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* [Bug middle-end/53303] New: Reload/RA issue on paradoxical subreg of subword regsiter for big endian targets
@ 2012-05-10 9:05 aurelien.buhrig.gcc at gmail dot com
2012-05-10 22:48 ` [Bug middle-end/53303] Reload/RA issue on word-sized paradoxical subregs for big-endian targets ebotcazou at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: aurelien.buhrig.gcc at gmail dot com @ 2012-05-10 9:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53303
Bug #: 53303
Summary: Reload/RA issue on paradoxical subreg of subword
regsiter for big endian targets
Classification: Unclassified
Product: gcc
Version: 4.6.3
Status: UNCONFIRMED
Severity: critical
Priority: P3
Component: middle-end
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: aurelien.buhrig.gcc@gmail.com
There is a RA issue with paradoxical subreg of sub-word register on big endian
targets.
It occurs on a private target but seems also to occur on the sparc 64-bit
target for 32-bit FP registers, and perhaps on hp-pa.
http://gcc.gnu.org/ml/gcc/2012-05/msg00028.html
The given workarounds do not work for my backend.
The target has SImode word_mode and for such an insn (generated during
combine):
(set (subreg:SI (reg:QI 21) 0)
(lshiftrt:SI (reg/v:SI 24) (const_int 31 [0x1f]))
reg:QI 21 is reloaded into (reg:QI 0 r0 [orig:21] [21]).
r0 is a HI register, which makes find_dummy_reload generating a segfault after
computing the subreg:SI regno, which is then -1.
I quickly had a look at assign_hard_reg (ira-color.c) but it seems the
information about such paradoxical subreg is not available from ira_allocno_t
nor ira_object_t when choosing the hard reg, and I'm not sure what to do.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/53303] Reload/RA issue on word-sized paradoxical subregs for big-endian targets
2012-05-10 9:05 [Bug middle-end/53303] New: Reload/RA issue on paradoxical subreg of subword regsiter for big endian targets aurelien.buhrig.gcc at gmail dot com
@ 2012-05-10 22:48 ` ebotcazou at gcc dot gnu.org
2012-05-24 7:51 ` aurelien.buhrig.gcc at gmail dot com
2012-06-18 16:14 ` [Bug middle-end/53303] Reload/RA issue on word paradoxical subregs aurelien.buhrig.gcc at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: ebotcazou at gcc dot gnu.org @ 2012-05-10 22:48 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53303
Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-05-10
CC| |ebotcazou at gcc dot
| |gnu.org
Version|4.6.3 |4.8.0
Summary|Reload/RA issue on |Reload/RA issue on
|paradoxical subreg of |word-sized paradoxical
|subword regsiter for big |subregs for big-endian
|endian targets |targets
Ever Confirmed|0 |1
Severity|critical |major
--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2012-05-10 22:42:55 UTC ---
This isn't critical for the FSF compiler, but nevertheless a major issue on BE.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/53303] Reload/RA issue on word-sized paradoxical subregs for big-endian targets
2012-05-10 9:05 [Bug middle-end/53303] New: Reload/RA issue on paradoxical subreg of subword regsiter for big endian targets aurelien.buhrig.gcc at gmail dot com
2012-05-10 22:48 ` [Bug middle-end/53303] Reload/RA issue on word-sized paradoxical subregs for big-endian targets ebotcazou at gcc dot gnu.org
@ 2012-05-24 7:51 ` aurelien.buhrig.gcc at gmail dot com
2012-06-18 16:14 ` [Bug middle-end/53303] Reload/RA issue on word paradoxical subregs aurelien.buhrig.gcc at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: aurelien.buhrig.gcc at gmail dot com @ 2012-05-24 7:51 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53303
--- Comment #2 from Aurelien Buhrig <aurelien.buhrig.gcc at gmail dot com> 2012-05-24 07:43:39 UTC ---
This bug is very annoying for me. I can't really work around it.
Let me know if there is something I can do to help fixing it...
Cheers,
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/53303] Reload/RA issue on word paradoxical subregs
2012-05-10 9:05 [Bug middle-end/53303] New: Reload/RA issue on paradoxical subreg of subword regsiter for big endian targets aurelien.buhrig.gcc at gmail dot com
2012-05-10 22:48 ` [Bug middle-end/53303] Reload/RA issue on word-sized paradoxical subregs for big-endian targets ebotcazou at gcc dot gnu.org
2012-05-24 7:51 ` aurelien.buhrig.gcc at gmail dot com
@ 2012-06-18 16:14 ` aurelien.buhrig.gcc at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: aurelien.buhrig.gcc at gmail dot com @ 2012-06-18 16:14 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53303
Aurelien Buhrig <aurelien.buhrig.gcc at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|Reload/RA issue on |Reload/RA issue on word
|word-sized paradoxical |paradoxical subregs
|subregs for big-endian |
|targets |
--- Comment #3 from Aurelien Buhrig <aurelien.buhrig.gcc at gmail dot com> 2012-06-18 16:14:17 UTC ---
This bug does not depends on endianess.
It also occurs on little endian target, when RA allocates such a paradoxical
register with the last hardware register which is smaller than a word (in
comparison with the first register for big-endian targets).
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-06-18 16:14 UTC | newest]
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2012-05-10 9:05 [Bug middle-end/53303] New: Reload/RA issue on paradoxical subreg of subword regsiter for big endian targets aurelien.buhrig.gcc at gmail dot com
2012-05-10 22:48 ` [Bug middle-end/53303] Reload/RA issue on word-sized paradoxical subregs for big-endian targets ebotcazou at gcc dot gnu.org
2012-05-24 7:51 ` aurelien.buhrig.gcc at gmail dot com
2012-06-18 16:14 ` [Bug middle-end/53303] Reload/RA issue on word paradoxical subregs aurelien.buhrig.gcc at gmail dot com
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