re PR c/51849 (-Wc99-compat would be considered useful)

	PR c/51849
gcc/
	* gcc/doc/invoke.texi: Document -Wc90-c99-compat.
gcc/c-family/
	* c-opts.c (sanitize_cpp_opts): Pass warn_c90_c99_compat to libcpp.
	* c.opt (Wc90-c99-compat): Add option.
gcc/c/
	* c-decl.c (build_array_declarator): Remove check for !flag_isoc99.
	Call pedwarn_c90 instead of pedwarn.
	(check_bitfield_type_and_width): Likewise.
	(declspecs_add_qual): Likewise.
	(declspecs_add_type): Likewise.
	(warn_variable_length_array): Unify function for -pedantic and -Wvla.
	Adjust to only call pedwarn_c90.
	(grokdeclarator): Remove pedantic && !flag_isoc99 check.  Call
	pedwarn_c90 instead of pedwarn.
	* c-errors.c (pedwarn_c90): Handle -Wc90-c99-compat.
	* c-parser.c (disable_extension_diagnostics): Handle
	warn_c90_c99_compat.
	(restore_extension_diagnostics): Likewise.
	(c_parser_enum_specifier): Remove check for !flag_isoc99.  Call
	pedwarn_c90 instead of pedwarn.
	(c_parser_initelt): Likewise.
	(c_parser_postfix_expression): Likewise.
	(c_parser_postfix_expression_after_paren_type): Likewise.
	(c_parser_compound_statement_nostart): Remove check for !flag_isoc99.
	* c-tree.h: Fix formatting.
	* c-typeck.c (build_array_ref): Remove check for !flag_isoc99.  Call
	pedwarn_c90 instead of pedwarn.
gcc/testsuite/
	* gcc.dg/Wc90-c99-compat-1.c: New test.
	* gcc.dg/Wc90-c99-compat-2.c: New test.
	* gcc.dg/Wc90-c99-compat-3.c: New test.
	* gcc.dg/Wc90-c99-compat-4.c: New test.
	* gcc.dg/Wc90-c99-compat-5.c: New test.
	* gcc.dg/Wc90-c99-compat-6.c: New test.
	* gcc.dg/wvla-1.c: Adjust dg-warning.
	* gcc.dg/wvla-2.c: Adjust dg-warning.
	* gcc.dg/wvla-4.c: Adjust dg-warning.
	* gcc.dg/wvla-6.c: Adjust dg-warning.
libcpp/
	* lex.c (_cpp_lex_direct): Warn when -Wc90-c99-compat is in effect.
	* charset.c (_cpp_valid_ucn): Likewise.
	* include/cpplib.h (cpp_options): Add cpp_warn_c90_c99_compat.
	* macro.c (replace_args): Warn when -Wc90-c99-compat is in effect.
	(parse_params): Likewise.

From-SVN: r213786

1 files changed, 25 insertions, 8 deletions

diff --git a/gcc/c/c-errors.c b/gcc/c/c-errors.c
index 92136e7..5a95b88 100644
--- a/gcc/c/c-errors.c
+++ b/gcc/c/c-errors.c
@@ -44,21 +44,38 @@ pedwarn_c99 (location_t location, int opt, const char *gmsgid, ...)
   va_end (ap);
 }
 
-/* Issue an ISO C90 pedantic warning MSGID.  This function is supposed to
-   be used for matters that are allowed in ISO C99 but not supported in
-   ISO C90, thus we explicitly don't pedwarn when C99 is specified.
-   (There is no flag_c90.)  */
+/* Issue an ISO C90 pedantic warning MSGID if -pedantic outside C99 mode,
+   otherwise issue warning MSGID if -Wc90-c99-compat is specified, or if
+   a specific option such as -Wlong-long is specified.
+   This function is supposed to be used for matters that are allowed in
+   ISO C99 but not supported in ISO C90, thus we explicitly don't pedwarn
+   when C99 is specified.  (There is no flag_c90.)  */
 
 void
 pedwarn_c90 (location_t location, int opt, const char *gmsgid, ...)
 {
   diagnostic_info diagnostic;
   va_list ap;
+  bool warned = false;
 
   va_start (ap, gmsgid);
-  diagnostic_set_info (&diagnostic, gmsgid, &ap, location,
-		       flag_isoc99 ? DK_WARNING : DK_PEDWARN);
-  diagnostic.option_index = opt;
-  report_diagnostic (&diagnostic);
+  if (pedantic && !flag_isoc99)
+    {
+      diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_PEDWARN);
+      diagnostic.option_index = opt;
+      warned = report_diagnostic (&diagnostic);
+    }
+  else if (opt != OPT_Wpedantic)
+    {
+      diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_WARNING);
+      diagnostic.option_index = opt;
+      warned = report_diagnostic (&diagnostic);
+    }
+  if (warn_c90_c99_compat && !warned)
+    {
+      diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_WARNING);
+      diagnostic.option_index = OPT_Wc90_c99_compat;
+      report_diagnostic (&diagnostic);
+    }
   va_end (ap);
 }