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| author | Eli Friedman <eli.friedman@gmail.com> | 2011-08-16 22:38:34 +0000 |
|---|---|---|
| committer | Eli Friedman <eli.friedman@gmail.com> | 2011-08-16 22:38:34 +0000 |
| commit | 207634263c6a5271d6a10f802c4970ffcd34d271 (patch) | |
| tree | f41e854323e9cbf87c473e7bc1602523531fa344 /lib/Analysis/InstructionSimplify.cpp | |
| parent | 194bd8982936c819a4b14335a4d08f28af8f3d42 (diff) | |
| download | llvm-207634263c6a5271d6a10f802c4970ffcd34d271.tar.gz llvm-207634263c6a5271d6a10f802c4970ffcd34d271.tar.bz2 llvm-207634263c6a5271d6a10f802c4970ffcd34d271.tar.xz | |
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137781 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/InstructionSimplify.cpp')
| -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)))) |