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* [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c
@ 2010-12-03 20:26 changpeng.fang at amd dot com
2010-12-03 20:37 ` [Bug rtl-optimization/46793] " steven at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: changpeng.fang at amd dot com @ 2010-12-03 20:26 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46793
Summary: -fschedule-insns causes ICE in compiling zlib/trees.c
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: changpeng.fang@amd.com
-fschedule-insns causes ICE in compiling zlib/trees.c:
trees.c:701:1: error: unable to find a register to spill in class ‘Q_REGS’
This failure only occurs for -m32 compilation.
To reproduce:
cd trunk/zlib
gcc trees.c -c -o ~/tree.o -O2 -fschedule-insns -m32
[~/gcc-4.6-20101120/zlib]$ gcc trees.c -c -o ~/tree.o -O2 -fschedule-insns -m32
trees.c: In function ‘build_tree’:
trees.c:701:1: error: unable to find a register to spill in class ‘Q_REGS’
trees.c:701:1: error: this is the insn:
(insn 473 429 164 18 (set (subreg:SI (reg:QI 83 [ iftmp.7 ]) 0)
(if_then_else:SI (ltu (reg:CC 17 flags)
(const_int 0 [0]))
(subreg:SI (reg:QI 388) 0)
(subreg:SI (reg:QI 83 [ iftmp.7 ]) 0))) trees.c:677 854
{*movsicc_noc}
(expr_list:REG_DEAD (reg:QI 388)
(expr_list:REG_DEAD (reg:CC 17 flags)
(nil))))
trees.c:701:1: internal compiler error: in spill_failure, at reload1.c:2105
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
This should be a regression (I only know 4.3 is working)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/46793] -fschedule-insns causes ICE in compiling zlib/trees.c
2010-12-03 20:26 [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c changpeng.fang at amd dot com
@ 2010-12-03 20:37 ` steven at gcc dot gnu.org
2010-12-03 20:52 ` changpeng.fang at amd dot com
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: steven at gcc dot gnu.org @ 2010-12-03 20:37 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46793
Steven Bosscher <steven at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |steven at gcc dot gnu.org
Resolution| |WONTFIX
--- Comment #1 from Steven Bosscher <steven at gcc dot gnu.org> 2010-12-03 20:36:52 UTC ---
Try with -fsched-pressure?
But -fschedule-insns on 32-bits ix86 is a Really Bad Idea. There are plenty bug
reports for similar failures. There are just not enough registers and too many
special constraints. This is not a fixable issue, beyond keeping
-fschedule-insns disabled.
=> WONTFIX
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/46793] -fschedule-insns causes ICE in compiling zlib/trees.c
2010-12-03 20:26 [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c changpeng.fang at amd dot com
2010-12-03 20:37 ` [Bug rtl-optimization/46793] " steven at gcc dot gnu.org
@ 2010-12-03 20:52 ` changpeng.fang at amd dot com
2010-12-03 21:05 ` steven at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: changpeng.fang at amd dot com @ 2010-12-03 20:52 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46793
--- Comment #2 from Changpeng Fang <changpeng.fang at amd dot com> 2010-12-03 20:52:11 UTC ---
This bug should be fixed.
We are trying to make -fschedule-insns default for x86, and this enablement
causes
bootstrapping failure at this point.
Of course we can work around this by just enabling it for 64 bit.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/46793] -fschedule-insns causes ICE in compiling zlib/trees.c
2010-12-03 20:26 [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c changpeng.fang at amd dot com
2010-12-03 20:37 ` [Bug rtl-optimization/46793] " steven at gcc dot gnu.org
2010-12-03 20:52 ` changpeng.fang at amd dot com
@ 2010-12-03 21:05 ` steven at gcc dot gnu.org
2010-12-03 21:24 ` changpeng.fang at amd dot com
2010-12-03 23:05 ` joseph at codesourcery dot com
4 siblings, 0 replies; 6+ messages in thread
From: steven at gcc dot gnu.org @ 2010-12-03 21:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46793
--- Comment #3 from Steven Bosscher <steven at gcc dot gnu.org> 2010-12-03 21:05:46 UTC ---
The bug is in the architecture, not in the scheduling pass. You cannot expect
scheduling before register allocation to always yield code that you can
register-allocate with just 3 general registers available.
Enabling it only for AMD64 is not a work-around, it's the only proper thing to
do if you want to enable the pre-RA scheduling pass by default.
And there is still -fsched-pressure that you could try.
But I doubt you will get a patch approved to enable scheduling for 32-bits
ix86. The failure you are seeing can be triggered quite easily even _without_
scheduling enabled. Just search bugzilla for all the "unable to find spill
register" bugs on i386, this one is far from unique.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/46793] -fschedule-insns causes ICE in compiling zlib/trees.c
2010-12-03 20:26 [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c changpeng.fang at amd dot com
` (2 preceding siblings ...)
2010-12-03 21:05 ` steven at gcc dot gnu.org
@ 2010-12-03 21:24 ` changpeng.fang at amd dot com
2010-12-03 23:05 ` joseph at codesourcery dot com
4 siblings, 0 replies; 6+ messages in thread
From: changpeng.fang at amd dot com @ 2010-12-03 21:24 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46793
--- Comment #4 from Changpeng Fang <changpeng.fang at amd dot com> 2010-12-03 21:24:06 UTC ---
Thanks, I understand the issue now.
Yes, -fschedule-insns and -fsched-pressure should be a paired options for
x86. -fsched-pressure does not solve the -m32 issue.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/46793] -fschedule-insns causes ICE in compiling zlib/trees.c
2010-12-03 20:26 [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c changpeng.fang at amd dot com
` (3 preceding siblings ...)
2010-12-03 21:24 ` changpeng.fang at amd dot com
@ 2010-12-03 23:05 ` joseph at codesourcery dot com
4 siblings, 0 replies; 6+ messages in thread
From: joseph at codesourcery dot com @ 2010-12-03 23:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46793
--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2010-12-03 23:04:52 UTC ---
We should disable this option (with a warning) in
ix86_option_override_internal if we don't think it can work reliably,
rather than leaving it to ICE.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-12-03 23:05 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2010-12-03 20:26 [Bug rtl-optimization/46793] New: -fschedule-insns causes ICE in compiling zlib/trees.c changpeng.fang at amd dot com
2010-12-03 20:37 ` [Bug rtl-optimization/46793] " steven at gcc dot gnu.org
2010-12-03 20:52 ` changpeng.fang at amd dot com
2010-12-03 21:05 ` steven at gcc dot gnu.org
2010-12-03 21:24 ` changpeng.fang at amd dot com
2010-12-03 23:05 ` joseph at codesourcery dot com
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