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* [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto
@ 2024-01-09 17:42 jamborm at gcc dot gnu.org
2024-01-09 17:43 ` [Bug target/113295] [14 Regression] " pinskia at gcc dot gnu.org
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: jamborm at gcc dot gnu.org @ 2024-01-09 17:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
Bug ID: 113295
Summary: SPEC 2006 416.gamess miscompares on Aarch64 when built
with -Ofast -march=native -flto
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jamborm at gcc dot gnu.org
Blocks: 26163
Target Milestone: ---
Host: aarch64-linux
Target: aarch64-linux
Our Aarch64 benchmarker (armv8.2-a+crypto+fp16+rcpc+dotprod+ssbs)
signals that SPEC 2006 416.gamess miscompares when built with -Ofast
-march=native -flto and master revision r14-7022-g34d339bbd0c1f5.
*** Miscompare of cytosine.2.out;
1120: 1 C 0.027630132 0.018067739 0.002234116
1 C -223.432234062 7.107716215 -9.326017293
^
1121: 2 C 0.012259576 -0.006051645 -0.000067202
2 C -205.307990130 -173.019401916 -6.442472179
^
1122: 3 C -0.012829758 0.003221329 -0.000743429
3 C -0.900001858 -263.923127366 3.131404191
^
1123: 4 N -0.041204707 0.020932737 -0.000372560
4 N 291.766837166 -257.876625173 10.788390925
^
1124: 5 C 0.057007688 0.032540385 -0.000909621
5 C -204.215830139 57.403322317 -0.929403441
^
1125: 6 N -0.015041867 -0.049945043 0.002129121
6 N 117.540483305 300.802327718 -10.562573219
^
1126: 7 O -0.076442899 -0.041673056 -0.000117411
7 O 481.672983389 238.169793443 3.121961894
^
1127: 8 N 0.034391335 -0.016048119 -0.001905357
8 N -247.780884876 91.547672097 -1.133077767
^
1128: 9 H 0.014938973 0.008953835 0.000373759
9 H -3.948185240 0.659195159 -0.007774350
^
1129: 10 H -0.002268325 0.023480419 0.000010207
10 H -0.160267091 -4.621874235 -0.178161165
Unfortunately at the moment don't have another access to another
adequate Aarch64 machine to debug further and so at this time I cannot
provide more information (and so the component "target" is likely
bogus, sorry).
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26163
[Bug 26163] [meta-bug] missed optimization in SPEC (2k17, 2k and 2k6 and 95)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
@ 2024-01-09 17:43 ` pinskia at gcc dot gnu.org
2024-02-19 13:13 ` tnfchris at gcc dot gnu.org
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-01-09 17:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|SPEC 2006 416.gamess |[14 Regression] SPEC 2006
|miscompares on Aarch64 when |416.gamess miscompares on
|built with -Ofast |Aarch64 when built with
|-march=native -flto |-Ofast -march=native -flto
Target Milestone|--- |14.0
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
2024-01-09 17:43 ` [Bug target/113295] [14 Regression] " pinskia at gcc dot gnu.org
@ 2024-02-19 13:13 ` tnfchris at gcc dot gnu.org
2024-02-21 10:25 ` tnfchris at gcc dot gnu.org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: tnfchris at gcc dot gnu.org @ 2024-02-19 13:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
Tamar Christina <tnfchris at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2024-02-19
Ever confirmed|0 |1
Priority|P3 |P1
CC| |tnfchris at gcc dot gnu.org
--- Comment #1 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
Ah, I missed this. Yeah we've seen it but didn't have time to track down untill
now.
however our CI shows it showed up between
g:ae034b9106fbdd855ec22ce221bb61a1a9a532c3 and
g:3333a064e4925afa1ad5f2f8c1350c4f57d631ce and
g:34d339bbd0c1f5b4ad9587e7ae8387c912cb028b is a target only change so unlikely
to be related.
bisecting.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
2024-01-09 17:43 ` [Bug target/113295] [14 Regression] " pinskia at gcc dot gnu.org
2024-02-19 13:13 ` tnfchris at gcc dot gnu.org
@ 2024-02-21 10:25 ` tnfchris at gcc dot gnu.org
2024-02-21 10:32 ` tnfchris at gcc dot gnu.org
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: tnfchris at gcc dot gnu.org @ 2024-02-21 10:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
--- Comment #2 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
bisected to
commit g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Thu Dec 14 13:46:16 2023 +0000
aarch64: Improve handling of accumulators in early-ra
Being very simplistic, early-ra just models an allocno's live range
as a single interval. This doesn't work well for single-register
accumulators that are updated multiple times in a loop, since in
and it still seems to be miscomparing today.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (2 preceding siblings ...)
2024-02-21 10:25 ` tnfchris at gcc dot gnu.org
@ 2024-02-21 10:32 ` tnfchris at gcc dot gnu.org
2024-02-21 11:07 ` [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a tnfchris at gcc dot gnu.org
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: tnfchris at gcc dot gnu.org @ 2024-02-21 10:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
--- Comment #3 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
I'm however able to reproduce it at -Ofast alone, no need for `-flto`
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (3 preceding siblings ...)
2024-02-21 10:32 ` tnfchris at gcc dot gnu.org
@ 2024-02-21 11:07 ` tnfchris at gcc dot gnu.org
2024-02-21 11:09 ` rsandifo at gcc dot gnu.org
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: tnfchris at gcc dot gnu.org @ 2024-02-21 11:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
Tamar Christina <tnfchris at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords|needs-bisection |
Summary|[14 Regression] SPEC 2006 |[14 Regression] SPEC 2006
|416.gamess miscompares on |416.gamess miscompares on
|Aarch64 when built with |Aarch64 when built with
|-Ofast -march=native -flto |-Ofast -mcpu=native since
| |g:2f46e3578d45ff060a0a329cb
| |39d4f52878f9d5a
--- Comment #4 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
most of the changes seem to be scheduling and register renaming, so I guess one
should compile with scheduling off to reduce the noise a bit.
detinp_ does have a weird transformation where a cluster of csel go missing and
replaced with mov, but the function is too big for me to quickly tell if this
is the issue.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (4 preceding siblings ...)
2024-02-21 11:07 ` [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a tnfchris at gcc dot gnu.org
@ 2024-02-21 11:09 ` rsandifo at gcc dot gnu.org
2024-02-21 18:37 ` rsandifo at gcc dot gnu.org
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rsandifo at gcc dot gnu.org @ 2024-02-21 11:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
Richard Sandiford <rsandifo at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |rsandifo at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #5 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
Mine. Could be the same as PR112922.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (5 preceding siblings ...)
2024-02-21 11:09 ` rsandifo at gcc dot gnu.org
@ 2024-02-21 18:37 ` rsandifo at gcc dot gnu.org
2024-02-23 14:13 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rsandifo at gcc dot gnu.org @ 2024-02-21 18:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
--- Comment #6 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
For me the miscompilation is in jkdmem_, where we end up allocating the same
registers to both arms of an fcsel. It sounds like it occurs elsewhere too.
I have a candidate fix, but need to think a bit more about it.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (6 preceding siblings ...)
2024-02-21 18:37 ` rsandifo at gcc dot gnu.org
@ 2024-02-23 14:13 ` cvs-commit at gcc dot gnu.org
2024-02-23 14:13 ` cvs-commit at gcc dot gnu.org
2024-02-23 14:17 ` rsandifo at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-02-23 14:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Richard Sandiford <rsandifo@gcc.gnu.org>:
https://gcc.gnu.org/g:8a16e06da97f51574cfad17e2cece2e58571305d
commit r14-9155-g8a16e06da97f51574cfad17e2cece2e58571305d
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Fri Feb 23 14:12:54 2024 +0000
aarch64: Add missing early-ra bookkeeping [PR113295]
416.gamess showed up two wrong-code bugs in early-ra. This patch
fixes the first of them. It was difficult to reduce the source code
to something that would meaningfully show the situation, so the
testcase uses a direct RTL sequence instead.
In the sequence:
(a) register <2> is set more than once
(b) register <2> is copied to a temporary (<4>)
(c) register <2> is the destination of an FCSEL between <4> and
another value (<5>)
(d) <4> and <2> are equivalent for <4>'s live range
(e) <5>'s and <2>'s live ranges do not intersect, and there is
a pseudo-copy between <5> and <2>
On its own, (d) implies that <4> can be treated as equivalent to <2>.
And on its own, (e) implies that <5> can share <2>'s register. But
<4>'s and <5>'s live ranges conflict, meaning that they cannot both
share the register together. A bit of missing bookkeeping meant that
the mechanism for detecting this didn't fire. We therefore ended up
with an FCSEL in which both inputs were the same register.
gcc/
PR target/113295
* config/aarch64/aarch64-early-ra.cc
(early_ra::find_related_start): Account for definitions by shared
registers when testing for a single register definition.
(early_ra::accumulate_defs): New function.
(early_ra::record_copy): If A shares B's register, fold A's
definition information into B's. Fold A's use information into
B's.
gcc/testsuite/
PR target/113295
* gcc.dg/rtl/aarch64/pr113295-1.c: New test.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (7 preceding siblings ...)
2024-02-23 14:13 ` cvs-commit at gcc dot gnu.org
@ 2024-02-23 14:13 ` cvs-commit at gcc dot gnu.org
2024-02-23 14:17 ` rsandifo at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-02-23 14:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Richard Sandiford <rsandifo@gcc.gnu.org>:
https://gcc.gnu.org/g:9f105cfdc1bca6c9224384b3044c4ca5894e1e4c
commit r14-9156-g9f105cfdc1bca6c9224384b3044c4ca5894e1e4c
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Fri Feb 23 14:12:55 2024 +0000
aarch64: Tighten early-ra chain test for wide registers [PR113295]
Most code in early-ra used is_chain_candidate to check whether we
should chain two allocnos. This included both tests that matter
for correctness and tests for certain heuristics.
Once that test passes for one pair of allocnos, we test whether
it's safe to chain the containing groups (which might contain
multiple allocnos for x2, x3 and x4 modes). This test used an
inline test for correctness only, deliberately skipping the
heuristics. However, this instance of the test was missing
some handling of equivalent allocnos.
This patch fixes things by making is_chain_candidate take a
strictness parameter: correctness only, or correctness + heuristics.
It then makes the group-chaining test use the correctness version
rather than trying to replicate it inline.
gcc/
PR target/113295
* config/aarch64/aarch64-early-ra.cc
(early_ra::test_strictness): New enum.
(early_ra::is_chain_candidate): Add a strictness parameter to
control whether only correctness matters, or whether both
correctness
and heuristics should be used. Handle multiple levels of
equivalence.
(early_ra::find_related_start): Update call accordingly.
(early_ra::strided_polarity_pref): Likewise.
(early_ra::form_chains): Likewise.
(early_ra::try_to_chain_allocnos): Use is_chain_candidate in
correctness mode rather than trying to inline the test.
gcc/testsuite/
PR target/113295
* gcc.target/aarch64/pr113295-2.c: New test.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/113295] [14 Regression] SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -mcpu=native since g:2f46e3578d45ff060a0a329cb39d4f52878f9d5a
2024-01-09 17:42 [Bug target/113295] New: SPEC 2006 416.gamess miscompares on Aarch64 when built with -Ofast -march=native -flto jamborm at gcc dot gnu.org
` (8 preceding siblings ...)
2024-02-23 14:13 ` cvs-commit at gcc dot gnu.org
@ 2024-02-23 14:17 ` rsandifo at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: rsandifo at gcc dot gnu.org @ 2024-02-23 14:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113295
Richard Sandiford <rsandifo at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
--- Comment #9 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 11+ messages in thread
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