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* [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg
@ 2023-06-02 10:26 gjl at gcc dot gnu.org
2023-06-02 10:27 ` [Bug target/110088] " gjl at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2023-06-02 10:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110088
Bug ID: 110088
Summary: [avr] Improve operation with const on l-reg after move
from d-reg
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: gjl at gcc dot gnu.org
Target Milestone: ---
The register allocator might generate code that moves a value from a d-reg to
an l-reg, and then performs operation like PLUS, IOR, AND with a constant. So
we have a sequence like:
lreg = dreg
lreg = lreg <op> const
This is expensive because lreg cannot handle const and needs a QI scratch to
load bytes of const. Instead, if dreg dies after the first insn, better code
is:
dreg = dreg <op> const
lreg = dreg
An RTL peephole can catch this.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/110088] [avr] Improve operation with const on l-reg after move from d-reg
2023-06-02 10:26 [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg gjl at gcc dot gnu.org
@ 2023-06-02 10:27 ` gjl at gcc dot gnu.org
2023-06-02 10:42 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2023-06-02 10:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110088
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |avr
Keywords| |missed-optimization
Priority|P3 |P5
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/110088] [avr] Improve operation with const on l-reg after move from d-reg
2023-06-02 10:26 [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg gjl at gcc dot gnu.org
2023-06-02 10:27 ` [Bug target/110088] " gjl at gcc dot gnu.org
@ 2023-06-02 10:42 ` cvs-commit at gcc dot gnu.org
2023-06-02 10:55 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-06-02 10:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110088
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Georg-Johann Lay <gjl@gcc.gnu.org>:
https://gcc.gnu.org/g:7bf89a919fdab9e18b7ad3efaa1a79f1d7520ddf
commit r14-1492-g7bf89a919fdab9e18b7ad3efaa1a79f1d7520ddf
Author: Georg-Johann Lay <avr@gjlay.de>
Date: Fri Jun 2 12:41:07 2023 +0200
target/110088: Improve operation of l-reg with const after move from d-reg.
After reload, there may be sequences like
lreg = dreg
lreg = lreg <op> const
with an LD_REGS dreg, non-LD_REGS lreg, and <op> in PLUS, IOR, AND.
If dreg dies after the first insn, it is possible to use
dreg = dreg <op> const
lreg = dreg
instead which is more efficient.
gcc/
PR target/110088
* config/avr/avr.md: Add an RTL peephole to optimize operations on
non-LD_REGS after a move from LD_REGS.
(piaop): New code iterator.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/110088] [avr] Improve operation with const on l-reg after move from d-reg
2023-06-02 10:26 [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg gjl at gcc dot gnu.org
2023-06-02 10:27 ` [Bug target/110088] " gjl at gcc dot gnu.org
2023-06-02 10:42 ` cvs-commit at gcc dot gnu.org
@ 2023-06-02 10:55 ` cvs-commit at gcc dot gnu.org
2023-06-02 11:02 ` cvs-commit at gcc dot gnu.org
2023-06-02 11:03 ` gjl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-06-02 10:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110088
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Georg-Johann Lay
<gjl@gcc.gnu.org>:
https://gcc.gnu.org/g:7cbaf2f96ec884d60e02d5d2a8a2f44ae0d390fd
commit r13-7408-g7cbaf2f96ec884d60e02d5d2a8a2f44ae0d390fd
Author: Georg-Johann Lay <avr@gjlay.de>
Date: Fri Jun 2 12:41:07 2023 +0200
target/110088: Improve operation of l-reg with const after move from d-reg.
After reload, there may be sequences like
lreg = dreg
lreg = lreg <op> const
with an LD_REGS dreg, non-LD_REGS lreg, and <op> in PLUS, IOR, AND.
If dreg dies after the first insn, it is possible to use
dreg = dreg <op> const
lreg = dreg
instead which is more efficient.
gcc/
PR target/110088
* config/avr/avr.md: Add an RTL peephole to optimize operations on
non-LD_REGS after a move from LD_REGS.
(piaop): New code iterator.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/110088] [avr] Improve operation with const on l-reg after move from d-reg
2023-06-02 10:26 [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg gjl at gcc dot gnu.org
` (2 preceding siblings ...)
2023-06-02 10:55 ` cvs-commit at gcc dot gnu.org
@ 2023-06-02 11:02 ` cvs-commit at gcc dot gnu.org
2023-06-02 11:03 ` gjl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-06-02 11:02 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110088
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Georg-Johann Lay
<gjl@gcc.gnu.org>:
https://gcc.gnu.org/g:6f8e64989c2418bb8a4050fc1f50039a7b9a0225
commit r12-9674-g6f8e64989c2418bb8a4050fc1f50039a7b9a0225
Author: Georg-Johann Lay <avr@gjlay.de>
Date: Fri Jun 2 12:41:07 2023 +0200
target/110088: Improve operation of l-reg with const after move from d-reg.
After reload, there may be sequences like
lreg = dreg
lreg = lreg <op> const
with an LD_REGS dreg, non-LD_REGS lreg, and <op> in PLUS, IOR, AND.
If dreg dies after the first insn, it is possible to use
dreg = dreg <op> const
lreg = dreg
instead which is more efficient.
gcc/
PR target/110088
* config/avr/avr.md: Add an RTL peephole to optimize operations on
non-LD_REGS after a move from LD_REGS.
(piaop): New code iterator.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/110088] [avr] Improve operation with const on l-reg after move from d-reg
2023-06-02 10:26 [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg gjl at gcc dot gnu.org
` (3 preceding siblings ...)
2023-06-02 11:02 ` cvs-commit at gcc dot gnu.org
@ 2023-06-02 11:03 ` gjl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2023-06-02 11:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110088
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|UNCONFIRMED |RESOLVED
--- Comment #4 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Fixed in v12.4 and v13.2+.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2023-06-02 10:26 [Bug target/110088] New: [avr] Improve operation with const on l-reg after move from d-reg gjl at gcc dot gnu.org
2023-06-02 10:27 ` [Bug target/110088] " gjl at gcc dot gnu.org
2023-06-02 10:42 ` cvs-commit at gcc dot gnu.org
2023-06-02 10:55 ` cvs-commit at gcc dot gnu.org
2023-06-02 11:02 ` cvs-commit at gcc dot gnu.org
2023-06-02 11:03 ` gjl at gcc dot gnu.org
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