diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
index f4ffe23420e7..8f556683c355 100644
--- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -988,7 +988,7 @@ void SelectInstVisitor::visitSelectInst(SelectInst &SI) {
     annotateOneSelectInst(SI);
     break;
   default:
-    assert(false && "Unknown visiting mode");
+    llvm_unreachable("Unknown visiting mode");
     break;
   }
 }