[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[bonzini at gnu dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

Paolo Bonzini <bonzini at gnu dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org
      Known to fail|                            |

--- Comment #8 from Paolo Bonzini <bonzini at gnu dot org> 2010-11-03 18:51:46 UTC ---
flag_wrapv should not be respected by combine because PLUS/MINUS in RTL should
_always_ have wrapping semantics.

The right place for this optimization is in fold-const.c, especially in the
current GCC world.

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[phython at gcc dot gnu dot org]

------- Additional Comments From phython at gcc dot gnu dot org  2005-07-28 04:52 -------
 Fixed in the commit above.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-07-28 04:40 -------
Subject: Bug 23047

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	phython@gcc.gnu.org	2005-07-28 04:40:06

Modified files:
	gcc            : ChangeLog simplify-rtx.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/gcc.c-torture/execute: pr23047.c pr23047.x 

Log message:
	2005-07-27  James A. Morrison  <phython@gcc.gnu.org>
	
	PR rtl-optimization/23047
	* simplify-rtx.c (simplify_const_relational_operation): Respect
	flag_wrapv for comparisons with ABS.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.9576&r2=2.9577
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/simplify-rtx.c.diff?cvsroot=gcc&r1=1.241&r2=1.242
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.5833&r2=1.5834
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/execute/pr23047.c.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/execute/pr23047.x.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-27 23:09 -------
*** Bug 23105 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |danglin at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[phython at gcc dot gnu dot org]

------- Additional Comments From phython at gcc dot gnu dot org  2005-07-24 22:38 -------
Created an attachment (id=9353)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9353&action=view)
Honour flag_wrapv


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |phython at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-24 14:01 -------
Caused by:

2002-07-20  Roger Sayle  <roger@eyesopen.com>

        * simplify-rtx.c (simplify_relational_operation): Optimize
        abs(x) < 0.0 (and abs(x) >= 0.0 when using -ffast-math).
This was introduced before -fwrapv was introduced.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |roger at eyesopen dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047

[Bug rtl-optimization/23047] Combine ignores flag_wrapv

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-24 13:57 -------
Confirmed.  Note this is does not effect i686 because on i686 we expand abs right away.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |wrong-code
   Last reconfirmed|0000-00-00 00:00:00         |2005-07-24 13:57:36
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23047