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* [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code
@ 2021-05-27 10:39 pinskia at gcc dot gnu.org
2023-05-20 2:25 ` [Bug middle-end/100798] " pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-05-27 10:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100798
Bug ID: 100798
Summary: a?~t:t and (-(!!a))^t don't produce the same assembly
code
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
While working on non GCC code, I notice these two functions don't produce the
assembly code:
int f(int a, int t)
{
return (a=='s' ? ~t : t);
}
int f1(int a, int t)
{
int t1 = -(a=='s');
return (t1 ^ t);
}
For aarch64, the first case produce the best, while on x86_64, I don't know
which is better, sete or cmov.
Note LLVM produces the same code for both, for aarch64, the csinv and
sete/neg/xor for x86_64.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/100798] a?~t:t and (-(!!a))^t don't produce the same assembly code
2021-05-27 10:39 [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code pinskia at gcc dot gnu.org
@ 2023-05-20 2:25 ` pinskia at gcc dot gnu.org
2023-08-07 19:04 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-05-20 2:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100798
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
To produce the same code we could do a match pattern:
(simplify
(cond @0 (bit_not @1) @1)
(bit_xor (neg (convert @0)) @1))
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/100798] a?~t:t and (-(!!a))^t don't produce the same assembly code
2021-05-27 10:39 [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code pinskia at gcc dot gnu.org
2023-05-20 2:25 ` [Bug middle-end/100798] " pinskia at gcc dot gnu.org
@ 2023-08-07 19:04 ` pinskia at gcc dot gnu.org
2023-08-08 0:55 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-07 19:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100798
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org
Ever confirmed|0 |1
Last reconfirmed| |2023-08-07
Status|UNCONFIRMED |ASSIGNED
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/100798] a?~t:t and (-(!!a))^t don't produce the same assembly code
2021-05-27 10:39 [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code pinskia at gcc dot gnu.org
2023-05-20 2:25 ` [Bug middle-end/100798] " pinskia at gcc dot gnu.org
2023-08-07 19:04 ` pinskia at gcc dot gnu.org
@ 2023-08-08 0:55 ` pinskia at gcc dot gnu.org
2023-08-09 19:22 ` cvs-commit at gcc dot gnu.org
2023-08-09 19:27 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-08 0:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100798
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch posted:
https://gcc.gnu.org/pipermail/gcc-patches/2023-August/626580.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/100798] a?~t:t and (-(!!a))^t don't produce the same assembly code
2021-05-27 10:39 [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code pinskia at gcc dot gnu.org
` (2 preceding siblings ...)
2023-08-08 0:55 ` pinskia at gcc dot gnu.org
@ 2023-08-09 19:22 ` cvs-commit at gcc dot gnu.org
2023-08-09 19:27 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-08-09 19:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100798
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:
https://gcc.gnu.org/g:7fb65f102851248bafa0815401d8bdcea6d7626c
commit r14-3110-g7fb65f102851248bafa0815401d8bdcea6d7626c
Author: Andrew Pinski <apinski@marvell.com>
Date: Mon Aug 7 10:47:09 2023 -0700
MATCH: [PR110937/PR100798] (a ? ~b : b) should be optimized to b ^ -(a)
This adds a simple match pattern for this case.
I noticed it a couple of different places.
One while I was looking at code generation of a parser and
also while I was looking at locations where bitwise_inverted_equal_p
should be used more.
Committed as approved after bootstrapped and tested on x86_64-linux-gnu
with no regressions.
PR tree-optimization/110937
PR tree-optimization/100798
gcc/ChangeLog:
* match.pd (`a ? ~b : b`): Handle this
case.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/bool-14.c: New test.
* gcc.dg/tree-ssa/bool-15.c: New test.
* gcc.dg/tree-ssa/phi-opt-33.c: New test.
* gcc.dg/tree-ssa/20030709-2.c: Update testcase
so `a ? -1 : 0` is not used to hit the match
pattern.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/100798] a?~t:t and (-(!!a))^t don't produce the same assembly code
2021-05-27 10:39 [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code pinskia at gcc dot gnu.org
` (3 preceding siblings ...)
2023-08-09 19:22 ` cvs-commit at gcc dot gnu.org
@ 2023-08-09 19:27 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-08-09 19:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100798
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
Target Milestone|--- |14.0
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-05-27 10:39 [Bug middle-end/100798] New: a?~t:t and (-(!!a))^t don't produce the same assembly code pinskia at gcc dot gnu.org
2023-05-20 2:25 ` [Bug middle-end/100798] " pinskia at gcc dot gnu.org
2023-08-07 19:04 ` pinskia at gcc dot gnu.org
2023-08-08 0:55 ` pinskia at gcc dot gnu.org
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