https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111597
--- Comment #3 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
(In reply to Jiu Fu Guo from comment #0)
> In match.pd there is a pattern:
> /* ((T)(A)) + CST -> (T)(A + CST) */
> #if GIMPLE
> (simplify
> (plus (convert:s SSA_NAME@0) INTEGER_CST@1)
> (if (TREE_CODE (TREE_TYPE (@0)) == INTEGER_TYPE
> && TREE_CODE (type) == INTEGER_TYPE
> && TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (@0))
> && int_fits_type_p (@1, TREE_TYPE (@0)))
> /* Perform binary operation inside the cast if the constant fits
> and (A + CST)'s range does not overflow. *
>
> But this pattern seems not in favor of all targets.
> For example, the below code hits this pattern,
>
> long foo1 (int x)
> {
> if (x>1000)
> return 0;
> int x1 = x +1;
> return (long) x1 + 40;
>
> }
For this code, without the pattern "((T)(A)) + CST -> (T)(A + CST)",
the final gimple code is:
x1_4 = x_3(D) + 1;
_1 = (long int) x1_4;
_5 = _1 + 40;
With the pattern,
the final gimple code is:
_4 = x_2(D) + 41;
_3 = (long int) _4;
So, this pattern would be "reasonable".
