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* [Bug rtl-optimization/55025] New: reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers
@ 2012-10-22 16:25 aurelien.buhrig.gcc at gmail dot com
2012-10-23 9:44 ` [Bug rtl-optimization/55025] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: aurelien.buhrig.gcc at gmail dot com @ 2012-10-22 16:25 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55025
Bug #: 55025
Summary: reg_nonzero_bits_for_combine/get_last_value: missing
mode check for hardware registers
Classification: Unclassified
Product: gcc
Version: 4.6.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: aurelien.buhrig.gcc@gmail.com
Created attachment 28511
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28511
patch
This bug occurs with gcc 4.6.3 for a private backend (big endian), but should
occurs on trunk. The testcase is pr27364.c, compiled with -Os.
In the following RTL, the hardware register (reg:HI r2), whose natural mode is
HImode, is set to 0, but when combining insn 12 and insn 13 insn (during
combine pass), the (reg:SI r2) is computed to be equivalent to
(const_int 0), which is wrong (it is (reg:HI r2) which is (const_int 0)).
(insn 51 9 52 3 (set (reg:HI 2 r2)
(const_int 0 [0])) gcc.c-torture/execute/pr27364.c:5 18 {*movhi1}
(expr_list:REG_DEAD (reg:HI 31)
(expr_list:REG_EQUAL (const_int 0 [0])
(nil))))
(insn 52 51 12 3 (set (reg:HI 3 r3 [orig:2+2 ] [2])
(reg/v:HI 20 [ number_of_digits_to_use ]))
gcc.c-torture/execute/pr27364.c:5 18 {*movhi1}
(expr_list:REG_DEAD (reg/v:HI 20 [ number_of_digits_to_use ])
(nil)))
(insn 12 52 13 3 (set (reg:SI 0 r0)
(const_int 3321928 [0x32b048]))
gcc.c-torture/execute/pr27364.c:5 19 {movsi}
(nil))
(insn 13 12 16 3 (parallel [
(set (reg:SI 0 r0)
(mult:SI (reg:SI 2 r2)
(reg:SI 0 r0)))
(clobber (reg:SI 2 r2))
]) gcc.c-torture/execute/pr27364.c:5 54 {*mulsi3_call}
(expr_list:REG_EQUAL (mult:SI (reg:SI 2 r2)
(const_int 3321928 [0x32b048]))
(expr_list:REG_DEAD (reg:HI 3 r3)
(expr_list:REG_UNUSED (reg:SI 2 r2)
(nil)))))
The problem comes from a missing mode check in both
reg_nonzero_bits_for_combine and get_last_value.
See http://gcc.gnu.org/ml/gcc/2012-10/msg00263.html for more information.
Note that the problem in get_last_value has already been reported (bug 49884).
The attached patch fixes the issue in gcc-4.6.3. Not yet boostraped on trunk.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug rtl-optimization/55025] reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers
2012-10-22 16:25 [Bug rtl-optimization/55025] New: reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers aurelien.buhrig.gcc at gmail dot com
@ 2012-10-23 9:44 ` rguenth at gcc dot gnu.org
2013-11-29 16:07 ` paulo@matos-sorge.com
2021-08-16 23:42 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-10-23 9:44 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55025
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2012-10-23 09:43:43 UTC ---
Please send patches to gcc-patches@gcc.gnu.org
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug rtl-optimization/55025] reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers
2012-10-22 16:25 [Bug rtl-optimization/55025] New: reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers aurelien.buhrig.gcc at gmail dot com
2012-10-23 9:44 ` [Bug rtl-optimization/55025] " rguenth at gcc dot gnu.org
@ 2013-11-29 16:07 ` paulo@matos-sorge.com
2021-08-16 23:42 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: paulo@matos-sorge.com @ 2013-11-29 16:07 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55025
Paulo J. Matos <paulo@matos-sorge.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |paulo@matos-sorge.com
--- Comment #2 from Paulo J. Matos <paulo@matos-sorge.com> ---
I think this can be closed. 4.6 is not maintained anymore and this is fixed in
current versions.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug rtl-optimization/55025] reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers
2012-10-22 16:25 [Bug rtl-optimization/55025] New: reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers aurelien.buhrig.gcc at gmail dot com
2012-10-23 9:44 ` [Bug rtl-optimization/55025] " rguenth at gcc dot gnu.org
2013-11-29 16:07 ` paulo@matos-sorge.com
@ 2021-08-16 23:42 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-16 23:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55025
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Target Milestone|--- |8.3
Keywords| |wrong-code
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=85805,
| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=71976
Known to work| |8.3.0, 9.1.0
Resolution|--- |FIXED
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
reg_nonzero_bits_for_combine was fixed at r9-2022 and got backported to gcc 8.3
by r8-9084.
get_last_value was fixed at r7-2295 and backported to GCC 6.2.0 by r6-8363 and
to gcc 5.5 by r5-9832.
So fully fixed for GCC 8.3.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-10-22 16:25 [Bug rtl-optimization/55025] New: reg_nonzero_bits_for_combine/get_last_value: missing mode check for hardware registers aurelien.buhrig.gcc at gmail dot com
2012-10-23 9:44 ` [Bug rtl-optimization/55025] " rguenth at gcc dot gnu.org
2013-11-29 16:07 ` paulo@matos-sorge.com
2021-08-16 23:42 ` pinskia at gcc dot gnu.org
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