On Tue, 1 Dec 2015, Jan Hubicka wrote:
> Hi,
> this is third part which enables us to change -fstrict-aliasing using
> optimize attribute. This ought to work safely now because inliner
> propagate the flag.
Ok.
Thanks,
Richard.
> Bootstrapped/regtested x86_64-linux.
>
> Honza
>
> * gcc.c-torture/execute/alias-1.c: New testcase.
> * c-common.c: Do not silently ignore -fstrict-aliasing changes.
> Index: testsuite/gcc.c-torture/execute/alias-1.c
> ===================================================================
> --- testsuite/gcc.c-torture/execute/alias-1.c (revision 0)
> +++ testsuite/gcc.c-torture/execute/alias-1.c (revision 0)
> @@ -0,0 +1,19 @@
> +int val;
> +
> +int *ptr = &val;
> +float *ptr2 = &val;
> +
> +__attribute__((optimize ("-fno-strict-aliasing")))
> +typepun ()
> +{
> + *ptr2=0;
> +}
> +
> +main()
> +{
> + *ptr=1;
> + typepun ();
> + if (*ptr)
> + __builtin_abort ();
> +}
> +
> Index: c-family/c-common.c
> ===================================================================
> --- c-family/c-common.c (revision 231097)
> +++ c-family/c-common.c (working copy)
> @@ -9988,7 +9988,6 @@ parse_optimize_options (tree args, bool
> bool ret = true;
> unsigned opt_argc;
> unsigned i;
> - int saved_flag_strict_aliasing;
> const char **opt_argv;
> struct cl_decoded_option *decoded_options;
> unsigned int decoded_options_count;
> @@ -10081,8 +10080,6 @@ parse_optimize_options (tree args, bool
> for (i = 1; i < opt_argc; i++)
> opt_argv[i] = (*optimize_args)[i];
>
> - saved_flag_strict_aliasing = flag_strict_aliasing;
> -
> /* Now parse the options. */
> decode_cmdline_options_to_array_default_mask (opt_argc, opt_argv,
> &decoded_options,
> @@ -10093,9 +10090,6 @@ parse_optimize_options (tree args, bool
>
> targetm.override_options_after_change();
>
> - /* Don't allow changing -fstrict-aliasing. */
> - flag_strict_aliasing = saved_flag_strict_aliasing;
> -
> optimize_args->truncate (0);
> return ret;
> }
>
>
--
Richard Biener <[email protected]>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
