[Bug middle-end/66872] fold a & ((1 << b) - 1) to a & ~(-1 << b)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66872

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2015-07-15 00:00:00         |2021-12-25

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
AARCH64 it is more obvious:
        mov     w2, 1
        lsl     w2, w2, w1
        sub     w2, w2, #1
        and     w0, w2, w0

vs
        mov     w2, -1
        lsl     w2, w2, w1
        bic     w0, w0, w2