[Bug tree-optimization/58656] New: rnflow regressing after r202826

[Bug tree-optimization/58656] New: rnflow regressing after r202826

[Ganesh.Gopalasubramanian at amd dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58656

            Bug ID: 58656
           Summary: rnflow regressing after r202826
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Ganesh.Gopalasubramanian at amd dot com

Seems the fix for 58464 is regressing rnflow of pb11.

Runtime log of rnflow

Before revision 202826
0:35.558 -> Completed program execution

After revision 202826 (after fix)
0:53.023 -> Completed program execution

The suse polyhedron benchmark log also shows this (after sep23).
http://gcc.opensuse.org/c++bench/polyhedron/polyhedron-summary.txt

[Bug tree-optimization/58656] [4.9 Regression] rnflow regressing after r202826

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58656

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
           Keywords|                            |missed-optimization
   Last reconfirmed|                            |2013-10-10
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
             Blocks|                            |58464
     Ever confirmed|0                           |1
            Summary|rnflow regressing after     |[4.9 Regression] rnflow
                   |r202826                     |regressing after r202826
   Target Milestone|---                         |4.9.0

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look next week.  The patch was supposed to not have any effect
on code generation.

[Bug tree-optimization/58656] [4.9 Regression] rnflow regressing after r202826

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58656

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
cptrf2 shows

   <bb 32>:
-  pretmp_278 = (integer(kind=8)) ival2_72;
-  pretmp_279 = pretmp_278 + -1;
-  pretmp_280 = *xxtrt_23(D)[pretmp_279];

   <bb 33>:
   # ival2_130 = PHI <ival2_50(32), ival2_138(36)>
   # ival2_134 = PHI <ival2_72(32), ival2_140(36)>
-  # prephitmp_281 = PHI <pretmp_280(32), prephitmp_255(36)>
   _131 = (integer(kind=8)) ival2_130;
   _132 = _131 + -1;
   _133 = *xxtrt_23(D)[_132];
   _135 = (integer(kind=8)) ival2_134;
   _136 = _135 + -1;
-  _137 = prephitmp_281;
+  _137 = *xxtrt_23(D)[_136];
   if (_133 < _137)
     goto <bb 34>;
   else

gentrs has a difference as well.  It's partial-PRE results differing
(we don't have many partial-PRE testcases).

The reason for the difference is likely "failed" translations which are
cached over insert iterations.  I have a patch.

[Bug tree-optimization/58656] [4.9 Regression] rnflow regressing after r202826

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58656

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu Oct 10 14:07:19 2013
New Revision: 203377

URL: http://gcc.gnu.org/viewcvs?rev=203377&root=gcc&view=rev
Log:
2013-10-10  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/58656
    * tree-ssa-pre.c (phi_translate): Do not cache failed
    translations.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-pre.c

[Bug tree-optimization/58656] [4.9 Regression] rnflow regressing after r202826

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58656

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

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

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.