[Bug target/25128] [m68k] Suboptimal comparisons against 65536

2016-11-21 Thread law at redhat dot com 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25128

Jeffrey A. Law  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 CC||law at redhat dot com
 Resolution|--- |FIXED

--- Comment #4 from Jeffrey A. Law  ---
Fixed on the trunk.

[Bug target/25128] [m68k] Suboptimal comparisons against 65536

2016-11-21 Thread law at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25128

--- Comment #3 from Jeffrey A. Law  ---
Author: law
Date: Mon Nov 21 18:19:12 2016
New Revision: 242676

URL: https://gcc.gnu.org/viewcvs?rev=242676=gcc=rev
Log:
PR target/25128
* config/m68k/predicates.md (swap_peephole_relational_operator): New
predicate.
* config/m68k/m68k.md (relational tests against 65535/65536): New
peephole2.

PR target/25128
* gcc.target/m68k/pr25128.c: New test.

Added:
trunk/gcc/testsuite/gcc.target/m68k/pr25128.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/m68k/m68k.md
trunk/gcc/config/m68k/predicates.md
trunk/gcc/testsuite/ChangeLog

[Bug target/25128] [m68k] Suboptimal comparisons against 65536

2008-06-10 Thread gunnar at greyhound-data dot com 


--- Comment #2 from gunnar at greyhound-data dot com  2008-06-10 16:02 
---

 Note that
 
 cmp.l #65535,%d0
 jbhi .L10
 
 can be replaced with
 
 swap %d0
 tst.w %d0
 jbne .L10
 
 A similar trick can be applied to signed comparisons as well.

But this trick will run slower on the higher 68k CPUs.
On 68040 or 68060 or SuperScalar Coldfire its better to generate less
instructions that do not have dependancies.

I think cmp.l #65535,%d0 is the code that should be generated by O2 as its
faster on many 68K models.
The shorter two instruction trick might be an option for compile optiont Os


Kind regards

Gunnar von Boehn


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25128

[Bug target/25128] [m68k] Suboptimal comparisons against 65536

2005-11-27 Thread kazu at gcc dot gnu dot org 


-- 

kazu at gcc dot gnu dot org changed:

   What|Removed |Added

   Severity|normal  |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25128

[Bug target/25128] [m68k] Suboptimal comparisons against 65536

2005-11-27 Thread pinskia at gcc dot gnu dot org 


--- Comment #1 from pinskia at gcc dot gnu dot org  2005-11-28 05:04 ---
Confirmed.


-- 

pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2005-11-28 05:04:23
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25128