[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ebotcazou at gcc dot
                   |                            |gnu.org
      Known to work|                            |
      Known to fail|                            |

--- Comment #11 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-10-22 16:56:59 UTC ---
While working on a related subject, the testcase started to regress.  IMHO the
fix only papers over the problem (try with -fno-trapping-math for example).
Even in the true edge of a conditional expression, you cannot infer a simple
equivalence as soon as there are or there might be signed zeros involved.

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683

--- Comment #12 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-10-23 15:57:13 UTC ---
Author: ebotcazou
Date: Sun Oct 23 15:57:09 2011
New Revision: 180340

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180340
Log:
    * fold-const.c (invert_tree_comparison): Always invert EQ_EXPR/NE_EXPR.

    PR tree-optimization/44683
    * tree-ssa-dom.c (record_edge_info): Record simple equivalences only if
    we can be sure that there are no signed zeros involved.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/tree-ssa-dom.c

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2010-06-27 11:23 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to fail|4.6.0                       |4.4.4 4.5.0
      Known to work|4.3.4                       |4.3.4 4.4.5 4.5.1 4.6.0
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2010-06-27 11:22 -------
Subject: Bug 44683

Author: rguenth
Date: Sun Jun 27 11:22:06 2010
New Revision: 161469

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=161469
Log:
2010-06-27  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/44683
        * tree-ssa-dom.c (record_edge_info): Record equivalences for the
        false edge from the inverted condition.

        * gcc.c-torture/execute/pr44683.c: New testcase.

Added:
    branches/gcc-4_4-branch/gcc/testsuite/gcc.c-torture/execute/pr44683.c
Modified:
    branches/gcc-4_4-branch/gcc/ChangeLog
    branches/gcc-4_4-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_4-branch/gcc/tree-ssa-dom.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2010-06-27 11:21 -------
Subject: Bug 44683

Author: rguenth
Date: Sun Jun 27 11:21:07 2010
New Revision: 161468

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=161468
Log:
2010-06-27  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/44683
        * tree-ssa-dom.c (record_edge_info): Record equivalences for the
        false edge from the inverted condition.

        * gcc.c-torture/execute/pr44683.c: New testcase.

Added:
    branches/gcc-4_5-branch/gcc/testsuite/gcc.c-torture/execute/pr44683.c
Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_5-branch/gcc/tree-ssa-dom.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2010-06-27 11:16 -------
Subject: Bug 44683

Author: rguenth
Date: Sun Jun 27 11:16:46 2010
New Revision: 161467

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=161467
Log:
2010-06-27  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/44683
        * tree-ssa-dom.c (record_edge_info): Record equivalences for the
        false edge from the inverted condition.

        * gcc.c-torture/execute/pr44683.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr44683.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-dom.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683

[Bug tree-optimization/44683] [4.4/4.5/4.6 Regression] Optimization bug with copysign builtin

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2010-06-27 08:50 -------
Indeed.  It's exposed by that patch.

DOM, from seeing x_2(D) != 0.0 records x_2(D) == 0.0 as equivalence.  This
is not correct if signed zeros can appear.

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
          Component|rtl-optimization            |tree-optimization
   Last reconfirmed|2010-06-26 22:57:46         |2010-06-27 08:50:38
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44683