* include/cpplib.h (struct cpp_options): Add new boolean flag

	warn_builtin_macro_redefined.
	* init.c (cpp_create_reader): Initialize warn_builtin_macro_redefined.
	* (struct builtin_operator): Split out from previous struct builtin,
	enhance extra const correctness.
	* (struct builtin_macro): Split out from previous struct builtin, add
	new always_warn_if_redefined flag, enhance const correctness.
	* (mark_named_operators): Use struct builtin_operator.
	* (cpp_init_special_builtins): Use struct builtin_macro, add NODE_WARN
	to builtins selectively.
	* macro.c (warn_of_redefinition): Return false if a builtin macro
	is not flagged with NODE_WARN.

	* c-opts.c (c_common_handle_option): Add handling for
	-Wbuiltin-macro-redefined command line option.
	* c.opt: Added builtin-macro-redefined option.
	* doc/invoke.texi (Warning Options): Add -Wbuiltin-macro-redefined
	documentation.

	* gcc.dg/builtin-redefine.c: New.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@140461 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 4 insertions, 0 deletions

diff --git a/gcc/c-opts.c b/gcc/c-opts.c
index 164ca4a0cdd..589b05be389 100644
--- a/gcc/c-opts.c
+++ b/gcc/c-opts.c
@@ -426,6 +426,10 @@ c_common_handle_option (size_t scode, const char *arg, int value)
 	warn_pointer_sign = 1;
       break;
 
+    case OPT_Wbuiltin_macro_redefined:
+      cpp_opts->warn_builtin_macro_redefined = value;
+      break;
+
     case OPT_Wcomment:
     case OPT_Wcomments:
       cpp_opts->warn_comments = value;