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* [Bug rtl-optimization/115505] New: missing optimization: thumb1 use ldmia/stmia for load store DI/DF data when possible
@ 2024-06-15 13:51 lis8215 at gmail dot com
2024-06-15 15:10 ` [Bug rtl-optimization/115505] " pinskia at gcc dot gnu.org
2024-06-15 20:35 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: lis8215 at gmail dot com @ 2024-06-15 13:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115505
Bug ID: 115505
Summary: missing optimization: thumb1 use ldmia/stmia for load
store DI/DF data when possible
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: lis8215 at gmail dot com
Target Milestone: ---
Created attachment 58438
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58438&action=edit
possible solution patch
At the moment GCC emits two ldr/str instructions for DI/DF modes load/store.
However there's a trick to use ldmia/stmia when address register in not
used anymore/dead or reused.
I don't know if it affects arm and/or thumb2 as well.
Patch for possible solution for thumb1 provided.
Comparing code size with the patch gives for v6-m/nofp:
libgcc: -52 bytes / -0.10%
Newlib's libc: -68 bytes / -0.03%
libm: -96 bytes / -0.10%
libstdc++: -140 bytes / -0.02%
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug rtl-optimization/115505] missing optimization: thumb1 use ldmia/stmia for load store DI/DF data when possible
2024-06-15 13:51 [Bug rtl-optimization/115505] New: missing optimization: thumb1 use ldmia/stmia for load store DI/DF data when possible lis8215 at gmail dot com
@ 2024-06-15 15:10 ` pinskia at gcc dot gnu.org
2024-06-15 20:35 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-15 15:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115505
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note patches should be posted to gcc-patches@ after reading
https://gcc.gnu.org/contribute.html .
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug rtl-optimization/115505] missing optimization: thumb1 use ldmia/stmia for load store DI/DF data when possible
2024-06-15 13:51 [Bug rtl-optimization/115505] New: missing optimization: thumb1 use ldmia/stmia for load store DI/DF data when possible lis8215 at gmail dot com
2024-06-15 15:10 ` [Bug rtl-optimization/115505] " pinskia at gcc dot gnu.org
@ 2024-06-15 20:35 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-06-15 20:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115505
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-06-15 13:51 [Bug rtl-optimization/115505] New: missing optimization: thumb1 use ldmia/stmia for load store DI/DF data when possible lis8215 at gmail dot com
2024-06-15 15:10 ` [Bug rtl-optimization/115505] " pinskia at gcc dot gnu.org
2024-06-15 20:35 ` pinskia at gcc dot gnu.org
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