diff options
| -rw-r--r-- | include/llvm/Analysis/BranchProbabilityInfo.h | 1 | ||||
| -rw-r--r-- | lib/Analysis/BranchProbabilityInfo.cpp | 32 |
2 files changed, 31 insertions, 2 deletions
diff --git a/include/llvm/Analysis/BranchProbabilityInfo.h b/include/llvm/Analysis/BranchProbabilityInfo.h index 2ced796..006daa0 100644 --- a/include/llvm/Analysis/BranchProbabilityInfo.h +++ b/include/llvm/Analysis/BranchProbabilityInfo.h @@ -122,6 +122,7 @@ private: bool calcLoopBranchHeuristics(BasicBlock *BB); bool calcZeroHeuristics(BasicBlock *BB); bool calcFloatingPointHeuristics(BasicBlock *BB); + bool calcInvokeHeuristics(BasicBlock *BB); }; } diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp index 2730ce6..b255ce6 100644 --- a/lib/Analysis/BranchProbabilityInfo.cpp +++ b/lib/Analysis/BranchProbabilityInfo.cpp @@ -1,4 +1,4 @@ -//===-- BranchProbabilityInfo.cpp - Branch Probability Analysis -*- C++ -*-===// +//===-- BranchProbabilityInfo.cpp - Branch Probability Analysis -----------===// // // The LLVM Compiler Infrastructure // @@ -78,6 +78,19 @@ static const uint32_t ZH_NONTAKEN_WEIGHT = 12; static const uint32_t FPH_TAKEN_WEIGHT = 20; static const uint32_t FPH_NONTAKEN_WEIGHT = 12; +/// \brief Invoke-terminating normal branch taken weight +/// +/// This is the weight for branching to the normal destination of an invoke +/// instruction. We expect this to happen most of the time. Set the weight to an +/// absurdly high value so that nested loops subsume it. +static const uint32_t IH_TAKEN_WEIGHT = 1024 * 1024 - 1; + +/// \brief Invoke-terminating normal branch not-taken weight. +/// +/// This is the weight for branching to the unwind destination of an invoke +/// instruction. This is essentially never taken. +static const uint32_t IH_NONTAKEN_WEIGHT = 1; + // Standard weight value. Used when none of the heuristics set weight for // the edge. static const uint32_t NORMAL_WEIGHT = 16; @@ -371,6 +384,19 @@ bool BranchProbabilityInfo::calcFloatingPointHeuristics(BasicBlock *BB) { return true; } +bool BranchProbabilityInfo::calcInvokeHeuristics(BasicBlock *BB) { + InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()); + if (!II) + return false; + + BasicBlock *Normal = II->getNormalDest(); + BasicBlock *Unwind = II->getUnwindDest(); + + setEdgeWeight(BB, Normal, IH_TAKEN_WEIGHT); + setEdgeWeight(BB, Unwind, IH_NONTAKEN_WEIGHT); + return true; +} + void BranchProbabilityInfo::getAnalysisUsage(AnalysisUsage &AU) const { AU.addRequired<LoopInfo>(); AU.setPreservesAll(); @@ -397,7 +423,9 @@ bool BranchProbabilityInfo::runOnFunction(Function &F) { continue; if (calcZeroHeuristics(*I)) continue; - calcFloatingPointHeuristics(*I); + if (calcFloatingPointHeuristics(*I)) + continue; + calcInvokeHeuristics(*I); } PostDominatedByUnreachable.clear(); |