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* [Bug rtl-optimization/44249] [4.4/4.5/4.6 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
@ 2010-10-01 12:04 ` jakub at gcc dot gnu.org
2010-11-24 15:17 ` ebotcazou at gcc dot gnu.org
` (9 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2010-10-01 12:04 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.4.5 |4.4.6
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.4/4.5/4.6 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
2010-10-01 12:04 ` [Bug rtl-optimization/44249] [4.4/4.5/4.6 Regression] IRA generates extra register move jakub at gcc dot gnu.org
@ 2010-11-24 15:17 ` ebotcazou at gcc dot gnu.org
2010-11-24 18:21 ` vmakarov at redhat dot com
` (8 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: ebotcazou at gcc dot gnu.org @ 2010-11-24 15:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
Last reconfirmed| |2010.11.24 15:14:39
CC| |ebotcazou at gcc dot
| |gnu.org
Ever Confirmed|0 |1
--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-24 15:14:39 UTC ---
There isn't just an extra move, the code is also different. Are you sure that
it results in inferior performances?
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.4/4.5/4.6 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
2010-10-01 12:04 ` [Bug rtl-optimization/44249] [4.4/4.5/4.6 Regression] IRA generates extra register move jakub at gcc dot gnu.org
2010-11-24 15:17 ` ebotcazou at gcc dot gnu.org
@ 2010-11-24 18:21 ` vmakarov at redhat dot com
2011-04-16 10:53 ` [Bug rtl-optimization/44249] [4.4/4.5/4.6/4.7 " jakub at gcc dot gnu.org
` (7 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: vmakarov at redhat dot com @ 2010-11-24 18:21 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
--- Comment #2 from Vladimir Makarov <vmakarov at redhat dot com> 2010-11-24 17:40:56 UTC ---
Reload creates additional insn for insn
(insn 9 7 11 2 (parallel [
(set (reg:DI 71)
(lshiftrt:DI (reg/v:DI 60 [ tag ])
(const_int 4 [0x4])))
(clobber (reg:CC 17 flags))
]) b.i:5 533 {*lshrdi3_1}
(expr_list:REG_DEAD (reg/v:DI 60 [ tag ])
(expr_list:REG_UNUSED (reg:CC 17 flags)
(nil))))
That is because r60 and r71 got different registers (0 an 1) even
although there is a copy between r71 and r60 which should result in
getting r70 hard register 0 as r60 one. It does not happen because
r68 already got 0 and it conflicts with r71:
r71: preferred GENERAL_REGS, alternative NO_REGS, cover GENERAL_REGS
r68: preferred AREG, alternative GENERAL_REGS, cover GENERAL_REGS
r60: preferred GENERAL_REGS, alternative NO_REGS, cover GENERAL_REGS
;; a0(r68,l0) conflicts: a1(r71,l0)
;; a4(r67,l0) conflicts: cp0:a1(r71)<->a3(r60)@1000:constraint
Popping a0(r68,l0) -- assign reg 0
Popping a3(r60,l0) -- assign reg 0
Popping a1(r71,l0) -- assign reg 1
Analogous insn for gcc-4.3 looks like
(insn:HI 9 7 11 2 b.i:4 (parallel [
(set (reg/v:DI 58 [ tag ])
(lshiftrt:DI (reg/v:DI 58 [ tag ])
(const_int 4 [0x4])))
(clobber (reg:CC 17 flags))
]) 514 {*lshrdi3_1_rex64} (expr_list:REG_UNUSED (reg:CC 17 flags)
(nil)))
It means there is no such problem as in gcc4.4+.
Insn 9 for gcc-4.3 is a result of regmove transformation. I have no
idea why regmove (which is present in gcc4.4+) does not do the same
for gcc4.4+ (probably because of some changes since 4.3).
The problem could be fixed in regmove or in IRA (which is probably
harder). But I don't know is it worth to do it. Because such
transformations result in longer live ranges of pseudos and might
result in worse code for other programs.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.4/4.5/4.6/4.7 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2010-11-24 18:21 ` vmakarov at redhat dot com
@ 2011-04-16 10:53 ` jakub at gcc dot gnu.org
2011-05-02 7:33 ` ebotcazou at gcc dot gnu.org
` (6 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2011-04-16 10:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.4.6 |4.4.7
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.4/4.5/4.6/4.7 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2011-04-16 10:53 ` [Bug rtl-optimization/44249] [4.4/4.5/4.6/4.7 " jakub at gcc dot gnu.org
@ 2011-05-02 7:33 ` ebotcazou at gcc dot gnu.org
2012-03-13 15:21 ` [Bug rtl-optimization/44249] [4.5/4.6/4.7/4.8 " jakub at gcc dot gnu.org
` (5 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: ebotcazou at gcc dot gnu.org @ 2011-05-02 7:33 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |NEW
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.5/4.6/4.7/4.8 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2011-05-02 7:33 ` ebotcazou at gcc dot gnu.org
@ 2012-03-13 15:21 ` jakub at gcc dot gnu.org
2012-07-02 11:59 ` rguenth at gcc dot gnu.org
` (4 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-03-13 15:21 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.4.7 |4.5.4
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-13 12:48:04 UTC ---
4.4 branch is being closed, moving to 4.5.4 target.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.5/4.6/4.7/4.8 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (5 preceding siblings ...)
2012-03-13 15:21 ` [Bug rtl-optimization/44249] [4.5/4.6/4.7/4.8 " jakub at gcc dot gnu.org
@ 2012-07-02 11:59 ` rguenth at gcc dot gnu.org
2012-10-09 21:01 ` [Bug rtl-optimization/44249] [4.6/4.7 " steven at gcc dot gnu.org
` (3 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-07-02 11:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.5.4 |4.6.4
--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-07-02 11:58:03 UTC ---
The 4.5 branch is being closed, adjusting target milestone.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.6/4.7 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (6 preceding siblings ...)
2012-07-02 11:59 ` rguenth at gcc dot gnu.org
@ 2012-10-09 21:01 ` steven at gcc dot gnu.org
2013-04-12 15:18 ` [Bug rtl-optimization/44249] [4.7 " jakub at gcc dot gnu.org
` (2 subsequent siblings)
10 siblings, 0 replies; 11+ messages in thread
From: steven at gcc dot gnu.org @ 2012-10-09 21:01 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Steven Bosscher <steven at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[4.6/4.7/4.8 Regression] |[4.6/4.7 Regression] IRA
|IRA generates extra |generates extra register
|register move |move
--- Comment #5 from Steven Bosscher <steven at gcc dot gnu.org> 2012-10-09 21:01:08 UTC ---
No extra move with trunk today:
$ cat t.c
extern unsigned long table[];
unsigned long foo(unsigned char *p) {
unsigned long tag = *p;
return table[tag >> 4] + table[tag & 0xf];
}
$ cat t.s
.file "t.c"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
movzbl (%rdi), %edx
movq %rdx, %rax
shrq $4, %rdx
andl $15, %eax
movq table(,%rax,8), %rax
addq table(,%rdx,8), %rax
ret
.cfi_endproc
.LFE0:
.size foo, .-foo
.ident "GCC: (GNU) 4.8.0 20121008 (experimental) \
[trunk revision 192219]"
.section .note.GNU-stack,"",@progbits
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.7 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (7 preceding siblings ...)
2012-10-09 21:01 ` [Bug rtl-optimization/44249] [4.6/4.7 " steven at gcc dot gnu.org
@ 2013-04-12 15:18 ` jakub at gcc dot gnu.org
2014-06-12 12:57 ` rguenth at gcc dot gnu.org
2015-06-22 14:23 ` rguenth at gcc dot gnu.org
10 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-04-12 15:18 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.6.4 |4.7.4
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-12 15:17:03 UTC ---
GCC 4.6.4 has been released and the branch has been closed.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.7 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (8 preceding siblings ...)
2013-04-12 15:18 ` [Bug rtl-optimization/44249] [4.7 " jakub at gcc dot gnu.org
@ 2014-06-12 12:57 ` rguenth at gcc dot gnu.org
2015-06-22 14:23 ` rguenth at gcc dot gnu.org
10 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-06-12 12:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work| |4.8.0
Target Milestone|4.7.4 |4.8.0
Known to fail| |4.7.4
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed with LRA.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug rtl-optimization/44249] [4.7 Regression] IRA generates extra register move
[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
` (9 preceding siblings ...)
2014-06-12 12:57 ` rguenth at gcc dot gnu.org
@ 2015-06-22 14:23 ` rguenth at gcc dot gnu.org
10 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2015-06-22 14:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44249
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
.
^ permalink raw reply [flat|nested] 11+ messages in thread
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[not found] <bug-44249-4@http.gcc.gnu.org/bugzilla/>
2010-10-01 12:04 ` [Bug rtl-optimization/44249] [4.4/4.5/4.6 Regression] IRA generates extra register move jakub at gcc dot gnu.org
2010-11-24 15:17 ` ebotcazou at gcc dot gnu.org
2010-11-24 18:21 ` vmakarov at redhat dot com
2011-04-16 10:53 ` [Bug rtl-optimization/44249] [4.4/4.5/4.6/4.7 " jakub at gcc dot gnu.org
2011-05-02 7:33 ` ebotcazou at gcc dot gnu.org
2012-03-13 15:21 ` [Bug rtl-optimization/44249] [4.5/4.6/4.7/4.8 " jakub at gcc dot gnu.org
2012-07-02 11:59 ` rguenth at gcc dot gnu.org
2012-10-09 21:01 ` [Bug rtl-optimization/44249] [4.6/4.7 " steven at gcc dot gnu.org
2013-04-12 15:18 ` [Bug rtl-optimization/44249] [4.7 " jakub at gcc dot gnu.org
2014-06-12 12:57 ` rguenth at gcc dot gnu.org
2015-06-22 14:23 ` rguenth at gcc dot gnu.org
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