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[InstCombine] use m_APInt instead of faking it

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llvm-svn: 292164
This commit is contained in:
Sanjay Patel 2017-01-16 21:24:41 +00:00
parent b20ccc6bb9
commit 42a6eec5b2
1 changed files with 14 additions and 20 deletions
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34
lib/Transforms/InstCombine/InstCombineShifts.cpp
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@ -312,7 +312,7 @@ static Value *getShiftedValue(Value *V, unsigned NumBits, bool isLeftShift,
/// Try to fold (X << C1) << C2, where the shifts are some combination of
/// shl/ashr/lshr.
static Instruction *
foldShiftByConstOfShiftByConst(BinaryOperator &I, ConstantInt *COp1,
foldShiftByConstOfShiftByConst(BinaryOperator &I, const APInt *COp1,
InstCombiner::BuilderTy *Builder) {
Value *Op0 = I.getOperand(0);
uint32_t TypeBits = Op0->getType()->getScalarSizeInBits();
@ -475,33 +475,26 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
BinaryOperator &I) {
bool isLeftShift = I.getOpcode() == Instruction::Shl;
ConstantInt *COp1 = nullptr;
if (ConstantDataVector *CV = dyn_cast<ConstantDataVector>(Op1))
COp1 = dyn_cast_or_null<ConstantInt>(CV->getSplatValue());
else if (ConstantVector *CV = dyn_cast<ConstantVector>(Op1))
COp1 = dyn_cast_or_null<ConstantInt>(CV->getSplatValue());
else
COp1 = dyn_cast<ConstantInt>(Op1);
if (!COp1)
const APInt *Op1C;
if (!match(Op1, m_APInt(Op1C)))
return nullptr;
// 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, &I)) {
canEvaluateShifted(Op0, Op1C->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, DL));
I, getShiftedValue(Op0, Op1C->getZExtValue(), isLeftShift, *this, DL));
}
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
uint32_t TypeBits = Op0->getType()->getScalarSizeInBits();
unsigned TypeBits = Op0->getType()->getScalarSizeInBits();
assert(!COp1->uge(TypeBits) &&
assert(!Op1C->uge(TypeBits) &&
"Shift over the type width should have been removed already");
// ((X*C1) << C2) == (X * (C1 << C2))
@ -525,7 +518,8 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
if (TrOp && I.isLogicalShift() && TrOp->isShift() &&
isa<ConstantInt>(TrOp->getOperand(1))) {
// Okay, we'll do this xform. Make the shift of shift.
Constant *ShAmt = ConstantExpr::getZExt(COp1, TrOp->getType());
Constant *ShAmt =
ConstantExpr::getZExt(cast<Constant>(Op1), TrOp->getType());
// (shift2 (shift1 & 0x00FF), c2)
Value *NSh = Builder->CreateBinOp(I.getOpcode(), TrOp, ShAmt,I.getName());
@ -542,10 +536,10 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
// shift. We know that it is a logical shift by a constant, so adjust the
// mask as appropriate.
if (I.getOpcode() == Instruction::Shl)
MaskV <<= COp1->getZExtValue();
MaskV <<= Op1C->getZExtValue();
else {
assert(I.getOpcode() == Instruction::LShr && "Unknown logical shift");
MaskV = MaskV.lshr(COp1->getZExtValue());
MaskV = MaskV.lshr(Op1C->getZExtValue());
}
// shift1 & 0x00FF
@ -579,7 +573,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
// (X + (Y << C))
Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), YS, V1,
Op0BO->getOperand(1)->getName());
uint32_t Op1Val = COp1->getLimitedValue(TypeBits);
unsigned Op1Val = Op1C->getLimitedValue(TypeBits);
APInt Bits = APInt::getHighBitsSet(TypeBits, TypeBits - Op1Val);
Constant *Mask = ConstantInt::get(I.getContext(), Bits);
@ -615,7 +609,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
// (X + (Y << C))
Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), V1, YS,
Op0BO->getOperand(0)->getName());
uint32_t Op1Val = COp1->getLimitedValue(TypeBits);
unsigned Op1Val = Op1C->getLimitedValue(TypeBits);
APInt Bits = APInt::getHighBitsSet(TypeBits, TypeBits - Op1Val);
Constant *Mask = ConstantInt::get(I.getContext(), Bits);
@ -686,7 +680,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
}
}
if (Instruction *Folded = foldShiftByConstOfShiftByConst(I, COp1, Builder))
if (Instruction *Folded = foldShiftByConstOfShiftByConst(I, Op1C, Builder))
return Folded;
return nullptr;