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| author | Sanjay Patel <spatel@rotateright.com> | 2014-10-02 21:10:54 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2014-10-02 21:10:54 +0000 |
| commit | 12d1ce540883d5d60a44459b96ff729016c5c01c (patch) | |
| tree | c9e3c2d9a6d7bdda98141d3b87489947a6e70231 /llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | |
| parent | d2208b59cfaa092dddb533587e7670247df9de30 (diff) | |
| download | llvm-12d1ce540883d5d60a44459b96ff729016c5c01c.zip llvm-12d1ce540883d5d60a44459b96ff729016c5c01c.tar.gz llvm-12d1ce540883d5d60a44459b96ff729016c5c01c.tar.bz2 | |
Optimize square root squared (PR21126).
When unsafe-fp-math is enabled, we can turn sqrt(X) * sqrt(X) into X.
This can happen in the real world when calculating x ** 3/2. This occurs
in test-suite/SingleSource/Benchmarks/BenchmarkGame/n-body.c.
Differential Revision: http://reviews.llvm.org/D5584
llvm-svn: 218906
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index da5d00d..0a19a48 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -531,6 +531,11 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) { } } + // sqrt(X) * sqrt(X) -> X + if (AllowReassociate && (Op0 == Op1)) + if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op0)) + if (II->getIntrinsicID() == Intrinsic::sqrt) + return ReplaceInstUsesWith(I, II->getOperand(0)); // Under unsafe algebra do: // X * log2(0.5*Y) = X*log2(Y) - X |