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* [Bug fortran/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
@ 2013-03-29 9:47 ` Joost.VandeVondele at mat dot ethz.ch
2013-03-29 22:19 ` tkoenig at gcc dot gnu.org
` (6 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: Joost.VandeVondele at mat dot ethz.ch @ 2013-03-29 9:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2009-11-01 16:21:21 |2013-03-29
CC| |Joost.VandeVondele at mat
| |dot ethz.ch
Blocks| |38654
--- Comment #14 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> 2013-03-29 09:46:53 UTC ---
The code in comment #0 is actually a frontend optimization, PR38654.
Noteworthy that the optimizers (ipa-cp plus others) do the right thing for the
tester in comment #1 at -O3 (but can't do this in the general case).
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
2013-03-29 9:47 ` [Bug fortran/41137] inefficient zeroing of an array Joost.VandeVondele at mat dot ethz.ch
@ 2013-03-29 22:19 ` tkoenig at gcc dot gnu.org
2013-03-29 22:39 ` burnus at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2013-03-29 22:19 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
--- Comment #15 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2013-03-29 22:19:05 UTC ---
The patch from comment#12 causes memory failure of the
following code:
module zero
implicit none
contains
subroutine foo(a)
real, contiguous :: a(:,:)
a(:,:) = 0
end subroutine foo
end module zero
program main
use zero
implicit none
real, dimension(5,5) :: a
a = 1.
call foo(a(1:5:2,1:5:2))
write (*,'(5F12.5)') a
end program main
which is a bit strange.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
2013-03-29 9:47 ` [Bug fortran/41137] inefficient zeroing of an array Joost.VandeVondele at mat dot ethz.ch
2013-03-29 22:19 ` tkoenig at gcc dot gnu.org
@ 2013-03-29 22:39 ` burnus at gcc dot gnu.org
2014-05-01 12:16 ` dominiq at lps dot ens.fr
` (4 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: burnus at gcc dot gnu.org @ 2013-03-29 22:39 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
Tobias Burnus <burnus at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |burnus at gcc dot gnu.org
--- Comment #16 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-03-29 22:38:58 UTC ---
Possible off-topic remark - or hitting right on the nail: Looking at
a(:,:,:,:)=0.0
and
a(5:) = 0.0
I wonder whether it couldn't be handled via RANGE_REF, e.g.
RANGE_REF(a,5,...) = { };
should work if I am not mistaken. Currently, we only do "a = 0.0" -> "a = {};".
See ARRAY_RANGE_REF in trans-expr.c's class_array_data_assign
(gfc_index_zero_node is the offset) for the usage; see also GCC internal manual
and Ada.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2013-03-29 22:39 ` burnus at gcc dot gnu.org
@ 2014-05-01 12:16 ` dominiq at lps dot ens.fr
2014-05-01 12:35 ` Joost.VandeVondele at mat dot ethz.ch
` (3 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: dominiq at lps dot ens.fr @ 2014-05-01 12:16 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
Dominique d'Humieres <dominiq at lps dot ens.fr> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work| |4.6.4, 4.7.3, 4.8.2, 4.9.0
Known to fail| |4.5.4
--- Comment #17 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
With -O3, I get the same timings for the test in comment 1 since gcc 4.6.4.
Could this PR be closed as FIXED or did I miss something in the discussion?
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2014-05-01 12:16 ` dominiq at lps dot ens.fr
@ 2014-05-01 12:35 ` Joost.VandeVondele at mat dot ethz.ch
2014-05-01 17:00 ` tkoenig at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: Joost.VandeVondele at mat dot ethz.ch @ 2014-05-01 12:35 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
--- Comment #18 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> ---
(In reply to Dominique d'Humieres from comment #17)
> With -O3, I get the same timings for the test in comment 1 since gcc 4.6.4.
> Could this PR be closed as FIXED or did I miss something in the discussion?
However, the difference remains if the subroutines would be in separate files
(comment #14), in fact, with '-O3 -fno-ipa-cp -fno-inline' the timings remain
poor:
> ./a.out
0.156975999
0.655900002
I think the issue is that the frontend could/should generate better code for
this.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug fortran/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2014-05-01 12:35 ` Joost.VandeVondele at mat dot ethz.ch
@ 2014-05-01 17:00 ` tkoenig at gcc dot gnu.org
2021-12-26 5:51 ` [Bug tree-optimization/41137] " pinskia at gcc dot gnu.org
2021-12-26 5:51 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 8+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2014-05-01 17:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
--- Comment #19 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Also see PR 55858.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug tree-optimization/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
` (5 preceding siblings ...)
2014-05-01 17:00 ` tkoenig at gcc dot gnu.org
@ 2021-12-26 5:51 ` pinskia at gcc dot gnu.org
2021-12-26 5:51 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 8+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-26 5:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Target Milestone|--- |10.0
Component|fortran |tree-optimization
Status|WAITING |RESOLVED
--- Comment #21 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed:
<bb 6> [local count: 118111600]:
# ivtmp.19_52 = PHI <0(5), ivtmp.19_49(6)>
# ivtmp.23_7 = PHI <_66(5), ivtmp.23_29(6)>
_37 = (real(kind=4) *) ivtmp.23_7;
__builtin_memset (_37, 0, _46);
ivtmp.19_49 = ivtmp.19_52 + 1;
ivtmp.23_29 = ivtmp.23_7 + _13;
if (ivtmp.19_49 == _76)
goto <bb 7>; [12.36%]
else
goto <bb 6>; [87.64%]
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug tree-optimization/41137] inefficient zeroing of an array
[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
` (6 preceding siblings ...)
2021-12-26 5:51 ` [Bug tree-optimization/41137] " pinskia at gcc dot gnu.org
@ 2021-12-26 5:51 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 8+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-26 5:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137
--- Comment #22 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this is even at -O2 for GCC 10 and above.
^ permalink raw reply [flat|nested] 8+ messages in thread
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[not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
2013-03-29 9:47 ` [Bug fortran/41137] inefficient zeroing of an array Joost.VandeVondele at mat dot ethz.ch
2013-03-29 22:19 ` tkoenig at gcc dot gnu.org
2013-03-29 22:39 ` burnus at gcc dot gnu.org
2014-05-01 12:16 ` dominiq at lps dot ens.fr
2014-05-01 12:35 ` Joost.VandeVondele at mat dot ethz.ch
2014-05-01 17:00 ` tkoenig at gcc dot gnu.org
2021-12-26 5:51 ` [Bug tree-optimization/41137] " pinskia at gcc dot gnu.org
2021-12-26 5:51 ` pinskia at gcc dot gnu.org
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