On Tue, 26 May 2015, Jan Hubicka wrote: > > Hi, > > > > On Fri, 22 May 2015, Jan Hubicka wrote: > > > > > Index: tree-streamer-out.c > > > =================================================================== > > > --- tree-streamer-out.c (revision 223508) > > > +++ tree-streamer-out.c (working copy) > > > @@ -346,6 +346,7 @@ pack_ts_type_common_value_fields (struct > > > alias-set zero to this type. */ > > > bp_pack_var_len_int (bp, (TYPE_ALIAS_SET (expr) == 0 > > > || (!in_lto_p > > > + && type_with_alias_set_p (expr) > > > && get_alias_set (expr) == 0)) ? 0 : -1); > > > > I find such interfaces very ugly. IOW, when it's always (or often) > > necessary to call check_foo_p() before foo() can be called then the > > checking should be part of foo() (and it should then return a conservative > > value, i.e. alias set 0), and that requirement not be imposed on the > > callers of foo(). I.e. why can't whatever checks you do in > > type_with_alias_set_p be included in get_alias_set? > > Because of sanity checking: I want to make alias sets of those types undefined > rather than having random values. The point is that using the alias set in > alias oracle querry is wrong.
You could have just returned 0 for the alias-set for !type_with_alias_set_p in get_alias_set. That avoids polluting the alias data structures and is neither random or wrong. > Now I run into the case that we do produce MEM exprs for incomplete variants > just to take their address so I was thinking the other day about defining an > invalid alias set -2, making get_alias_set to return it and ICE later when > query > is actually made? > > We do have wrong query problems at least in ipa-icf, so I think it is > worthwhile > sanity check. > > > > > + front-end routine) and use it. > > > + > > > + We may be called to produce MEM RTX for variable of incomplete type. > > > + This MEM RTX will only be used to produce address of a vairable, so > > > + we do not need to compute alias set. */ > > > + if (!DECL_P (t) || type_with_alias_set_p (TYPE_MAIN_VARIANT (TREE_TYPE > > > (t)))) > > > + attrs.alias = get_alias_set (t); > > > > And if the checking needs to go down the main-variant chain then this > > should be done inside type_with_alias_set_p(), not in the caller, > > otherwise even the symmetry between arguments of type_with_alias_set_p(xy) > > and get_alias_set(xy) is destroyed (but see above for why I think > > type_with_alias_set_p shouldn't even exist). > > Yep, good point - I will cleanup this. > > Honza > > -- Richard Biener <rguent...@suse.de> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham Norton, HRB 21284 (AG Nuernberg)
