http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51895
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-19 10:16:07 UTC --- (In reply to comment #3) > > bftype = TREE_TYPE (base); > > if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode) > > bftype = TREE_TYPE (exp); > > return expand_expr (build3 (BIT_FIELD_REF, bftype, > > base, > > TYPE_SIZE (TREE_TYPE (exp)), > > bit_offset), > > target, tmode, modifier); > > base here is TImode (x PARM_DECL), but exp is BLKmode, so this returns a > > TImode > > pseudo. Shouldn't it store it into a BLKmode temporary and return that MEM > > instead? > > Using a BIT_FIELD_REF looked most convenient. Using extract_bit_field > may also be an option (which I suppose is what the above ends up doing?) I think if exp is BLKmode, then we don't want to do a BIT_FIELD_REF nor extract_bit_field. We IMHO need to store base into a temporary and just adjust the MEM. Or extract the bit field and then store it into a temporary and adjust, but the former looks easier.
