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Transform (sub 0, (zext bool to A)) to (sext bool to A) and

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(sub 0, (sext bool to A)) to (zext bool to A).

Patch by Muhammad Ahmad
Reviewed by Duncan Sands

llvm-svn: 173093
This commit is contained in:
Paul Redmond
2013-01-21 21:57:20 +00:00
parent 830875bbda
commit 9d86a4a3b6
4 changed files with 22 additions and 4 deletions
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10
llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
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@@ -1250,6 +1250,16 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
if (SimplifyDemandedInstructionBits(I))
return &I;
// Fold (sub 0, (zext bool to B)) --> (sext bool to B)
if (C->isZero() && match(Op1, m_ZExt(m_Value(X))))
if (X->getType()->isIntegerTy(1))
return CastInst::CreateSExtOrBitCast(X, Op1->getType());
// Fold (sub 0, (sext bool to B)) --> (zext bool to B)
if (C->isZero() && match(Op1, m_SExt(m_Value(X))))
if (X->getType()->isIntegerTy(1))
return CastInst::CreateZExtOrBitCast(X, Op1->getType());
}