[Bug middle-end/103406] [12 Regression] gcc -O0 behaves differently on "DBL_MAX related operations" than gcc -O1 and above

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103406

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
simplify_binary_operation_1 has

      /* ((-a) + b) -> (b - a) and similarly for (a + (-b)).  These
         transformations are safe even for IEEE.  */
      if (GET_CODE (op0) == NEG)
        return simplify_gen_binary (MINUS, mode, op1, XEXP (op0, 0));
      else if (GET_CODE (op1) == NEG)
        return simplify_gen_binary (MINUS, mode, op0, XEXP (op1, 0));