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* [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
@ 2023-12-20 18:35 craig.topper at gmail dot com
2023-12-20 18:38 ` [Bug target/113095] " pinskia at gcc dot gnu.org
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: craig.topper at gmail dot com @ 2023-12-20 18:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
Bug ID: 113095
Summary: RISC-V: movcc no longer used for coremark crc
functions with -mtune=sifive-7-series
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: craig.topper at gmail dot com
Target Milestone: ---
In gcc 12, the crc functions in coremark used the "movcc" macrofusion pattern
of a branch over a single mv. In gcc 13, a longer branchless sequence is used.
https://godbolt.org/z/9xvcxo5Y9
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
@ 2023-12-20 18:38 ` pinskia at gcc dot gnu.org
2023-12-20 18:46 ` craig.topper at gmail dot com
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-12-20 18:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
What is the cost of the movcc here? IIRC this is really dependent on the cost
model in the backend?
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
2023-12-20 18:38 ` [Bug target/113095] " pinskia at gcc dot gnu.org
@ 2023-12-20 18:46 ` craig.topper at gmail dot com
2023-12-20 18:47 ` craig.topper at gmail dot com
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: craig.topper at gmail dot com @ 2023-12-20 18:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
--- Comment #2 from Craig Topper <craig.topper at gmail dot com> ---
The branch+mv macrofusion should execute together. The visible latency to other
instructions is 1 cycle.
The hardware can predicate most ALU instructions, not just mv. So even better
would be putting the xor after the branch instead of a mv.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
2023-12-20 18:38 ` [Bug target/113095] " pinskia at gcc dot gnu.org
2023-12-20 18:46 ` craig.topper at gmail dot com
@ 2023-12-20 18:47 ` craig.topper at gmail dot com
2023-12-20 18:50 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: craig.topper at gmail dot com @ 2023-12-20 18:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
--- Comment #3 from Craig Topper <craig.topper at gmail dot com> ---
Our FPGA data is showing this as a 5% regression. I'll try to check on an
Unmatched board to confirm.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
` (2 preceding siblings ...)
2023-12-20 18:47 ` craig.topper at gmail dot com
@ 2023-12-20 18:50 ` pinskia at gcc dot gnu.org
2024-01-24 17:20 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-12-20 18:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Anyways this was introduced by r13-4459-g6508d5e5a1a8c0
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
` (3 preceding siblings ...)
2023-12-20 18:50 ` pinskia at gcc dot gnu.org
@ 2024-01-24 17:20 ` cvs-commit at gcc dot gnu.org
2024-01-30 7:44 ` [Bug target/113095] [13 Regression] " pinskia at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-01-24 17:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jeff Law <law@gcc.gnu.org>:
https://gcc.gnu.org/g:fb54b9772816968032518d4008be5090e0d95109
commit r14-8396-gfb54b9772816968032518d4008be5090e0d95109
Author: Monk Chiang <monk.chiang@sifive.com>
Date: Wed Jan 24 10:19:28 2024 -0700
[PATCH v3] RISC-V: Add split pattern to generate SFB instructions.
[PR113095]
Since the match.pd transforms (zero_one == 0) ? y : z <op> y,
into ((typeof(y))zero_one * z) <op> y. Add splitters to recongize
this expression to generate SFB instructions.
gcc/ChangeLog:
PR target/113095
* config/riscv/sfb.md: New splitters to rewrite single bit
sign extension as the condition to SFB instructions.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/sfb.c: New test.
* gcc.target/riscv/pr113095.c: New test.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] [13 Regression] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
` (4 preceding siblings ...)
2024-01-24 17:20 ` cvs-commit at gcc dot gnu.org
@ 2024-01-30 7:44 ` pinskia at gcc dot gnu.org
2024-04-30 9:13 ` cvs-commit at gcc dot gnu.org
2024-04-30 9:21 ` kito at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-01-30 7:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |13.3
Known to work| |14.0
Summary|RISC-V: movcc no longer |[13 Regression] RISC-V:
|used for coremark crc |movcc no longer used for
|functions with |coremark crc functions with
|-mtune=sifive-7-series |-mtune=sifive-7-series
Ever confirmed|0 |1
Last reconfirmed| |2024-01-30
Status|UNCONFIRMED |NEW
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] [13 Regression] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
` (5 preceding siblings ...)
2024-01-30 7:44 ` [Bug target/113095] [13 Regression] " pinskia at gcc dot gnu.org
@ 2024-04-30 9:13 ` cvs-commit at gcc dot gnu.org
2024-04-30 9:21 ` kito at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-04-30 9:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Kito Cheng <kito@gcc.gnu.org>:
https://gcc.gnu.org/g:6335baaf31c0f1f0952d1a3f507b0e5655b1136f
commit r13-8663-g6335baaf31c0f1f0952d1a3f507b0e5655b1136f
Author: Monk Chiang <monk.chiang@sifive.com>
Date: Wed Jan 24 10:19:28 2024 -0700
[PATCH v3] RISC-V: Add split pattern to generate SFB instructions.
[PR113095]
Since the match.pd transforms (zero_one == 0) ? y : z <op> y,
into ((typeof(y))zero_one * z) <op> y. Add splitters to recongize
this expression to generate SFB instructions.
gcc/ChangeLog:
PR target/113095
* config/riscv/riscv.md: New splitters to rewrite single bit
sign extension as the condition to SFB instructions.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/sfb.c: New test.
* gcc.target/riscv/pr113095.c: New test.
(cherry picked from commit fb54b9772816968032518d4008be5090e0d95109)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/113095] [13 Regression] RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series
2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
` (6 preceding siblings ...)
2024-04-30 9:13 ` cvs-commit at gcc dot gnu.org
@ 2024-04-30 9:21 ` kito at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: kito at gcc dot gnu.org @ 2024-04-30 9:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113095
Kito Cheng <kito at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #8 from Kito Cheng <kito at gcc dot gnu.org> ---
Fixed on both trunk and GCC 13
^ permalink raw reply [flat|nested] 9+ messages in thread
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2023-12-20 18:35 [Bug target/113095] New: RISC-V: movcc no longer used for coremark crc functions with -mtune=sifive-7-series craig.topper at gmail dot com
2023-12-20 18:38 ` [Bug target/113095] " pinskia at gcc dot gnu.org
2023-12-20 18:46 ` craig.topper at gmail dot com
2023-12-20 18:47 ` craig.topper at gmail dot com
2023-12-20 18:50 ` pinskia at gcc dot gnu.org
2024-01-24 17:20 ` cvs-commit at gcc dot gnu.org
2024-01-30 7:44 ` [Bug target/113095] [13 Regression] " pinskia at gcc dot gnu.org
2024-04-30 9:13 ` cvs-commit at gcc dot gnu.org
2024-04-30 9:21 ` kito at gcc dot gnu.org
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