//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include <cstring>
using namespace llvm;
assert(V && "No Value?");
assert(Depth <= MaxDepth && "Limit Search Depth");
unsigned BitWidth = Mask.getBitWidth();
- assert((V->getType()->isIntOrIntVector() || isa<PointerType>(V->getType())) &&
- "Not integer or pointer type!");
+ assert((V->getType()->isIntOrIntVectorTy() || V->getType()->isPointerTy())
+ && "Not integer or pointer type!");
assert((!TD ||
TD->getTypeSizeInBits(V->getType()->getScalarType()) == BitWidth) &&
- (!V->getType()->isIntOrIntVector() ||
+ (!V->getType()->isIntOrIntVectorTy() ||
V->getType()->getScalarSizeInBits() == BitWidth) &&
KnownZero.getBitWidth() == BitWidth &&
KnownOne.getBitWidth() == BitWidth &&
// Null and aggregate-zero are all-zeros.
if (isa<ConstantPointerNull>(V) ||
isa<ConstantAggregateZero>(V)) {
- KnownOne.clear();
+ KnownOne.clearAllBits();
KnownZero = Mask;
return;
}
// Handle a constant vector by taking the intersection of the known bits of
// each element.
if (ConstantVector *CV = dyn_cast<ConstantVector>(V)) {
- KnownZero.set(); KnownOne.set();
+ KnownZero.setAllBits(); KnownOne.setAllBits();
for (unsigned i = 0, e = CV->getNumOperands(); i != e; ++i) {
APInt KnownZero2(BitWidth, 0), KnownOne2(BitWidth, 0);
ComputeMaskedBits(CV->getOperand(i), Mask, KnownZero2, KnownOne2,
KnownZero = Mask & APInt::getLowBitsSet(BitWidth,
CountTrailingZeros_32(Align));
else
- KnownZero.clear();
- KnownOne.clear();
+ KnownZero.clearAllBits();
+ KnownOne.clearAllBits();
return;
}
// A weak GlobalAlias is totally unknown. A non-weak GlobalAlias has
// the bits of its aliasee.
if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
if (GA->mayBeOverridden()) {
- KnownZero.clear(); KnownOne.clear();
+ KnownZero.clearAllBits(); KnownOne.clearAllBits();
} else {
ComputeMaskedBits(GA->getAliasee(), Mask, KnownZero, KnownOne,
TD, Depth+1);
return;
}
- KnownZero.clear(); KnownOne.clear(); // Start out not knowing anything.
+ KnownZero.clearAllBits(); KnownOne.clearAllBits(); // Start out not knowing anything.
if (Depth == MaxDepth || Mask == 0)
return; // Limit search depth.
// Also compute a conserative estimate for high known-0 bits.
// More trickiness is possible, but this is sufficient for the
// interesting case of alignment computation.
- KnownOne.clear();
+ KnownOne.clearAllBits();
unsigned TrailZ = KnownZero.countTrailingOnes() +
KnownZero2.countTrailingOnes();
unsigned LeadZ = std::max(KnownZero.countLeadingOnes() +
AllOnes, KnownZero2, KnownOne2, TD, Depth+1);
unsigned LeadZ = KnownZero2.countLeadingOnes();
- KnownOne2.clear();
- KnownZero2.clear();
+ KnownOne2.clearAllBits();
+ KnownZero2.clearAllBits();
ComputeMaskedBits(I->getOperand(1),
AllOnes, KnownZero2, KnownOne2, TD, Depth+1);
unsigned RHSUnknownLeadingOnes = KnownOne2.countLeadingZeros();
unsigned SrcBitWidth;
// Note that we handle pointer operands here because of inttoptr/ptrtoint
// which fall through here.
- if (isa<PointerType>(SrcTy))
+ if (SrcTy->isPointerTy())
SrcBitWidth = TD->getTypeSizeInBits(SrcTy);
else
SrcBitWidth = SrcTy->getScalarSizeInBits();
- APInt MaskIn(Mask);
- MaskIn.zextOrTrunc(SrcBitWidth);
- KnownZero.zextOrTrunc(SrcBitWidth);
- KnownOne.zextOrTrunc(SrcBitWidth);
+ APInt MaskIn = Mask.zextOrTrunc(SrcBitWidth);
+ KnownZero = KnownZero.zextOrTrunc(SrcBitWidth);
+ KnownOne = KnownOne.zextOrTrunc(SrcBitWidth);
ComputeMaskedBits(I->getOperand(0), MaskIn, KnownZero, KnownOne, TD,
Depth+1);
- KnownZero.zextOrTrunc(BitWidth);
- KnownOne.zextOrTrunc(BitWidth);
+ KnownZero = KnownZero.zextOrTrunc(BitWidth);
+ KnownOne = KnownOne.zextOrTrunc(BitWidth);
// Any top bits are known to be zero.
if (BitWidth > SrcBitWidth)
KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - SrcBitWidth);
}
case Instruction::BitCast: {
const Type *SrcTy = I->getOperand(0)->getType();
- if ((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+ if ((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) &&
// TODO: For now, not handling conversions like:
// (bitcast i64 %x to <2 x i32>)
- !isa<VectorType>(I->getType())) {
+ !I->getType()->isVectorTy()) {
ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, TD,
Depth+1);
return;
// Compute the bits in the result that are not present in the input.
unsigned SrcBitWidth = I->getOperand(0)->getType()->getScalarSizeInBits();
- APInt MaskIn(Mask);
- MaskIn.trunc(SrcBitWidth);
- KnownZero.trunc(SrcBitWidth);
- KnownOne.trunc(SrcBitWidth);
+ APInt MaskIn = Mask.trunc(SrcBitWidth);
+ KnownZero = KnownZero.trunc(SrcBitWidth);
+ KnownOne = KnownOne.trunc(SrcBitWidth);
ComputeMaskedBits(I->getOperand(0), MaskIn, KnownZero, KnownOne, TD,
Depth+1);
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- KnownZero.zext(BitWidth);
- KnownOne.zext(BitWidth);
+ KnownZero = KnownZero.zext(BitWidth);
+ KnownOne = KnownOne.zext(BitWidth);
// If the sign bit of the input is known set or clear, then we know the
// top bits of the result.
APInt Mask2(Mask.shl(ShiftAmt));
ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero,KnownOne, TD,
Depth+1);
- assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
+ assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
KnownOne = APIntOps::lshr(KnownOne, ShiftAmt);
// high bits known zero.
APInt Mask2(Mask.shl(ShiftAmt));
ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero, KnownOne, TD,
Depth+1);
- assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
+ assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
KnownOne = APIntOps::lshr(KnownOne, ShiftAmt);
}
// fall through
case Instruction::Add: {
- // If one of the operands has trailing zeros, than the bits that the
+ // If one of the operands has trailing zeros, then the bits that the
// other operand has in those bit positions will be preserved in the
// result. For an add, this works with either operand. For a subtract,
// this only works if the known zeros are in the right operand.
}
case Instruction::SRem:
if (ConstantInt *Rem = dyn_cast<ConstantInt>(I->getOperand(1))) {
- APInt RA = Rem->getValue();
- if (RA.isPowerOf2() || (-RA).isPowerOf2()) {
- APInt LowBits = RA.isStrictlyPositive() ? (RA - 1) : ~RA;
+ APInt RA = Rem->getValue().abs();
+ if (RA.isPowerOf2()) {
+ APInt LowBits = RA - 1;
APInt Mask2 = LowBits | APInt::getSignBit(BitWidth);
ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero2, KnownOne2, TD,
Depth+1);
- // If the sign bit of the first operand is zero, the sign bit of
- // the result is zero. If the first operand has no one bits below
- // the second operand's single 1 bit, its sign will be zero.
+ // The low bits of the first operand are unchanged by the srem.
+ KnownZero = KnownZero2 & LowBits;
+ KnownOne = KnownOne2 & LowBits;
+
+ // If the first operand is non-negative or has all low bits zero, then
+ // the upper bits are all zero.
if (KnownZero2[BitWidth-1] || ((KnownZero2 & LowBits) == LowBits))
- KnownZero2 |= ~LowBits;
+ KnownZero |= ~LowBits;
- KnownZero |= KnownZero2 & Mask;
+ // If the first operand is negative and not all low bits are zero, then
+ // the upper bits are all one.
+ if (KnownOne2[BitWidth-1] && ((KnownOne2 & LowBits) != 0))
+ KnownOne |= ~LowBits;
- assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
+ KnownZero &= Mask;
+ KnownOne &= Mask;
+
+ assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
}
}
break;
KnownZero |= ~LowBits & Mask;
ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero, KnownOne, TD,
Depth+1);
- assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
+ assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
break;
}
}
unsigned Leaders = std::max(KnownZero.countLeadingOnes(),
KnownZero2.countLeadingOnes());
- KnownOne.clear();
+ KnownOne.clearAllBits();
KnownZero = APInt::getHighBitsSet(BitWidth, Leaders) & Mask;
break;
}
- case Instruction::Alloca:
- case Instruction::Malloc: {
- AllocationInst *AI = cast<AllocationInst>(V);
+ case Instruction::Alloca: {
+ AllocaInst *AI = cast<AllocaInst>(V);
unsigned Align = AI->getAlignment();
- if (Align == 0 && TD) {
- if (isa<AllocaInst>(AI))
- Align = TD->getABITypeAlignment(AI->getType()->getElementType());
- else if (isa<MallocInst>(AI)) {
- // Malloc returns maximally aligned memory.
- Align = TD->getABITypeAlignment(AI->getType()->getElementType());
- Align =
- std::max(Align,
- (unsigned)TD->getABITypeAlignment(
- Type::getDoubleTy(V->getContext())));
- Align =
- std::max(Align,
- (unsigned)TD->getABITypeAlignment(
- Type::getInt64Ty(V->getContext())));
- }
- }
+ if (Align == 0 && TD)
+ Align = TD->getABITypeAlignment(AI->getType()->getElementType());
if (Align > 0)
KnownZero = Mask & APInt::getLowBitsSet(BitWidth,
///
unsigned llvm::ComputeNumSignBits(Value *V, const TargetData *TD,
unsigned Depth) {
- assert((TD || V->getType()->isIntOrIntVector()) &&
+ assert((TD || V->getType()->isIntOrIntVectorTy()) &&
"ComputeNumSignBits requires a TargetData object to operate "
"on non-integer values!");
const Type *Ty = V->getType();
switch (Operator::getOpcode(V)) {
default: break;
case Instruction::SExt:
- Tmp = TyBits-cast<IntegerType>(U->getOperand(0)->getType())->getBitWidth();
+ Tmp = TyBits - U->getOperand(0)->getType()->getScalarSizeInBits();
return ComputeNumSignBits(U->getOperand(0), TD, Depth+1) + Tmp;
case Instruction::AShr:
Tmp += C->getZExtValue();
if (Tmp > TyBits) Tmp = TyBits;
}
+ // vector ashr X, <C, C, C, C> -> adds C sign bits
+ if (ConstantVector *C = dyn_cast<ConstantVector>(U->getOperand(1))) {
+ if (ConstantInt *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) {
+ Tmp += CI->getZExtValue();
+ if (Tmp > TyBits) Tmp = TyBits;
+ }
+ }
return Tmp;
case Instruction::Shl:
if (ConstantInt *C = dyn_cast<ConstantInt>(U->getOperand(1))) {
Tmp2 = ComputeNumSignBits(U->getOperand(1), TD, Depth+1);
if (Tmp2 == 1) return 1;
- return std::min(Tmp, Tmp2)-1;
- break;
+ return std::min(Tmp, Tmp2)-1;
case Instruction::Sub:
Tmp2 = ComputeNumSignBits(U->getOperand(1), TD, Depth+1);
// is, at worst, one more bit than the inputs.
Tmp = ComputeNumSignBits(U->getOperand(0), TD, Depth+1);
if (Tmp == 1) return 1; // Early out.
- return std::min(Tmp, Tmp2)-1;
- break;
+ return std::min(Tmp, Tmp2)-1;
+
+ case Instruction::PHI: {
+ PHINode *PN = cast<PHINode>(U);
+ // Don't analyze large in-degree PHIs.
+ if (PN->getNumIncomingValues() > 4) break;
+
+ // Take the minimum of all incoming values. This can't infinitely loop
+ // because of our depth threshold.
+ Tmp = ComputeNumSignBits(PN->getIncomingValue(0), TD, Depth+1);
+ for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
+ if (Tmp == 1) return Tmp;
+ Tmp = std::min(Tmp,
+ ComputeNumSignBits(PN->getIncomingValue(i), TD, Depth+1));
+ }
+ return Tmp;
+ }
+
case Instruction::Trunc:
// FIXME: it's tricky to do anything useful for this, but it is an important
// case for targets like X86.
return std::max(FirstAnswer, std::min(TyBits, Mask.countLeadingZeros()));
}
+/// ComputeMultiple - This function computes the integer multiple of Base that
+/// equals V. If successful, it returns true and returns the multiple in
+/// Multiple. If unsuccessful, it returns false. It looks
+/// through SExt instructions only if LookThroughSExt is true.
+bool llvm::ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
+ bool LookThroughSExt, unsigned Depth) {
+ const unsigned MaxDepth = 6;
+
+ assert(V && "No Value?");
+ assert(Depth <= MaxDepth && "Limit Search Depth");
+ assert(V->getType()->isIntegerTy() && "Not integer or pointer type!");
+
+ const Type *T = V->getType();
+
+ ConstantInt *CI = dyn_cast<ConstantInt>(V);
+
+ if (Base == 0)
+ return false;
+
+ if (Base == 1) {
+ Multiple = V;
+ return true;
+ }
+
+ ConstantExpr *CO = dyn_cast<ConstantExpr>(V);
+ Constant *BaseVal = ConstantInt::get(T, Base);
+ if (CO && CO == BaseVal) {
+ // Multiple is 1.
+ Multiple = ConstantInt::get(T, 1);
+ return true;
+ }
+
+ if (CI && CI->getZExtValue() % Base == 0) {
+ Multiple = ConstantInt::get(T, CI->getZExtValue() / Base);
+ return true;
+ }
+
+ if (Depth == MaxDepth) return false; // Limit search depth.
+
+ Operator *I = dyn_cast<Operator>(V);
+ if (!I) return false;
+
+ switch (I->getOpcode()) {
+ default: break;
+ case Instruction::SExt:
+ if (!LookThroughSExt) return false;
+ // otherwise fall through to ZExt
+ case Instruction::ZExt:
+ return ComputeMultiple(I->getOperand(0), Base, Multiple,
+ LookThroughSExt, Depth+1);
+ case Instruction::Shl:
+ case Instruction::Mul: {
+ Value *Op0 = I->getOperand(0);
+ Value *Op1 = I->getOperand(1);
+
+ if (I->getOpcode() == Instruction::Shl) {
+ ConstantInt *Op1CI = dyn_cast<ConstantInt>(Op1);
+ if (!Op1CI) return false;
+ // Turn Op0 << Op1 into Op0 * 2^Op1
+ APInt Op1Int = Op1CI->getValue();
+ uint64_t BitToSet = Op1Int.getLimitedValue(Op1Int.getBitWidth() - 1);
+ APInt API(Op1Int.getBitWidth(), 0);
+ API.setBit(BitToSet);
+ Op1 = ConstantInt::get(V->getContext(), API);
+ }
+
+ Value *Mul0 = NULL;
+ if (ComputeMultiple(Op0, Base, Mul0, LookThroughSExt, Depth+1)) {
+ if (Constant *Op1C = dyn_cast<Constant>(Op1))
+ if (Constant *MulC = dyn_cast<Constant>(Mul0)) {
+ if (Op1C->getType()->getPrimitiveSizeInBits() <
+ MulC->getType()->getPrimitiveSizeInBits())
+ Op1C = ConstantExpr::getZExt(Op1C, MulC->getType());
+ if (Op1C->getType()->getPrimitiveSizeInBits() >
+ MulC->getType()->getPrimitiveSizeInBits())
+ MulC = ConstantExpr::getZExt(MulC, Op1C->getType());
+
+ // V == Base * (Mul0 * Op1), so return (Mul0 * Op1)
+ Multiple = ConstantExpr::getMul(MulC, Op1C);
+ return true;
+ }
+
+ if (ConstantInt *Mul0CI = dyn_cast<ConstantInt>(Mul0))
+ if (Mul0CI->getValue() == 1) {
+ // V == Base * Op1, so return Op1
+ Multiple = Op1;
+ return true;
+ }
+ }
+
+ Value *Mul1 = NULL;
+ if (ComputeMultiple(Op1, Base, Mul1, LookThroughSExt, Depth+1)) {
+ if (Constant *Op0C = dyn_cast<Constant>(Op0))
+ if (Constant *MulC = dyn_cast<Constant>(Mul1)) {
+ if (Op0C->getType()->getPrimitiveSizeInBits() <
+ MulC->getType()->getPrimitiveSizeInBits())
+ Op0C = ConstantExpr::getZExt(Op0C, MulC->getType());
+ if (Op0C->getType()->getPrimitiveSizeInBits() >
+ MulC->getType()->getPrimitiveSizeInBits())
+ MulC = ConstantExpr::getZExt(MulC, Op0C->getType());
+
+ // V == Base * (Mul1 * Op0), so return (Mul1 * Op0)
+ Multiple = ConstantExpr::getMul(MulC, Op0C);
+ return true;
+ }
+
+ if (ConstantInt *Mul1CI = dyn_cast<ConstantInt>(Mul1))
+ if (Mul1CI->getValue() == 1) {
+ // V == Base * Op0, so return Op0
+ Multiple = Op0;
+ return true;
+ }
+ }
+ }
+ }
+
+ // We could not determine if V is a multiple of Base.
+ return false;
+}
+
/// CannotBeNegativeZero - Return true if we can prove that the specified FP
/// value is never equal to -0.0.
///
if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
// sqrt(-0.0) = -0.0, no other negative results are possible.
if (II->getIntrinsicID() == Intrinsic::sqrt)
- return CannotBeNegativeZero(II->getOperand(1), Depth+1);
+ return CannotBeNegativeZero(II->getArgOperand(0), Depth+1);
if (const CallInst *CI = dyn_cast<CallInst>(I))
if (const Function *F = CI->getCalledFunction()) {
if (F->isDeclaration()) {
// abs(x) != -0.0
if (F->getName() == "abs") return true;
- // abs[lf](x) != -0.0
- if (F->getName() == "absf") return true;
- if (F->getName() == "absl") return true;
+ // fabs[lf](x) != -0.0
+ if (F->getName() == "fabs") return true;
+ if (F->getName() == "fabsf") return true;
+ if (F->getName() == "fabsl") return true;
+ if (F->getName() == "sqrt" || F->getName() == "sqrtf" ||
+ F->getName() == "sqrtl")
+ return CannotBeNegativeZero(CI->getArgOperand(0), Depth+1);
}
}
return false;
}
+/// isBytewiseValue - If the specified value can be set by repeating the same
+/// byte in memory, return the i8 value that it is represented with. This is
+/// true for all i8 values obviously, but is also true for i32 0, i32 -1,
+/// i16 0xF0F0, double 0.0 etc. If the value can't be handled with a repeated
+/// byte store (e.g. i16 0x1234), return null.
+Value *llvm::isBytewiseValue(Value *V) {
+ // All byte-wide stores are splatable, even of arbitrary variables.
+ if (V->getType()->isIntegerTy(8)) return V;
+
+ // Constant float and double values can be handled as integer values if the
+ // corresponding integer value is "byteable". An important case is 0.0.
+ if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
+ if (CFP->getType()->isFloatTy())
+ V = ConstantExpr::getBitCast(CFP, Type::getInt32Ty(V->getContext()));
+ if (CFP->getType()->isDoubleTy())
+ V = ConstantExpr::getBitCast(CFP, Type::getInt64Ty(V->getContext()));
+ // Don't handle long double formats, which have strange constraints.
+ }
+
+ // We can handle constant integers that are power of two in size and a
+ // multiple of 8 bits.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+ unsigned Width = CI->getBitWidth();
+ if (isPowerOf2_32(Width) && Width > 8) {
+ // We can handle this value if the recursive binary decomposition is the
+ // same at all levels.
+ APInt Val = CI->getValue();
+ APInt Val2;
+ while (Val.getBitWidth() != 8) {
+ unsigned NextWidth = Val.getBitWidth()/2;
+ Val2 = Val.lshr(NextWidth);
+ Val2 = Val2.trunc(Val.getBitWidth()/2);
+ Val = Val.trunc(Val.getBitWidth()/2);
+
+ // If the top/bottom halves aren't the same, reject it.
+ if (Val != Val2)
+ return 0;
+ }
+ return ConstantInt::get(V->getContext(), Val);
+ }
+ }
+
+ // A ConstantArray is splatable if all its members are equal and also
+ // splatable.
+ if (ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
+ if (CA->getNumOperands() == 0)
+ return 0;
+
+ Value *Val = isBytewiseValue(CA->getOperand(0));
+ if (!Val)
+ return 0;
+
+ for (unsigned I = 1, E = CA->getNumOperands(); I != E; ++I)
+ if (CA->getOperand(I-1) != CA->getOperand(I))
+ return 0;
+
+ return Val;
+ }
+
+ // Conceptually, we could handle things like:
+ // %a = zext i8 %X to i16
+ // %b = shl i16 %a, 8
+ // %c = or i16 %a, %b
+ // but until there is an example that actually needs this, it doesn't seem
+ // worth worrying about.
+ return 0;
+}
+
+
// This is the recursive version of BuildSubAggregate. It takes a few different
// arguments. Idxs is the index within the nested struct From that we are
// looking at now (which is of type IndexedType). IdxSkip is the number of
static Value *BuildSubAggregate(Value *From, Value* To, const Type *IndexedType,
SmallVector<unsigned, 10> &Idxs,
unsigned IdxSkip,
- LLVMContext &Context,
Instruction *InsertBefore) {
const llvm::StructType *STy = llvm::dyn_cast<llvm::StructType>(IndexedType);
if (STy) {
Idxs.push_back(i);
Value *PrevTo = To;
To = BuildSubAggregate(From, To, STy->getElementType(i), Idxs, IdxSkip,
- Context, InsertBefore);
+ InsertBefore);
Idxs.pop_back();
if (!To) {
// Couldn't find any inserted value for this index? Cleanup
// we might be able to find the complete struct somewhere.
// Find the value that is at that particular spot
- Value *V = FindInsertedValue(From, Idxs.begin(), Idxs.end(), Context);
+ Value *V = FindInsertedValue(From, Idxs.begin(), Idxs.end());
if (!V)
return NULL;
//
// All inserted insertvalue instructions are inserted before InsertBefore
static Value *BuildSubAggregate(Value *From, const unsigned *idx_begin,
- const unsigned *idx_end, LLVMContext &Context,
+ const unsigned *idx_end,
Instruction *InsertBefore) {
assert(InsertBefore && "Must have someplace to insert!");
const Type *IndexedType = ExtractValueInst::getIndexedType(From->getType(),
SmallVector<unsigned, 10> Idxs(idx_begin, idx_end);
unsigned IdxSkip = Idxs.size();
- return BuildSubAggregate(From, To, IndexedType, Idxs, IdxSkip,
- Context, InsertBefore);
+ return BuildSubAggregate(From, To, IndexedType, Idxs, IdxSkip, InsertBefore);
}
/// FindInsertedValue - Given an aggregrate and an sequence of indices, see if
/// If InsertBefore is not null, this function will duplicate (modified)
/// insertvalues when a part of a nested struct is extracted.
Value *llvm::FindInsertedValue(Value *V, const unsigned *idx_begin,
- const unsigned *idx_end, LLVMContext &Context,
- Instruction *InsertBefore) {
+ const unsigned *idx_end, Instruction *InsertBefore) {
// Nothing to index? Just return V then (this is useful at the end of our
// recursion)
if (idx_begin == idx_end)
return V;
// We have indices, so V should have an indexable type
- assert((isa<StructType>(V->getType()) || isa<ArrayType>(V->getType()))
+ assert((V->getType()->isStructTy() || V->getType()->isArrayTy())
&& "Not looking at a struct or array?");
assert(ExtractValueInst::getIndexedType(V->getType(), idx_begin, idx_end)
&& "Invalid indices for type?");
if (isa<ConstantArray>(C) || isa<ConstantStruct>(C))
// Recursively process this constant
return FindInsertedValue(C->getOperand(*idx_begin), idx_begin + 1,
- idx_end, Context, InsertBefore);
+ idx_end, InsertBefore);
} else if (InsertValueInst *I = dyn_cast<InsertValueInst>(V)) {
// Loop the indices for the insertvalue instruction in parallel with the
// requested indices
// %C = insertvalue {i32, i32 } %A, i32 11, 1
// which allows the unused 0,0 element from the nested struct to be
// removed.
- return BuildSubAggregate(V, idx_begin, req_idx,
- Context, InsertBefore);
+ return BuildSubAggregate(V, idx_begin, req_idx, InsertBefore);
else
// We can't handle this without inserting insertvalues
return 0;
// looking for, then.
if (*req_idx != *i)
return FindInsertedValue(I->getAggregateOperand(), idx_begin, idx_end,
- Context, InsertBefore);
+ InsertBefore);
}
// If we end up here, the indices of the insertvalue match with those
// requested (though possibly only partially). Now we recursively look at
// the inserted value, passing any remaining indices.
return FindInsertedValue(I->getInsertedValueOperand(), req_idx, idx_end,
- Context, InsertBefore);
+ InsertBefore);
} else if (ExtractValueInst *I = dyn_cast<ExtractValueInst>(V)) {
// If we're extracting a value from an aggregrate that was extracted from
// something else, we can extract from that something else directly instead.
&& "Number of indices added not correct?");
return FindInsertedValue(I->getAggregateOperand(), Idxs.begin(), Idxs.end(),
- Context, InsertBefore);
+ InsertBefore);
}
// Otherwise, we don't know (such as, extracting from a function return value
// or load instruction)
return 0;
}
+/// GetPointerBaseWithConstantOffset - Analyze the specified pointer to see if
+/// it can be expressed as a base pointer plus a constant offset. Return the
+/// base and offset to the caller.
+Value *llvm::GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
+ const TargetData &TD) {
+ Operator *PtrOp = dyn_cast<Operator>(Ptr);
+ if (PtrOp == 0) return Ptr;
+
+ // Just look through bitcasts.
+ if (PtrOp->getOpcode() == Instruction::BitCast)
+ return GetPointerBaseWithConstantOffset(PtrOp->getOperand(0), Offset, TD);
+
+ // If this is a GEP with constant indices, we can look through it.
+ GEPOperator *GEP = dyn_cast<GEPOperator>(PtrOp);
+ if (GEP == 0 || !GEP->hasAllConstantIndices()) return Ptr;
+
+ gep_type_iterator GTI = gep_type_begin(GEP);
+ for (User::op_iterator I = GEP->idx_begin(), E = GEP->idx_end(); I != E;
+ ++I, ++GTI) {
+ ConstantInt *OpC = cast<ConstantInt>(*I);
+ if (OpC->isZero()) continue;
+
+ // Handle a struct and array indices which add their offset to the pointer.
+ if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
+ Offset += TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
+ } else {
+ uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType());
+ Offset += OpC->getSExtValue()*Size;
+ }
+ }
+
+ // Re-sign extend from the pointer size if needed to get overflow edge cases
+ // right.
+ unsigned PtrSize = TD.getPointerSizeInBits();
+ if (PtrSize < 64)
+ Offset = (Offset << (64-PtrSize)) >> (64-PtrSize);
+
+ return GetPointerBaseWithConstantOffset(GEP->getPointerOperand(), Offset, TD);
+}
+
+
/// GetConstantStringInfo - This function computes the length of a
/// null-terminated C string pointed to by V. If successful, it returns true
/// and returns the string in Str. If unsuccessful, it returns false.
-bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
+bool llvm::GetConstantStringInfo(const Value *V, std::string &Str,
+ uint64_t Offset,
bool StopAtNul) {
// If V is NULL then return false;
if (V == NULL) return false;
// Look through bitcast instructions.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
+ if (const BitCastInst *BCI = dyn_cast<BitCastInst>(V))
return GetConstantStringInfo(BCI->getOperand(0), Str, Offset, StopAtNul);
// If the value is not a GEP instruction nor a constant expression with a
// GEP instruction, then return false because ConstantArray can't occur
// any other way
- User *GEP = 0;
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
+ const User *GEP = 0;
+ if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
GEP = GEPI;
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
if (CE->getOpcode() == Instruction::BitCast)
return GetConstantStringInfo(CE->getOperand(0), Str, Offset, StopAtNul);
if (CE->getOpcode() != Instruction::GetElementPtr)
// Make sure the index-ee is a pointer to array of i8.
const PointerType *PT = cast<PointerType>(GEP->getOperand(0)->getType());
const ArrayType *AT = dyn_cast<ArrayType>(PT->getElementType());
- if (AT == 0 || AT->getElementType() != Type::getInt8Ty(V->getContext()))
+ if (AT == 0 || !AT->getElementType()->isIntegerTy(8))
return false;
// Check to make sure that the first operand of the GEP is an integer and
// has value 0 so that we are sure we're indexing into the initializer.
- ConstantInt *FirstIdx = dyn_cast<ConstantInt>(GEP->getOperand(1));
+ const ConstantInt *FirstIdx = dyn_cast<ConstantInt>(GEP->getOperand(1));
if (FirstIdx == 0 || !FirstIdx->isZero())
return false;
// into the array. If this occurs, we can't say anything meaningful about
// the string.
uint64_t StartIdx = 0;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
StartIdx = CI->getZExtValue();
else
return false;
StopAtNul);
}
- if (MDString *MDStr = dyn_cast<MDString>(V)) {
- Str = MDStr->getString();
- return true;
- }
-
// The GEP instruction, constant or instruction, must reference a global
// variable that is a constant and is initialized. The referenced constant
// initializer is the array that we'll use for optimization.
- GlobalVariable* GV = dyn_cast<GlobalVariable>(V);
+ const GlobalVariable* GV = dyn_cast<GlobalVariable>(V);
if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
return false;
- Constant *GlobalInit = GV->getInitializer();
+ const Constant *GlobalInit = GV->getInitializer();
// Handle the ConstantAggregateZero case
if (isa<ConstantAggregateZero>(GlobalInit)) {
}
// Must be a Constant Array
- ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
- if (Array == 0 ||
- Array->getType()->getElementType() != Type::getInt8Ty(V->getContext()))
+ const ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
+ if (Array == 0 || !Array->getType()->getElementType()->isIntegerTy(8))
return false;
// Get the number of elements in the array
// to in the array.
Str.reserve(NumElts-Offset);
for (unsigned i = Offset; i != NumElts; ++i) {
- Constant *Elt = Array->getOperand(i);
- ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+ const Constant *Elt = Array->getOperand(i);
+ const ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
if (!CI) // This array isn't suitable, non-int initializer.
return false;
if (StopAtNul && CI->isZero())
// The array isn't null terminated, but maybe this is a memcpy, not a strcpy.
return true;
}
+
+// These next two are very similar to the above, but also look through PHI
+// nodes.
+// TODO: See if we can integrate these two together.
+
+/// GetStringLengthH - If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'. If we can't, return 0.
+static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {
+ // Look through noop bitcast instructions.
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
+ return GetStringLengthH(BCI->getOperand(0), PHIs);
+
+ // If this is a PHI node, there are two cases: either we have already seen it
+ // or we haven't.
+ if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (!PHIs.insert(PN))
+ return ~0ULL; // already in the set.
+
+ // If it was new, see if all the input strings are the same length.
+ uint64_t LenSoFar = ~0ULL;
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+ uint64_t Len = GetStringLengthH(PN->getIncomingValue(i), PHIs);
+ if (Len == 0) return 0; // Unknown length -> unknown.
+
+ if (Len == ~0ULL) continue;
+
+ if (Len != LenSoFar && LenSoFar != ~0ULL)
+ return 0; // Disagree -> unknown.
+ LenSoFar = Len;
+ }
+
+ // Success, all agree.
+ return LenSoFar;
+ }
+
+ // strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
+ if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
+ uint64_t Len1 = GetStringLengthH(SI->getTrueValue(), PHIs);
+ if (Len1 == 0) return 0;
+ uint64_t Len2 = GetStringLengthH(SI->getFalseValue(), PHIs);
+ if (Len2 == 0) return 0;
+ if (Len1 == ~0ULL) return Len2;
+ if (Len2 == ~0ULL) return Len1;
+ if (Len1 != Len2) return 0;
+ return Len1;
+ }
+
+ // If the value is not a GEP instruction nor a constant expression with a
+ // GEP instruction, then return unknown.
+ User *GEP = 0;
+ if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
+ GEP = GEPI;
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ if (CE->getOpcode() != Instruction::GetElementPtr)
+ return 0;
+ GEP = CE;
+ } else {
+ return 0;
+ }
+
+ // Make sure the GEP has exactly three arguments.
+ if (GEP->getNumOperands() != 3)
+ return 0;
+
+ // Check to make sure that the first operand of the GEP is an integer and
+ // has value 0 so that we are sure we're indexing into the initializer.
+ if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
+ if (!Idx->isZero())
+ return 0;
+ } else
+ return 0;
+
+ // If the second index isn't a ConstantInt, then this is a variable index
+ // into the array. If this occurs, we can't say anything meaningful about
+ // the string.
+ uint64_t StartIdx = 0;
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
+ StartIdx = CI->getZExtValue();
+ else
+ return 0;
+
+ // The GEP instruction, constant or instruction, must reference a global
+ // variable that is a constant and is initialized. The referenced constant
+ // initializer is the array that we'll use for optimization.
+ GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
+ if (!GV || !GV->isConstant() || !GV->hasInitializer() ||
+ GV->mayBeOverridden())
+ return 0;
+ Constant *GlobalInit = GV->getInitializer();
+
+ // Handle the ConstantAggregateZero case, which is a degenerate case. The
+ // initializer is constant zero so the length of the string must be zero.
+ if (isa<ConstantAggregateZero>(GlobalInit))
+ return 1; // Len = 0 offset by 1.
+
+ // Must be a Constant Array
+ ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
+ if (!Array || !Array->getType()->getElementType()->isIntegerTy(8))
+ return false;
+
+ // Get the number of elements in the array
+ uint64_t NumElts = Array->getType()->getNumElements();
+
+ // Traverse the constant array from StartIdx (derived above) which is
+ // the place the GEP refers to in the array.
+ for (unsigned i = StartIdx; i != NumElts; ++i) {
+ Constant *Elt = Array->getOperand(i);
+ ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+ if (!CI) // This array isn't suitable, non-int initializer.
+ return 0;
+ if (CI->isZero())
+ return i-StartIdx+1; // We found end of string, success!
+ }
+
+ return 0; // The array isn't null terminated, conservatively return 'unknown'.
+}
+
+/// GetStringLength - If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'. If we can't, return 0.
+uint64_t llvm::GetStringLength(Value *V) {
+ if (!V->getType()->isPointerTy()) return 0;
+
+ SmallPtrSet<PHINode*, 32> PHIs;
+ uint64_t Len = GetStringLengthH(V, PHIs);
+ // If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
+ // an empty string as a length.
+ return Len == ~0ULL ? 1 : Len;
+}
+
+Value *llvm::GetUnderlyingObject(Value *V, unsigned MaxLookup) {
+ if (!V->getType()->isPointerTy())
+ return V;
+ for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) {
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+ V = GEP->getPointerOperand();
+ } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ V = cast<Operator>(V)->getOperand(0);
+ } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
+ if (GA->mayBeOverridden())
+ return V;
+ V = GA->getAliasee();
+ } else {
+ // See if InstructionSimplify knows any relevant tricks.
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ // TODO: Aquire TargetData and DominatorTree and use them.
+ if (Value *Simplified = SimplifyInstruction(I, 0, 0)) {
+ V = Simplified;
+ continue;
+ }
+
+ return V;
+ }
+ assert(V->getType()->isPointerTy() && "Unexpected operand type!");
+ }
+ return V;
+}
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