[Bug middle-end/67912] New: [6 regression] ICE in gen_lowpart_common, at emit-rtl.c:1399

["ro at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67912

            Bug ID: 67912
           Summary: [6 regression] ICE in gen_lowpart_common, at
                    emit-rtl.c:1399
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: hubicka at gcc dot gnu.org
  Target Milestone: ---
              Host: i386-pc-solaris2.*
            Target: i386-pc-solaris2.*
             Build: i386-pc-solaris2.*

Solaris/x86 bootstrap is currently broken compiling the 64-bit s-regpat.adb:

$ /var/gcc/regression/trunk/10-gcc/build/./gcc/xgcc
-B/var/gcc/regression/trunk/10-gcc/build/./gcc/
-B/vol/gcc/i386-pc-solaris2.10/bin/ -B/vol/gcc/i386-pc-solaris2.10/lib/
-isystem /vol/gcc/i386-pc-solaris2.10/include -isystem
/vol/gcc/i386-pc-solaris2.10/sys-include    -c -g -O2 -m64 -fpic  -W -Wall
-gnatpg -nostdinc -m64  s-regpat.adb -o s-regpat.o
+===========================GNAT BUG DETECTED==============================+
| 6.0.0 20151009 (experimental) [trunk revision 228636] (i386-pc-solaris2.10)
GCC error:|
| in gen_lowpart_common, at emit-rtl.c:1399                                |
| Error detected around s-regpat.adb:1029:22           

This happens already with the stage1 compiler, though.  A reghunt determined
that
this patch

2015-10-07  Jan Hubicka  <hubicka@ucw.cz>

        * expr.c (store_expr_with_bounds): Handle aggregate moves from
        BLKmode.
        * gimple-expr.c (useless_type_conversion_p): Do not use TYPE_CANONICAL
        to define gimple type system; compare aggregates only by size.

is the culprit.

  Rainer