement(i)))
return true;
}
return false;
}
bool Constant::containsUndefOrPoisonElement() const {
return containsUndefinedElement(
this, [&](const auto *C) { return isa<UndefValue>(C); });
}
bool Constant::containsPoisonElement() const {
return containsUndefinedElement(
this, [&](const auto *C) { return isa<PoisonValue>(C); });
}
bool Constant::containsConstantExpression() const {
if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i)
if (isa<ConstantExpr>(getAggregateElement(i)))
return true;
}
return false;
}
/// Constructor to create a '0' constant of arbitrary type.
Constant *Constant::getNullValue(Type *Ty) {
switch (Ty->getTypeID()) {
case Type::IntegerTyID:
return ConstantInt::get(Ty, 0);
case Type::HalfTyID:
return ConstantFP::get(Ty->getContext(),
APFloat::getZero(APFloat::IEEEhalf()));
case Type::BFloatTyID:
return ConstantFP::get(Ty->getContext(),
APFloat::getZero(APFloat::BFloat()));
case Type::FloatTyID:
return ConstantFP::get(Ty->getContext(),
APFloat::getZero(APFloat::IEEEsingle()));
case Type::DoubleTyID:
return ConstantFP::get(Ty->getContext(),
APFloat::getZero(APFloat::IEEEdouble()));
case Type::X86_FP80TyID:
return ConstantFP::get(Ty->getContext(),
APFloat::getZero(APFloat::x87DoubleExtended()));
case Type::FP128TyID:
return ConstantFP::get(Ty->getContext(),
APFloat::getZero(APFloat::IEEEquad()));
case Type::PPC_FP128TyID:
return ConstantFP::get(Ty->getContext(),
APFloat(APFloat::PPCDoubleDouble(),
APInt::getNullValue(128)));
case Type::PointerTyID:
return ConstantPointerNull::get(cast<PointerType>(Ty));
case Type::StructTyID:
case Type::ArrayTyID:
case Type::FixedVectorTyID:
case Type::ScalableVectorTyID:
return ConstantAggregateZero::get(Ty);
case Type::TokenTyID:
return ConstantTokenNone::get(Ty->getContext());
default:
// Function, Label, or Opaque type?
llvm_unreachable("Cannot create a null constant of that type!");
}
}
Constant *Constant::getIntegerValue(Type *Ty, const APInt &V) {
Type *ScalarTy = Ty->getScalarType();
// Create the base integer constant.
Constant *C = ConstantInt::get(Ty->getContext(), V);
// Convert an integer to a pointer, if necessary.
if (PointerType *PTy = dyn_cast<PointerType>(ScalarTy))
C = ConstantExpr::getIntToPtr(C, PTy);
// Broadcast a scalar to a vector, if necessary.
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
C = ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
Constant *Constant::getAllOnesValue(Type *Ty) {
if (IntegerType *ITy = dyn_cast<IntegerType>(Ty))
return ConstantInt::get(Ty->getContext(),
APInt::getAllOnesValue(ITy->getBitWidth()));
if (Ty->isFloatingPointTy()) {
APFloat FL = APFloat::getAllOnesValue(Ty->getFltSemantics(),
Ty->getPrimitiveSizeInBits());
return ConstantFP::get(Ty->getContext(), FL);
}
VectorType *VTy = cast<VectorType>(Ty);
return ConstantVector::getSplat(VTy->getElementCount(),
getAllOnesValue(VTy->getElementType()));
}
Constant *Constant::getAggregateElement(unsigned Elt) const {
if (const auto *CC = dyn_cast<ConstantAggregate>(this))
return Elt < CC->getNumOperands() ? CC->getOperand(Elt) : nullptr;
// FIXME: getNumElements() will fail for non-fixed vector types.
if (isa<ScalableVectorType>(getType()))
return nullptr;
if (const auto *CAZ = dyn_cast<ConstantAggregateZero>(this))
return Elt < CAZ->getNumElements() ? CAZ->getElementValue(Elt) : nullptr;
if (const auto *PV = dyn_cast<PoisonValue>(this))
return Elt < PV->getNumElements() ? PV->getElementValue(Elt) : nullptr;
if (const auto *UV = dyn_cast<UndefValue>(this))
return Elt < UV->getNumElements() ? UV->getElementValue(Elt) : nullptr;
if (const auto *CDS = dyn_cast<ConstantDataSequential>(this))
return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt)
: nullptr;
return nullptr;
}
Constant *Constant::getAggregateElement(Constant *Elt) const {
assert(isa<IntegerType>(Elt->getType()) && "Index must be an integer");
if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt)) {
// Check if the constant fits into an uint64_t.
if (CI->getValue().getActiveBits() > 64)
return nullptr;
return getAggregateElement(CI->getZExtValue());
}
return nullptr;
}
void Constant::destroyConstant() {
/// First call destroyConstantImpl on the subclass. This gives the subclass
/// a chance to remove the constant from any maps/pools it's contained in.
switch (getValueID()) {
default:
llvm_unreachable("Not a constant!");
#define HANDLE_CONSTANT(Name) \
case Value::Name##Val: \
cast<Name>(this)->destroyConstantImpl(); \
break;
#include "llvm/IR/Value.def"
}
// When a Constant is destroyed, there may be lingering
// references to the constant by other constants in the constant pool. These
// constants are implicitly dependent on the module that is being deleted,
// but they don't know that. Because we only find out when the CPV is
// deleted, we must now notify all of our users (that should only be
// Constants) that they are, in fact, invalid now and should be deleted.
//
while (!use_empty()) {
Value *V = user_back();
#ifndef NDEBUG // Only in -g mode...
if (!isa<Constant>(V)) {
dbgs() << "While deleting: " << *this
<< "\n\nUse still stuck around after Def is destroyed: " << *V
<< "\n\n";
}
#endif
assert(isa<Constant>(V) && "References remain to Constant being destroyed");
cast<Constant>(V)->destroyConstant();
// The constant should remove itself from our use list...
assert((use_empty() || user_back() != V) && "Constant not removed!");
}
// Value has no outstanding references it is safe to delete it now...
deleteConstant(this);
}
void llvm::deleteConstant(Constant *C) {
switch (C->getValueID()) {
case Constant::ConstantIntVal:
delete static_cast<ConstantInt *>(C);
break;
case Constant::ConstantFPVal:
delete static_cast<ConstantFP *>(C);
break;
case Constant::ConstantAggregateZeroVal:
delete static_cast<ConstantAggregateZero *>(C);
break;
case Constant::ConstantArrayVal:
delete static_cast<ConstantArray *>(C);
break;
case Constant::ConstantStructVal:
delete static_cast<ConstantStruct *>(C);
break;
case Constant::ConstantVectorVal:
delete static_cast<ConstantVector *>(C);
break;
case Constant::ConstantPointerNullVal:
delete static_cast<ConstantPointerNull *>(C);
break;
case Constant::ConstantDataArrayVal:
delete static_cast<ConstantDataArray *>(C);
break;
case Constant::ConstantDataVectorVal:
delete static_cast<ConstantDataVector *>(C);
break;
case Constant::ConstantTokenNoneVal:
delete static_cast<ConstantTokenNone *>(C);
break;
case Constant::BlockAddressVal:
delete static_cast<BlockAddress *>(C);
break;
case Constant::DSOLocalEquivalentVal:
delete static_cast<DSOLocalEquivalent *>(C);
break;
case Constant::UndefValueVal:
delete static_cast<UndefValue *>(C);
break;
case Constant::PoisonValueVal:
delete static_cast<PoisonValue *>(C);
break;
case Constant::ConstantExprVal:
if (isa<UnaryConstantExpr>(C))
delete static_cast<UnaryConstantExpr *>(C);
else if (isa<BinaryConstantExpr>(C))
delete static_cast<BinaryConstantExpr *>(C);
else if (isa<SelectConstantExpr>(C))
delete static_cast<SelectConstantExpr *>(C);
else if (isa<ExtractElementConstantExpr>(C))
delete static_cast<ExtractElementConstantExpr *>(C);
else if (isa<InsertElementConstantExpr>(C))
delete static_cast<InsertElementConstantExpr *>(C);
else if (isa<ShuffleVectorConstantExpr>(C))
delete static_cast<ShuffleVectorConstantExpr *>(C);
else if (isa<ExtractValueConstantExpr>(C))
delete static_cast<ExtractValueConstantExpr *>(C);
else if (isa<InsertValueConstantExpr>(C))
delete static_cast<InsertValueConstantExpr *>(C);
else if (isa<GetElementPtrConstantExpr>(C))
delete static_cast<GetElementPtrConstantExpr *>(C);
else if (isa<CompareConstantExpr>(C))
delete static_cast<CompareConstantExpr *>(C);
else
llvm_unreachable("Unexpected constant expr");
break;
default:
llvm_unreachable("Unexpected constant");
}
}
static bool canTrapImpl(const Constant *C,
SmallPtrSetImpl<const ConstantExpr *> &NonTrappingOps) {
assert(C->getType()->isFirstClassType() && "Cannot evaluate aggregate vals!");
// The only thing that could possibly trap are constant exprs.
const ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
if (!CE)
return false;
// ConstantExpr traps if any operands can trap.
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
if (ConstantExpr *Op = dyn_cast<ConstantExpr>(CE->getOperand(i))) {
if (NonTrappingOps.insert(Op).second && canTrapImpl(Op, NonTrappingOps))
return true;
}
}
// Otherwise, only specific operations can trap.
switch (CE->getOpcode()) {
default:
return false;
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::URem:
case Instruction::SRem:
// Div and rem can trap if the RHS is not known to be non-zero.
if (!isa<ConstantInt>(CE->getOperand(1)) ||CE->getOperand(1)->isNullValue())
return true;
return false;
}
}
bool Constant::canTrap() const {
SmallPtrSet<const ConstantExpr *, 4> NonTrappingOps;
return canTrapImpl(this, NonTrappingOps);
}
/// Check if C contains a GlobalValue for which Predicate is true.
static bool
ConstHasGlobalValuePredicate(const Constant *C,
bool (*Predicate)(const GlobalValue *)) {
SmallPtrSet<const Constant *, 8> Visited;
SmallVector<const Constant *, 8> WorkList;
WorkList.push_back(C);
Visited.insert(C);
while (!WorkList.empty()) {
const Constant *WorkItem = WorkList.pop_back_val();
if (const auto *GV = dyn_cast<GlobalValue>(WorkItem))
if (Predicate(GV))
return true;
for (const Value *Op : WorkItem->operands()) {
const Constant *ConstOp = dyn_cast<Constant>(Op);
if (!ConstOp)
continue;
if (Visited.insert(ConstOp).second)
WorkList.push_back(ConstOp);
}
}
return false;
}
bool Constant::isThreadDependent() const {
auto DLLImportPredicate = [](const GlobalValue *GV) {
return GV->isThreadLocal();
};
return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
}
bool Constant::isDLLImportDependent() const {
auto DLLImportPredicate = [](const GlobalValue *GV) {
return GV->hasDLLImportStorageClass();
};
return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
}
bool Constant::isConstantUsed() const {
for (const User *U : users()) {
const Constant *UC = dyn_cast<Constant>(U);
if (!UC || isa<GlobalValue>(UC))
return true;
if (UC->isConstantUsed())
return true;
}
return false;
}
bool Constant::needsDynamicRelocation() const {
return getRelocationInfo() == GlobalRelocation;
}
bool Constant::needsRelocation() const {
return getRelocationInfo() != NoRelocation;
}
Constant::PossibleRelocationsTy Constant::getRelocationInfo() const {
if (isa<GlobalValue>(this))
return GlobalRelocation; // Global reference.
if (const BlockAddress *BA = dyn_cast<BlockAddress>(this))
return BA->getFunction()->getRelocationInfo();
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
if (CE->getOpcode() == Instruction::Sub) {
ConstantExpr *LHS = dyn_cast<ConstantExpr>(CE->getOperand(0));
ConstantExpr *RHS = dyn_cast<ConstantExpr>(CE->getOperand(1));
if (LHS && RHS && LHS->getOpcode() == Instruction::PtrToInt &&
RHS->getOpcode() == Instruction::PtrToInt) {
Constant *LHSOp0 = LHS->getOperand(0);
Constant *RHSOp0 = RHS->getOperand(0);
// While raw uses of blockaddress need to be relocated, differences
// between two of them don't when they are for labels in the same
// function. This is a common idiom when creating a table for the
// indirect goto extension, so we handle it efficiently here.
if (isa<BlockAddress>(LHSOp0) && isa<BlockAddress>(RHSOp0) &&
cast<BlockAddress>(LHSOp0)->getFunction() ==
cast<BlockAddress>(RHSOp0)->getFunction())
return NoRelocation;
// Relative pointers do not need to be dynamically relocated.
if (auto *RHSGV =
dyn_cast<GlobalValue>(RHSOp0->stripInBoundsConstantOffsets())) {
auto *LHS = LHSOp0->stripInBoundsConstantOffsets();
if (auto *LHSGV = dyn_cast<GlobalValue>(LHS)) {
if (LHSGV->isDSOLocal() && RHSGV->isDSOLocal())
return LocalRelocation;
} else if (isa<DSOLocalEquivalent>(LHS)) {
if (RHSGV->isDSOLocal())
return LocalRelocation;
}
}
}
}
}
PossibleRelocationsTy Result = NoRelocation;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
Result =
std::max(cast<Constant>(getOperand(i))->getRelocationInfo(), Result);
return Result;
}
/// If the specified constantexpr is dead, remove it. This involves recursively
/// eliminating any dead users of the constantexpr.
static bool removeDeadUsersOfConstant(const Constant *C) {
if (isa<GlobalValue>(C)) return false; // Cannot remove this
while (!C->use_empty()) {
const Constant *User = dyn_cast<Constant>(C->user_back());
if (!User) return false; // Non-constant usage;
if (!removeDeadUsersOfConstant(User))
return false; // Constant wasn't dead
}
// If C is only used by metadata, it should not be preserved but should have
// its uses replaced.
if (C->isUsedByMetadata()) {
const_cast<Constant *>(C)->replaceAllUsesWith(
UndefValue::get(C->getType()));
}
const_cast<Constant*>(C)->destroyConstant();
return true;
}
void Constant::removeDeadConstantUsers() const {
Value::const_user_iterator I = user_begin(), E = user_end();
Value::const_user_iterator LastNonDeadUser = E;
while (I != E) {
const Constant *User = dyn_cast<Constant>(*I);
if (!User) {
LastNonDeadUser = I;
++I;
continue;
}
if (!removeDeadUsersOfConstant(User)) {
// If the constant wasn't dead, remember that this was the last live use
// and move on to the next constant.
LastNonDeadUser = I;
++I;
continue;
}
// If the constant was dead, then the iterator is invalidated.
if (LastNonDeadUser == E)
I = user_begin();
else
I = std::next(LastNonDeadUser);
}
}
Constant *Constant::replaceUndefsWith(Constant *C, Constant *Replacement) {
assert(C && Replacement && "Expected non-nullptr constant arguments");
Type *Ty = C->getType();
if (match(C, m_Undef())) {
assert(Ty == Replacement->getType() && "Expected matching types");
return Replacement;
}
// Don't know how to deal with this constant.
auto *VTy = dyn_cast<FixedVectorType>(Ty);
if (!VTy)
return C;
unsigned NumElts = VTy->getNumElements();
SmallVector<Constant *, 32> NewC(NumElts);
for (unsigned i = 0; i != NumElts; ++i) {
Constant *EltC = C->getAggregateElement(i);
assert((!EltC || EltC->getType() == Replacement->getType()) &&
"Expected matching types");
NewC[i] = EltC && match(EltC, m_Undef()) ? Replacement : EltC;
}
return ConstantVector::get(NewC);
}
Constant *Constant::mergeUndefsWith(Constant *C, Constant *Other) {
assert(C && Other && "Expected non-nullptr constant arguments");
if (match(C, m_Undef()))
return C;
Type *Ty = C->getType();
if (match(Other, m_Undef()))
return UndefValue::get(Ty);
auto *VTy = dyn_cast<FixedVectorType>(Ty);
if (!VTy)
return C;
Type *EltTy = VTy->getElementType();
unsigned NumElts = VTy->getNumElements();
assert(isa<FixedVectorType>(Other->getType()) &&
cast<FixedVectorType>(Other->getType())->getNumElements() == NumElts &&
"Type mismatch");
bool FoundExtraUndef = false;
SmallVector<Constant *, 32> NewC(NumElts);
for (unsigned I = 0; I != NumElts; ++I) {
NewC[I] = C->getAggregateElement(I);
Constant *OtherEltC = Other->getAggregateElement(I);
assert(NewC[I] && OtherEltC && "Unknown vector element");
if (!match(NewC[I], m_Undef()) && match(OtherEltC, m_Undef())) {
NewC[I] = UndefValue::get(EltTy);
FoundExtraUndef = true;
}
}
if (FoundExtraUndef)
return ConstantVector::get(NewC);
return C;
}
//===----------------------------------------------------------------------===//
// ConstantInt
//===----------------------------------------------------------------------===//
ConstantInt::ConstantInt(IntegerType *Ty, const APInt &V)
: ConstantData(Ty, ConstantIntVal), Val(V) {
assert(V.getBitWidth() == Ty->getBitWidth() && "Invalid constant for type");
}
ConstantInt *ConstantInt::getTrue(LLVMContext &Context) {
LLVMContextImpl *pImpl = Context.pImpl;
if (!pImpl->TheTrueVal)
pImpl->TheTrueVal = ConstantInt::get(Type::getInt1Ty(Context), 1);
return pImpl->TheTrueVal;
}
ConstantInt *ConstantInt::getFalse(LLVMContext &Context) {
LLVMContextImpl *pImpl = Context.pImpl;
if (!pImpl->TheFalseVal)
pImpl->TheFalseVal = ConstantInt::get(Type::getInt1Ty(Context), 0);
return pImpl->TheFalseVal;
}
ConstantInt *ConstantInt::getBool(LLVMContext &Context, bool V) {
return V ? getTrue(Context) : getFalse(Context);
}
Constant *ConstantInt::getTrue(Type *Ty) {
assert(Ty->isIntOrIntVectorTy(1) && "Type not i1 or vector of i1.");
ConstantInt *TrueC = ConstantInt::getTrue(Ty->getContext());
if (auto *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), TrueC);
return TrueC;
}
Constant *ConstantInt::getFalse(Type *Ty) {
assert(Ty->isIntOrIntVectorTy(1) && "Type not i1 or vector of i1.");
ConstantInt *FalseC = ConstantInt::getFalse(Ty->getContext());
if (auto *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), FalseC);
return FalseC;
}
Constant *ConstantInt::getBool(Type *Ty, bool V) {
return V ? getTrue(Ty) : getFalse(Ty);
}
// Get a ConstantInt from an APInt.
ConstantInt *ConstantInt::get(LLVMContext &Context, const APInt &V) {
// get an existing value or the insertion position
LLVMContextImpl *pImpl = Context.pImpl;
std::unique_ptr<ConstantInt> &Slot = pImpl->IntConstants[V];
if (!Slot) {
// Get the corresponding integer type for the bit width of the value.
IntegerType *ITy = IntegerType::get(Context, V.getBitWidth());
Slot.reset(new ConstantInt(ITy, V));
}
assert(Slot->getType() == IntegerType::get(Context, V.getBitWidth()));
return Slot.get();
}
Constant *ConstantInt::get(Type *Ty, uint64_t V, bool isSigned) {
Constant *C = get(cast<IntegerType>(Ty->getScalarType()), V, isSigned);
// For vectors, broadcast the value.
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
ConstantInt *ConstantInt::get(IntegerType *Ty, uint64_t V, bool isSigned) {
return get(Ty->getContext(), APInt(Ty->getBitWidth(), V, isSigned));
}
ConstantInt *ConstantInt::getSigned(IntegerType *Ty, int64_t V) {
return get(Ty, V, true);
}
Constant *ConstantInt::getSigned(Type *Ty, int64_t V) {
return get(Ty, V, true);
}
Constant *ConstantInt::get(Type *Ty, const APInt& V) {
ConstantInt *C = get(Ty->getContext(), V);
assert(C->getType() == Ty->getScalarType() &&
"ConstantInt type doesn't match the type implied by its value!");
// For vectors, broadcast the value.
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
ConstantInt *ConstantInt::get(IntegerType* Ty, StringRef Str, uint8_t radix) {
return get(Ty->getContext(), APInt(Ty->getBitWidth(), Str, radix));
}
/// Remove the constant from the constant table.
void ConstantInt::destroyConstantImpl() {
llvm_unreachable("You can't ConstantInt->destroyConstantImpl()!");
}
//===----------------------------------------------------------------------===//
// ConstantFP
//===----------------------------------------------------------------------===//
Constant *ConstantFP::get(Type *Ty, double V) {
LLVMContext &Context = Ty->getContext();
APFloat FV(V);
bool ignored;
FV.convert(Ty->getScalarType()->getFltSemantics(),
APFloat::rmNearestTiesToEven, &ignored);
Constant *C = get(Context, FV);
// For vectors, broadcast the value.
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
Constant *ConstantFP::get(Type *Ty, const APFloat &V) {
ConstantFP *C = get(Ty->getContext(), V);
assert(C->getType() == Ty->getScalarType() &&
"ConstantFP type doesn't match the type implied by its value!");
// For vectors, broadcast the value.
if (auto *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
Constant *ConstantFP::get(Type *Ty, StringRef Str) {
LLVMContext &Context = Ty->getContext();
APFloat FV(Ty->getScalarType()->getFltSemantics(), Str);
Constant *C = get(Context, FV);
// For vectors, broadcast the value.
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
Constant *ConstantFP::getNaN(Type *Ty, bool Negative, uint64_t Payload) {
const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
APFloat NaN = APFloat::getNaN(Semantics, Negative, Payload);
Constant *C = get(Ty->getContext(), NaN);
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
Constant *ConstantFP::getQNaN(Type *Ty, bool Negative, APInt *Payload) {
const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
APFloat NaN = APFloat::getQNaN(Semantics, Negative, Payload);
Constant *C = get(Ty->getContext(), NaN);
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;
}
Constant *ConstantFP::getSNaN(Type *Ty, bool Negative, APInt *Payload) {
const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
APFloat NaN = APFloat::getSNaN(Semantics, Negative, Payload);
Constant *C = get(Ty->getContext(), NaN);
if (VectorType *VTy = dyn_cast<VectorType>(Ty))
return ConstantVector::getSplat(VTy->getElementCount(), C);
return C;