[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[matt at use dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

Matt Hargett <matt at use dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |matt at use dot net

--- Comment #9 from Matt Hargett <matt at use dot net> 2011-04-27 17:52:06 UTC ---
This appears to be fixed in 4.6.0. Mark as resolved?

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> 2011-04-27 18:32:34 UTC ---
(In reply to comment #9)
> This appears to be fixed in 4.6.0. Mark as resolved?

Need to add a few testcases first.

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

Richard Guenther <rguenth at gcc dot gnu.org> changed:

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

--- Comment #13 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-28 09:57:05 UTC ---
Fi-xed.

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.6.0

--- Comment #12 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-28 09:56:52 UTC ---
Fixed.  Thanks for noticing.

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

--- Comment #11 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-28 09:55:46 UTC ---
Author: rguenth
Date: Thu Apr 28 09:55:41 2011
New Revision: 173064

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173064
Log:
2011-04-28  Richard Guenther  <rguenther@suse.de>

    PR tree-optimization/40052
    PR tree-optimization/15347
    * gcc.dg/tree-ssa/vrp57.c: New testcase.
    * gcc.dg/pr15347.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/pr15347.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp57.c
Modified:
    trunk/gcc/testsuite/ChangeLog

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347
Bug 15347 depends on bug 15459, which changed state.

Bug 15459 Summary: [meta-bug] there should be a tree combiner like the rtl one
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=15459

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

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[pinskia at gcc dot gnu dot org]

------- Comment #7 from pinskia at gcc dot gnu dot org  2005-12-07 03:23 -------
I should note that the first testcase in comment #0 in the bug is fixed but not
the second, non reduced one.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2005-09-07 18:50:42         |2005-12-07 03:23:13
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[pinskia at gcc dot gnu dot org]

------- Comment #8 from pinskia at gcc dot gnu dot org  2006-09-17 08:44 -------
Just to clarify what testcase is still broken, here it is:
void baz (void)
{
  if ("<12ers" + 1 == 0)
    bar ();
}

------
The reason why strchr testcase is fixed is because we turn the strchr call into
&"<12ers"[1].


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
   Last reconfirmed|2006-03-01 02:45:29         |2006-09-17 08:44:52
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

[Bug optimization/15347] New: [tree-ssa] fold if ("<12ers" + 1 == 0).

[kazu at cs dot umass dot edu]

void bar ();

int
foo (void)
{
  if ("<12ers" + 1 == 0)
    bar ();
}

which is reduced from from

extern const char tree_code_type[];

extern char *strchr (__const char *__s, int __c) __attribute__ ((__pure__));

extern void abort (void) __attribute__ ((__noreturn__));

int
foo (int a)
{
  if (tree_code_type[a] == '1')
    if (strchr ("<12ers", tree_code_type[a]) == 0)
      abort ();
}

which is in turn reduced from find_base_decl() in alias.c.

-- 
           Summary: [tree-ssa] fold if ("<12ers" + 1 == 0).
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Keywords: pessimizes-code
          Severity: normal
          Priority: P2
         Component: 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=15347

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 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=15347

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-06-01 06:45 -------
Now that Steven's strchr patch is in, let me reiterate the problem.

void bar (void);

void
foo (void)
{
  int c = '1';

  if (strchr ("<12ers", c) == 0)
    bar ();
}

void
baz (void)
{
  int c = '1';

  if ("<12ers" + 1 == 0)
    bar ();
}

The last tree-ssa form looks like:

;; Function foo (foo)

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

<bb 0>:
  T.0_2 = "<12ers" + 1B;
  if (T.0_2 == 0B) goto <L0>; else goto <L1>;

<L0>:;
  bar () [tail call];

<L1>:;
  return;

}



;; Function baz (baz)

baz ()
{
  int c;

<bb 0>:
  if ("<12ers" == -1B) goto <L0>; else goto <L1>;

<L0>:;
  bar () [tail call];

<L1>:;
  return;

}

In either case, we miss the folding opportunity.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-06-01 06:47 -------
"int c = '1';" in baz() in comment #4 is an unintended garbage.
Please ignore it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347

[Bug tree-optimization/15347] [tree-ssa] fold if ("<12ers" + 1 == 0).

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-03 23:22 -------
I should note that "12ers" == 0 is folded to false by:
      /* If this is an equality comparison of the address of a non-weak
         object against zero, then we know the result.  */

So improving that part will help.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15347