http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51628
--- Comment #21 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2013-04-03 08:51:44 UTC --- > One of the C frontend issues is that the type of the address of > the field of the packed struct is int *, not int attribute((aligned(1))) > *. And this is so because nothing adjusts the type of the FIELD_DECL > to be a less aligned type. That is, we have > > <field_decl 0x7ffff6d245f0 i > type <integer_type 0x7ffff6d175e8 int public SI > size <integer_cst 0x7ffff6d1a0c0 constant 32> > unit size <integer_cst 0x7ffff6d1a0e0 constant 4> > align 32 symtab 0 alias set -1 canonical type 0x7ffff6d175e8 > precision 32 min <integer_cst 0x7ffff6d1a060 -2147483648> max <integer_cst > 0x7ffff6d1a080 2147483647> > pointer_to_this <pointer_type 0x7ffff6d1f2a0>> > packed SI file t.c line 2 col 9 size <integer_cst 0x7ffff6d1a0c0 32> > unit size <integer_cst 0x7ffff6d1a0e0 4> > align 8 offset_align 128 > offset <integer_cst 0x7ffff6d02d80 type <integer_type 0x7ffff6d17000 > sizetype> constant 0> > bit offset <integer_cst 0x7ffff6d02e00 type <integer_type > 0x7ffff6d170a8 bitsizetype> constant 0> context <record_type > 0x7ffff6e1c3f0 Foo>> This is on x86, right? If the alignment of the field cannot be guaranteed to be that of its type, then it should be made a bit-field. Maybe it's already made a bit-field on strict-alignment targets.
