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* [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0)
@ 2023-01-10 13:03 yann at ywg dot ch
2023-01-10 14:47 ` [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047 marxin at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: yann at ywg dot ch @ 2023-01-10 13:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
Bug ID: 108358
Summary: Dead Code Elimination Regression at -Os (trunk vs.
12.2.0)
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: yann at ywg dot ch
Target Milestone: ---
Created attachment 54233
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54233&action=edit
presented code as file
cat case.c #25
struct a {
int b;
int c;
short d;
int e;
int f;
};
struct g {
struct a f;
struct a h;
};
int i;
void foo();
void bar31_(void);
int main() {
struct g j, l = {2, 1, 6, 1, 1, 7, 5, 1, 0, 1};
for (; i; ++i)
bar31_();
j = l;
struct g m = j;
struct g k = m;
if (k.h.b)
;
else
foo();
}
`gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -Os` can not eliminate
`foo` but `gcc-releases/gcc-12.2.0 -Os` can.
`gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -Os -S -o /dev/stdout
case.c`
--------- OUTPUT ---------
main:
.LFB0:
.cfi_startproc
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_offset 3, -16
movl $.LC0, %esi
movl $10, %ecx
subq $80, %rsp
.cfi_def_cfa_offset 96
leaq 40(%rsp), %rdi
leaq 40(%rsp), %rbx
rep movsl
.L2:
cmpl $0, i(%rip)
je .L7
call bar31_
incl i(%rip)
jmp .L2
.L7:
movq %rsp, %rdi
movl $10, %ecx
movq %rbx, %rsi
rep movsl
cmpl $0, 20(%rsp)
jne .L4
xorl %eax, %eax
call foo
.L4:
addq $80, %rsp
.cfi_def_cfa_offset 16
xorl %eax, %eax
popq %rbx
.cfi_def_cfa_offset 8
ret
---------- END OUTPUT ---------
`gcc-releases/gcc-12.2.0 -Os -S -o /dev/stdout case.c`
--------- OUTPUT ---------
main:
.LFB0:
.cfi_startproc
cmpl $0, i(%rip)
jne .L7
xorl %eax, %eax
ret
.L7:
pushq %rax
.cfi_def_cfa_offset 16
.L3:
call bar31_
incl i(%rip)
cmpl $0, i(%rip)
jne .L3
xorl %eax, %eax
popq %rdx
.cfi_def_cfa_offset 8
ret
---------- END OUTPUT ---------
Bisects to:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=f6c168f8c06047bfaa3005e570126831b8855dcc
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047
2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
@ 2023-01-10 14:47 ` marxin at gcc dot gnu.org
2023-02-21 13:20 ` rguenth at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: marxin at gcc dot gnu.org @ 2023-01-10 14:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|Dead Code Elimination |[13 Regression] Dead Code
|Regression at -Os (trunk |Elimination Regression at
|vs. 12.2.0) |-Os since
| |r13-3378-gf6c168f8c06047
Target Milestone|--- |13.0
Last reconfirmed| |2023-01-10
Ever confirmed|0 |1
CC| |jamborm at gcc dot gnu.org,
| |marxin at gcc dot gnu.org
Status|UNCONFIRMED |NEW
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047
2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
2023-01-10 14:47 ` [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047 marxin at gcc dot gnu.org
@ 2023-02-21 13:20 ` rguenth at gcc dot gnu.org
2023-03-27 11:56 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-02-21 13:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2023-01-10 00:00:00 |2023-2-21
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Re-confirmed but not analyzed yet.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047
2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
2023-01-10 14:47 ` [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047 marxin at gcc dot gnu.org
2023-02-21 13:20 ` rguenth at gcc dot gnu.org
@ 2023-03-27 11:56 ` rguenth at gcc dot gnu.org
2023-04-08 14:37 ` law at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-03-27 11:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Both -O2 and -O1 can optimize away the call to foo. For -Os we end up with
<bb 2> [local count: 118111600]:
l = *.LC0;
goto <bb 4>; [100.00%]
<bb 3> [local count: 955630225]:
bar31_ ();
i.0_1 = i;
_2 = i.0_1 + 1;
i = _2;
<bb 4> [local count: 1073741824]:
i.1_3 = i;
if (i.1_3 != 0)
goto <bb 3>; [89.00%]
else
goto <bb 5>; [11.00%]
<bb 5> [local count: 118111600]:
j = l;
m$h$b_18 = j.h.b;
if (m$h$b_18 != 0)
goto <bb 7>; [67.00%]
else
goto <bb 6>; [33.00%]
<bb 6> [local count: 38976828]:
foo ();
but FREs looking through the j = l copy causes us to fail disambiguating
against the cycle because of 'abort_on_visited' which I think is a bit
overeager here.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047
2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
` (2 preceding siblings ...)
2023-03-27 11:56 ` rguenth at gcc dot gnu.org
@ 2023-04-08 14:37 ` law at gcc dot gnu.org
2023-04-26 6:57 ` [Bug tree-optimization/108358] [13/14 " rguenth at gcc dot gnu.org
2023-07-27 9:25 ` rguenth at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: law at gcc dot gnu.org @ 2023-04-08 14:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
Jeffrey A. Law <law at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |law at gcc dot gnu.org
Priority|P3 |P2
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/108358] [13/14 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047
2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
` (3 preceding siblings ...)
2023-04-08 14:37 ` law at gcc dot gnu.org
@ 2023-04-26 6:57 ` rguenth at gcc dot gnu.org
2023-07-27 9:25 ` rguenth at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-04-26 6:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|13.0 |13.2
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.1 is being released, retargeting bugs to GCC 13.2.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/108358] [13/14 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047
2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
` (4 preceding siblings ...)
2023-04-26 6:57 ` [Bug tree-optimization/108358] [13/14 " rguenth at gcc dot gnu.org
@ 2023-07-27 9:25 ` rguenth at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-07-27 9:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108358
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|13.2 |13.3
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.2 is being released, retargeting bugs to GCC 13.3.
^ permalink raw reply [flat|nested] 7+ messages in thread
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2023-01-10 13:03 [Bug tree-optimization/108358] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) yann at ywg dot ch
2023-01-10 14:47 ` [Bug tree-optimization/108358] [13 Regression] Dead Code Elimination Regression at -Os since r13-3378-gf6c168f8c06047 marxin at gcc dot gnu.org
2023-02-21 13:20 ` rguenth at gcc dot gnu.org
2023-03-27 11:56 ` rguenth at gcc dot gnu.org
2023-04-08 14:37 ` law at gcc dot gnu.org
2023-04-26 6:57 ` [Bug tree-optimization/108358] [13/14 " rguenth at gcc dot gnu.org
2023-07-27 9:25 ` rguenth at gcc dot gnu.org
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