* [Bug c/94889] Negate function not getting optimised to negate call
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
@ 2020-04-30 14:42 ` gabravier at gmail dot com
2020-04-30 14:52 ` [Bug c/94889] Negate function not getting optimised to bitwise not satanichiya at waifu dot club
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: gabravier at gmail dot com @ 2020-04-30 14:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
Gabriel Ravier <gabravier at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |gabravier at gmail dot com
--- Comment #1 from Gabriel Ravier <gabravier at gmail dot com> ---
For some reason, I can reproduce this, but only if `-mavx2` is not present.
Having AVX2 enabled somehow ends up makes it so this is optimized to a `return
~x`.
(Also, this means that it is a bitwise not and not a negate that this should
optimize down to)
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug c/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
2020-04-30 14:42 ` [Bug c/94889] " gabravier at gmail dot com
@ 2020-04-30 14:52 ` satanichiya at waifu dot club
2020-04-30 14:57 ` satanichiya at waifu dot club
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: satanichiya at waifu dot club @ 2020-04-30 14:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
--- Comment #2 from Gooby <satanichiya at waifu dot club> ---
Meant to say NOT, excuse me
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug c/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
2020-04-30 14:42 ` [Bug c/94889] " gabravier at gmail dot com
2020-04-30 14:52 ` [Bug c/94889] Negate function not getting optimised to bitwise not satanichiya at waifu dot club
@ 2020-04-30 14:57 ` satanichiya at waifu dot club
2020-04-30 15:14 ` gabravier at gmail dot com
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From: satanichiya at waifu dot club @ 2020-04-30 14:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
--- Comment #3 from Gooby <satanichiya at waifu dot club> ---
Meant to say NOT, excuse me
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug c/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
` (2 preceding siblings ...)
2020-04-30 14:57 ` satanichiya at waifu dot club
@ 2020-04-30 15:14 ` gabravier at gmail dot com
2020-04-30 19:50 ` [Bug tree-optimization/94889] " pinskia at gcc dot gnu.org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: gabravier at gmail dot com @ 2020-04-30 15:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
--- Comment #4 from Gabriel Ravier <gabravier at gmail dot com> ---
Investigated it a bit.
It looks like with `-mavx2` the pcom pass decides to vectorize the loop, and it
then later gets mowed down into a `~`.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
` (3 preceding siblings ...)
2020-04-30 15:14 ` gabravier at gmail dot com
@ 2020-04-30 19:50 ` pinskia at gcc dot gnu.org
2020-05-01 7:04 ` schwab@linux-m68k.org
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From: pinskia at gcc dot gnu.org @ 2020-04-30 19:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Severity|normal |enhancement
Component|c |tree-optimization
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
` (4 preceding siblings ...)
2020-04-30 19:50 ` [Bug tree-optimization/94889] " pinskia at gcc dot gnu.org
@ 2020-05-01 7:04 ` schwab@linux-m68k.org
2021-08-22 0:25 ` pinskia at gcc dot gnu.org
2023-10-12 3:46 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: schwab@linux-m68k.org @ 2020-05-01 7:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
--- Comment #5 from Andreas Schwab <schwab@linux-m68k.org> ---
Note that 1<<31 is undefined.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
` (5 preceding siblings ...)
2020-05-01 7:04 ` schwab@linux-m68k.org
@ 2021-08-22 0:25 ` pinskia at gcc dot gnu.org
2023-10-12 3:46 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-22 0:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-08-22
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
Note two related testcases:
int negone(int x)
{
for(int i=0;i<sizeof(int)*8;i++)
{
x |= (int)1<<i;
}
return x;
}
int zero(int x)
{
for(int i=0;i<sizeof(int)*8;i++)
{
x &= (int)1<<i;
}
return x;
}
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/94889] Negate function not getting optimised to bitwise not
2020-04-30 14:32 [Bug c/94889] New: Negate function not getting optimised to negate call satanichiya at waifu dot club
` (6 preceding siblings ...)
2021-08-22 0:25 ` pinskia at gcc dot gnu.org
@ 2023-10-12 3:46 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-10-12 3:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94889
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
Target Milestone|--- |13.0
--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
final value replacement:
x_11 = PHI <x_7(3)>
with expr: ~x_4(D)
final stmt:
x_11 = ~x_4(D);
All fixed in GCC 13 for all 3 testcases even.
^ permalink raw reply [flat|nested] 9+ messages in thread