Enhance BranchProbabilityInfo::calcUnreachableHeuristics for InvokeInst

[oota-llvm.git] / lib / Analysis / BranchProbabilityInfo.cpp

diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp
index 6cdf43a06a9f559f47a725814e327420d9144f0b..a0d6123b5835fad20a3d1e210f203b5e3d951981 100644 (file)
--- a/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/lib/Analysis/BranchProbabilityInfo.cpp
@@ -147,6 +147,16 @@ bool BranchProbabilityInfo::calcUnreachableHeuristics(BasicBlock *BB) {
   if (TI->getNumSuccessors() == 1 || UnreachableEdges.empty())
     return false;
 
+  // If the terminator is an InvokeInst, check only the normal destination block
+  // as the unwind edge of InvokeInst is also very unlikely taken.
+  if (auto *II = dyn_cast<InvokeInst>(TI))
+    if (PostDominatedByUnreachable.count(II->getNormalDest())) {
+      PostDominatedByUnreachable.insert(BB);
+      // Return false here so that edge weights for InvokeInst could be decided
+      // in calcInvokeHeuristics().
+      return false;
+    }
+
   uint32_t UnreachableWeight =
     std::max(UR_TAKEN_WEIGHT / (unsigned)UnreachableEdges.size(), MIN_WEIGHT);
   for (SmallVectorImpl<unsigned>::iterator I = UnreachableEdges.begin(),