[llvm] [PowerPC] Exploit xxeval instruction for ternary patterns - part 1 (PR #141733)

[Tony Varghese via llvm-commits]

tonykuttai wrote:

- Latest commit supports vector operand types `v4i32, v2i64, v16i8 and v8i16` operand datatypes of xxeval.
- `XXEvalVSelectWithXAnd` class used for `v4i32 and v2i64` types that `xxeval` supports.
- `XXEvalVSelectWithXAndCast` class used for `v16i8 and v8i16` types that needs casting support.
- `xxeval` instruction supports `VSRC` as input operands which inturn supports only `v4i32,v4f32,v2f64,v2i64` types.

https://github.com/llvm/llvm-project/pull/141733