diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 11094e99397..fb4c6142fa6 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -428,7 +428,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
       II->setArgOperand(1, LHS);
       return II;
     }
-    [[clang::fallthrough]];
+    // fall through
 
   case Intrinsic::usub_with_overflow:
   case Intrinsic::ssub_with_overflow: {