1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp b/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
index ee1fec0..805bdb4 100644
--- a/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
+++ b/llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
@@ -1350,6 +1350,10 @@ static bool foldMemChr(CallInst *Call, DomTreeUpdater *DTU,
   BB->getTerminator()->eraseFromParent();
   SwitchInst *SI = IRB.CreateSwitch(
       IRB.CreateTrunc(Call->getArgOperand(1), ByteTy), BBNext, N);
+  // We can't know the precise weights here, as they would depend on the value
+  // distribution of Call->getArgOperand(1). So we just mark it as "unknown".
+  setExplicitlyUnknownBranchWeightsIfProfiled(*SI, *Call->getFunction(),
+                                              DEBUG_TYPE);
   Type *IndexTy = DL.getIndexType(Call->getType());
   SmallVector<DominatorTree::UpdateType, 8> Updates;