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| author | David Majnemer <david.majnemer@gmail.com> | 2013-07-09 22:01:22 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2013-07-09 22:01:22 +0000 |
| commit | a80fed7e581517d69f46815644585bdcedcdf726 (patch) | |
| tree | 855fa938610a6df3d1c90f596672735a942dab0e /llvm/lib/Analysis/InstructionSimplify.cpp | |
| parent | 1014fcfd9984b6d56e93e7d387061243e7f32a35 (diff) | |
| download | bcm5719-llvm-a80fed7e581517d69f46815644585bdcedcdf726.tar.gz bcm5719-llvm-a80fed7e581517d69f46815644585bdcedcdf726.zip | |
InstSimplify: X >> X -> 0
llvm-svn: 185973
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index bf7745143da..d66ecca928a 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1363,6 +1363,10 @@ static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse)) return V; + // X >> X -> 0 + if (Op0 == Op1) + return Constant::getNullValue(Op0->getType()); + // undef >>l X -> 0 if (match(Op0, m_Undef())) return Constant::getNullValue(Op0->getType()); @@ -1391,6 +1395,10 @@ static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse)) return V; + // X >> X -> 0 + if (Op0 == Op1) + return Constant::getNullValue(Op0->getType()); + // all ones >>a X -> all ones if (match(Op0, m_AllOnes())) return Op0; |
