[llvm] MathExtras: rewrite some methods to never overflow (PR #95556)

[Jay Foad via llvm-commits]

jayfoad wrote:

> It looks like this does have some overhead in practice

It would be good to know which functions are hot, and with what kind of arguments.

Do we have a good way to specialize these functions when Y is known to be a power of 2, e.g. with something like `if (__builtin_constant_p(Y) && isPowerOf2(Y))`?

https://github.com/llvm/llvm-project/pull/95556