[Bug tree-optimization/34172] New: Missed store ccp optimization

[Bug tree-optimization/34172] New: Missed store ccp optimization

[eres at il dot ibm dot com]

#define N 256

struct
{
  int x;
  int y;
} S[100];

int z[100];

int
foo (int y)
{
  int x;

  S[5].x = 4;
  S[5].y = 0;

  x = S[5].x;

  return (x);
}

On powerpc64-linux, r130275 with -O2 we get:
(taken from .store_ccp dump file)

foo (y)
{
  int x;

<bb 2>:
  S[5].x = 4;
  S[5].y = 0;
  x_1 = S[5].x;
  return x_1;

}

[A patch was submitted
(http://gcc.gnu.org/ml/gcc-patches/2007-06/msg01901.html) which is no longer
relevant because of -http://gcc.gnu.org/ml/gcc-patches/2007-08/msg01370.html.]


-- 
           Summary: Missed store ccp optimization
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: eres at il dot ibm dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34172

[Bug tree-optimization/34172] Missed store ccp optimization

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2007-11-21 12:04 -------
Note that only store _copyprop_ was removed for now.  But yes, store ccp
removal
is on the plate.  Note that this and similar bugs should be fixed by extending
value-numbering to disambiguate memory accesses itself and not only relying on
virtual operands.

Confirmed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-11-21 12:04:28
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34172

[Bug tree-optimization/34172] Missed store ccp optimization

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
           Keywords|                            |missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34172

[Bug tree-optimization/34172] Missed store ccp optimization

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2007-11-30 10:25 -------
Mine.  I have a patch.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rguenth at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-11-21 12:04:28         |2007-11-30 10:25:34
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34172

[Bug tree-optimization/34172] Missed store ccp optimization

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2008-03-14 17:06 -------
Subject: Bug 34172

Author: rguenth
Date: Fri Mar 14 17:05:48 2008
New Revision: 133222

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=133222
Log:
2008-03-14  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/34172
        * tree-flow.h (refs_may_alias_p): Declare.
        (get_single_def_stmt): Likewise.
        (get_single_def_stmt_from_phi): Likewise.
        (get_single_def_stmt_with_phi): Likewise.
        * tree-dfa.c (refs_may_alias_p): New function.
        (get_single_def_stmt): Likewise.
        (get_single_def_stmt_from_phi): Likewise.
        (get_single_def_stmt_with_phi): Likewise.
        * tree-ssa-sccvn.c (get_def_ref_stmt_vuses): New function.
        (vn_reference_lookup_1): New helper function.
        (vn_reference_lookup): Walk the virtual use-def chain to
        continue searching for a match if the def does not alias the
        reference we are looking for.

        * gcc.dg/tree-ssa/ssa-fre-11.c: New testcase.
        * gcc.dg/tree-ssa/ssa-fre-12.c: Likewise.
        * gcc.dg/tree-ssa/ssa-fre-13.c: Likewise.
        * gcc.dg/tree-ssa/ssa-fre-14.c: Likewise.
        * gcc.dg/tree-ssa/ssa-fre-15.c: Likewise.
        * gcc.dg/tree-ssa/20031106-4.c: Remove XFAIL.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-11.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-12.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-13.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-14.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-15.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/tree-ssa/20031106-4.c
    trunk/gcc/tree-dfa.c
    trunk/gcc/tree-flow.h
    trunk/gcc/tree-ssa-sccvn.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34172

[Bug tree-optimization/34172] Missed store ccp optimization

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2008-03-14 17:25 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34172