[llvm] [LAA] Switch safe-distance APIs to operate in elements instead of bits, NFCI'ish (PR #191867)

[Andrei Elovikov via llvm-commits]

eas wrote:

Rebase on current trunk plus

> > > > > It looks like this may change vectorization results in some cases, which I think is unexpected. Should hopefully have a reproducer soonish
> > > > 
> > > > 
> > > > Hi @fhahn , any updates on this?
> > > 
> > > 
> > > Hi @fhahn , kind ping on this one as well, thanks!
> > 
> > 
> > @fhahn, gentle ping.
> 
> @fhahn, ping

one more ping, @fhahn 

https://github.com/llvm/llvm-project/pull/191867