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[InstCombine] refactor folds for mul with negated operands; NFCI

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This keeps with our current usage of 'match' and is easier to see that
the optional NSW only applies in the non-constant operand case. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325140 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjay Patel
2018-02-14 16:50:55 +00:00
parent c8281cb44f
commit 8be336f7ed
1 changed files with 14 additions and 10 deletions
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lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+14 -10
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@@ -270,15 +270,20 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
}
}
if (Value *Op0v = dyn_castNegVal(Op0)) { // -X * -Y = X*Y
if (Value *Op1v = dyn_castNegVal(Op1)) {
BinaryOperator *BO = BinaryOperator::CreateMul(Op0v, Op1v);
if (I.hasNoSignedWrap() &&
match(Op0, m_NSWSub(m_Value(), m_Value())) &&
match(Op1, m_NSWSub(m_Value(), m_Value())))
BO->setHasNoSignedWrap();
return BO;
}
// -X * C --> X * -C
Value *X, *Y;
Constant *Op1C;
if (match(Op0, m_Neg(m_Value(X))) && match(Op1, m_Constant(Op1C)))
return BinaryOperator::CreateMul(X, ConstantExpr::getNeg(Op1C));
// -X * -Y --> X * Y
if (match(Op0, m_Neg(m_Value(X))) && match(Op1, m_Neg(m_Value(Y)))) {
auto *NewMul = BinaryOperator::CreateMul(X, Y);
if (I.hasNoSignedWrap() &&
cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap() &&
cast<OverflowingBinaryOperator>(Op1)->hasNoSignedWrap())
NewMul->setHasNoSignedWrap();
return NewMul;
}
// (X / Y) * Y = X - (X % Y)
@@ -342,7 +347,6 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
// (bool X) * Y --> X ? Y : 0
// Y * (bool X) --> X ? Y : 0
Value *X;
if (match(Op0, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(X, Op1, ConstantInt::get(I.getType(), 0));
if (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))