Avoid -Wunused-macros warning for #pragma GCC target added macros (PR target/58944)

Submitted by Jakub Jelinek on Jan. 17, 2014, 7:58 p.m.

Details

Message ID 20140117195808.GM892@tucnak.redhat.com
State New
Headers show

Commit Message

Jakub Jelinek Jan. 17, 2014, 7:58 p.m.
Hi!

It makes no sense to warn about unused macros that weren't defined
by the user, but the compiler instead injected them, the user
has no control on them.
For macros predefined at the beginning of the CU we don't get warnings
because they don't match MAIN_FILE_P, but macros added for #pragma GCC target
get location_t from the location of the pragma (and without libcpp hacks
that could possibly slow down preprocessing I don't see how to get around
it), so the following hack seems to be easiest.  All newly created macros
when -Wunused-macros isn't on are initialized with macro->used = true,
and never warned about for this warning, so this patch just arranges for
all the cpp_define calls from #pragma GCC target to set that.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2014-01-17  Jakub Jelinek  <jakub@redhat.com>

	PR target/58944
	* config/i386/i386-c.c (ix86_pragma_target_parse): Temporarily
	clear cpp_get_options (parse_in)->warn_unused_macros for
	ix86_target_macros_internal with cpp_define.

	* gcc.target/i386/pr58944.c: Drop -march=native from dg-options.
	Remove dg-prune-output lines.


	Jakub

Comments

Uros Bizjak Jan. 18, 2014, 10:07 a.m.
On Fri, Jan 17, 2014 at 8:58 PM, Jakub Jelinek <jakub@redhat.com> wrote:

> It makes no sense to warn about unused macros that weren't defined
> by the user, but the compiler instead injected them, the user
> has no control on them.
> For macros predefined at the beginning of the CU we don't get warnings
> because they don't match MAIN_FILE_P, but macros added for #pragma GCC target
> get location_t from the location of the pragma (and without libcpp hacks
> that could possibly slow down preprocessing I don't see how to get around
> it), so the following hack seems to be easiest.  All newly created macros
> when -Wunused-macros isn't on are initialized with macro->used = true,
> and never warned about for this warning, so this patch just arranges for
> all the cpp_define calls from #pragma GCC target to set that.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2014-01-17  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/58944
>         * config/i386/i386-c.c (ix86_pragma_target_parse): Temporarily
>         clear cpp_get_options (parse_in)->warn_unused_macros for
>         ix86_target_macros_internal with cpp_define.
>
>         * gcc.target/i386/pr58944.c: Drop -march=native from dg-options.
>         Remove dg-prune-output lines.

OK.

Thanks,
Uros.

Patch hide | download patch | download mbox

--- gcc/config/i386/i386-c.c.jj	2014-01-03 11:41:06.000000000 +0100
+++ gcc/config/i386/i386-c.c	2014-01-17 14:24:15.828447673 +0100
@@ -458,6 +458,13 @@  ix86_pragma_target_parse (tree args, tre
 			       (enum fpmath_unit) prev_opt->x_ix86_fpmath,
 			       cpp_undef);
 
+  /* For the definitions, ensure all newly defined macros are considered
+     as used for -Wunused-macros.  There is no point warning about the
+     compiler predefined macros.  */
+  cpp_options *cpp_opts = cpp_get_options (parse_in);
+  unsigned char saved_warn_unused_macros = cpp_opts->warn_unused_macros;
+  cpp_opts->warn_unused_macros = 0;
+
   /* Define all of the macros for new options that were just turned on.  */
   ix86_target_macros_internal (cur_isa & diff_isa,
 			       cur_arch,
@@ -465,6 +472,8 @@  ix86_pragma_target_parse (tree args, tre
 			       (enum fpmath_unit) cur_opt->x_ix86_fpmath,
 			       cpp_define);
 
+  cpp_opts->warn_unused_macros = saved_warn_unused_macros;
+
   return true;
 }
 
--- gcc/testsuite/gcc.target/i386/pr58944.c.jj	2013-12-03 08:27:22.000000000 +0100
+++ gcc/testsuite/gcc.target/i386/pr58944.c	2014-01-17 14:29:53.288756542 +0100
@@ -1,11 +1,7 @@ 
 /* { dg-do compile } */
-/* { dg-options "-Wunused-macros -march=native" } */
+/* { dg-options "-Wunused-macros" } */
 
 #pragma GCC push_options
 #pragma GCC target("xsaveopt")
 void fn1(void) {}
 #pragma GCC pop_options
-
-/* { dg-prune-output "macro \"__code_model_" } */ 
-/* { dg-prune-output "macro \"__XSAVE__\" is not used" } */ 
-/* { dg-prune-output "macro \"__XSAVEOPT__\" is not used" } */