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* [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2
@ 2010-07-20 7:59 carrot at google dot com
2010-07-20 8:37 ` [Bug target/44999] " steven at gcc dot gnu dot org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: carrot at google dot com @ 2010-07-20 7:59 UTC (permalink / raw)
To: gcc-bugs
Compile the following code with options -march=armv7-a -mthumb -Os
int tp(int x, int y)
{
return (x & 0xff) - (y & 0xffff);
}
GCC generates:
uxth r1, r1
and r0, r0, #255 //A
subs r0, r0, r1
bx lr
Instruction A is 32 bit, it can be replace by uxtb, a 16 bit equivalent
instruction.
A possible implementation is to call gen_thumb2_zero_extendqisi2_v6 in pattern
(define_expand "andsi3").
--
Summary: "and r0, r0, #255" can be replace with uxtb in thumb2
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: carrot at google dot com
GCC build triplet: i686-linux
GCC host triplet: i686-linux
GCC target triplet: arm-eabi
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44999
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44999] "and r0, r0, #255" can be replace with uxtb in thumb2
2010-07-20 7:59 [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2 carrot at google dot com
@ 2010-07-20 8:37 ` steven at gcc dot gnu dot org
2010-07-20 22:48 ` pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: steven at gcc dot gnu dot org @ 2010-07-20 8:37 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from steven at gcc dot gnu dot org 2010-07-20 08:37 -------
Note, it's often helpful for us non-ARM-assembly-gurus to explain the pattern
you would like to have, instead of the mnemonic :-)
--
steven 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 |2010-07-20 08:37:31
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44999
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44999] "and r0, r0, #255" can be replace with uxtb in thumb2
2010-07-20 7:59 [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2 carrot at google dot com
2010-07-20 8:37 ` [Bug target/44999] " steven at gcc dot gnu dot org
@ 2010-07-20 22:48 ` pinskia at gcc dot gnu dot org
2010-07-24 19:47 ` rearnsha at gcc dot gnu dot org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2010-07-20 22:48 UTC (permalink / raw)
To: gcc-bugs
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Keywords| |missed-optimization
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44999
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44999] "and r0, r0, #255" can be replace with uxtb in thumb2
2010-07-20 7:59 [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2 carrot at google dot com
2010-07-20 8:37 ` [Bug target/44999] " steven at gcc dot gnu dot org
2010-07-20 22:48 ` pinskia at gcc dot gnu dot org
@ 2010-07-24 19:47 ` rearnsha at gcc dot gnu dot org
2010-08-21 17:29 ` mikpe at it dot uu dot se
2010-08-22 4:34 ` carrot at google dot com
4 siblings, 0 replies; 6+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2010-07-24 19:47 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from rearnsha at gcc dot gnu dot org 2010-07-24 19:47 -------
*** This bug has been marked as a duplicate of 43461 ***
--
rearnsha at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44999
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44999] "and r0, r0, #255" can be replace with uxtb in thumb2
2010-07-20 7:59 [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2 carrot at google dot com
` (2 preceding siblings ...)
2010-07-24 19:47 ` rearnsha at gcc dot gnu dot org
@ 2010-08-21 17:29 ` mikpe at it dot uu dot se
2010-08-22 4:34 ` carrot at google dot com
4 siblings, 0 replies; 6+ messages in thread
From: mikpe at it dot uu dot se @ 2010-08-21 17:29 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from mikpe at it dot uu dot se 2010-08-21 17:28 -------
Didn't Carrot's r163184 fix this PR and its dupe PR43461?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44999
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44999] "and r0, r0, #255" can be replace with uxtb in thumb2
2010-07-20 7:59 [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2 carrot at google dot com
` (3 preceding siblings ...)
2010-08-21 17:29 ` mikpe at it dot uu dot se
@ 2010-08-22 4:34 ` carrot at google dot com
4 siblings, 0 replies; 6+ messages in thread
From: carrot at google dot com @ 2010-08-22 4:34 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from carrot at google dot com 2010-08-22 04:34 -------
Both have been fixed. But I don't have the permission to close PR43461.(In
reply to comment #3)
> Didn't Carrot's r163184 fix this PR and its dupe PR43461?
>
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44999
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-08-22 4:34 UTC | newest]
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2010-07-20 7:59 [Bug target/44999] New: "and r0, r0, #255" can be replace with uxtb in thumb2 carrot at google dot com
2010-07-20 8:37 ` [Bug target/44999] " steven at gcc dot gnu dot org
2010-07-20 22:48 ` pinskia at gcc dot gnu dot org
2010-07-24 19:47 ` rearnsha at gcc dot gnu dot org
2010-08-21 17:29 ` mikpe at it dot uu dot se
2010-08-22 4:34 ` carrot at google dot com
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