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* [Bug c/31642] New: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc
@ 2007-04-20 14:45 kenneth dot hoste at elis dot ugent dot be
2007-04-20 17:25 ` [Bug middle-end/31642] " pinskia at gcc dot gnu dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: kenneth dot hoste at elis dot ugent dot be @ 2007-04-20 14:45 UTC (permalink / raw)
To: gcc-bugs
Using -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts
-fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop
-ftree-copyrename on the SPEC CPU2000 benchmark 176.gcc yields an infinite loop
(using the train input which usually runs for 2s runs for hours).
This is confirmed on Fedora Core 4 / x86 (Intel Pentium 4), and also on an
linux/amd64 for which I have no details.
Removing any of the -fno-X flags seems to solve the issue, and adding
-ffloat-store doesn't change a thing, which suggests this is not floating-point
(convergence) related.
--
Summary: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-
tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-
tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-
copyrename yields an infinite loop in SPEC benchmark
176.gcc
Product: gcc
Version: 4.1.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: kenneth dot hoste at elis dot ugent dot be
GCC host triplet: i686-Linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31642
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug middle-end/31642] -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc
2007-04-20 14:45 [Bug c/31642] New: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc kenneth dot hoste at elis dot ugent dot be
@ 2007-04-20 17:25 ` pinskia at gcc dot gnu dot org
2007-04-20 18:24 ` [Bug c/31642] " kenneth dot hoste at elis dot ugent dot be
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-04-20 17:25 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2007-04-20 18:24 -------
We need a testcase.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |pinskia at gcc dot gnu dot
| |org
Status|UNCONFIRMED |WAITING
Component|c |middle-end
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31642
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug c/31642] -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc
2007-04-20 14:45 [Bug c/31642] New: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc kenneth dot hoste at elis dot ugent dot be
2007-04-20 17:25 ` [Bug middle-end/31642] " pinskia at gcc dot gnu dot org
@ 2007-04-20 18:24 ` kenneth dot hoste at elis dot ugent dot be
2007-04-20 19:52 ` [Bug middle-end/31642] " kenneth dot hoste at elis dot ugent dot be
2008-02-03 14:22 ` steven at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: kenneth dot hoste at elis dot ugent dot be @ 2007-04-20 18:24 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from kenneth dot hoste at elis dot ugent dot be 2007-04-20 19:24 -------
(In reply to comment #1)
> We need a testcase.
>
I would provide one if I knew how, I'm quite new at this... Any pointers?
--
kenneth dot hoste at elis dot ugent dot be changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|middle-end |c
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31642
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug middle-end/31642] -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc
2007-04-20 14:45 [Bug c/31642] New: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc kenneth dot hoste at elis dot ugent dot be
2007-04-20 17:25 ` [Bug middle-end/31642] " pinskia at gcc dot gnu dot org
2007-04-20 18:24 ` [Bug c/31642] " kenneth dot hoste at elis dot ugent dot be
@ 2007-04-20 19:52 ` kenneth dot hoste at elis dot ugent dot be
2008-02-03 14:22 ` steven at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: kenneth dot hoste at elis dot ugent dot be @ 2007-04-20 19:52 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from kenneth dot hoste at elis dot ugent dot be 2007-04-20 20:51 -------
identifying source code lines corresponding to infinite loop using GDB:
(gdb) backtrace
#0 regclass (f=0x9ac29f4, nregs=71) at regclass.c:732
#1 0x08065d5c in rest_of_compilation (decl=0x9b4526c) at toplev.c:3056
#2 0x0805713b in finish_function (nested=0) at c-decl.c:6791
#3 0x08048a25 in yyparse () at c-parse.c:1684
#4 0x08066a83 in compile_file (name=Variable "name" is not available.
) at toplev.c:2227
#5 0x080681a3 in main (argc=4, argv=0xbf945ea4) at toplev.c:3921
(gdb) n
736 else if ((GET_CODE (insn) == INSN
(gdb) n
717 for (insn = f; insn; insn = NEXT_INSN (insn))
(gdb) n
729 if (GET_CODE (insn) == NOTE
(gdb) n
732 else if (GET_CODE (insn) == NOTE
(gdb) n
736 else if ((GET_CODE (insn) == INSN
(gdb) n
717 for (insn = f; insn; insn = NEXT_INSN (insn))
(gdb) backtrace
#0 regclass (f=0x9ac29f4, nregs=71) at regclass.c:717
#1 0x08065d5c in rest_of_compilation (decl=0x9b4526c) at toplev.c:3056
#2 0x0805713b in finish_function (nested=0) at c-decl.c:6791
#3 0x08048a25 in yyparse () at c-parse.c:1684
#4 0x08066a83 in compile_file (name=Variable "name" is not available.
) at toplev.c:2227
#5 0x080681a3 in main (argc=4, argv=0xbf945ea4) at toplev.c:3921
(gdb)
The program seems stuck in the for-loop at line 717. The value for insn
seems to be cycling (it's taking different values, but cycles back to a
previous value).
Any pointers on how to reduce this further are welcome... Since this is
(pretty old though) GCC code (the 176.gcc corresponds to a 2.x version of GCC I
believe), maybe someone can shed soem light on this? I'm not at all familiar
with GCCs insides...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31642
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug middle-end/31642] -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc
2007-04-20 14:45 [Bug c/31642] New: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc kenneth dot hoste at elis dot ugent dot be
` (2 preceding siblings ...)
2007-04-20 19:52 ` [Bug middle-end/31642] " kenneth dot hoste at elis dot ugent dot be
@ 2008-02-03 14:22 ` steven at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: steven at gcc dot gnu dot org @ 2008-02-03 14:22 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from steven at gcc dot gnu dot org 2008-02-03 14:21 -------
No test case, no activity, and, really, quite old already. Please re-open if
you can still reproduce this.
--
steven at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31642
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2008-02-03 14:22 UTC | newest]
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2007-04-20 14:45 [Bug c/31642] New: -O2 -fno-guess-branch-probability -fno-tree-ch -fno-tree-dominator-opts -fno-tree-lrs -fno-tree-dce -fno-tree-vrp -funit-at-a-time -ftree-copy-prop -ftree-copyrename yields an infinite loop in SPEC benchmark 176.gcc kenneth dot hoste at elis dot ugent dot be
2007-04-20 17:25 ` [Bug middle-end/31642] " pinskia at gcc dot gnu dot org
2007-04-20 18:24 ` [Bug c/31642] " kenneth dot hoste at elis dot ugent dot be
2007-04-20 19:52 ` [Bug middle-end/31642] " kenneth dot hoste at elis dot ugent dot be
2008-02-03 14:22 ` steven at gcc dot gnu dot org
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