diff --git a/compiler-rt/lib/gwp_asan/platform_specific/utilities_posix.cpp b/compiler-rt/lib/gwp_asan/platform_specific/utilities_posix.cpp
--- a/compiler-rt/lib/gwp_asan/platform_specific/utilities_posix.cpp
+++ b/compiler-rt/lib/gwp_asan/platform_specific/utilities_posix.cpp
@@ -84,6 +84,7 @@
   case AlignmentStrategy::DEFAULT:
     __builtin_unreachable();
   }
+  __builtin_unreachable();
 }
 
 } // namespace gwp_asan