[Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor

2023-02-17 Thread pinskia at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692

--- Comment #4 from Andrew Pinski  ---
(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

[Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor

2023-02-17 Thread gabravier at gmail dot com via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692

--- Comment #3 from Gabriel Ravier  ---
This seems to be fixed on trunk now, I think ?

[Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor

2022-07-05 Thread cvs-commit at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692

--- Comment #2 from CVS Commits  ---
The master branch has been updated by Roger Sayle :

https://gcc.gnu.org/g:d458c53a6f37c8c49aa854d12e6867b4d914555f

commit r13-1507-gd458c53a6f37c8c49aa854d12e6867b4d914555f
Author: Roger Sayle 
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  
Uroš Bizjak  

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.

[Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor

2020-08-25 Thread rguenth at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692

Richard Biener  changed:

   What|Removed |Added

   Last reconfirmed||2020-08-25
 Ever confirmed|0   |1
 Status|UNCONFIRMED |NEW

[Bug rtl-optimization/96692] Failure to optimize xor+or+xor to andnot+xor

2020-08-18 Thread pinskia at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96692

Andrew Pinski  changed:

   What|Removed |Added

   Severity|normal  |enhancement
  Component|tree-optimization   |rtl-optimization

--- Comment #1 from Andrew Pinski  ---
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.