[llvm] [ValueTracking] Support trunc nuw condition in isImpliedCondition (PR #141528)

[Andreas Jonson via llvm-commits]

andjo403 wrote:

> LGTM. Thank you!
> 
> Can you have a look at the following more canonical pattern?
> 
> Alive2: https://alive2.llvm.org/ce/z/SgMDwv
> 
> ```
> define i1 @src(i8 %x, i1 %c) {
>   %trunc = trunc nuw i8 %x to i1
>   %cmp = icmp eq i8 %x, 0
>   %sel11 = and i1 %cmp, %c ; <- select i1 %cmp, i1 %c, i1 false
>   %sel2 = select i1 %trunc, i1 true, i1 %sel11
>   ret i1 %sel2
> }
> 
> define i1 @tgt(i8 %x, i1 %c) {
>   %trunc = trunc nuw i8 %x to i1
>   %sel2 = select i1 %trunc, i1 true, i1 %c
>   ret i1 %sel2
> }
> ```

@dtcxzyw hade a look at this pattern and created a change for it but there is no improvements in llvm-opt-benchmark so it seems like it is not common.

https://github.com/llvm/llvm-project/pull/141528