Re: [PATCH] Fix PR middle-end/17813

[Jan Hubicka <hubicka@ucw.cz>]

> 
> On Sat, 16 Oct 2004, Eric Botcazou wrote:
> > 2004-10-16  Eric Botcazou  <ebotcazou@libertysurf.fr>
> >
> > 	PR middle-end/17813
> > 	* explow.c (emit_stack_save): Emit pending stack adjustments.
> > 	(emit_stack_restore): Likewise.
> 
> 
> This is OK for mainline.  A slight improvement might be to add a new
> ignore_pending_stack_adjust function (like clear_pending_stack_adjust)
> that resets stack_pointer_delta and pending_stack_adjust to zero, and
> call that in emit_stack_restore.  Currently, we'll emit a "dead" stack
> adjustment immediately prior to restoring the stack pointer, and then
> leave it to the RTL optimizers to clean up.  All we really need to do
> is flush the "memory" of the pending adjustment.

RTL optimizers are not terribly smart about optimizing stack
adjustments.  WOuld be possible to double check if they are really
elliminated?
> 
> 
> It's also not clear whether the two builtins __builtin_stack_save and
> __builtin_stack_restore need to be documented in extend.texi, or if
> they're intended purely as internal placeholders.  Zdenek?

For purely internal builtins we probably should have something
preventing frontend from recognizing them in the input source so user
can't confuse us.

Honza
> 
> Roger
> --