Re: PATCH for sibcalls on i386

[Andreas Bauer <baueran at in dot tum dot de>]

> int
> i386_function_ok_for_sibcall (decl, exp)
>      tree decl, exp;
> {
>   /* If we are generating position-independent code, we cannot sibcall
>      optimize any indirect call, or a direct call to a global
>      function, as the PLT requires %ebx be live.  */
>   if (flag_pic && (!decl || !TREE_PUBLIC (decl)))
>     return 0;
>
> [...]
>
>   /* Otherwise okay.  */
>   return 1;
> }

I agree, indeed this is much nicer.  I will incorporate the change into
my next series of patches.

> Andreas, may I suggest that you split the patch?  It will be easier
> for people to review it, which means it will get committed faster, if
> you make these changes in three separate stages.

Yes, I will try to come up with smaller patches. (I'm still somewhat new
to the gcc business, sorry.)

> First make the mechanical changes necessary to add the 'exp' parameter
> to FUNCTION_OK_FOR_SIBCALL, and update the documentation.  Do not
> change calls.c or any of the definitions at this stage.  Please
> consider turning FUNCTION_OK_FOR_SIBCALL into a "target hook" with
> this patch, too.
> 
> Second, change all the definitions of FUNCTION_OK_FOR_SIBCALL to
> return false if fndecl is null, remove the hardwired 'decl != 0' check
> from calls.c, and again update the documentation.
> 
> Third, change the i386 machine description and FUNCTION_OK_FOR_SIBCALL
> hook to accept indirect sibcalls when possible.

Sounds all good to me.  Thank you a lot for the useful comments.

Cheers,
Andi.