http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49330
--- Comment #4 from rguenther at suse dot de <rguenther at suse dot de> 2011-06-09 10:08:55 UTC --- On Thu, 9 Jun 2011, jakub at gcc dot gnu.org wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49330 > > Jakub Jelinek <jakub at gcc dot gnu.org> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |jakub at gcc dot gnu.org > > --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-06-09 > 10:04:28 UTC --- > Ugh. > base_alias_check for > (symbol_ref:DI ("x") <var_decl 0x7ffff1a32000 x>) > and > (plus:DI (reg:DI 62 [ d.1 ]) > (symbol_ref:DI ("y") <var_decl 0x7ffff1a320a0 y>)) > returns 0. I'm afraid dropping the base_alias_check call would significantly > penalize generated code, after all we still sometimes have MEM accesses > without > MEM_EXPR. Perhaps we could rely on REG_POINTER bits, extend them to > SYMBOL_REF > too and only do return NULL from find_base_term if SYMBOL_REF doesn't have > SYMBOL_REF_POINTER bit set. During CSE etc., when replacing a pseudo with its > definition REG_POINTER/SYMBOL_REF_POINTER would be kept only if it is set on > the pseudo being optimized away as well. Thus, any casts from pointers to > correspondingly sized integers and back would be seen in the RTL. Maybe restrict the base_alias_check to var-decls that do not have their address taken? Points-to analysis should conver them. Richard.
