[Bug tree-optimization/117692] [15 Regression] The VRP pass is introducing new signed integer overflow

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117692

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|The VRP pass is introducing |[15 Regression] The VRP
                   |new signed integer overflow |pass is introducing new
                   |                            |signed integer overflow
   Last reconfirmed|                            |2024-11-19
           Keywords|                            |wrong-code
             Status|UNCONFIRMED                 |NEW
   Target Milestone|---                         |15.0
     Ever confirmed|0                           |1

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> Applying pattern match.pd:5600, gimple-match-3.cc:3136
> gimple_simplified to _7 = x_2(D) * 25;
> _5 = _7 + 800;
> Folded into: _5 = _7 + 800;

This pattern:
/* ((X /[ex] C1) +- C2) * (C1 * C3)  -->  (X * C3) +- (C1 * C2 * C3).  */
(for op (plus minus)
 (simplify
  (mult (convert1? (op (convert2? (exact_div @0 INTEGER_CST@1))
                       poly_int_tree_p@2))
        poly_int_tree_p@3)
  (with { poly_widest_int factor; }
   (if (tree_nop_conversion_p (type, TREE_TYPE (@2))
        && tree_nop_conversion_p (TREE_TYPE (@0), TREE_TYPE (@2))
        && multiple_p (wi::to_poly_widest (@3), wi::to_widest (@1), &factor))
    (with
      {
        wi::overflow_type overflow;
        wide_int mul;
      }
     (if (types_match (type, TREE_TYPE (@2))
          && types_match (TREE_TYPE (@0), TREE_TYPE (@2))
          && TREE_CODE (@2) == INTEGER_CST
          && TREE_CODE (@3) == INTEGER_CST
          && (mul = wi::mul (wi::to_wide (@2), wi::to_wide (@3),
                             TYPE_SIGN (type), &overflow),
              !overflow))
      (op (mult @0 { wide_int_to_tree (type, factor); })
          { wide_int_to_tree (type, mul); })
      (with { tree utype = unsigned_type_for (type); }
       (convert (op (mult (convert:utype @0)
                          { wide_int_to_tree (utype, factor); })
                    (mult (convert:utype @3) (convert:utype @2)))))))))))


Caused by r15-4603-g8d01bc7dc453a4 .