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* [Bug target/109657] New: (a ? -1 : 0) | b could be optimized better for aarch64
@ 2023-04-27 22:47 pinskia at gcc dot gnu.org
2023-04-28 5:07 ` [Bug target/109657] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-04-27 22:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109657
Bug ID: 109657
Summary: (a ? -1 : 0) | b could be optimized better for aarch64
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P3
Component: target
Assignee: pinskia at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Target: aarch64-*-*
Take (at -O2):
```
unsigned b(unsigned a, unsigned b){
if(b){
return -1;
}
return a;
}
unsigned b1(unsigned a, unsigned b){
unsigned t = b ? -1 : 0;
return a | t;
}
```
Right now we produce:
```
b:
cmp w1, 0
csinv w0, w0, wzr, eq
ret
b1:
cmp w1, 0
csetm w1, ne
orr w0, w1, w0
ret
```
We can help combine here by adding a pattern for:
(set (reg/i:SI 0 x0)
(ior:SI (neg:SI (ne:SI (reg:CC 66 cc)
(const_int 0 [0])))
(reg:SI 102)))
Which is the same as
(set (reg/i:SI 0 x0)
(if_then_else:SI (eq (reg:CC 66 cc)
(const_int 0 [0]))
(reg:SI 97)
(const_int -1 [0xffffffffffffffff])))
pattern.
I suspect both are considered canonical too.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/109657] (a ? -1 : 0) | b could be optimized better for aarch64
2023-04-27 22:47 [Bug target/109657] New: (a ? -1 : 0) | b could be optimized better for aarch64 pinskia at gcc dot gnu.org
@ 2023-04-28 5:07 ` pinskia at gcc dot gnu.org
2023-04-28 23:35 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-04-28 5:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109657
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Ever confirmed|0 |1
Last reconfirmed| |2023-04-28
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 022eef80bc1..5109e8abdbe 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -4203,6 +4203,30 @@ (define_insn "*cmovsi_insn_uxtw"
[(set_attr "type" "csel, csel, csel, csel, csel, mov_imm, mov_imm")]
)
+;; Convert -(cmp) | a into cmp ? -1 : a to be canonical in the backend.
+;;(set (reg/i:SI 0 x0)
+;; (ior:SI (neg:SI (ne:SI (reg:CC 66 cc)
+;; (const_int 0 [0])))
+;; (reg:SI 102)))
+
+
+(define_insn_and_split "*cmov<mode>_insn_m1"
+ [(set (match_operand:GPI 0 "register_operand" "=r")
+ (ior:GPI
+ (neg:GPI
+ (match_operator:GPI 1 "aarch64_comparison_operator"
+ [(match_operand 2 "cc_register" "") (const_int 0)]))
+ (match_operand 3 "register_operand" "r")))]
+ ""
+ "#"
+ "&& true"
+ [(set (match_dup 0)
+ (if_then_else:GPI (match_dup 1)
+ (const_int -1) (match_dup 3)))]
+ {}
+ [(set_attr "type" "csel")]
+)
+
(define_insn "*cmovdi_insn_uxtw"
[(set (match_operand:DI 0 "register_operand" "=r")
(if_then_else:DI
Will clean up the comment and add a testcase tomorrow.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/109657] (a ? -1 : 0) | b could be optimized better for aarch64
2023-04-27 22:47 [Bug target/109657] New: (a ? -1 : 0) | b could be optimized better for aarch64 pinskia at gcc dot gnu.org
2023-04-28 5:07 ` [Bug target/109657] " pinskia at gcc dot gnu.org
@ 2023-04-28 23:35 ` pinskia at gcc dot gnu.org
2023-05-02 21:10 ` cvs-commit at gcc dot gnu.org
2023-05-02 21:11 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-04-28 23:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109657
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
URL| |https://gcc.gnu.org/piperma
| |il/gcc-patches/2023-April/6
| |17108.html
Keywords| |patch
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch posted:
https://gcc.gnu.org/pipermail/gcc-patches/2023-April/617108.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/109657] (a ? -1 : 0) | b could be optimized better for aarch64
2023-04-27 22:47 [Bug target/109657] New: (a ? -1 : 0) | b could be optimized better for aarch64 pinskia at gcc dot gnu.org
2023-04-28 5:07 ` [Bug target/109657] " pinskia at gcc dot gnu.org
2023-04-28 23:35 ` pinskia at gcc dot gnu.org
@ 2023-05-02 21:10 ` cvs-commit at gcc dot gnu.org
2023-05-02 21:11 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-05-02 21:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109657
--- Comment #3 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:7cc33d12dca84befde69259a17fab8224e2e4025
commit r14-412-g7cc33d12dca84befde69259a17fab8224e2e4025
Author: Andrew Pinski <apinski@marvell.com>
Date: Fri Apr 28 05:22:34 2023 +0000
target: [PR109657] (a ? -1 : 0) | b could be optimized better for aarch64
There is no canonical form for this case defined. So the aarch64 backend
needs
a pattern to match both of these forms.
The forms are:
(set (reg/i:SI 0 x0)
(if_then_else:SI (eq (reg:CC 66 cc)
(const_int 0 [0]))
(reg:SI 97)
(const_int -1 [0xffffffffffffffff])))
and
(set (reg/i:SI 0 x0)
(ior:SI (neg:SI (ne:SI (reg:CC 66 cc)
(const_int 0 [0])))
(reg:SI 102)))
Currently the aarch64 backend matches the first form so this
patch adds a insn_and_split to match the second form and
convert it to the first form.
OK? Bootstrapped and tested on aarch64-linux-gnu with no regressions
PR target/109657
gcc/ChangeLog:
* config/aarch64/aarch64.md (*cmov<mode>_insn_m1): New
insn_and_split pattern.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/csinv-2.c: New test.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/109657] (a ? -1 : 0) | b could be optimized better for aarch64
2023-04-27 22:47 [Bug target/109657] New: (a ? -1 : 0) | b could be optimized better for aarch64 pinskia at gcc dot gnu.org
` (2 preceding siblings ...)
2023-05-02 21:10 ` cvs-commit at gcc dot gnu.org
@ 2023-05-02 21:11 ` pinskia at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-05-02 21:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109657
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Target Milestone|--- |14.0
Status|ASSIGNED |RESOLVED
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-05-02 21:11 UTC | newest]
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2023-04-27 22:47 [Bug target/109657] New: (a ? -1 : 0) | b could be optimized better for aarch64 pinskia at gcc dot gnu.org
2023-04-28 5:07 ` [Bug target/109657] " pinskia at gcc dot gnu.org
2023-04-28 23:35 ` pinskia at gcc dot gnu.org
2023-05-02 21:10 ` cvs-commit at gcc dot gnu.org
2023-05-02 21:11 ` pinskia at gcc dot gnu.org
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