Re: RFC: Hack to make restrict more useful

["Richard Guenther" <richard dot guenther at gmail dot com>]

On 9/1/07, Mark Mitchell <mark@codesourcery.com> wrote:
> This bug:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33272
>
> is about a situation in which -fargument-noalias works better than
> putting "restrict" on all pointer arguments to a function, even though
> that should be logically equivalent.  Using "restrict" for all arguments
> to a function is probably one of the most common cases of "restrict";
> that's what you want for things like the test case I posted, and for
> other Fortran-ish code.
>
> I have a prototype hack which changes checks of flag_argument_noalias !=
> 0 to also check for the presence of "restrict" on all pointer arguments.
>  This fixes the test case, modulo a C front-end bug which Joseph has
> volunteered to fix.
>
> To make that a real patch, here's what I plan to do:
>
> (1) Add a flag to "struct function" to say "all pointer arguments are
> restrict".
>
> (2) Lazily set it, when something wants to check it.
>
> (3) Change checks of flag_argument_noalias to call a function
> argument_noalias() which will return an "int" with the same meaning as
> flag_argument_noalias.
>
> Does that plan sound OK to folks?

AFAIK Danny had been "fixing restrict" on his working agenda lately.  No
idea what the status on that is, though.

Richard.