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* [Bug target/100266] New: [RISCV] Provide programmatic implementation of CAS
@ 2021-04-26 12:14 christophm30 at gmail dot com
2021-04-26 12:47 ` [Bug target/100266] " christophm30 at gmail dot com
2021-05-06 1:20 ` cvs-commit at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: christophm30 at gmail dot com @ 2021-04-26 12:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100266
Bug ID: 100266
Summary: [RISCV] Provide programmatic implementation of CAS
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: christophm30 at gmail dot com
Target Milestone: ---
At the moment CAS is implemented in form of a hard-coded sequence in sync.md.
When implementing this in a programmatic way (i.e. in riscv.c) we can make this
code much more maintainable. Moving this into C-code also allows to properly
emit the proper fences for ensuring the required memory ordering.
To do so we need to basically do the following:
* model LR and SC INSNs
* implement riscv_expand_compare_and_swap () in riscv.c
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/100266] [RISCV] Provide programmatic implementation of CAS
2021-04-26 12:14 [Bug target/100266] New: [RISCV] Provide programmatic implementation of CAS christophm30 at gmail dot com
@ 2021-04-26 12:47 ` christophm30 at gmail dot com
2021-05-06 1:20 ` cvs-commit at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: christophm30 at gmail dot com @ 2021-04-26 12:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100266
--- Comment #1 from Christoph M. <christophm30 at gmail dot com> ---
A patchset to resolve this can be found here:
https://gcc.gnu.org/pipermail/gcc-patches/2021-April/568684.html
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/100266] [RISCV] Provide programmatic implementation of CAS
2021-04-26 12:14 [Bug target/100266] New: [RISCV] Provide programmatic implementation of CAS christophm30 at gmail dot com
2021-04-26 12:47 ` [Bug target/100266] " christophm30 at gmail dot com
@ 2021-05-06 1:20 ` cvs-commit at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-05-06 1:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100266
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jim Wilson <wilson@gcc.gnu.org>:
https://gcc.gnu.org/g:e1fcf14f33e4f371aae8ae497ca58a760d53ca6d
commit r12-527-ge1fcf14f33e4f371aae8ae497ca58a760d53ca6d
Author: Christoph Muellner <cmuellner@gcc.gnu.org>
Date: Wed May 5 21:23:41 2021 +0200
RISC-V: Generate helpers for cbranch4.
On RISC-V we are facing the fact, that our conditional branches
require Pmode conditions. Currently, we generate them explicitly
with a check for Pmode and then calling the proper generator
(i.e. gen_cbranchdi4 on RV64 and gen_cbranchsi4 on RV32).
Let's simplify this code by generating the INSN helpers
and use gen_cbranch4 (Pmode).
gcc/
PR target/100266
* config/riscv/riscv.c (riscv_block_move_loop): Use cbranch helper.
* config/riscv/riscv.md (cbranch<mode>4): Generate helpers.
(stack_protect_test): Use cbranch helper.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-04-26 12:14 [Bug target/100266] New: [RISCV] Provide programmatic implementation of CAS christophm30 at gmail dot com
2021-04-26 12:47 ` [Bug target/100266] " christophm30 at gmail dot com
2021-05-06 1:20 ` cvs-commit at gcc dot gnu.org
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