http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56474
--- Comment #13 from rguenther at suse dot de <rguenther at suse dot de> 2013-03-05 09:05:04 UTC --- On Mon, 4 Mar 2013, ebotcazou at gcc dot gnu.org wrote: > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56474 > > --- Comment #12 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2013-03-04 > 16:18:21 UTC --- > > So, can the Ada FE be changed to use that? Hacks like this belong with a > > comment in the FE that needs them IMHO. > > The 2 other related hacks are in stor-layout.c line 2214 and 2236 though and > there are a lot of calls to size_binop in the Ada front-end. IMO this one is > really benign compared to the others. Note the hacks all boil down to the fact that FEs use signed array domains but unsigned sizetype TYPE_DOMAIN. The C and C++ FE were adjusted to use (unsigned) [1, 0] for zero-sized arrays - I believe the current hacks are all because of Ada (and yes, I invented them to not need to fiddle with the Ada FE when removing TYPE_IS_SIZETYPE). There is still the Ada FE bug I opened that shows that arrays with [0, USIZETYPE_MAX] vs. [SSIZETYPE_MIN, SSIZETYPE_MAX] do not work. Independent of any hacks to fix the current error to address that you need to work to fix the signedness issue (which may of course require middle-end adjustments). If you don't want overflow you can as well re-set TREE_OVERFLOW on the result ... (just to give another option).
