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| author | Sanjay Patel <spatel@rotateright.com> | 2018-08-08 16:19:22 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2018-08-08 16:19:22 +0000 |
| commit | fe839695a8b9986da53f5587e901aca0a4e46c90 (patch) | |
| tree | 744b3ce48922ce7e2420073fd4ca7b3f4f74ded3 /llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | |
| parent | 2054dd79c200f2a3b7d6e770dd92a1908fbc25dc (diff) | |
| download | bcm5719-llvm-fe839695a8b9986da53f5587e901aca0a4e46c90.tar.gz bcm5719-llvm-fe839695a8b9986da53f5587e901aca0a4e46c90.zip | |
[InstCombine] fold fadd+fsub with common operand
This is a sibling to the simplify from:
https://reviews.llvm.org/rL339174
llvm-svn: 339267
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index f3fe09f1cb0..8b355dcd1b2 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1911,6 +1911,11 @@ Instruction *InstCombiner::visitFSub(BinaryOperator &I) { if (match(Op0, m_FSub(m_Specific(Op1), m_Value(X)))) return BinaryOperator::CreateFNegFMF(X, &I); + // Y - (X + Y) --> -X + // Y - (Y + X) --> -X + if (match(Op1, m_c_FAdd(m_Specific(Op0), m_Value(X)))) + return BinaryOperator::CreateFNegFMF(X, &I); + // TODO: This performs reassociative folds for FP ops. Some fraction of the // functionality has been subsumed by simple pattern matching here and in // InstSimplify. We should let a dedicated reassociation pass handle more |
