* [Bug debug/103046] [11/12 Regression] Incorrect debug info for uint128 bit shift in gcc 11.2
2021-11-02 14:11 [Bug debug/103046] New: Incorrect debug info for uint128 bit shift in gcc 11.2 liyd2021 at gmail dot com
@ 2021-11-02 15:46 ` jakub at gcc dot gnu.org
2021-11-05 9:23 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-11-02 15:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103046
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |11.3
Ever confirmed|0 |1
Summary|Incorrect debug info for |[11/12 Regression]
|uint128 bit shift in gcc |Incorrect debug info for
|11.2 |uint128 bit shift in gcc
| |11.2
CC| |jakub at gcc dot gnu.org
Last reconfirmed| |2021-11-02
Status|UNCONFIRMED |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with my r11-7757-gfc9c4e5fc50c7fcbd27d6cb3dd372f7da8216954 aka PR99562
change.
Untested fix:
2021-11-02 Jakub Jelinek <jakub@redhat.com>
PR debug/103046
* dwarf2out.c (add_const_value_attribute) <case CONST_WIDE_INT>: Round
prec up to next HOST_BITS_PER_WIDE_INT multiple.
--- gcc/dwarf2out.c.jj 2021-10-08 10:52:47.086531820 +0200
+++ gcc/dwarf2out.c 2021-11-02 16:25:24.505504356 +0100
@@ -20102,6 +20102,7 @@ add_const_value_attribute (dw_die_ref di
unsigned int prec = MIN (wi::min_precision (w1, UNSIGNED),
(unsigned int) CONST_WIDE_INT_NUNITS (rtl)
* HOST_BITS_PER_WIDE_INT);
+ prec = ROUND_UP (prec, HOST_BITS_PER_WIDE_INT);
wide_int w = wide_int::from (w1, prec, UNSIGNED);
add_AT_wide (die, DW_AT_const_value, w);
}
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug debug/103046] [11/12 Regression] Incorrect debug info for uint128 bit shift in gcc 11.2
2021-11-02 14:11 [Bug debug/103046] New: Incorrect debug info for uint128 bit shift in gcc 11.2 liyd2021 at gmail dot com
2021-11-02 15:46 ` [Bug debug/103046] [11/12 Regression] " jakub at gcc dot gnu.org
@ 2021-11-05 9:23 ` cvs-commit at gcc dot gnu.org
2021-11-05 13:38 ` [Bug debug/103046] [11 " rguenth at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-11-05 9:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103046
--- Comment #2 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:155f6b2be421b0f84e478e34fbf72ee0bb9e36bc
commit r12-4933-g155f6b2be421b0f84e478e34fbf72ee0bb9e36bc
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Nov 5 10:20:10 2021 +0100
dwarf2out: Fix up CONST_WIDE_INT handling once more [PR103046]
My last change to CONST_WIDE_INT handling in add_const_value_attribute
broke
handling of CONST_WIDE_INT constants like ((__uint128_t) 1 << 120).
wi::min_precision (w1, UNSIGNED) in that case 121, but wide_int::from
creates a wide_int that has 0 and 0xff00000000000000ULL in its elts and
precision 121. When we output that, we output both elements and thus emit
0, 0xff00000000000000 instead of the desired 0, 0x0100000000000000.
IMHO we should actually pass machine_mode to add_const_value_attribute from
callers, so that we know exactly what precision we want. Because
hypothetically, if say mode is OImode and the CONST_WIDE_INT value fits
into
128 bits or 192 bits, we'd emit just those 128 or 192 bits but debug info
users would expect 256 bits.
On
typedef unsigned __int128 U;
int
main ()
{
U a = (U) 1 << 120;
U b = 0xffffffffffffffffULL;
U c = ((U) 0xffffffff00000000ULL) << 64;
return 0;
}
vanilla gcc incorrectly emits 0, 0xff00000000000000 for a,
0xffffffffffffffff alone (DW_FORM_data8) for b and 0, 0xffffffff00000000
for c. gcc with the previously posted PR103046 patch emits
0, 0x0100000000000000 for a, 0xffffffffffffffff alone for b and
0, 0xffffffff00000000 for c. And with this patch we emit
0, 0x0100000000000000 for a, 0xffffffffffffffff, 0 for b and
0, 0xffffffff00000000 for c.
So, the patch below certainly causes larger debug info (well, 128-bit
integers are pretty rare), but in this case the question is if it isn't
more correct, as debug info consumers generally will not know if they
should sign or zero extend the value in DW_AT_const_value.
The previous code assumes they will always zero extend it...
2021-11-05 Jakub Jelinek <jakub@redhat.com>
PR debug/103046
* dwarf2out.c (add_const_value_attribute): Add MODE argument, use
it
in CONST_WIDE_INT handling. Adjust recursive calls.
(add_location_or_const_value_attribute): Pass DECL_MODE (decl) to
new add_const_value_attribute argument.
(tree_add_const_value_attribute): Pass TYPE_MODE (type) to new
add_const_value_attribute argument.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug debug/103046] [11 Regression] Incorrect debug info for uint128 bit shift in gcc 11.2
2021-11-02 14:11 [Bug debug/103046] New: Incorrect debug info for uint128 bit shift in gcc 11.2 liyd2021 at gmail dot com
2021-11-02 15:46 ` [Bug debug/103046] [11/12 Regression] " jakub at gcc dot gnu.org
2021-11-05 9:23 ` cvs-commit at gcc dot gnu.org
@ 2021-11-05 13:38 ` rguenth at gcc dot gnu.org
2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
2021-11-29 9:08 ` jakub at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-11-05 13:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103046
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
Known to work| |12.0
Summary|[11/12 Regression] |[11 Regression] Incorrect
|Incorrect debug info for |debug info for uint128 bit
|uint128 bit shift in gcc |shift in gcc 11.2
|11.2 |
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
fixed on trunk.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug debug/103046] [11 Regression] Incorrect debug info for uint128 bit shift in gcc 11.2
2021-11-02 14:11 [Bug debug/103046] New: Incorrect debug info for uint128 bit shift in gcc 11.2 liyd2021 at gmail dot com
` (2 preceding siblings ...)
2021-11-05 13:38 ` [Bug debug/103046] [11 " rguenth at gcc dot gnu.org
@ 2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
2021-11-29 9:08 ` jakub at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-11-29 8:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103046
--- Comment #4 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:41db2576afc4f3bf993778ad80529f2bf4ddd6cf
commit r11-9328-g41db2576afc4f3bf993778ad80529f2bf4ddd6cf
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Nov 5 10:20:10 2021 +0100
dwarf2out: Fix up CONST_WIDE_INT handling once more [PR103046]
My last change to CONST_WIDE_INT handling in add_const_value_attribute
broke
handling of CONST_WIDE_INT constants like ((__uint128_t) 1 << 120).
wi::min_precision (w1, UNSIGNED) in that case 121, but wide_int::from
creates a wide_int that has 0 and 0xff00000000000000ULL in its elts and
precision 121. When we output that, we output both elements and thus emit
0, 0xff00000000000000 instead of the desired 0, 0x0100000000000000.
IMHO we should actually pass machine_mode to add_const_value_attribute from
callers, so that we know exactly what precision we want. Because
hypothetically, if say mode is OImode and the CONST_WIDE_INT value fits
into
128 bits or 192 bits, we'd emit just those 128 or 192 bits but debug info
users would expect 256 bits.
On
typedef unsigned __int128 U;
int
main ()
{
U a = (U) 1 << 120;
U b = 0xffffffffffffffffULL;
U c = ((U) 0xffffffff00000000ULL) << 64;
return 0;
}
vanilla gcc incorrectly emits 0, 0xff00000000000000 for a,
0xffffffffffffffff alone (DW_FORM_data8) for b and 0, 0xffffffff00000000
for c. gcc with the previously posted PR103046 patch emits
0, 0x0100000000000000 for a, 0xffffffffffffffff alone for b and
0, 0xffffffff00000000 for c. And with this patch we emit
0, 0x0100000000000000 for a, 0xffffffffffffffff, 0 for b and
0, 0xffffffff00000000 for c.
So, the patch below certainly causes larger debug info (well, 128-bit
integers are pretty rare), but in this case the question is if it isn't
more correct, as debug info consumers generally will not know if they
should sign or zero extend the value in DW_AT_const_value.
The previous code assumes they will always zero extend it...
2021-11-05 Jakub Jelinek <jakub@redhat.com>
PR debug/103046
* dwarf2out.c (add_const_value_attribute): Add MODE argument, use
it
in CONST_WIDE_INT handling. Adjust recursive calls.
(add_location_or_const_value_attribute): Pass DECL_MODE (decl) to
new add_const_value_attribute argument.
(tree_add_const_value_attribute): Pass TYPE_MODE (type) to new
add_const_value_attribute argument.
(cherry picked from commit 155f6b2be421b0f84e478e34fbf72ee0bb9e36bc)
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug debug/103046] [11 Regression] Incorrect debug info for uint128 bit shift in gcc 11.2
2021-11-02 14:11 [Bug debug/103046] New: Incorrect debug info for uint128 bit shift in gcc 11.2 liyd2021 at gmail dot com
` (3 preceding siblings ...)
2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
@ 2021-11-29 9:08 ` jakub at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-11-29 9:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103046
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 11.3 too.
^ permalink raw reply [flat|nested] 6+ messages in thread