[Bug tree-optimization/64193] Decreased performance after r173250

[Bug tree-optimization/64193] Decreased performance after r173250

[cederman at gaisler dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #1 from Daniel Cederman <cederman at gaisler dot com> ---
Created attachment 34197
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34197&action=edit
assembly output with r173250

[Bug tree-optimization/64193] Decreased performance after r173250

[cederman at gaisler dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #2 from Daniel Cederman <cederman at gaisler dot com> ---
Created attachment 34198
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34198&action=edit
assembly output without r173250

[Bug tree-optimization/64193] [4.8/4.9/5 Regression] Decreased performance after r173250

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-12-08
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
   Target Milestone|---                         |4.8.4
            Summary|Decreased performance after |[4.8/4.9/5 Regression]
                   |r173250                     |Decreased performance after
                   |                            |r173250
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.  Note the rev. was backported to GCC 4.5 and up.

[Bug tree-optimization/64193] [4.8/4.9/5 Regression] Decreased performance after r173250

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 34229
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34229&action=edit
patch

Ok, I see the regression introduced by that rev., but on trunk (r218479)
I get the same code generated with/without the attached fix.  I'm using
-O3 -m32 -march=i686 on x86_64-linux.

Probably the regression was mitigated by the partial fix for PR63677:

2014-11-20   Richard Biener  <rguenther@suse.de>

        PR tree-optimization/63677
        * tree-ssa-dom.c: Include gimplify.h for unshare_expr.
        (avail_exprs_stack): Make a vector of pairs.
        (struct hash_expr_elt): Replace stmt member with vop member.
        (expr_elt_hasher::equal): Simplify.
...

where DOM now catches the CSE opportunities FRE no longer did.

[Bug tree-optimization/64193] [4.8/4.9/5 Regression] Decreased performance after r173250

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 9 Dec 2014, cederman at gaisler dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193
> 
> --- Comment #5 from Daniel Cederman <cederman at gaisler dot com> ---
> > Probably the regression was mitigated by the partial fix for PR63677:
> 
> Yes, that seems to be the case for my attached example. Do you think that the
> regression is mitigated in general, or is your attached fix also needed?

I am testing my fix and will install it nevertheless - it is required
to get full optimistic value-numbering again.  It would be also the
fix that is appropriate for backporting (if any of them is).

[Bug tree-optimization/64193] [4.8/4.9/5 Regression] Decreased performance after r173250

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #7 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
AFAICT if there is any speedup with the patch in comment 5, it is negligible on
a 2.8Ghz Corei7 and x86_64-apple-darwin14: ~7.1s with/without the patch. Note
that the timing in the test is not very precise.

[Bug tree-optimization/64193] [4.8/4.9/5 Regression] Decreased performance after r173250

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #8 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 9 Dec 2014, dominiq at lps dot ens.fr wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193
> 
> --- Comment #7 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> AFAICT if there is any speedup with the patch in comment 5, it is negligible on
> a 2.8Ghz Corei7 and x86_64-apple-darwin14: ~7.1s with/without the patch. Note
> that the timing in the test is not very precise.

As said the patch is more interesting on the 4.9 branch where the DOM
improvements do not mitigate its effect (or with -fno-tree-dominator-opts)

[Bug tree-optimization/64193] [4.8/4.9 Regression] Decreased performance after r173250

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue Dec  9 14:25:09 2014
New Revision: 218515

URL: https://gcc.gnu.org/viewcvs?rev=218515&root=gcc&view=rev
Log:
2014-12-09  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/64193
    * tree-ssa-alias.c (walk_non_aliased_vuses): Add valueize parameter
    and valueize the VUSE before looking up the def stmt.
    * tree-ssa-alias.h (walk_non_aliased_vuses): Adjust prototype.
    * tree-ssa-sccvn.c (vn_reference_lookup_pieces): Pass vn_valueize
    to walk_non_aliased_vuses.
    (vn_reference_lookup): Likewise.
    * tree-ssa-dom.c (lookup_avail_expr): Pass NULL as valueize
    callback to walk_non_aliased_vuses.

    * gcc.dg/tree-ssa/ssa-fre-43.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-43.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-alias.c
    trunk/gcc/tree-ssa-alias.h
    trunk/gcc/tree-ssa-dom.c
    trunk/gcc/tree-ssa-sccvn.c

[Bug tree-optimization/64193] [4.8/4.9 Regression] Decreased performance after r173250

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
      Known to work|                            |5.0
            Summary|[4.8/4.9/5 Regression]      |[4.8/4.9 Regression]
                   |Decreased performance after |Decreased performance after
                   |r173250                     |r173250
      Known to fail|                            |4.8.3, 4.9.2

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

[Bug tree-optimization/64193] [4.8/4.9 Regression] Decreased performance after r173250

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193
Bug 64193 depends on bug 64312, which changed state.

Bug 64312 Summary: [5 Regression] ICE: Segmentation fault
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64312

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug tree-optimization/64193] [4.8/4.9 Regression] Decreased performance after r173250

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.4                       |4.8.5

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.8.4 has been released.

[Bug tree-optimization/64193] [4.8/4.9 Regression] Decreased performance after r173250

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.5                       |4.9.3

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
The gcc-4_8-branch is being closed, re-targeting regressions to 4.9.3.

[Bug tree-optimization/64193] [4.9 Regression] Decreased performance after r173250

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.9.3 has been released.

[Bug tree-optimization/64193] [4.9 Regression] Decreased performance after r173250

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.9.3                       |4.9.4