[Bug tree-optimization/31982] New: Missed forw prop with indirect ref and addr. (and char types or sizeof(type) == 1)

[Bug tree-optimization/31982] New: Missed forw prop with indirect ref and addr. (and char types or sizeof(type) == 1)

[pinskia at gcc dot gnu dot org]

This testcase should pass:
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-forwprop" }  */

/* We should be able to optimize this to b->t[i] = 1 during
   early optimizations.  */

struct a
{
  char t[10];
};

struct a *b;

void f(__SIZE_TYPE__ i)
{
  int *c = b->t;
  c[i] = 1;
}

/* { dg-final { scan-tree-dump "t\\\[i.*\\\] = 1;" "forwprop1" { xfail *-*-* }
} } */
/* { dg-final { scan-tree-dump "t\\\[i.*\\\] = 1;" "forwprop2" } } */
/* { dg-final { cleanup-tree-dump "forwprop?" } } */


---------

I found this while fixing up forwprop for the pointer plus branch.
forwprop is looking for a MULT_EXPR which does not exist in this case.


-- 
           Summary: Missed forw prop with indirect ref and addr. (and char
                    types or sizeof(type) == 1)
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31982

[Bug tree-optimization/31982] Missed forw prop with indirect ref and addr. (and char types or sizeof(type) == 1)

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2007-05-24 11:11 -------
Confirmed.  Of course it needs to read

  char *c = b->t;


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-05-24 11:11:24
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31982

[Bug tree-optimization/31982] Missed forw prop with indirect ref and addr. (and char types or sizeof(type) == 1)

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2007-05-24 11:22 -------
I have a patch for this one.


-- 

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|2007-05-24 11:11:24         |2007-05-24 11:22:40
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31982

[Bug tree-optimization/31982] Missed forw prop with indirect ref and addr. (and char types or sizeof(type) == 1)

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2007-05-25 10:07 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31982

[Bug tree-optimization/31982] Missed forw prop with indirect ref and addr. (and char types or sizeof(type) == 1)

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2007-05-25 10:07 -------
Fixed.


------- Comment #4 from rguenth at gcc dot gnu dot org  2007-05-25 10:07 -------
Subject: Bug 31982

Author: rguenth
Date: Fri May 25 09:07:29 2007
New Revision: 125058

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=125058
Log:
2007-05-24  Richard Guenther  <rguenther@suse.de>
        Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR tree-optimization/31982
        * tree-ssa-forwprop.c
        (forward_propagate_addr_into_variable_array_index): Handle arrays
        with element size one.

        * gcc.dg/tree-ssa/forwprop-2.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/forwprop-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-forwprop.c


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31982