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| author | David Majnemer <david.majnemer@gmail.com> | 2013-05-06 21:21:31 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2013-05-06 21:21:31 +0000 |
| commit | 8ec23cb07e22198a720c4e151241059cca215c08 (patch) | |
| tree | 992d7bc3a38cb201502c179d1fd08c22b4bac0a2 /lib | |
| parent | e305e03d6f71f70a7102f15ac5ff6fd93cf9e818 (diff) | |
| download | llvm-8ec23cb07e22198a720c4e151241059cca215c08.tar.gz llvm-8ec23cb07e22198a720c4e151241059cca215c08.tar.bz2 llvm-8ec23cb07e22198a720c4e151241059cca215c08.tar.xz | |
InstCombine: (X ^ signbit) + C -> X + (signbit ^ C)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181249 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineAddSub.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 1aa51d06cb..166f8dfdb4 100644 --- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -974,6 +974,11 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { return BinaryOperator::CreateSub(ConstantExpr::getAdd(XorRHS, CI), XorLHS); } + // (X + signbit) + C could have gotten canonicalized to (X ^ signbit) + C, + // transform them into (X + (signbit ^ C)) + if (XorRHS->getValue().isSignBit()) + return BinaryOperator::CreateAdd(XorLHS, + ConstantExpr::getXor(XorRHS, CI)); } } |