[Bug target/47908] New: attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[Bug target/47908] New: attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

           Summary: attribute((optimize(2))) causes ICE in
                    m68k_sched_issue_rate
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikpe@it.uu.se


When targeting m68k-linux, if a function declaration has
__attribute__((__optimize__(2))), then gcc ICEs in m68k_sched_issue_rate:

> cat O16384.c
__attribute__((__optimize__(2))) void foo (void) { }
> objdir/gcc/xgcc -Bobjdir/gcc -S O16384.c
O16384.c: In function 'foo':
O16384.c:1:1: internal compiler error: in m68k_sched_issue_rate, at
config/m68k/m68k.c:6055
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

The immediate cause is that m68k_sched_cpu indicates a non-ColdFire target, and
m68k_sched_issue_rate explicitly calls gcc_unreachable in that case.  I don't
know why attribute((optimize(2))) causes scheduling to be attempted, esp. since
m68k_option_override seems to disable a number of scheduling-related flags.

This bug causes gcc.dg/O16384.c to fail with gcc-4.4.5/4.5.2/4.6.0 on
m68k-linux.  With gcc-4.3.5 the optimize attribute is ignored and there is no
ICE.

> objdir/gcc/xgcc -v
Using built-in specs.
COLLECT_GCC=objdir/gcc/xgcc
Target: m68k-unknown-linux
Configured with: /tmp/gcc-4.6-20110219/configure --target=m68k-unknown-linux
--prefix=/home/mikpe/pkgs/linux-x86/cross-m68k
--with-gmp=/home/mikpe/pkgs/linux-x86/gmp-4.3.2
--with-mpfr=/home/mikpe/pkgs/linux-x86/mpfr-2.4.2
--with-mpc=/home/mikpe/pkgs/linux-x86/mpc-0.8.2 --disable-plugin --disable-lto
--disable-nls --enable-shared --disable-libmudflap --disable-multilib
--enable-threads=posix --enable-checking=release --enable-languages=c
Thread model: posix
gcc version 4.6.0 20110219 (experimental) (GCC)

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #1 from Mikael Pettersson <mikpe at it dot uu.se> 2011-02-26 21:04:19 UTC ---
Other test cases that fail for the same reason include gcc.dg/pr37106-1.c,
gcc.dg/pr43562.c, and gcc.dg/pr43564.c.

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #2 from Mikael Pettersson <mikpe at it dot uu.se> 2011-03-01 23:45:01 UTC ---
m68k needs to define TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE in order to override
the instruction scheduling options implied by attribute((optimize(2))).

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[alanh at fairlite dot co.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

Alan Hourihane <alanh at fairlite dot co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |alanh at fairlite dot co.uk

--- Comment #3 from Alan Hourihane <alanh at fairlite dot co.uk> 2011-04-10 18:36:37 UTC ---
I'm also hitting this when compiling tar 1.26 with gcc 4.5.2 from Gentoo.

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #4 from Mikael Pettersson <mikpe at it dot uu.se> 2011-04-11 07:36:17 UTC ---
I have fully tested patches to fix this for 4.4.5, 4.5.2, and 4.6.0 (presumably
that one will also work for 4.7 but I haven't checked), but I've avoided
posting them because the FSF hasn't yet confirmed that my copyright assignment
is in place. (They've had the papers for ages.) I just pinged them again.

Meanwhile you can just comment out any offending attribute((optimize(...))).

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[schwab@linux-m68k.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tg at mirbsd dot org

--- Comment #5 from Andreas Schwab <schwab@linux-m68k.org> 2011-07-26 20:57:11 UTC ---
*** Bug 49856 has been marked as a duplicate of this bug. ***

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[tg at mirbsd dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #6 from Thorsten Glaser <tg at mirbsd dot org> 2011-07-27 23:29:13 UTC ---
Mikael, can you please publish your “fully tested patches to fix this for
4.4.5, 4.5.2, and 4.6.0” so we can at least include this in the packages?

If the FSF itself (i.e. gnulib) starts using those pragmas which cause
this ICE, I think we’re going to see more and more popping up; I could
convince the maintainer of libvirt to include the m68k workaround in
his package (compile with -DWRAPV -fwrapv) but that doesn’t really scale.

Without the copyright assignment (WTF is going on there, mine took about
three weeks!) it’s still distributable under GPL, just with you as author.

Thanks!

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #7 from Mikael Pettersson <mikpe at it dot uu.se> 2011-07-29 11:44:34 UTC ---
Created attachment 24863
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24863
fix for gcc-4.5.3 and gcc-4.4.6

A patch for trunk and gcc-4.6.1 has been posted:
http://gcc.gnu.org/ml/gcc-patches/2011-07/msg02514.html

I'm attaching the corresponding patch for gcc-4.5.3 and gcc-4.4.6 here, in case
anyone needs the fix for those branches.

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[schwab at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #8 from Andreas Schwab <schwab at gcc dot gnu.org> 2011-07-31 15:01:02 UTC ---
Author: schwab
Date: Sun Jul 31 15:00:58 2011
New Revision: 176975

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176975
Log:
Author: Mikael Pettersson <mikpe@it.uu.se>

PR target/47908
* gcc/config/m68k/m68k.c (m68k_override_options_after_change): New function.
Disable instruction scheduling for non-ColdFire targets.
(TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE): Define.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/m68k/m68k.c

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[schwab at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #9 from Andreas Schwab <schwab at gcc dot gnu.org> 2011-07-31 15:09:28 UTC ---
Author: schwab
Date: Sun Jul 31 15:09:25 2011
New Revision: 176976

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176976
Log:
Author: Mikael Pettersson <mikpe@it.uu.se>

PR target/47908
* gcc/config/m68k/m68k.c (m68k_override_options_after_change): New function.
Disable instruction scheduling for non-ColdFire targets.
(TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE): Define.

Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/config/m68k/m68k.c

[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[owner at bugs dot debian.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

--- Comment #10 from owner at bugs dot debian.org 2011-08-01 13:45:23 UTC ---
Thank you for the additional information you have supplied regarding
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[Bug target/47908] attribute((optimize(2))) causes ICE in m68k_sched_issue_rate

[schwab@linux-m68k.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47908

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED

--- Comment #11 from Andreas Schwab <schwab@linux-m68k.org> 2011-08-22 11:58:27 UTC ---
Fixed for 4.6 and trunk.