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* [Bug target/25113] New: [m68k] lshiftrt and some other insns are conservative on cc0
@ 2005-11-27 2:30 kazu at gcc dot gnu dot org
2005-11-27 23:31 ` [Bug target/25113] " kazu at gcc dot gnu dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: kazu at gcc dot gnu dot org @ 2005-11-27 2:30 UTC (permalink / raw)
To: gcc-bugs
Consider:
unsigned int bar (void);
void
foo (void)
{
unsigned int a = bar ();
a >>= 2;
if (a == 0)
bar ();
}
./cc1 -quiet -O2 -m5200 -fomit-frame-pointer generates
foo:
move.l %a2,-(%sp)
lea bar,%a2
jbsr (%a2)
lsr.l #2,%d0
tst.l %d0
jbne .L4
jbsr (%a2)
.L4:
move.l (%sp)+,%a2
rts
Note that tst.l is not necessary because lsr.l sets the zero flag correctly.
See notice_update_cc and its frequent use of CC_STATUS_INIT.
--
Summary: [m68k] lshiftrt and some other insns are conservative on
cc0
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
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25113
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/25113] [m68k] lshiftrt and some other insns are conservative on cc0
2005-11-27 2:30 [Bug target/25113] New: [m68k] lshiftrt and some other insns are conservative on cc0 kazu at gcc dot gnu dot org
@ 2005-11-27 23:31 ` kazu at gcc dot gnu dot org
2005-11-28 5:06 ` pinskia at gcc dot gnu dot org
2010-02-24 22:03 ` law at redhat dot com
2 siblings, 0 replies; 4+ 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=25113
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/25113] [m68k] lshiftrt and some other insns are conservative on cc0
2005-11-27 2:30 [Bug target/25113] New: [m68k] lshiftrt and some other insns are conservative on cc0 kazu at gcc dot gnu dot org
2005-11-27 23:31 ` [Bug target/25113] " kazu at gcc dot gnu dot org
@ 2005-11-28 5:06 ` pinskia at gcc dot gnu dot org
2010-02-24 22:03 ` law at redhat dot com
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-11-28 5:06 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2005-11-28 05:06 -------
Confirmed, isn't it better just to convert m68k to a non cc0 target?
--
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 05:06:13
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25113
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/25113] [m68k] lshiftrt and some other insns are conservative on cc0
2005-11-27 2:30 [Bug target/25113] New: [m68k] lshiftrt and some other insns are conservative on cc0 kazu at gcc dot gnu dot org
2005-11-27 23:31 ` [Bug target/25113] " kazu at gcc dot gnu dot org
2005-11-28 5:06 ` pinskia at gcc dot gnu dot org
@ 2010-02-24 22:03 ` law at redhat dot com
2 siblings, 0 replies; 4+ messages in thread
From: law at redhat dot com @ 2010-02-24 22:03 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from law at redhat dot com 2010-02-24 22:02 -------
This was fixed by the cond-optab merge. The redundant tst instruction is no
longer generated.
--
law at redhat dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25113
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-02-24 22:03 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2005-11-27 2:30 [Bug target/25113] New: [m68k] lshiftrt and some other insns are conservative on cc0 kazu at gcc dot gnu dot org
2005-11-27 23:31 ` [Bug target/25113] " kazu at gcc dot gnu dot org
2005-11-28 5:06 ` pinskia at gcc dot gnu dot org
2010-02-24 22:03 ` law at redhat dot com
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