[Bug lto/51635] [4.7 regression] ICE in in dwarf2out_finish, at dwarf2out.c:22494 when building Firefox's libxul

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51635

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-12-20 12:13:27 UTC ---
(gdb) call debug_tree (context)
 <record_type 0x7ffff58bd7e0 nsSVGEffects asm_written QI
...
(gdb) call debug_tree (context->type_common.name)
 <type_decl 0x7ffff58ad958 nsSVGEffects
    type <record_type 0x7ffff58bd7e0 nsSVGEffects asm_written QI
...
    public VOID file /tmp/test2.ii line 3256 col 17
    align 8 context <translation_unit_decl 0x7ffff5a42f18 D.2349>>
(gdb) call lookup_type_die (context)
$1 = (struct die_struct *) 0x7ffff58fdd70
(gdb) call debug_tree (node->created_for)
 <type_decl 0x7ffff58dc2e0 FramePropertyDescriptor
    type <record_type 0x7ffff58bd9d8 FramePropertyDescriptor BLK
...
    asm_written used nonlocal VOID file /tmp/test.ii line 2611 col 51
    align 1 context <record_type 0x7ffff58bd7e0 nsSVGEffects>

so it's DECL_CONTEXT is a type from a different TU.  And indeed in the
types TYPE_FIELDS we have

 <type_decl 0x7ffff58ada10 nsSVGEffects
    type <record_type 0x7ffff58bd7e0 nsSVGEffects asm_written QI

which is another instance of the TYPE_DECL.  That asks for proper merging
of those TYPE_DECLs :(