Random cutnpasted suspicious warning, maybe related:

g++ -c   -g -O2 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE  -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wwrite-strings -Wcast-qual -Wmissing-format-attribute -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -fno-common  -DHAVE_CONFIG_H -DGENERATOR_FILE -I. -Ibuild -I/tmp/hpautotest-gcc0/gcc/gcc -I/tmp/hpautotest-gcc0/gcc/gcc/build -I/tmp/hpautotest-gcc0/gcc/gcc/../include -I/tmp/hpautotest-gcc0/gcc/gcc/../libcpp/include -I/tmp/hpautotest-gcc0/cris-elf/gccobj/./gmp -I/tmp/hpautotest-gcc0/gcc/gmp -I/tmp/hpautotest-gcc0/cris-elf/gccobj/./mpfr -I/tmp/hpautotest-gcc0/gcc/mpfr -I/tmp/hpautotest-gcc0/gcc/mpc/src  -I/tmp/hpautotest-gcc0/gcc/gcc/../libdecnumber -I/tmp/hpautotest-gcc0/gcc/gcc/../libdecnumber/dpd -I../libdecnumber -I/tmp/hpautotest-gcc0/gcc/gcc/../libbacktrace    \
		-o build/read-rtl.o /tmp/hpautotest-gcc0/gcc/gcc/read-rtl.c
In file included from /tmp/hpautotest-gcc0/gcc/gcc/rtl.h:29,
                 from /tmp/hpautotest-gcc0/gcc/gcc/read-rtl.c:30:
/tmp/hpautotest-gcc0/gcc/gcc/vec.h: In static member function 'static size_t vec<T, A, vl_embed>::embedded_size(unsigned int) [with T = mapping*, A = va_heap]':
/tmp/hpautotest-gcc0/gcc/gcc/vec.h:299:   instantiated from 'static void va_heap::reserve(vec<T, va_heap, vl_embed>*&, unsigned int, bool) [with T = mapping*]'
/tmp/hpautotest-gcc0/gcc/gcc/vec.h:1445:   instantiated from 'bool vec<T, A, vl_ptr>::reserve(unsigned int, bool) [with T = mapping*, A = va_heap]'
/tmp/hpautotest-gcc0/gcc/gcc/vec.h:1540:   instantiated from 'T* vec<T, A, vl_ptr>::safe_push(const T&) [with T = mapping*, A = va_heap]'
/tmp/hpautotest-gcc0/gcc/gcc/read-rtl.c:389:   instantiated from here
/tmp/hpautotest-gcc0/gcc/gcc/vec.h:1069: warning: invalid access to non-static data member 'vec<mapping*, va_heap, vl_embed>::data_'  of NULL object
/tmp/hpautotest-gcc0/gcc/gcc/vec.h:1069: warning: (perhaps the 'offsetof' macro was used incorrectly)

(In reply to comment #0)
> /tmp/hpautotest-gcc0/gcc/libgfortran/generated/matmul_i1.c:79:1: internal
> compiler error: Illegal instruction

Not observed with gcc-4.7.2-2.fc17.x86_64.

BTW, SIGILL sounds like it's forced by gcc in response to something it sees as invalid, that must not be executed.

(In reply to comment #2)
> (In reply to comment #0)
> > /tmp/hpautotest-gcc0/gcc/libgfortran/generated/matmul_i1.c:79:1: internal
> > compiler error: Illegal instruction
> 
> Not observed with gcc-4.7.2-2.fc17.x86_64.

But does happen with "gcc version 4.1.2 20070925 (Red Hat 4.1.2-33)" as well as "gcc version 4.4.5 (Debian 4.4.5-8)".

And those are the gcc versions I have at an arm-length.  There's more at CFarm, but IIRC most of them are gcc-4.4 era and earlier.

Maybe there's some -fpermissive or -fno-strict-aliasing combo to stick there.
I don't really like the thought of raising the minimum gcc version already...

I could get this problem with my native build. 

gcc version used for build is 4.3.4 [gcc-4_3-branch revision 152973]

I'm seeing the same failure for PowerPC build of trunk.

Minimal test case (with minimal options) reduced from matmul_i1.i:

[bergner@igoo pr55381]$ cat pr55381.i 
void
foo (char * dest, char s, long ycount)
{
  long y;
  for (y = 0; y < ycount; y++)
    dest[y] = s;
}
[bergner@igoo pr55381]$ /home/bergner/gcc/build/gcc-fsf-mainline-asan-pthaugen/./gcc/xgcc -B/home/bergner/gcc/build/gcc-fsf-mainline-asan-pthaugen/./gcc/ -ftree-vectorize -O1 -S pr55381.i 
xgcc: internal compiler error: Trace/breakpoint trap (program cc1)
0x100079a3 execute
	/home/bergner/gcc/gcc-fsf-mainline-asan/gcc/gcc.c:2772
0x1000c8d7 do_spec(char const*)
	/home/bergner/gcc/gcc-fsf-mainline-asan/gcc/gcc.c:4245
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

I saw this using a 4.4.6 based compiler.

Also broken on ia64 with gcc 4.3.2.

/usr/local/gcc/test/Build/./gcc/xgcc -B/usr/local/gcc/test/Build/./gcc/ -B/usr/ia64-suse-linux/bin/ -B/usr/ia64-suse-linux/lib/ -isystem /usr/ia64-suse-linux/include -isystem /usr/ia64-suse-linux/sys-include    -O2 -g -O2  -O2 -g -DIN_GCC   -DUSE_LIBUNWIND_EXCEPTIONS -W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include   -fPIC -DUSE_GAS_SYMVER -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector   -fPIC -DUSE_GAS_SYMVER -I. -I. -I../.././gcc -I../../../libgcc -I../../../libgcc/. -I../../../libgcc/../gcc -I../../../libgcc/../include  -DHAVE_CC_TLS  -o _mulvdi3.o -MT _mulvdi3.o -MD -MP -MF _mulvdi3.dep -DL_mulvdi3 -c ../../../libgcc/libgcc2.c -fvisibility=hidden -DHIDE_EXPORTS
../../../libgcc/libgcc2.c: In function ‘__mulvti3’:
../../../libgcc/libgcc2.c:397:1: internal compiler error: Segmentation fault
 }
 ^
0x40000000008bc6cf crash_signal
        ../../gcc/toplev.c:334
0x4000000000cb49bf vec<rtx_def*, va_stack, vl_ptr>::reserve(unsigned int, bool)
        ../../gcc/vec.h:1443
0x4000000000cb49bf vec<rtx_def*, va_stack, vl_ptr>::safe_push(rtx_def* const&)
        ../../gcc/vec.h:1540
0x4000000000cb49bf values_to_stack
        ../../gcc/var-tracking.c:8585
0x4000000001083dcf htab_traverse_noresize
        ../../libiberty/hashtab.c:784
0x4000000000cabdbf process_changed_values
        ../../gcc/var-tracking.c:8704
0x4000000000cac1bf emit_notes_for_changes
        ../../gcc/var-tracking.c:8743
0x4000000000cadaaf emit_notes_for_differences
        ../../gcc/var-tracking.c:8863
0x4000000000cadaaf vt_emit_notes
        ../../gcc/var-tracking.c:9238
0x4000000000cb476f variable_tracking_main_1
        ../../gcc/var-tracking.c:10066
0x4000000000cb476f variable_tracking_main()
        ../../gcc/var-tracking.c:10080
0x4000000000d0254f ia64_reorg
        ../../gcc/config/ia64/ia64.c:9798
0x40000000007fd05f rest_of_handle_machine_reorg
        ../../gcc/reorg.c:4152

I don't have access to old compilers locally.  I'm trying with a cross from one of the sparc boxes in the farm that has gcc 4.3.2.

(In reply to comment #8)
> I don't have access to old compilers locally.  I'm trying with a cross from one
> of the sparc boxes in the farm that has gcc 4.3.2.

Revision r193667 seems to have fixed this, not unexpectedly.

(In reply to comment #9)
> Revision r193667 seems to have fixed this, not unexpectedly.

...so I just went ahead and closed this PR.