* [Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor
2020-08-18 21:37 [Bug tree-optimization/96692] New: Failure to optimize xor+or+xor to andnot+xor gabravier at gmail dot com
@ 2020-08-18 22:12 ` pinskia at gcc dot gnu.org
2020-08-25 10:52 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2020-08-18 22:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Component|tree-optimization |rtl-optimization
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This transformation should only happen if there is an andnot instruction.
For an example if there is no andnot instruction, there will be 3 dependent
instruction while in the first case, there are two independent instructions
followed by one dependent ones.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor
2020-08-18 21:37 [Bug tree-optimization/96692] New: Failure to optimize xor+or+xor to andnot+xor gabravier at gmail dot com
2020-08-18 22:12 ` [Bug rtl-optimization/96692] " pinskia at gcc dot gnu.org
@ 2020-08-25 10:52 ` rguenth at gcc dot gnu.org
2022-07-05 16:57 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-08-25 10:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2020-08-25
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor
2020-08-18 21:37 [Bug tree-optimization/96692] New: Failure to optimize xor+or+xor to andnot+xor gabravier at gmail dot com
2020-08-18 22:12 ` [Bug rtl-optimization/96692] " pinskia at gcc dot gnu.org
2020-08-25 10:52 ` rguenth at gcc dot gnu.org
@ 2022-07-05 16:57 ` cvs-commit at gcc dot gnu.org
2023-02-18 2:01 ` gabravier at gmail dot com
2023-02-18 2:04 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-07-05 16:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Roger Sayle <sayle@gcc.gnu.org>:
https://gcc.gnu.org/g:d458c53a6f37c8c49aa854d12e6867b4d914555f
commit r13-1507-gd458c53a6f37c8c49aa854d12e6867b4d914555f
Author: Roger Sayle <roger@nextmovesoftware.com>
Date: Tue Jul 5 17:55:53 2022 +0100
PR rtl-optimization/96692: ((A|B)^C)^A using andn with -mbmi on x86.
This patch addresses PR rtl-optimization/96692 on x86_64, by providing
a set of combine splitters to convert the three operation ((A|B)^C)^D
into a two operation sequence using andn when either A or B is the same
register as C or D. This is essentially a reassociation problem that's
only a win if the target supports an and-not instruction (as with -mbmi).
Hence for the new test case:
int f(int a, int b, int c)
{
return (a ^ b) ^ (a | c);
}
GCC on x86_64-pc-linux-gnu wth -O2 -mbmi would previously generate:
xorl %edi, %esi
orl %edx, %edi
movl %esi, %eax
xorl %edi, %eax
ret
but with this patch now generates:
andn %edx, %edi, %eax
xorl %esi, %eax
ret
2022-07-05 Roger Sayle <roger@nextmovesoftware.com>
Uroš Bizjak <ubizjak@gmail.com>
gcc/ChangeLog
PR rtl-optimization/96692
* config/i386/i386.md (define_split): Split ((A | B) ^ C) ^ D
as (X & ~Y) ^ Z on target BMI when either C or D is A or B.
gcc/testsuite/ChangeLog
PR rtl-optimization/96692
* gcc.target/i386/bmi-andn-4.c: New test case.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor
2020-08-18 21:37 [Bug tree-optimization/96692] New: Failure to optimize xor+or+xor to andnot+xor gabravier at gmail dot com
` (2 preceding siblings ...)
2022-07-05 16:57 ` cvs-commit at gcc dot gnu.org
@ 2023-02-18 2:01 ` gabravier at gmail dot com
2023-02-18 2:04 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: gabravier at gmail dot com @ 2023-02-18 2:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692
--- Comment #3 from Gabriel Ravier <gabravier at gmail dot com> ---
This seems to be fixed on trunk now, I think ?
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor
2020-08-18 21:37 [Bug tree-optimization/96692] New: Failure to optimize xor+or+xor to andnot+xor gabravier at gmail dot com
` (3 preceding siblings ...)
2023-02-18 2:01 ` gabravier at gmail dot com
@ 2023-02-18 2:04 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-02-18 2:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Gabriel Ravier from comment #3)
> This seems to be fixed on trunk now, I think ?
On x86_64-linux-gnu yes but on aarch64 it is not optimized just yet:
f(int, int, int):
eor w1, w0, w1
orr w0, w0, w2
eor w0, w1, w0
ret
f1(int, int, int):
bic w0, w2, w0
eor w0, w0, w1
ret
^ permalink raw reply [flat|nested] 6+ messages in thread