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| author | Cameron McInally <cameron.mcinally@nyu.edu> | 2019-05-20 21:00:42 +0000 |
|---|---|---|
| committer | Cameron McInally <cameron.mcinally@nyu.edu> | 2019-05-20 21:00:42 +0000 |
| commit | 8bec58d5f72e1d6c6f1fe5931e49755e9eabe38f (patch) | |
| tree | 7991babba08b765d50034b0fc7f018fa02e745ce /llvm/lib | |
| parent | ac5c8318d76943a4667685a9940b6a5f4a035168 (diff) | |
| download | bcm5719-llvm-8bec58d5f72e1d6c6f1fe5931e49755e9eabe38f.tar.gz bcm5719-llvm-8bec58d5f72e1d6c6f1fe5931e49755e9eabe38f.zip | |
[NFC][InstCombine] Add FIXME for one-use check on constant negation transforms.
llvm-svn: 361197
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 421d49fdcb7..2d608e74b69 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1830,6 +1830,8 @@ static Instruction *foldFNegIntoConstant(Instruction &I) { // Fold negation into constant operand. This is limited with one-use because // fneg is assumed better for analysis and cheaper in codegen than fmul/fdiv. // -(X * C) --> X * (-C) + // FIXME: It's arguable whether these should be m_OneUse or not. The current + // belief is that the FNeg allows for better reassociation opportunities. if (match(&I, m_FNeg(m_OneUse(m_FMul(m_Value(X), m_Constant(C)))))) return BinaryOperator::CreateFMulFMF(X, ConstantExpr::getFNeg(C), &I); // -(X / C) --> X / (-C) |
