[Bug tree-optimization/15738] New: [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[Bug tree-optimization/15738] New: [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[kazu at cs dot umass dot edu]

char *
foo (const char *s)
{
  int c = 0;
  return strrchr (s, c);
}

I get:

foo (s)
{
  int c;
  char * T.0;

<bb 0>:
  T.0_3 = strrchr (s_2, 0) [tail call];
  return T.0_3;

}

If you write "strrchr (s, 0)" in the first place,
then you get "strchr (s, 0)" with the help of simplify_builtin().

Once this optimization is done, I think we can remove
expand_builtin_strchr and expand_builtin_strrchr.

-- 
           Summary: [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is
                    known to be 0
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738

[Bug tree-optimization/15738] [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-05-30 21:49 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |missed-optimization
   Last reconfirmed|0000-00-00 00:00:00         |2004-05-30 21:49:28
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738

[Bug tree-optimization/15738] [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-05-31 13:21 -------
I've got a patch in testing.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |kazu at cs dot umass dot edu
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738

[Bug tree-optimization/15738] [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-06-01 05:29 -------
A patch:

http://gcc.gnu.org/ml/gcc-patches/2004-06/msg00009.html


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738

[Bug tree-optimization/15738] [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-06-02 18:41 -------
Subject: Bug 15738

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	kazu@gcc.gnu.org	2004-06-02 18:41:41

Modified files:
	gcc            : ChangeLog builtins.c 

Log message:
	PR tree-optimization/15738.
	* builtins.c (fold_builtin_strchr): Transform
	strrchr (s, '\0') to strchr (s, '\0').

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.3821&r2=2.3822
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/builtins.c.diff?cvsroot=gcc&r1=1.330&r2=1.331



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738

[Bug tree-optimization/15738] [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-06-02 18:44 -------
Just checked in a patch.


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738

[Bug tree-optimization/15738] [tree-ssa] Convert strrchr(s, c) to strchr(s, c) if c is known to be 0

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15738