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* [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
@ 2022-06-14 21:37 gabravier at gmail dot com
2022-06-14 21:39 ` [Bug tree-optimization/105983] " pinskia at gcc dot gnu.org
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: gabravier at gmail dot com @ 2022-06-14 21:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
Bug ID: 105983
Summary: Failure to optimize (b != 0) && (a >= b) as well as
the same pattern with binary and
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
bool f(unsigned a, unsigned b)
{
return (b != 0) && (a >= b);
}
This can be optimized to `return (b != 0) & (a >= b);`, which is itself
optimized to `return (b - 1) > a;`. GCC outputs code equivalent to `return (b
!= 0) & (a >= b);` (at least on x86) whereas if that code is compiled it would
output `return (b - 1) > a;`, while LLVM has no trouble directly outputting the
optimal code.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
@ 2022-06-14 21:39 ` pinskia at gcc dot gnu.org
2022-06-14 21:41 ` pinskia at gcc dot gnu.org
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-06-14 21:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
2022-06-14 21:39 ` [Bug tree-optimization/105983] " pinskia at gcc dot gnu.org
@ 2022-06-14 21:41 ` pinskia at gcc dot gnu.org
2022-06-14 21:45 ` pinskia at gcc dot gnu.org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-06-14 21:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
aarch64 GCC is able to compile it to:
f(unsigned int, unsigned int):
cmp w1, 0
ccmp w1, w0, 2, ne
cset w0, ls
ret
While aarch64 LLVM does:
sub w8, w1, #1
cmp w8, w0
cset w0, lo
ret
depending on the pipeline, they might be the same or the ccmp might be better
slightly.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
2022-06-14 21:39 ` [Bug tree-optimization/105983] " pinskia at gcc dot gnu.org
2022-06-14 21:41 ` pinskia at gcc dot gnu.org
@ 2022-06-14 21:45 ` pinskia at gcc dot gnu.org
2022-06-15 12:26 ` jakub at gcc dot gnu.org
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-06-14 21:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Blocks| |19987
Last reconfirmed| |2022-06-14
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, the issue is GCC does not even handle:
bool f(unsigned a, unsigned b)
{
bool t = (b != 0);
bool t1 = (a >= b);
return t & t1;
}
I suspect this is a fold-const.cc which has not been moved over to match.pd
yet.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19987
[Bug 19987] [meta-bug] fold missing optimizations in general
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (2 preceding siblings ...)
2022-06-14 21:45 ` pinskia at gcc dot gnu.org
@ 2022-06-15 12:26 ` jakub at gcc dot gnu.org
2022-06-15 13:32 ` jakub at gcc dot gnu.org
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-15 12:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
On generic, what opimizes this is:
/* y == XXX_MIN || x < y --> x <= y - 1 */
(simplify
(bit_ior:c (eq:s @1 min_value) (lt:s @0 @1))
(if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
&& TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
(le @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
/* y != XXX_MIN && x >= y --> x > y - 1 */
(simplify
(bit_and:c (ne:s @1 min_value) (ge:s @0 @1))
(if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
&& TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
(gt @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
in match.pd when & is used instead of &&.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (3 preceding siblings ...)
2022-06-15 12:26 ` jakub at gcc dot gnu.org
@ 2022-06-15 13:32 ` jakub at gcc dot gnu.org
2022-06-15 14:13 ` rearnsha at gcc dot gnu.org
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-15 13:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
--- gcc/match.pd.jj 2022-06-15 12:52:04.640981511 +0200
+++ gcc/match.pd 2022-06-15 15:28:55.916225336 +0200
@@ -2379,14 +2379,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* y == XXX_MIN || x < y --> x <= y - 1 */
(simplify
- (bit_ior:c (eq:s @1 min_value) (lt:s @0 @1))
+ (bit_ior:c (eq:s @1 min_value) (lt:cs @0 @1))
(if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
&& TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
(le @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
/* y != XXX_MIN && x >= y --> x > y - 1 */
(simplify
- (bit_and:c (ne:s @1 min_value) (ge:s @0 @1))
+ (bit_and:c (ne:s @1 min_value) (ge:cs @0 @1))
(if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
&& TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
(gt @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
fixes this.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (4 preceding siblings ...)
2022-06-15 13:32 ` jakub at gcc dot gnu.org
@ 2022-06-15 14:13 ` rearnsha at gcc dot gnu.org
2022-06-15 14:20 ` rearnsha at gcc dot gnu.org
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rearnsha at gcc dot gnu.org @ 2022-06-15 14:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
--- Comment #5 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> --- gcc/match.pd.jj 2022-06-15 12:52:04.640981511 +0200
> +++ gcc/match.pd 2022-06-15 15:28:55.916225336 +0200
> @@ -2379,14 +2379,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>
> /* y == XXX_MIN || x < y --> x <= y - 1 */
> (simplify
> - (bit_ior:c (eq:s @1 min_value) (lt:s @0 @1))
> + (bit_ior:c (eq:s @1 min_value) (lt:cs @0 @1))
> (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
> && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
> (le @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
>
> /* y != XXX_MIN && x >= y --> x > y - 1 */
> (simplify
> - (bit_and:c (ne:s @1 min_value) (ge:s @0 @1))
> + (bit_and:c (ne:s @1 min_value) (ge:cs @0 @1))
> (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
> && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
> (gt @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
>
> fixes this.
But doesn't that regress
bool f(unsigned a, unsigned b)
{
return (b != 0) & (a >= b);
}
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (5 preceding siblings ...)
2022-06-15 14:13 ` rearnsha at gcc dot gnu.org
@ 2022-06-15 14:20 ` rearnsha at gcc dot gnu.org
2022-06-15 14:50 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rearnsha at gcc dot gnu.org @ 2022-06-15 14:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
--- Comment #6 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
(In reply to Richard Earnshaw from comment #5)
> (In reply to Jakub Jelinek from comment #4)
> > --- gcc/match.pd.jj 2022-06-15 12:52:04.640981511 +0200
> > +++ gcc/match.pd 2022-06-15 15:28:55.916225336 +0200
> > @@ -2379,14 +2379,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> >
> > /* y == XXX_MIN || x < y --> x <= y - 1 */
> > (simplify
> > - (bit_ior:c (eq:s @1 min_value) (lt:s @0 @1))
> > + (bit_ior:c (eq:s @1 min_value) (lt:cs @0 @1))
> > (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
> > && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
> > (le @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
> >
> > /* y != XXX_MIN && x >= y --> x > y - 1 */
> > (simplify
> > - (bit_and:c (ne:s @1 min_value) (ge:s @0 @1))
> > + (bit_and:c (ne:s @1 min_value) (ge:cs @0 @1))
> > (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
> > && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@1)))
> > (gt @0 (minus @1 { build_int_cst (TREE_TYPE (@1), 1); }))))
> >
> > fixes this.
>
> But doesn't that regress
>
> bool f(unsigned a, unsigned b)
> {
> return (b != 0) & (a >= b);
> }
Ignore that - I'm confusing reports.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (6 preceding siblings ...)
2022-06-15 14:20 ` rearnsha at gcc dot gnu.org
@ 2022-06-15 14:50 ` jakub at gcc dot gnu.org
2022-06-16 12:37 ` cvs-commit at gcc dot gnu.org
2022-06-16 12:39 ` jakub at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-15 14:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 53146
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53146&action=edit
gcc13-pr105983.patch
Full untested patch.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (7 preceding siblings ...)
2022-06-15 14:50 ` jakub at gcc dot gnu.org
@ 2022-06-16 12:37 ` cvs-commit at gcc dot gnu.org
2022-06-16 12:39 ` jakub at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-06-16 12:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:9642d07c35f14b9917cd115e8a9f0210fbcdcf4f
commit r13-1134-g9642d07c35f14b9917cd115e8a9f0210fbcdcf4f
Author: Jakub Jelinek <jakub@redhat.com>
Date: Thu Jun 16 14:37:06 2022 +0200
match.pd: Improve y == MIN || x < y optimization [PR105983]
On the following testcase, we only optimize bar where this optimization
is performed at GENERIC folding time, but on GIMPLE it doesn't trigger
anymore, as we actually don't see
(bit_and (ne @1 min_value) (ge @0 @1))
but
(bit_and (ne @1 min_value) (le @1 @0))
genmatch handles :c modifier not just on commutative operations, but
also comparisons and in that case it means it swaps the comparison.
2022-06-16 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/105983
* match.pd (y == XXX_MIN || x < y -> x <= y - 1,
y != XXX_MIN && x >= y -> x > y - 1): Use :cs instead of :s
on non-equality comparisons.
* gcc.dg/tree-ssa/pr105983.c: New test.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/105983] Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and
2022-06-14 21:37 [Bug tree-optimization/105983] New: Failure to optimize (b != 0) && (a >= b) as well as the same pattern with binary and gabravier at gmail dot com
` (8 preceding siblings ...)
2022-06-16 12:37 ` cvs-commit at gcc dot gnu.org
@ 2022-06-16 12:39 ` jakub at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-16 12:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105983
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 11+ messages in thread
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