https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78684
--- Comment #6 from amker at gcc dot gnu.org --- (In reply to Jakub Jelinek from comment #5) > (In reply to amker from comment #4) > > (In reply to Jakub Jelinek from comment #3) > > > neg_step is true, because DR_STEP (dr_a.dr) is (ssizetype) -8. > > > But idx_step is 0xffffffffffffffffUL. > > > Note > > > tree_int_cst_compare (idx_step, size_zero_node) < 0 > > > is just weird, why don't you use tree_int_cst_sgn? > > > > Hi Jakub, do you mean tree_int_cst_sign_bit? Thanks. > > No, I mean what I wrote, i.e. > /* Return an indication of the sign of the integer constant T. > The return value is -1 if T < 0, 0 if T == 0, and 1 if T > 0. > Note that -1 will never be returned if T's type is unsigned. */ > > int > tree_int_cst_sgn (const_tree t) > ... > defined in tree.c. Ok, in this case I need to check idx_step is negative if it's signed type; or idx_step has sign bit if it's unsigned type (negative step in effect). tree_int_cst_sgn always returning 1 for (sizetype)-1 looks not working here? Thanks.
