[llvm] [ConstantRange][LVI] Add initial support for `multiplyWithNoWrap` (PR #92356)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

TBH I have been having a hard time understanding some of the failures that arise when testing exhaustively mul nuw w/ optimality `CheckNonWrappedOnly`. For instance, for input ranges `[0,5)`, `[6,-1)` (bitwidth 4), I get the following:
```
Failure
Value of: NotPreferred(PossibleCR)
  Actual: false (Inputs = [0,5), [6,-1), CR = full-set, BetterCR = [6,1))
Expected: true

Failure
Value of: NotPreferred(PossibleCR)
  Actual: false (Inputs = [0,5), [6,-1), CR = full-set, BetterCR = [0,-1))
Expected: true
```
Isn't the union of the two sets full-set? What am I missing?

https://github.com/llvm/llvm-project/pull/92356