[Bug tree-optimization/21294] New: Missed removal of null pointer check

[Bug tree-optimization/21294] New: Missed removal of null pointer check

[pinskia at gcc dot gnu dot org]

struct f
{
  int i;
};
void link_error ();
void g(struct f *i)
{
  i->i = 1;
  if (&i->i == 0)
    link_error ();
}
int main()
{
  struct f n;
  g(&n);
}

There should be no references to link_error.
The following is optimized:
void link_error ();
void g(int *i)
{
  *i = 1;
  if (i == 0)
    link_error ();
}
int main()
{
  int n;
  g(&n);
}

-- 
           Summary: Missed removal of null pointer check
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-30 01:46 -------
For VRP to catch this, extract_range_from_unary_expr has to be enhanced to deal with ADDR_EXPR.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[kazu at cs dot umass dot edu]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kazu at cs dot umass dot edu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[kazu at cs dot umass dot edu]

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2005-04-30 03:34 -------
I've got a patch in testing.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-02 13:54 -------
Patch posted here: <http://gcc.gnu.org/ml/gcc-patches/2005-05/msg00076.html>.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2005-
                   |                            |05/msg00076.html
           Keywords|                            |patch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-05-02 18:06 -------
Subject: Bug 21294

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	kazu@gcc.gnu.org	2005-05-02 18:06:28

Modified files:
	gcc            : ChangeLog tree-vrp.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/gcc.dg/tree-ssa: pr21294.c 

Log message:
	gcc/
	PR tree-optimization/21294
	* tree-vrp.c (vrp_expr_computes_nonzero): New.
	(extract_range_from_expr): Call vrp_expr_computes_nonzero.
	
	testsuite/
	PR tree-optimization/21294
	* gcc.dg/tree-ssa/pr21294.c: New.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8562&r2=2.8563
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-vrp.c.diff?cvsroot=gcc&r1=2.14&r2=2.15
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.5427&r2=1.5428
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/tree-ssa/pr21294.c.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294

[Bug tree-optimization/21294] Missed removal of null pointer check

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2005-05-02 18:07 -------
Just checked in a patch.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21294