http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51994
--- Comment #34 from rguenther at suse dot de <rguenther at suse dot de> 2012-02-02 08:56:04 UTC --- On Wed, 1 Feb 2012, ebotcazou at gcc dot gnu.org wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51994 > > --- Comment #32 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2012-02-01 > 16:34:30 UTC --- > > The base object can be an indirect reference, so yes, there doesn't have > > to be an overall positive offset (well, yes, to the _real_ object, > > but we don't see that). > > If this is an indirect reference, there is no base object by definition. So > I'm not sure we should care in get_inner_reference and, in any case, I'm not > sure what to do. Probably avoid sending MEM_REF to get_inner_reference in > this > case, > after all it's clearly not a handled_component_p-like thing. Well, you can have component refs wrapped around a MEM_REF (or formerly an INDIRECT_REF). The only difference now is that the MEM_REF may have a (negative) constant offset embedded. Now, only if the MEM_REF is based on an ADDR_EXPR (and thus a real object) we factor in its (possibly negative) offset to bitpos. So, hum - now I don't see as easily that we can get a negative bitpos from a not undefined input ... (maybe except for the Ada fat pointer case). So your patch is probably ok (can you try verifying we don't get (too much) codegen differences on a bootstrap?) Richard.
