1 files changed, 16 insertions, 3 deletions
diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp
index 5eb95003f5d8..a06ee096d54c 100644
--- a/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/lib/Analysis/BranchProbabilityInfo.cpp
@@ -118,6 +118,13 @@ static const uint32_t ZH_NONTAKEN_WEIGHT = 12;
 static const uint32_t FPH_TAKEN_WEIGHT = 20;
 static const uint32_t FPH_NONTAKEN_WEIGHT = 12;
 
+/// This is the probability for an ordered floating point comparison.
+static const uint32_t FPH_ORD_WEIGHT = 1024 * 1024 - 1;
+/// This is the probability for an unordered floating point comparison, it means
+/// one or two of the operands are NaN. Usually it is used to test for an
+/// exceptional case, so the result is unlikely.
+static const uint32_t FPH_UNO_WEIGHT = 1;
+
 /// Invoke-terminating normal branch taken weight
 ///
 /// This is the weight for branching to the normal destination of an invoke
@@ -778,6 +785,8 @@ bool BranchProbabilityInfo::calcFloatingPointHeuristics(const BasicBlock *BB) {
   if (!FCmp)
     return false;
 
+  uint32_t TakenWeight = FPH_TAKEN_WEIGHT;
+  uint32_t NontakenWeight = FPH_NONTAKEN_WEIGHT;
   bool isProb;
   if (FCmp->isEquality()) {
     // f1 == f2 -> Unlikely
@@ -786,9 +795,13 @@ bool BranchProbabilityInfo::calcFloatingPointHeuristics(const BasicBlock *BB) {
   } else if (FCmp->getPredicate() == FCmpInst::FCMP_ORD) {
     // !isnan -> Likely
     isProb = true;
+    TakenWeight = FPH_ORD_WEIGHT;
+    NontakenWeight = FPH_UNO_WEIGHT;
   } else if (FCmp->getPredicate() == FCmpInst::FCMP_UNO) {
     // isnan -> Unlikely
     isProb = false;
+    TakenWeight = FPH_ORD_WEIGHT;
+    NontakenWeight = FPH_UNO_WEIGHT;
   } else {
     return false;
   }
@@ -798,8 +811,7 @@ bool BranchProbabilityInfo::calcFloatingPointHeuristics(const BasicBlock *BB) {
   if (!isProb)
     std::swap(TakenIdx, NonTakenIdx);
 
-  BranchProbability TakenProb(FPH_TAKEN_WEIGHT,
-                              FPH_TAKEN_WEIGHT + FPH_NONTAKEN_WEIGHT);
+  BranchProbability TakenProb(TakenWeight, TakenWeight + NontakenWeight);
   setEdgeProbability(BB, TakenIdx, TakenProb);
   setEdgeProbability(BB, NonTakenIdx, TakenProb.getCompl());
   return true;
@@ -1014,7 +1026,8 @@ void BranchProbabilityInfoWrapperPass::getAnalysisUsage(
 
 bool BranchProbabilityInfoWrapperPass::runOnFunction(Function &F) {
   const LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-  const TargetLibraryInfo &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+  const TargetLibraryInfo &TLI =
+      getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
   BPI.calculate(F, LI, &TLI);
   return false;
 }