[Bug tree-optimization/100958] two_value_replacement should move to match.pd

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100958

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is the start of the conversion to match.pd, there must be an easier way to
see the range too:
#if GIMPLE
/* Optimize
   x in range [cst1, cst2] where cst2 = cst1 + 1
   (x op CSTN) ? CST3 : CST4
   # where op is == or != and N is 1 or 2
   # where cst3 == cst4 + 1 or cst4 == cst3 + 1
   to x + (min (cst3, cst4) - cst1) or
  (min (cst3, cst4) + cst1) - x depending on op, N and which
   of cst3 and cst4 is smaller.  */
(for eqne (eq ne)
 (simplify
  (cond (eqne @0 INTEGER_CST@1) INTEGER_CST@2 INTEGER_CST@3)
  (if (tree_int_cst_lt (@2, @3)
       ? wi::to_widest (@2) + 1 != wi::to_widest (@3)
       : wi::to_widest (@3) + 1 != wi::to_widest (@2))
   (with { wide_int min, max;
           value_range r;
           get_range_query (cfun)->range_of_expr (r, lhs);

           if (r.kind () == VR_RANGE)
             {
               min = r.lower_bound ();
               max = r.upper_bound ();
             }
           else
             {
               int prec = TYPE_PRECISION (TREE_TYPE (lhs));
               signop sgn = TYPE_SIGN (TREE_TYPE (lhs));
               min = wi::min_value (prec, sgn);
               max = wi::max_value (prec, sgn);
             }
         }
    (if (min + 1 == max
         && (wi::to_wide (@1) == min
             || wi::to_wide (@1) == max))

#endif