1 files changed, 12 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
index c92d48396c8..47278e19283 100644
--- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -1188,11 +1188,22 @@ void PGOUseFunc::setBranchWeights() {
   }
 }
 
+static bool isIndirectBrTarget(BasicBlock *BB) {
+  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
+    if (isa<IndirectBrInst>((*PI)->getTerminator()))
+      return true;
+  }
+  return false;
+}
+
 void PGOUseFunc::annotateIrrLoopHeaderWeights() {
   DEBUG(dbgs() << "\nAnnotating irreducible loop header weights.\n");
   // Find irr loop headers
   for (auto &BB : F) {
-    if (BFI->isIrrLoopHeader(&BB)) {
+    // As a heuristic also annotate indrectbr targets as they have a high chance
+    // to become an irreducible loop header after the indirectbr tail
+    // duplication.
+    if (BFI->isIrrLoopHeader(&BB) || isIndirectBrTarget(&BB)) {
       TerminatorInst *TI = BB.getTerminator();
       const UseBBInfo &BBCountInfo = getBBInfo(&BB);
       setIrrLoopHeaderMetadata(M, TI, BBCountInfo.CountValue);