diff options
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index cfff9c03c8..89e55a4651 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -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)))) |