http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49721
--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> 2011-07-28 21:39:47 UTC --- (In reply to comment #3) > (In reply to comment #2) > > The question is we have > > > > (zero_extend:DI (plus:SI (FOO:SI) (const_int Y))) > > > > Is is OK to transform it to > > > > (plus:DI (zero_extend:DI (FOO:SI)) (const_int Y)) > > It is valid if addresses can never extend across singed SI_MAX and SI_MIN. For POINTERS_EXTEND_UNSIGNED > 0, the valid address arrange is 0 to UINT_MAX.