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* [Bug target/25114]  New: [m68k] Inefficient inequality comparisons with small integers
@ 2005-11-27  2:36 kazu at gcc dot gnu dot org
  2005-11-27 23:31 ` [Bug target/25114] [m68k] Suboptimal " kazu at gcc dot gnu dot org
  2005-11-28  5:05 ` pinskia at gcc dot gnu dot org
  0 siblings, 2 replies; 3+ messages in thread
From: kazu at gcc dot gnu dot org @ 2005-11-27  2:36 UTC (permalink / raw)
  To: gcc-bugs

Consider:

unsigned int bar (void);

void
foo (void)
{
  unsigned int a = bar ();
  if (a <= 3)
    bar ();
}

./cc1 -quiet -O2 -fomit-frame-pointer generates

foo:
        move.l %a2,-(%sp)
        lea bar,%a2
        jbsr (%a2)
        moveq #3,%d1
        cmp.l %d0,%d1
        jbcs .L4
        jbsr (%a2)
.L4:
        move.l (%sp)+,%a2
        rts

Note that

        moveq #3,%d1
        cmp.l %d0,%d1
        jbcs .L4

can be replaced with

        lsr.l #2,%d0
        jbne .L4

This bug depends on PR 25113 because GCC needs to know that lsr.l sets
the zero flag correctly.


-- 
           Summary: [m68k] Inefficient inequality comparisons with small
                    integers
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at gcc dot gnu dot org
GCC target triplet: m68k-elf
 BugsThisDependsOn: 25113


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25114


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [Bug target/25114] [m68k] Suboptimal inequality comparisons with small integers
  2005-11-27  2:36 [Bug target/25114] New: [m68k] Inefficient inequality comparisons with small integers kazu at gcc dot gnu dot org
@ 2005-11-27 23:31 ` kazu at gcc dot gnu dot org
  2005-11-28  5:05 ` pinskia at gcc dot gnu dot org
  1 sibling, 0 replies; 3+ messages in thread
From: kazu at gcc dot gnu dot org @ 2005-11-27 23:31 UTC (permalink / raw)
  To: gcc-bugs



-- 

kazu at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25114


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [Bug target/25114] [m68k] Suboptimal inequality comparisons with small integers
  2005-11-27  2:36 [Bug target/25114] New: [m68k] Inefficient inequality comparisons with small integers kazu at gcc dot gnu dot org
  2005-11-27 23:31 ` [Bug target/25114] [m68k] Suboptimal " kazu at gcc dot gnu dot org
@ 2005-11-28  5:05 ` pinskia at gcc dot gnu dot org
  1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-11-28  5:05 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #1 from pinskia at gcc dot gnu dot org  2005-11-28 05:05 -------
Confirmed.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-11-28 05:05:10
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25114


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2005-11-28  5:05 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-11-27  2:36 [Bug target/25114] New: [m68k] Inefficient inequality comparisons with small integers kazu at gcc dot gnu dot org
2005-11-27 23:31 ` [Bug target/25114] [m68k] Suboptimal " kazu at gcc dot gnu dot org
2005-11-28  5:05 ` pinskia at gcc dot gnu dot org

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