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* [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits
@ 2022-09-27 15:18 pinskia at gcc dot gnu.org
2022-09-27 15:18 ` [Bug tree-optimization/107052] " pinskia at gcc dot gnu.org
` (8 more replies)
0 siblings, 9 replies; 10+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-27 15:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
Bug ID: 107052
Summary: Range of __builtin_popcount can be improved with
nonzerobits
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Take:
```
void link_failure();
void f(int a)
{
a &= 0x300;
int b = __builtin_popcount(a);
if (b > 3)
link_failure();
}
```
The if statement should be optimized away as the only values for popcount here
is 0-3.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
@ 2022-09-27 15:18 ` pinskia at gcc dot gnu.org
2022-09-27 15:24 ` pinskia at gcc dot gnu.org
` (7 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-27 15:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
CC| |aldyh at gcc dot gnu.org
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
2022-09-27 15:18 ` [Bug tree-optimization/107052] " pinskia at gcc dot gnu.org
@ 2022-09-27 15:24 ` pinskia at gcc dot gnu.org
2022-09-27 15:33 ` aldyh at gcc dot gnu.org
` (6 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-27 15:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this testcase is optimized by clang/llvm.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
2022-09-27 15:18 ` [Bug tree-optimization/107052] " pinskia at gcc dot gnu.org
2022-09-27 15:24 ` pinskia at gcc dot gnu.org
@ 2022-09-27 15:33 ` aldyh at gcc dot gnu.org
2022-09-27 15:36 ` pinskia at gcc dot gnu.org
` (5 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: aldyh at gcc dot gnu.org @ 2022-09-27 15:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
Aldy Hernandez <aldyh at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2022-09-27
CC| |amacleod at redhat dot com
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #2 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Don't you mean the only values for popcount are 0-2? I mean, there are only
two bits that could be 1 with a mask of 0x300. Or am I missing something?
Either way, your check is for b > 3, and we should be able to fold that away.
There are two problems here. The cast of a_4 to a.0_1 dropped the nonzero
mask. I would've expected that a cast to a number of the same precision would
keep the 0x300 mask, instead we have:
a.0_1 : [irange] unsigned int [0, 768] NONZERO 0x3ff
If we had the 0x300 mask available in cfn_popcount::fold_range(), then we could
fold it. The second problem is that cfn_popcont, does not look at the nonzero
bits at all.
=========== BB 2 ============
Imports: a_3(D)
Exports: a.0_1 a_3(D) a_4 b_5
a.0_1 : a_3(D)(I) a_4
a_4 : a_3(D)(I)
b_5 : a.0_1 a_3(D)(I) a_4
a_3(D) [irange] int VARYING
<bb 2> :
a_4 = a_3(D) & 768;
a.0_1 = (unsigned int) a_4;
b_5 = __builtin_popcount (a.0_1);
if (b_5 > 3)
goto <bb 3>; [INV]
else
goto <bb 4>; [INV]
a.0_1 : [irange] unsigned int [0, 768] NONZERO 0x3ff
a_4 : [irange] int [0, 768] NONZERO 0x300
b_5 : [irange] int [0, 10] NONZERO 0xf
2->3 (T) a.0_1 : [irange] unsigned int [0, 768] NONZERO 0x3ff
2->3 (T) a_4 : [irange] int [0, 768] NONZERO 0x300
2->3 (T) b_5 : [irange] int [4, 10] NONZERO 0xf
2->4 (F) a.0_1 : [irange] unsigned int [0, 768] NONZERO 0x3ff
2->4 (F) a_4 : [irange] int [0, 768] NONZERO 0x300
2->4 (F) b_5 : [irange] int [0, 3] NONZERO 0x3
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
` (2 preceding siblings ...)
2022-09-27 15:33 ` aldyh at gcc dot gnu.org
@ 2022-09-27 15:36 ` pinskia at gcc dot gnu.org
2022-09-27 15:54 ` aldyh at gcc dot gnu.org
` (4 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-27 15:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Aldy Hernandez from comment #2)
> Don't you mean the only values for popcount are 0-2? I mean, there are only
> two bits that could be 1 with a mask of 0x300. Or am I missing something?
Yes, 0-2 I am still trying to wake up.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
` (3 preceding siblings ...)
2022-09-27 15:36 ` pinskia at gcc dot gnu.org
@ 2022-09-27 15:54 ` aldyh at gcc dot gnu.org
2022-09-27 16:22 ` aldyh at gcc dot gnu.org
` (3 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: aldyh at gcc dot gnu.org @ 2022-09-27 15:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
--- Comment #4 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> (In reply to Aldy Hernandez from comment #2)
> > Don't you mean the only values for popcount are 0-2? I mean, there are only
> > two bits that could be 1 with a mask of 0x300. Or am I missing something?
>
> Yes, 0-2 I am still trying to wake up.
No worries, just trying to make sure I understand things correctly.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
` (4 preceding siblings ...)
2022-09-27 15:54 ` aldyh at gcc dot gnu.org
@ 2022-09-27 16:22 ` aldyh at gcc dot gnu.org
2022-10-05 12:22 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: aldyh at gcc dot gnu.org @ 2022-09-27 16:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
--- Comment #5 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Created attachment 53633
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53633&action=edit
patch in testing
This might do it.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
` (5 preceding siblings ...)
2022-09-27 16:22 ` aldyh at gcc dot gnu.org
@ 2022-10-05 12:22 ` cvs-commit at gcc dot gnu.org
2022-10-05 12:22 ` cvs-commit at gcc dot gnu.org
2022-10-05 12:23 ` aldyh at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-10-05 12:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Aldy Hernandez <aldyh@gcc.gnu.org>:
https://gcc.gnu.org/g:ae56d600d223e996054483d7d7033ec8e258d39d
commit r13-3085-gae56d600d223e996054483d7d7033ec8e258d39d
Author: Aldy Hernandez <aldyh@redhat.com>
Date: Tue Oct 4 17:03:54 2022 +0200
[PR tree-optimization/107052] range-ops: Pass nonzero masks through cast.
Track nonzero masks through a cast in range-ops.
PR tree-optimization/107052
gcc/ChangeLog:
* range-op.cc (operator_cast::fold_range): Set nonzero mask.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
` (6 preceding siblings ...)
2022-10-05 12:22 ` cvs-commit at gcc dot gnu.org
@ 2022-10-05 12:22 ` cvs-commit at gcc dot gnu.org
2022-10-05 12:23 ` aldyh at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-10-05 12:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Aldy Hernandez <aldyh@gcc.gnu.org>:
https://gcc.gnu.org/g:4c451631f722c9939260a5c2fc209802a47e525f
commit r13-3086-g4c451631f722c9939260a5c2fc209802a47e525f
Author: Aldy Hernandez <aldyh@redhat.com>
Date: Tue Oct 4 17:05:10 2022 +0200
[PR tree-optimization/107052] range-ops: Take into account nonzero mask in
popcount.
PR tree-optimization/107052
gcc/ChangeLog:
* gimple-range-op.cc (cfn_popcount::fold_range): Take into account
nonzero bit mask.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/107052] Range of __builtin_popcount can be improved with nonzerobits
2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
` (7 preceding siblings ...)
2022-10-05 12:22 ` cvs-commit at gcc dot gnu.org
@ 2022-10-05 12:23 ` aldyh at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: aldyh at gcc dot gnu.org @ 2022-10-05 12:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107052
Aldy Hernandez <aldyh at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
--- Comment #8 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
fixed
^ permalink raw reply [flat|nested] 10+ messages in thread
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2022-09-27 15:18 [Bug tree-optimization/107052] New: Range of __builtin_popcount can be improved with nonzerobits pinskia at gcc dot gnu.org
2022-09-27 15:18 ` [Bug tree-optimization/107052] " pinskia at gcc dot gnu.org
2022-09-27 15:24 ` pinskia at gcc dot gnu.org
2022-09-27 15:33 ` aldyh at gcc dot gnu.org
2022-09-27 15:36 ` pinskia at gcc dot gnu.org
2022-09-27 15:54 ` aldyh at gcc dot gnu.org
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