//
//===----------------------------------------------------------------------===//
-#include "InstCombine.h"
+#include "InstCombineInternal.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/IntrinsicInst.h"
return nullptr;
}
-/// CanEvaluateShifted - See if we can compute the specified value, but shifted
+/// See if we can compute the specified value, but shifted
/// logically to the left or right by some number of bits. This should return
/// true if the expression can be computed for the same cost as the current
/// expression tree. This is used to eliminate extraneous shifting from things
/// this succeeds, the GetShiftedValue function will be called to produce the
/// value.
static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
- InstCombiner &IC) {
+ InstCombiner &IC, Instruction *CxtI) {
// We can always evaluate constants shifted.
if (isa<Constant>(V))
return true;
case Instruction::Or:
case Instruction::Xor:
// Bitwise operators can all arbitrarily be arbitrarily evaluated shifted.
- return CanEvaluateShifted(I->getOperand(0), NumBits, isLeftShift, IC) &&
- CanEvaluateShifted(I->getOperand(1), NumBits, isLeftShift, IC);
+ return CanEvaluateShifted(I->getOperand(0), NumBits, isLeftShift, IC, I) &&
+ CanEvaluateShifted(I->getOperand(1), NumBits, isLeftShift, IC, I);
case Instruction::Shl: {
// We can often fold the shift into shifts-by-a-constant.
// profitable unless we know the and'd out bits are already zero.
if (CI->getZExtValue() > NumBits) {
unsigned LowBits = TypeWidth - CI->getZExtValue();
- if (MaskedValueIsZero(I->getOperand(0),
- APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))
+ if (IC.MaskedValueIsZero(I->getOperand(0),
+ APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits,
+ 0, CxtI))
return true;
}
// profitable unless we know the and'd out bits are already zero.
if (CI->getValue().ult(TypeWidth) && CI->getZExtValue() > NumBits) {
unsigned LowBits = CI->getZExtValue() - NumBits;
- if (MaskedValueIsZero(I->getOperand(0),
- APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))
+ if (IC.MaskedValueIsZero(I->getOperand(0),
+ APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits,
+ 0, CxtI))
return true;
}
}
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
- return CanEvaluateShifted(SI->getTrueValue(), NumBits, isLeftShift, IC) &&
- CanEvaluateShifted(SI->getFalseValue(), NumBits, isLeftShift, IC);
+ return CanEvaluateShifted(SI->getTrueValue(), NumBits, isLeftShift,
+ IC, SI) &&
+ CanEvaluateShifted(SI->getFalseValue(), NumBits, isLeftShift, IC, SI);
}
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
// get into trouble with cyclic PHIs here because we only consider
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
- if (!CanEvaluateShifted(PN->getIncomingValue(i), NumBits, isLeftShift,IC))
+ for (Value *IncValue : PN->incoming_values())
+ if (!CanEvaluateShifted(IncValue, NumBits, isLeftShift,
+ IC, PN))
return false;
return true;
}
}
}
-/// GetShiftedValue - When CanEvaluateShifted returned true for an expression,
+/// When CanEvaluateShifted returned true for an expression,
/// this value inserts the new computation that produces the shifted value.
static Value *GetShiftedValue(Value *V, unsigned NumBits, bool isLeftShift,
- InstCombiner &IC) {
+ InstCombiner &IC, const DataLayout &DL) {
// We can always evaluate constants shifted.
if (Constant *C = dyn_cast<Constant>(V)) {
if (isLeftShift)
V = IC.Builder->CreateLShr(C, NumBits);
// If we got a constantexpr back, try to simplify it with TD info.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
- V = ConstantFoldConstantExpression(CE, IC.getDataLayout(),
- IC.getTargetLibraryInfo());
+ V = ConstantFoldConstantExpression(CE, DL, IC.getTargetLibraryInfo());
return V;
}
case Instruction::Or:
case Instruction::Xor:
// Bitwise operators can all arbitrarily be arbitrarily evaluated shifted.
- I->setOperand(0, GetShiftedValue(I->getOperand(0), NumBits,isLeftShift,IC));
- I->setOperand(1, GetShiftedValue(I->getOperand(1), NumBits,isLeftShift,IC));
+ I->setOperand(
+ 0, GetShiftedValue(I->getOperand(0), NumBits, isLeftShift, IC, DL));
+ I->setOperand(
+ 1, GetShiftedValue(I->getOperand(1), NumBits, isLeftShift, IC, DL));
return I;
case Instruction::Shl: {
}
case Instruction::Select:
- I->setOperand(1, GetShiftedValue(I->getOperand(1), NumBits,isLeftShift,IC));
- I->setOperand(2, GetShiftedValue(I->getOperand(2), NumBits,isLeftShift,IC));
+ I->setOperand(
+ 1, GetShiftedValue(I->getOperand(1), NumBits, isLeftShift, IC, DL));
+ I->setOperand(
+ 2, GetShiftedValue(I->getOperand(2), NumBits, isLeftShift, IC, DL));
return I;
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
- PN->setIncomingValue(i, GetShiftedValue(PN->getIncomingValue(i),
- NumBits, isLeftShift, IC));
+ PN->setIncomingValue(i, GetShiftedValue(PN->getIncomingValue(i), NumBits,
+ isLeftShift, IC, DL));
return PN;
}
}
// See if we can propagate this shift into the input, this covers the trivial
// cast of lshr(shl(x,c1),c2) as well as other more complex cases.
if (I.getOpcode() != Instruction::AShr &&
- CanEvaluateShifted(Op0, COp1->getZExtValue(), isLeftShift, *this)) {
+ CanEvaluateShifted(Op0, COp1->getZExtValue(), isLeftShift, *this, &I)) {
DEBUG(dbgs() << "ICE: GetShiftedValue propagating shift through expression"
" to eliminate shift:\n IN: " << *Op0 << "\n SH: " << I <<"\n");
- return ReplaceInstUsesWith(I,
- GetShiftedValue(Op0, COp1->getZExtValue(), isLeftShift, *this));
+ return ReplaceInstUsesWith(
+ I, GetShiftedValue(Op0, COp1->getZExtValue(), isLeftShift, *this, DL));
}
// See if we can simplify any instructions used by the instruction whose sole
}
- // If the operand is an bitwise operator with a constant RHS, and the
+ // If the operand is a bitwise operator with a constant RHS, and the
// shift is the only use, we can pull it out of the shift.
if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
bool isValid = true; // Valid only for And, Or, Xor
if (Value *V = SimplifyVectorOp(I))
return ReplaceInstUsesWith(I, V);
- if (Value *V = SimplifyShlInst(I.getOperand(0), I.getOperand(1),
- I.hasNoSignedWrap(), I.hasNoUnsignedWrap(),
- DL))
+ if (Value *V =
+ SimplifyShlInst(I.getOperand(0), I.getOperand(1), I.hasNoSignedWrap(),
+ I.hasNoUnsignedWrap(), DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Instruction *V = commonShiftTransforms(I))
// If the shifted-out value is known-zero, then this is a NUW shift.
if (!I.hasNoUnsignedWrap() &&
MaskedValueIsZero(I.getOperand(0),
- APInt::getHighBitsSet(Op1C->getBitWidth(), ShAmt))) {
+ APInt::getHighBitsSet(Op1C->getBitWidth(), ShAmt),
+ 0, &I)) {
I.setHasNoUnsignedWrap();
return &I;
}
// If the shifted out value is all signbits, this is a NSW shift.
if (!I.hasNoSignedWrap() &&
- ComputeNumSignBits(I.getOperand(0)) > ShAmt) {
+ ComputeNumSignBits(I.getOperand(0), 0, &I) > ShAmt) {
I.setHasNoSignedWrap();
return &I;
}
if (Value *V = SimplifyVectorOp(I))
return ReplaceInstUsesWith(I, V);
- if (Value *V = SimplifyLShrInst(I.getOperand(0), I.getOperand(1),
- I.isExact(), DL))
+ if (Value *V = SimplifyLShrInst(I.getOperand(0), I.getOperand(1), I.isExact(),
+ DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Instruction *R = commonShiftTransforms(I))
// If the shifted-out value is known-zero, then this is an exact shift.
if (!I.isExact() &&
- MaskedValueIsZero(Op0,APInt::getLowBitsSet(Op1C->getBitWidth(),ShAmt))){
+ MaskedValueIsZero(Op0, APInt::getLowBitsSet(Op1C->getBitWidth(), ShAmt),
+ 0, &I)){
I.setIsExact();
return &I;
}
if (Value *V = SimplifyVectorOp(I))
return ReplaceInstUsesWith(I, V);
- if (Value *V = SimplifyAShrInst(I.getOperand(0), I.getOperand(1),
- I.isExact(), DL))
+ if (Value *V = SimplifyAShrInst(I.getOperand(0), I.getOperand(1), I.isExact(),
+ DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Instruction *R = commonShiftTransforms(I))
// have a sign-extend idiom.
Value *X;
if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1)))) {
- // If the left shift is just shifting out partial signbits, delete the
- // extension.
- if (cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
- return ReplaceInstUsesWith(I, X);
-
// If the input is an extension from the shifted amount value, e.g.
// %x = zext i8 %A to i32
// %y = shl i32 %x, 24
// If the shifted-out value is known-zero, then this is an exact shift.
if (!I.isExact() &&
- MaskedValueIsZero(Op0,APInt::getLowBitsSet(Op1C->getBitWidth(),ShAmt))){
+ MaskedValueIsZero(Op0,APInt::getLowBitsSet(Op1C->getBitWidth(),ShAmt),
+ 0, &I)){
I.setIsExact();
return &I;
}
// See if we can turn a signed shr into an unsigned shr.
if (MaskedValueIsZero(Op0,
- APInt::getSignBit(I.getType()->getScalarSizeInBits())))
+ APInt::getSignBit(I.getType()->getScalarSizeInBits()),
+ 0, &I))
return BinaryOperator::CreateLShr(Op0, Op1);
- // Arithmetic shifting an all-sign-bit value is a no-op.
- unsigned NumSignBits = ComputeNumSignBits(Op0);
- if (NumSignBits == Op0->getType()->getScalarSizeInBits())
- return ReplaceInstUsesWith(I, Op0);
-
return nullptr;
}
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