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* [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree
@ 2022-06-30 11:03 aldyh at gcc dot gnu.org
2022-06-30 18:18 ` [Bug middle-end/106144] " jakub at gcc dot gnu.org
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: aldyh at gcc dot gnu.org @ 2022-06-30 11:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
Bug ID: 106144
Summary: wide_int shifted_mask() and mask() do not agree
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: aldyh at gcc dot gnu.org
CC: amacleod at redhat dot com, mikestump at comcast dot net,
rsandifo at gcc dot gnu.org
Target Milestone: ---
A mask of 128 bits should match a shifted mask of 128 bits where the shift is
0, but the following assert is failing:
{
wide_int mask1 = wi::mask (128, false, 128);
wide_int mask2 = wi::shifted_mask (0, 128, false, 128);
mask1.dump ();
mask2.dump ();
gcc_assert (mask1 == mask2);
}
The output is:
[...,0xffffffffffffffff], precision = 128
[0xffffffffffffffff,0xffffffffffffffff], precision = 128
I would expect both masks to be the same.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
@ 2022-06-30 18:18 ` jakub at gcc dot gnu.org
2022-06-30 18:50 ` jakub at gcc dot gnu.org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-30 18:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think this is a bug in wi::shifted_mask, { -1 } with len = 1 from wi::mask is
canonical 128-bit precision -1, { -1, -1 } with len = 2 from wi::shifted_mask
is not.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
2022-06-30 18:18 ` [Bug middle-end/106144] " jakub at gcc dot gnu.org
@ 2022-06-30 18:50 ` jakub at gcc dot gnu.org
2022-07-01 8:09 ` aldyh at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2022-06-30 18:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
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
Last reconfirmed| |2022-06-30
Ever confirmed|0 |1
Status|UNCONFIRMED |ASSIGNED
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 53228
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53228&action=edit
gcc13-pr106144.patch
Untested fix.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
2022-06-30 18:18 ` [Bug middle-end/106144] " jakub at gcc dot gnu.org
2022-06-30 18:50 ` jakub at gcc dot gnu.org
@ 2022-07-01 8:09 ` aldyh at gcc dot gnu.org
2022-07-01 9:19 ` cvs-commit at gcc dot gnu.org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: aldyh at gcc dot gnu.org @ 2022-07-01 8:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
--- Comment #3 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #2)
> Created attachment 53228 [details]
> gcc13-pr106144.patch
>
> Untested fix.
Thanks.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
` (2 preceding siblings ...)
2022-07-01 8:09 ` aldyh at gcc dot gnu.org
@ 2022-07-01 9:19 ` cvs-commit at gcc dot gnu.org
2022-07-30 9:34 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-07-01 9:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
--- Comment #4 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:e52592073f6df3d7a3acd9f0436dcc32a8b7493d
commit r13-1381-ge52592073f6df3d7a3acd9f0436dcc32a8b7493d
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Jul 1 11:17:41 2022 +0200
wide-int: Fix up wi::shifted_mask [PR106144]
As the following self-test testcase shows, wi::shifted_mask sometimes
doesn't create canonicalized wide_ints, which then fail to compare equal
to canonicalized wide_ints with the same value.
In particular, wi::mask (128, false, 128) gives { -1 } with len 1 and prec
128,
while wi::shifted_mask (0, 128, false, 128) gives { -1, -1 } with len 2
and prec 128.
The problem is that the code is written with the assumption that there are
3 bit blocks (or 2 if start is 0), but doesn't consider the possibility
where there are 2 bit blocks (or 1 if start is 0) where the highest block
isn't present. In that case, there is the optional block of negate ? 0 :
-1
elts, followed by just one elt (either one from the if (shift) or just
negate ? -1 : 0) and the rest is implicit sign-extension.
Only if end < prec there is 1 or more bits above it that have different bit
value and so we need to emit all the elts till end and then one more elt.
if (end == prec) would work too, because we have:
if (width > prec - start)
width = prec - start;
unsigned int end = start + width;
so end is guaranteed to be end <= prec, dunno what is preferred.
2022-07-01 Jakub Jelinek <jakub@redhat.com>
PR middle-end/106144
* wide-int.cc (wi::shifted_mask): If end >= prec, return right
after
emitting element for shift or if shift is 0 first element after
start.
(wide_int_cc_tests): Add tests for equivalency of wi::mask and
wi::shifted_mask with 0 start.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
` (3 preceding siblings ...)
2022-07-01 9:19 ` cvs-commit at gcc dot gnu.org
@ 2022-07-30 9:34 ` cvs-commit at gcc dot gnu.org
2022-11-04 8:30 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-07-30 9:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:527dccb33e54ffe49fb1507fc4539968f48a9d12
commit r12-8643-g527dccb33e54ffe49fb1507fc4539968f48a9d12
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Jul 1 11:17:41 2022 +0200
wide-int: Fix up wi::shifted_mask [PR106144]
As the following self-test testcase shows, wi::shifted_mask sometimes
doesn't create canonicalized wide_ints, which then fail to compare equal
to canonicalized wide_ints with the same value.
In particular, wi::mask (128, false, 128) gives { -1 } with len 1 and prec
128,
while wi::shifted_mask (0, 128, false, 128) gives { -1, -1 } with len 2
and prec 128.
The problem is that the code is written with the assumption that there are
3 bit blocks (or 2 if start is 0), but doesn't consider the possibility
where there are 2 bit blocks (or 1 if start is 0) where the highest block
isn't present. In that case, there is the optional block of negate ? 0 :
-1
elts, followed by just one elt (either one from the if (shift) or just
negate ? -1 : 0) and the rest is implicit sign-extension.
Only if end < prec there is 1 or more bits above it that have different bit
value and so we need to emit all the elts till end and then one more elt.
if (end == prec) would work too, because we have:
if (width > prec - start)
width = prec - start;
unsigned int end = start + width;
so end is guaranteed to be end <= prec, dunno what is preferred.
2022-07-01 Jakub Jelinek <jakub@redhat.com>
PR middle-end/106144
* wide-int.cc (wi::shifted_mask): If end >= prec, return right
after
emitting element for shift or if shift is 0 first element after
start.
(wide_int_cc_tests): Add tests for equivalency of wi::mask and
wi::shifted_mask with 0 start.
(cherry picked from commit e52592073f6df3d7a3acd9f0436dcc32a8b7493d)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
` (4 preceding siblings ...)
2022-07-30 9:34 ` cvs-commit at gcc dot gnu.org
@ 2022-11-04 8:30 ` cvs-commit at gcc dot gnu.org
2023-05-03 15:18 ` cvs-commit at gcc dot gnu.org
2023-05-04 7:18 ` jakub at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-11-04 8:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:4d853d49202a3b9fdaade64a6d5f920304c2b38d
commit r11-10355-g4d853d49202a3b9fdaade64a6d5f920304c2b38d
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Jul 1 11:17:41 2022 +0200
wide-int: Fix up wi::shifted_mask [PR106144]
As the following self-test testcase shows, wi::shifted_mask sometimes
doesn't create canonicalized wide_ints, which then fail to compare equal
to canonicalized wide_ints with the same value.
In particular, wi::mask (128, false, 128) gives { -1 } with len 1 and prec
128,
while wi::shifted_mask (0, 128, false, 128) gives { -1, -1 } with len 2
and prec 128.
The problem is that the code is written with the assumption that there are
3 bit blocks (or 2 if start is 0), but doesn't consider the possibility
where there are 2 bit blocks (or 1 if start is 0) where the highest block
isn't present. In that case, there is the optional block of negate ? 0 :
-1
elts, followed by just one elt (either one from the if (shift) or just
negate ? -1 : 0) and the rest is implicit sign-extension.
Only if end < prec there is 1 or more bits above it that have different bit
value and so we need to emit all the elts till end and then one more elt.
if (end == prec) would work too, because we have:
if (width > prec - start)
width = prec - start;
unsigned int end = start + width;
so end is guaranteed to be end <= prec, dunno what is preferred.
2022-07-01 Jakub Jelinek <jakub@redhat.com>
PR middle-end/106144
* wide-int.cc (wi::shifted_mask): If end >= prec, return right
after
emitting element for shift or if shift is 0 first element after
start.
(wide_int_cc_tests): Add tests for equivalency of wi::mask and
wi::shifted_mask with 0 start.
(cherry picked from commit e52592073f6df3d7a3acd9f0436dcc32a8b7493d)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
` (5 preceding siblings ...)
2022-11-04 8:30 ` cvs-commit at gcc dot gnu.org
@ 2023-05-03 15:18 ` cvs-commit at gcc dot gnu.org
2023-05-04 7:18 ` jakub at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-05-03 15:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:6e7bf9bc3e51d2d0d0df3d810cb20624594573cf
commit r10-11334-g6e7bf9bc3e51d2d0d0df3d810cb20624594573cf
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Jul 1 11:17:41 2022 +0200
wide-int: Fix up wi::shifted_mask [PR106144]
As the following self-test testcase shows, wi::shifted_mask sometimes
doesn't create canonicalized wide_ints, which then fail to compare equal
to canonicalized wide_ints with the same value.
In particular, wi::mask (128, false, 128) gives { -1 } with len 1 and prec
128,
while wi::shifted_mask (0, 128, false, 128) gives { -1, -1 } with len 2
and prec 128.
The problem is that the code is written with the assumption that there are
3 bit blocks (or 2 if start is 0), but doesn't consider the possibility
where there are 2 bit blocks (or 1 if start is 0) where the highest block
isn't present. In that case, there is the optional block of negate ? 0 :
-1
elts, followed by just one elt (either one from the if (shift) or just
negate ? -1 : 0) and the rest is implicit sign-extension.
Only if end < prec there is 1 or more bits above it that have different bit
value and so we need to emit all the elts till end and then one more elt.
if (end == prec) would work too, because we have:
if (width > prec - start)
width = prec - start;
unsigned int end = start + width;
so end is guaranteed to be end <= prec, dunno what is preferred.
2022-07-01 Jakub Jelinek <jakub@redhat.com>
PR middle-end/106144
* wide-int.cc (wi::shifted_mask): If end >= prec, return right
after
emitting element for shift or if shift is 0 first element after
start.
(wide_int_cc_tests): Add tests for equivalency of wi::mask and
wi::shifted_mask with 0 start.
(cherry picked from commit e52592073f6df3d7a3acd9f0436dcc32a8b7493d)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug middle-end/106144] wide_int shifted_mask() and mask() do not agree
2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
` (6 preceding siblings ...)
2023-05-03 15:18 ` cvs-commit at gcc dot gnu.org
@ 2023-05-04 7:18 ` jakub at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2023-05-04 7:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106144
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 10.5 too.
^ permalink raw reply [flat|nested] 9+ messages in thread
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2022-06-30 11:03 [Bug middle-end/106144] New: wide_int shifted_mask() and mask() do not agree aldyh at gcc dot gnu.org
2022-06-30 18:18 ` [Bug middle-end/106144] " jakub at gcc dot gnu.org
2022-06-30 18:50 ` jakub at gcc dot gnu.org
2022-07-01 8:09 ` aldyh at gcc dot gnu.org
2022-07-01 9:19 ` cvs-commit at gcc dot gnu.org
2022-07-30 9:34 ` cvs-commit at gcc dot gnu.org
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