* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
@ 2020-11-09 11:50 ` jakub at gcc dot gnu.org
2020-11-09 12:21 ` rguenth at gcc dot gnu.org
` (6 subsequent siblings)
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From: jakub at gcc dot gnu.org @ 2020-11-09 11:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2020-11-09
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
Ever confirmed|0 |1
Summary|wrong code at -O1 and above |[10/11 Regression] wrong
|on x86_64-pc-linux-gnu |code at -O1 and above on
| |x86_64-pc-linux-gnu since
| |r10-6809
CC| |jakub at gcc dot gnu.org
Target Milestone|--- |10.3
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with my r10-6809-g7f5617b00445dcc861a498a4cecc8aaa59e05b8c
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
2020-11-09 11:50 ` [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809 jakub at gcc dot gnu.org
@ 2020-11-09 12:21 ` rguenth at gcc dot gnu.org
2020-11-09 13:53 ` jakub at gcc dot gnu.org
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From: rguenth at gcc dot gnu.org @ 2020-11-09 12:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
CC| |rguenth at gcc dot gnu.org
Keywords| |wrong-code
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
2020-11-09 11:50 ` [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809 jakub at gcc dot gnu.org
2020-11-09 12:21 ` rguenth at gcc dot gnu.org
@ 2020-11-09 13:53 ` jakub at gcc dot gnu.org
2020-11-10 10:18 ` cvs-commit at gcc dot gnu.org
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From: jakub at gcc dot gnu.org @ 2020-11-09 13:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 49525
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49525&action=edit
gcc11-pr97764.patch
Untested fix.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
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2020-11-09 13:53 ` jakub at gcc dot gnu.org
@ 2020-11-10 10:18 ` cvs-commit at gcc dot gnu.org
2020-11-10 10:21 ` cvs-commit at gcc dot gnu.org
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From: cvs-commit at gcc dot gnu.org @ 2020-11-10 10:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
--- Comment #3 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:c69325a5db450dbac198f76f1162734af05a1061
commit r11-4867-gc69325a5db450dbac198f76f1162734af05a1061
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue Nov 10 11:17:46 2020 +0100
sccvn: Fix up push_partial_def little-endian bitfield handling [PR97764]
This patch fixes a thinko in the left-endian push_partial_def path.
As the testcase shows, we have 3 bitfields in the struct,
bitoff bitsize
0 3
3 28
31 1
the corresponding read is the byte at offset 3 (i.e. 24 bits)
and push_partial_def first handles the full store ({}) to all bits
and then is processing the store to the middle bitfield with value of -1.
Here are the interesting spots:
pd.offset -= offseti;
this adjusts the pd to { -21, 28 }, the (for little-endian lowest) 21
bits aren't interesting to us, we only care about the upper 7.
len = native_encode_expr (pd.rhs, this_buffer, bufsize,
MAX (0, -pd.offset) / BITS_PER_UNIT);
native_encode_expr has the offset parameter in bytes and we tell it
that we aren't interested in the first (lowest) two bytes of the number.
It encodes 0xff, 0xff with len == 2 then.
HOST_WIDE_INT size = pd.size;
if (pd.offset < 0)
size -= ROUND_DOWN (-pd.offset, BITS_PER_UNIT);
we get 28 - 16, i.e. 12 - the 16 is subtracting those 2 bytes that we
omitted in native_encode_expr.
size = MIN (size, (HOST_WIDE_INT) needed_len * BITS_PER_UNIT);
needed_len is how many bytes the read at most needs, and that is 1,
so we get size 8 and copy all 8 bits (i.e. a single byte plus nothing)
from the native_encode_expr filled this_buffer; this incorrectly sets
the byte to 0xff when we want 0x7f. The above line is correct for the
pd.offset >= 0 case when we don't skip anything, but for the pd.offset < 0
case we need to subtract also the remainder of the bits we aren't
interested
in (the code shifts the bytes by that number of bits).
If it weren't for the big-endian path, we could as well do
if (pd.offset < 0)
size += pd.offset;
but the big-endian path needs it differently.
With the following patch, amnt is 3 and we subtract from 12 the (8 - 3)
bits and thus get the 7 which is the value we want.
2020-11-10 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/97764
* tree-ssa-sccvn.c (vn_walk_cb_data::push_partial_def): For
little-endian stores with negative pd.offset, subtract
BITS_PER_UNIT - amnt from size if amnt is non-zero.
* gcc.c-torture/execute/pr97764.c: New test.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
` (3 preceding siblings ...)
2020-11-10 10:18 ` cvs-commit at gcc dot gnu.org
@ 2020-11-10 10:21 ` cvs-commit at gcc dot gnu.org
2020-11-10 10:33 ` rguenth at gcc dot gnu.org
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From: cvs-commit at gcc dot gnu.org @ 2020-11-10 10:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
--- Comment #4 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:4b47f86c40a071fbcad5bce5001b1b689748a2e8
commit r10-8998-g4b47f86c40a071fbcad5bce5001b1b689748a2e8
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue Nov 10 11:17:46 2020 +0100
sccvn: Fix up push_partial_def little-endian bitfield handling [PR97764]
This patch fixes a thinko in the left-endian push_partial_def path.
As the testcase shows, we have 3 bitfields in the struct,
bitoff bitsize
0 3
3 28
31 1
the corresponding read is the byte at offset 3 (i.e. 24 bits)
and push_partial_def first handles the full store ({}) to all bits
and then is processing the store to the middle bitfield with value of -1.
Here are the interesting spots:
pd.offset -= offseti;
this adjusts the pd to { -21, 28 }, the (for little-endian lowest) 21
bits aren't interesting to us, we only care about the upper 7.
len = native_encode_expr (pd.rhs, this_buffer, bufsize,
MAX (0, -pd.offset) / BITS_PER_UNIT);
native_encode_expr has the offset parameter in bytes and we tell it
that we aren't interested in the first (lowest) two bytes of the number.
It encodes 0xff, 0xff with len == 2 then.
HOST_WIDE_INT size = pd.size;
if (pd.offset < 0)
size -= ROUND_DOWN (-pd.offset, BITS_PER_UNIT);
we get 28 - 16, i.e. 12 - the 16 is subtracting those 2 bytes that we
omitted in native_encode_expr.
size = MIN (size, (HOST_WIDE_INT) needed_len * BITS_PER_UNIT);
needed_len is how many bytes the read at most needs, and that is 1,
so we get size 8 and copy all 8 bits (i.e. a single byte plus nothing)
from the native_encode_expr filled this_buffer; this incorrectly sets
the byte to 0xff when we want 0x7f. The above line is correct for the
pd.offset >= 0 case when we don't skip anything, but for the pd.offset < 0
case we need to subtract also the remainder of the bits we aren't
interested
in (the code shifts the bytes by that number of bits).
If it weren't for the big-endian path, we could as well do
if (pd.offset < 0)
size += pd.offset;
but the big-endian path needs it differently.
With the following patch, amnt is 3 and we subtract from 12 the (8 - 3)
bits and thus get the 7 which is the value we want.
2020-11-10 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/97764
* tree-ssa-sccvn.c (vn_walk_cb_data::push_partial_def): For
little-endian stores with negative pd.offset, subtract
BITS_PER_UNIT - amnt from size if amnt is non-zero.
* gcc.c-torture/execute/pr97764.c: New test.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
` (4 preceding siblings ...)
2020-11-10 10:21 ` cvs-commit at gcc dot gnu.org
@ 2020-11-10 10:33 ` rguenth at gcc dot gnu.org
2020-11-10 10:35 ` jakub at gcc dot gnu.org
2020-12-01 11:29 ` jakub at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-11-10 10:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |hubicka at gcc dot gnu.org
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
*** Bug 97775 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
` (5 preceding siblings ...)
2020-11-10 10:33 ` rguenth at gcc dot gnu.org
@ 2020-11-10 10:35 ` jakub at gcc dot gnu.org
2020-12-01 11:29 ` jakub at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2020-11-10 10:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/97764] [10/11 Regression] wrong code at -O1 and above on x86_64-pc-linux-gnu since r10-6809
2020-11-09 11:39 [Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu zhendong.su at inf dot ethz.ch
` (6 preceding siblings ...)
2020-11-10 10:35 ` jakub at gcc dot gnu.org
@ 2020-12-01 11:29 ` jakub at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2020-12-01 11:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |haoxintu at gmail dot com
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
*** Bug 98074 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 9+ messages in thread