[PATCH] Use rtx_refs_may_alias_p instead of alias_sets_conflict_p in

[Bingfeng Mei]

Sorry, I will check in patch and always enable Werror next time.

Cheers,
Bingefng

> -----Original Message-----
> From: H.J. Lu [mailto:hjl.tools@gmail.com]
> Sent: 09 August 2010 16:53
> To: Bingfeng Mei
> Cc: Richard Guenther; Michael Matz; Diego Novillo; gcc-
> patches@gcc.gnu.org
> Subject: Re: [PATCH] Use rtx_refs_may_alias_p instead of
> alias_sets_conflict_p in
> 
> On Mon, Aug 9, 2010 at 5:41 AM, Bingfeng Mei <bmei@broadcom.com> wrote:
> > Hi,
> > I created a new may_alias_p function as Richard proposed. The
> function
> > disables offset-based memory disambiguation and TBAA, it is also
> slightly
> > more conservative than true/output/anti_dependence. For example,
> > write_dependence checks:
> >  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
> >    return 1;
> >  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
> >    return 1;
> >
> > true_depdence checks both above and following (isn't above
> > statement redundant then?).
> >  if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
> >    return 1;
> > may_alias_p takes more conservative check of the latter one only.
> >
> > Since insn_alias_sets_conflict_p is misnamed and only used once by
> ddg.c,
> > it & friends (walk_mems_1, walk_mems_2) are moved into ddg.c and
> > renamed as insns_may_alias_p.
> >
> > The patch is bootstrapped on x86_64-unknown-linux-gnu and tested.
> > OK for trunk?
> >
> > Thanks,
> > Bingfeng
> >
> >
> > 2010-08-10  Bingfeng Mei  <bmei@broadcom.com>
> >
> >        * ddg.c (walk_mems_2): Moved from alias.c, use may_alias_p
> instead of
> >        alias_sets_conflict_p.
> >        (walk_mems_1): Moved from alias.c.
> >        (insns_may_alias_p): New function, originally
> insn_alias_sets_conflict_p
> >        in alias.c.
> >        (add_inter_loop_mem_dep): Use insns_may_alias_p now.
> >        * cse.c (cse_insn): New argument in calling
> nonoverlapping_memrefs_p.
> >        * alias.c (walk_mems_2): Moved to ddg.c.
> >        (walk_mems_1): Ditto.
> >        (insn_alias_sets_conflict_p): Renamed to insns_may_alias_p and
> moved
> >        to ddg.c.
> >        (nonoverlapping_memrefs_p): Add flag to guard offset-based
> memory
> >        disambiguation.
> >        *(may_alias_p): New function to check whether two memory
> expression
> >        may alias or not. Currently used in buidling inter-iteration
> memory
> >        dependence.
> >        *alias.h (nonoverlapping_memrefs_p): New flag as third
> argument.
> >        (insn_alias_sets_conflict_p): Removed
> >        *rtl.h (may_alias_p): New function prototype.
> >
> 
> Gcc is broken:
> 
> ../../src-trunk/gcc/alias.c: In function 'may_alias_p':
> ../../src-trunk/gcc/alias.c:2537:7: error: unused variable 'ret'
> [-Werror=unused-variable]
> cc1: all warnings being treated as errors
> 
> 
> H.J.