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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-10-21 21:13:47 +0000 |
|---|---|---|
| committer | Stephen Hines <srhines@google.com> | 2011-11-14 09:11:02 -0800 |
| commit | c182018f1bfc2fc86359bb135a03d88c23e39e43 (patch) | |
| tree | 0bdf23ce23d3022f5d9695d43778a830488df32b /lib/Analysis | |
| parent | f2ab2836bd32969e6963ace5008609ec87742f3f (diff) | |
| download | external_llvm-c182018f1bfc2fc86359bb135a03d88c23e39e43.tar.gz external_llvm-c182018f1bfc2fc86359bb135a03d88c23e39e43.tar.bz2 external_llvm-c182018f1bfc2fc86359bb135a03d88c23e39e43.zip | |
Extend the floating point heuristic to consider NaN checks unlikely.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142687 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis')
| -rw-r--r-- | lib/Analysis/BranchProbabilityInfo.cpp | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp index 6e8d7e0115..fc69da9e67 100644 --- a/lib/Analysis/BranchProbabilityInfo.cpp +++ b/lib/Analysis/BranchProbabilityInfo.cpp @@ -391,15 +391,28 @@ bool BranchProbabilityAnalysis::calcFloatingPointHeuristics(BasicBlock *BB) { Value *Cond = BI->getCondition(); FCmpInst *FCmp = dyn_cast<FCmpInst>(Cond); - if (!FCmp || !FCmp->isEquality()) + if (!FCmp) return false; + bool isProb; + if (FCmp->isEquality()) { + // f1 == f2 -> Unlikely + // f1 != f2 -> Likely + isProb = !FCmp->isTrueWhenEqual(); + } else if (FCmp->getPredicate() == FCmpInst::FCMP_ORD) { + // !isnan -> Likely + isProb = true; + } else if (FCmp->getPredicate() == FCmpInst::FCMP_UNO) { + // isnan -> Unlikely + isProb = false; + } else { + return false; + } + BasicBlock *Taken = BI->getSuccessor(0); BasicBlock *NonTaken = BI->getSuccessor(1); - // f1 == f2 -> Unlikely - // f1 != f2 -> Likely - if (FCmp->isTrueWhenEqual()) + if (!isProb) std::swap(Taken, NonTaken); BP->setEdgeWeight(BB, Taken, FPH_TAKEN_WEIGHT); |