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* [Bug rtl-optimization/109019] New: Failure to optimize b + c -1
@ 2023-03-03 23:49 tkoenig at gcc dot gnu.org
2023-03-03 23:57 ` [Bug rtl-optimization/109019] " jakub at gcc dot gnu.org
2023-03-04 0:01 ` tkoenig at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2023-03-03 23:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109019
Bug ID: 109019
Summary: Failure to optimize b + c -1
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: tkoenig at gcc dot gnu.org
Target Milestone: ---
Looks like a general RTL issue, I see this on POWER, RV64 and ARM64 (the
latter two on godbolt).
[tkoenig@gcc135 ~]$ cat c.c
long foo (long b, long c)
{
return b + c - 1;
}
[tkoenig@gcc135 ~]$ gcc -O3 -S c.c
[tkoenig@gcc135 ~]$ cat c.s
.file "c.c"
.machine power8
.abiversion 2
.section ".text"
.align 2
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
add 3,3,4
addi 3,3,-1
blr
.long 0
.byte 0,0,0,0,0,0,0,0
.cfi_endproc
.LFE0:
.size foo,.-foo
.ident "GCC: (GNU) 13.0.1 20230215 (experimental)"
.section .note.GNU-stack,"",@progbits
This should be
addi 3,4,-1
ret
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug rtl-optimization/109019] Failure to optimize b + c -1
2023-03-03 23:49 [Bug rtl-optimization/109019] New: Failure to optimize b + c -1 tkoenig at gcc dot gnu.org
@ 2023-03-03 23:57 ` jakub at gcc dot gnu.org
2023-03-04 0:01 ` tkoenig at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: jakub at gcc dot gnu.org @ 2023-03-03 23:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109019
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
How could it?
addi 3,4,-1
blr
would be return c - 1; rather than return b + c - 1;
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug rtl-optimization/109019] Failure to optimize b + c -1
2023-03-03 23:49 [Bug rtl-optimization/109019] New: Failure to optimize b + c -1 tkoenig at gcc dot gnu.org
2023-03-03 23:57 ` [Bug rtl-optimization/109019] " jakub at gcc dot gnu.org
@ 2023-03-04 0:01 ` tkoenig at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2023-03-04 0:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109019
Thomas Koenig <tkoenig at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Urgh,too late in the evening, I guess. Sorry for the noise.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-03-04 0:01 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2023-03-03 23:49 [Bug rtl-optimization/109019] New: Failure to optimize b + c -1 tkoenig at gcc dot gnu.org
2023-03-03 23:57 ` [Bug rtl-optimization/109019] " jakub at gcc dot gnu.org
2023-03-04 0:01 ` tkoenig at gcc dot gnu.org
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