[llvm] [NVPTX] Add TTI support for folding isspacep in InferAS (PR #114486)

[Alex MacLean via llvm-commits]

AlexMaclean wrote:

> Could be taken up in a separate PR, but could we get these `nvvm.isspacep.*` intrinsics documented in the NVPTX usage guide?

I've created https://github.com/llvm/llvm-project/pull/114839 to address this.

https://github.com/llvm/llvm-project/pull/114486