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Extend the undef ^ undef idiom once more. No testcase: I can't figure out how to actually trigger the codepath in question at the moment, but it might get exposed in the future.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137781 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman 2011-08-16 22:38:34 +00:00
parent 194bd89829
commit 207634263c
1 changed files with 5 additions and 4 deletions
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9
lib/Analysis/InstructionSimplify.cpp
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@ -1348,6 +1348,11 @@ static Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
std::swap(Op0, Op1);
}
// A ^ A = 0
// Do this first so that we catch the undef ^ undef "idiom".
if (Op0 == Op1)
return Constant::getNullValue(Op0->getType());
// A ^ undef -> undef
if (match(Op1, m_Undef()))
return Op1;
@ -1356,10 +1361,6 @@ static Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
if (match(Op1, m_Zero()))
return Op0;
// A ^ A = 0
if (Op0 == Op1)
return Constant::getNullValue(Op0->getType());
// A ^ ~A = ~A ^ A = -1
if (match(Op0, m_Not(m_Specific(Op1))) ||
match(Op1, m_Not(m_Specific(Op0))))