diff options
Diffstat (limited to 'lib/Analysis/BranchProbabilityInfo.cpp')
-rw-r--r-- | lib/Analysis/BranchProbabilityInfo.cpp | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp index 14800f4..8799a71 100644 --- a/lib/Analysis/BranchProbabilityInfo.cpp +++ b/lib/Analysis/BranchProbabilityInfo.cpp @@ -379,6 +379,14 @@ bool BranchProbabilityInfo::calcZeroHeuristics(BasicBlock *BB) { if (!CV) return false; + // If the LHS is the result of AND'ing a value with a single bit bitmask, + // we don't have information about probabilities. + if (Instruction *LHS = dyn_cast<Instruction>(CI->getOperand(0))) + if (LHS->getOpcode() == Instruction::And) + if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) + if (AndRHS->getUniqueInteger().isPowerOf2()) + return false; + bool isProb; if (CV->isZero()) { switch (CI->getPredicate()) { @@ -499,25 +507,23 @@ bool BranchProbabilityInfo::runOnFunction(Function &F) { // Walk the basic blocks in post-order so that we can build up state about // the successors of a block iteratively. - for (po_iterator<BasicBlock *> I = po_begin(&F.getEntryBlock()), - E = po_end(&F.getEntryBlock()); - I != E; ++I) { - DEBUG(dbgs() << "Computing probabilities for " << I->getName() << "\n"); - if (calcUnreachableHeuristics(*I)) + for (auto BB : post_order(&F.getEntryBlock())) { + DEBUG(dbgs() << "Computing probabilities for " << BB->getName() << "\n"); + if (calcUnreachableHeuristics(BB)) continue; - if (calcMetadataWeights(*I)) + if (calcMetadataWeights(BB)) continue; - if (calcColdCallHeuristics(*I)) + if (calcColdCallHeuristics(BB)) continue; - if (calcLoopBranchHeuristics(*I)) + if (calcLoopBranchHeuristics(BB)) continue; - if (calcPointerHeuristics(*I)) + if (calcPointerHeuristics(BB)) continue; - if (calcZeroHeuristics(*I)) + if (calcZeroHeuristics(BB)) continue; - if (calcFloatingPointHeuristics(*I)) + if (calcFloatingPointHeuristics(BB)) continue; - calcInvokeHeuristics(*I); + calcInvokeHeuristics(BB); } PostDominatedByUnreachable.clear(); |