[Bug tree-optimization/52005] New: tree-ssa-combineif does not work with some cfgs

[Bug tree-optimization/52005] New: tree-ssa-combineif does not work with some cfgs

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52005

             Bug #: 52005
           Summary: tree-ssa-combineif does not work with some cfgs
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: pinskia@gcc.gnu.org


Take:
int f(int x, int a, int b)
{
  int t = 0;
  int c = 1 << a;
  if (!(x & 1))
    t = 0;
  else
    if (x & (1 << 2))
      t = 1;
    else
      t = 0;
  return t;
}

int f1(int x, int a, int b)
{
  int t = 0;
  int c = 1 << a;
  if (x & 1)
    if (x & (1 << 2))
      t = 1;
  return t;
}
--- CUT ---
Both codes are the same.  The first case is not optimized while the second is.
The reason is we have code in ifcombine which only looks for the second case. 
While the first is not caught.

[Bug tree-optimization/52005] tree-ssa-combineif does not work with some cfgs

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52005

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-01-26
         AssignedTo|unassigned at gcc dot       |pinskia at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-01-26 03:55:07 UTC ---
I have a patch.

[Bug tree-optimization/52005] tree-ssa-combineif does not work with some cfgs

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52005

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-01-26 22:08:05 UTC ---
Here is another testcase:
int f(int x, int a, int b)
{
  int t = 0;
  int c = 1 << a;
  if (!(x & 1))
    t = 0;
  else
    if (x & (1 << 2))
      t = g();
    else
      t = 0;
  return t;
}

The original testcase is not currently optimized with current patch but the
above one is.  I am still on the case of the original testcase.

[Bug tree-optimization/52005] tree-ssa-combineif does not work with some cfgs

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52005

--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> 2012-08-06 16:38:52 UTC ---
Author: glisse
Date: Mon Aug  6 16:38:48 2012
New Revision: 190184

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190184
Log:
2012-08-06 Marc Glisse <marc.glisse@inria.fr>

gcc/
    PR tree-optimization/51938
    PR tree-optimization/52005
    * tree-ssa-ifcombine.c (ifcombine_ifandif): New parameters for
    inverted conditions.
    (ifcombine_iforif): Remove, merge code into ifcombine_ifandif.
    (tree_ssa_ifcombine_bb): Update calls to the above. Detect !a&&b
    and !a||b patterns.

gcc/testsuite/
    PR tree-optimization/51938
    PR tree-optimization/52005
    * gcc.dg/tree-ssa/ssa-ifcombine-8.c: New testcase.
    * gcc.dg/tree-ssa/ssa-ifcombine-9.c: Likewise.
    * gcc.dg/tree-ssa/ssa-ifcombine-10.c: Likewise.
    * gcc.dg/tree-ssa/ssa-ifcombine-11.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-10.c   (with props)
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-11.c   (with props)
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-8.c   (with props)
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c   (with props)
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-ifcombine.c

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-10.c
            ('svn:eol-style' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-10.c
            ('svn:keywords' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-11.c
            ('svn:eol-style' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-11.c
            ('svn:keywords' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-8.c
            ('svn:eol-style' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-8.c
            ('svn:keywords' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c
            ('svn:eol-style' added)

Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c
            ('svn:keywords' added)

[Bug tree-optimization/52005] tree-ssa-combineif does not work with some cfgs

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52005

Marc Glisse <glisse at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
                 CC|                            |glisse at gcc dot gnu.org
         Resolution|                            |FIXED

--- Comment #4 from Marc Glisse <glisse at gcc dot gnu.org> 2012-08-06 16:58:16 UTC ---
All the above testcases are now optimized (at least at -O2).