`ilog(2)` -> `ilog2()` and `ilog(10)` -> `ilog10`

[tgross35]

What it does

If calls to ilog or checked_ilog are made with a known constant 2 or 10, suggest replacing them with the fixed-base versions ilog2 or ilog10.

Advantage

The fixed-base versions produce more performant code https://rust.godbolt.org/z/ffjx1Gjh7

Drawbacks

No response

Example

let a = x.ilog(2)
let b = x.ilog(10);
let c = x.checked_ilog(2);
let d = x.checked_ilog(10);

Could be written as:

let a = x.ilog2()
let b = x.ilog10();
let c = x.checked_ilog2();
let d = x.checked_ilog10();

[ChaiTRex]

This seems to be a subissue of #12894.

[tgross35]

You're right! Not much need for this then.