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| author | David Majnemer <david.majnemer@gmail.com> | 2014-09-17 04:16:35 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2014-09-17 04:16:35 +0000 |
| commit | b435a4214e5920e56dd2e9fb5fb29bb2d4e98fab (patch) | |
| tree | ded4fd97a32f32c0f9007df848fb85b2d56b2e20 /llvm/lib/Analysis/InstructionSimplify.cpp | |
| parent | 29298664d907ad227991075add40b46893867930 (diff) | |
| download | llvm-b435a4214e5920e56dd2e9fb5fb29bb2d4e98fab.zip llvm-b435a4214e5920e56dd2e9fb5fb29bb2d4e98fab.tar.gz llvm-b435a4214e5920e56dd2e9fb5fb29bb2d4e98fab.tar.bz2 | |
InstSimplify: Don't allow (x srem y) urem y -> x srem y
Let's consider the case where:
%x i16 = 32768
%y i16 = 384
%x srem %y = 65408
(%x srem %y) urem %y = 128
llvm-svn: 217939
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 039d828..f2f6706 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1171,10 +1171,12 @@ static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, if (Op0 == Op1) return Constant::getNullValue(Op0->getType()); - // ((X % Y) % Y) -> (X % Y) - if (match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) { + // (X % Y) % Y -> X % Y + if ((Opcode == Instruction::SRem && + match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) || + (Opcode == Instruction::URem && + match(Op0, m_URem(m_Value(), m_Specific(Op1))))) return Op0; - } // If the operation is with the result of a select instruction, check whether // operating on either branch of the select always yields the same value. |