diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -465,7 +465,8 @@
 
 option(CLANG_ENABLE_PROTO_FUZZER "Build Clang protobuf fuzzer." OFF)
 
-option(CLANG_ROUND_TRIP_CC1_ARGS "Round-trip command line arguments in -cc1." OFF)
+option(CLANG_ROUND_TRIP_CC1_ARGS
+  "Round-trip command line arguments in -cc1." ${LLVM_ENABLE_ASSERTIONS})
 
 if(NOT CLANG_ENABLE_STATIC_ANALYZER AND CLANG_ENABLE_ARCMT)
   message(FATAL_ERROR "Cannot disable static analyzer while enabling ARCMT or Z3")