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* [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed
@ 2005-06-23 5:02 pinskia at gcc dot gnu dot org
2005-06-23 5:04 ` [Bug middle-end/22156] " pinskia at gcc dot gnu dot org
` (12 more replies)
0 siblings, 13 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-23 5:02 UTC (permalink / raw)
To: gcc-bugs
Take the following code:
struct s
{
int i1:1;
int i2:1;
int i3:1;
};
void f(struct s *x, struct s *y) { *x = *y; }
In 3.4.0 (and currently with the C++ compiler too), we were able to get optimal code:
movl 8(%esp), %eax
movl (%eax), %edx
movl 4(%esp), %eax
movl %edx, (%eax)
ret
But in (and after) 4.0.0 and the C compiler we get:
f:
pushl %esi
pushl %ebx
movl 16(%esp), %eax
movl 12(%esp), %esi
movzbl (%eax), %eax
movb %al, %dl
movb %al, %bl
salb $5, %al
sarb $7, %al
movzbl %al, %ecx
movl (%esi), %eax
salb $6, %dl
andl $1, %ecx
sarb $7, %dl
movzbl %dl, %edx
salb $7, %bl
andl $-7, %eax
sall $2, %ecx
andl $1, %edx
sarb $7, %bl
addl %edx, %edx
orl %ecx, %eax
orl %edx, %eax
movzbl %bl, %edx
andl $1, %edx
andl $-2, %eax
orl %edx, %eax
movl %eax, (%esi)
popl %ebx
popl %esi
ret
Which is much worse
--
Summary: [4.0/4.1 Regression] bit-field copying regressed
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P2
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: pinskia at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
OtherBugsDependingO 19466
nThis:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
@ 2005-06-23 5:04 ` pinskia at gcc dot gnu dot org
2005-06-23 5:11 ` pinskia at gcc dot gnu dot org
` (11 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-23 5:04 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-23 05:04 -------
Note this also effects PPC, though not as badly as there is only one load:
in 3.3.3:
_f:
lwz r0,0(r4)
stw r0,0(r3)
blr
in 4.0.0 and above:
_f:
lwz r11,0(r4)
lwz r0,0(r3)
slwi r2,r11,2
slwi r9,r11,1
rlwimi r0,r2,30,2,2
rlwimi r0,r9,31,1,1
rlwimi r0,r11,0,0,0
stw r0,0(r3)
blr
--
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.0.1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
2005-06-23 5:04 ` [Bug middle-end/22156] " pinskia at gcc dot gnu dot org
@ 2005-06-23 5:11 ` pinskia at gcc dot gnu dot org
2005-06-23 5:34 ` pinskia at gcc dot gnu dot org
` (10 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-23 5:11 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-23 05:11 -------
The main difference between the C++ front-end and the C front-end in this respect is how they
repesent bit-fields.
for the C++ front-end we get the following output from SRA:
Cannot scalarize variable D.1693 because its type cannot be decomposed
but for the C front-end we get:
Scan results:
D.1237: n_uses=0 n_copies=2
Initial instantiation for D.1237
Using element-copy for D.1237
D.1237.i1 -> SR.12
D.1237.i2 -> SR.13
D.1237.i3 -> SR.14
So to me this looks like a SRA bug in that it should be using BIT_FIELD_REF instead if it can.
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |rth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
2005-06-23 5:04 ` [Bug middle-end/22156] " pinskia at gcc dot gnu dot org
2005-06-23 5:11 ` pinskia at gcc dot gnu dot org
@ 2005-06-23 5:34 ` pinskia at gcc dot gnu dot org
2005-06-23 13:09 ` kazu at cs dot umass dot edu
` (9 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-23 5:34 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |22157
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (2 preceding siblings ...)
2005-06-23 5:34 ` pinskia at gcc dot gnu dot org
@ 2005-06-23 13:09 ` kazu at cs dot umass dot edu
2005-06-23 13:18 ` pluto at agmk dot net
` (8 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: kazu at cs dot umass dot edu @ 2005-06-23 13:09 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |kazu at cs dot umass dot edu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (3 preceding siblings ...)
2005-06-23 13:09 ` kazu at cs dot umass dot edu
@ 2005-06-23 13:18 ` pluto at agmk dot net
2005-06-23 19:49 ` pinskia at gcc dot gnu dot org
` (7 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pluto at agmk dot net @ 2005-06-23 13:18 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |pluto at agmk dot net
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (4 preceding siblings ...)
2005-06-23 13:18 ` pluto at agmk dot net
@ 2005-06-23 19:49 ` pinskia at gcc dot gnu dot org
2005-07-04 10:26 ` pinskia at gcc dot gnu dot org
` (6 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-23 19:49 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-23 19:49 -------
I have a fix, it does what I recommended in 22157.
--
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |pinskia at gcc dot gnu dot
|dot org |org
Status|UNCONFIRMED |ASSIGNED
Ever Confirmed| |1
Last reconfirmed|0000-00-00 00:00:00 |2005-06-23 19:49:18
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (5 preceding siblings ...)
2005-06-23 19:49 ` pinskia at gcc dot gnu dot org
@ 2005-07-04 10:26 ` pinskia at gcc dot gnu dot org
2005-07-04 10:32 ` pinskia at gcc dot gnu dot org
` (5 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-07-04 10:26 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-07-04 10:26 -------
I am no longer working on this, this is a much harder problem than I sugested. This is basically the
same as PR 18268.
--
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |18268
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (6 preceding siblings ...)
2005-07-04 10:26 ` pinskia at gcc dot gnu dot org
@ 2005-07-04 10:32 ` pinskia at gcc dot gnu dot org
2005-07-08 1:44 ` mmitchel at gcc dot gnu dot org
` (4 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-07-04 10:32 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|pinskia at gcc dot gnu dot |unassigned at gcc dot gnu
|org |dot org
Status|ASSIGNED |NEW
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (7 preceding siblings ...)
2005-07-04 10:32 ` pinskia at gcc dot gnu dot org
@ 2005-07-08 1:44 ` mmitchel at gcc dot gnu dot org
2005-08-05 20:45 ` pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: mmitchel at gcc dot gnu dot org @ 2005-07-08 1:44 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.0.1 |4.0.2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (8 preceding siblings ...)
2005-07-08 1:44 ` mmitchel at gcc dot gnu dot org
@ 2005-08-05 20:45 ` pinskia at gcc dot gnu dot org
2005-09-14 17:35 ` pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-08-05 20:45 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-08-05 20:45 -------
If we add more bit-fields, that is now fixed in 4.0.2 and 4.1.0 by:
2005-08-04 Richard Henderson <rth@redhat.com>
PR 21529
* params.def (PARAM_SRA_MAX_STRUCTURE_COUNT): New.
* params.h (SRA_MAX_STRUCTURE_COUNT): New.
* tree-sra.c (decide_block_copy): Use it. Disable element copy
if we'd have to instantiate too many members.
But the orginal code is not fixed as we don't have too many members.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (9 preceding siblings ...)
2005-08-05 20:45 ` pinskia at gcc dot gnu dot org
@ 2005-09-14 17:35 ` pinskia at gcc dot gnu dot org
2005-09-15 14:27 ` pinskia at gcc dot gnu dot org
2005-09-27 16:25 ` mmitchel at gcc dot gnu dot org
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-09-14 17:35 UTC (permalink / raw)
To: gcc-bugs
--
Bug 22156 depends on bug 18268, which changed state.
Bug 18268 Summary: structure copy propagation not done
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18268
What |Old Value |New Value
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (10 preceding siblings ...)
2005-09-14 17:35 ` pinskia at gcc dot gnu dot org
@ 2005-09-15 14:27 ` pinskia at gcc dot gnu dot org
2005-09-27 16:25 ` mmitchel at gcc dot gnu dot org
12 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-09-15 14:27 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-09-15 14:27 -------
*** Bug 22157 has been marked as a duplicate of this bug. ***
--
Bug 22156 depends on bug 22157, which changed state.
Bug 22157 Summary: [4.0/4.1 Regression] struct copying code gen
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22157
What |Old Value |New Value
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
` (11 preceding siblings ...)
2005-09-15 14:27 ` pinskia at gcc dot gnu dot org
@ 2005-09-27 16:25 ` mmitchel at gcc dot gnu dot org
12 siblings, 0 replies; 17+ messages in thread
From: mmitchel at gcc dot gnu dot org @ 2005-09-27 16:25 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.0.2 |4.0.3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
[not found] <bug-22156-6528@http.gcc.gnu.org/bugzilla/>
2005-10-13 21:06 ` pinskia at gcc dot gnu dot org
2005-10-27 20:32 ` pinskia at gcc dot gnu dot org
@ 2005-10-30 23:32 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-10-30 23:32 UTC (permalink / raw)
To: gcc-bugs
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P2 |P5
Target Milestone|4.2.0 |4.1.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
[not found] <bug-22156-6528@http.gcc.gnu.org/bugzilla/>
2005-10-13 21:06 ` pinskia at gcc dot gnu dot org
@ 2005-10-27 20:32 ` pinskia at gcc dot gnu dot org
2005-10-30 23:32 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-10-27 20:32 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from pinskia at gcc dot gnu dot org 2005-10-27 20:31 -------
Nothing can happen until 4.2.0 for this issue really as we need a real copy
prop for structs.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.0.3 |4.2.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
* [Bug middle-end/22156] [4.0/4.1 Regression] bit-field copying regressed
[not found] <bug-22156-6528@http.gcc.gnu.org/bugzilla/>
@ 2005-10-13 21:06 ` pinskia at gcc dot gnu dot org
2005-10-27 20:32 ` pinskia at gcc dot gnu dot org
2005-10-30 23:32 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 17+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-10-13 21:06 UTC (permalink / raw)
To: gcc-bugs
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |minor
Last reconfirmed|2005-06-23 19:49:18 |2005-10-13 21:06:28
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22156
^ permalink raw reply [flat|nested] 17+ messages in thread
end of thread, other threads:[~2005-10-30 23:32 UTC | newest]
Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-06-23 5:02 [Bug middle-end/22156] New: [4.0/4.1 Regression] bit-field copying regressed pinskia at gcc dot gnu dot org
2005-06-23 5:04 ` [Bug middle-end/22156] " pinskia at gcc dot gnu dot org
2005-06-23 5:11 ` pinskia at gcc dot gnu dot org
2005-06-23 5:34 ` pinskia at gcc dot gnu dot org
2005-06-23 13:09 ` kazu at cs dot umass dot edu
2005-06-23 13:18 ` pluto at agmk dot net
2005-06-23 19:49 ` pinskia at gcc dot gnu dot org
2005-07-04 10:26 ` pinskia at gcc dot gnu dot org
2005-07-04 10:32 ` pinskia at gcc dot gnu dot org
2005-07-08 1:44 ` mmitchel at gcc dot gnu dot org
2005-08-05 20:45 ` pinskia at gcc dot gnu dot org
2005-09-14 17:35 ` pinskia at gcc dot gnu dot org
2005-09-15 14:27 ` pinskia at gcc dot gnu dot org
2005-09-27 16:25 ` mmitchel at gcc dot gnu dot org
[not found] <bug-22156-6528@http.gcc.gnu.org/bugzilla/>
2005-10-13 21:06 ` pinskia at gcc dot gnu dot org
2005-10-27 20:32 ` pinskia at gcc dot gnu dot org
2005-10-30 23:32 ` pinskia at gcc dot gnu dot org
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