[Bug tree-optimization/120952] GCC fails to optimize division to shift when divisor is non-constant power of two

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120952

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
As noted in Bug 118681 comment 8, when we know it's a power of two we can do:

    return (bytes + alignment - 1) & ~(alignment - 1);

to get even better codegen.