[Bug tree-optimization/125707] (~a)>>a should be simplified into -1 for signed types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125707

--- Comment #3 from Drea Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Kael Franco from comment #2)
> Created attachment 64700 [details]
> Proposed patch

Use build_minus_one_cst instead of `build_int_cst (type, -1);`