[llvm] [AMDGPU][SDAG] Enable ISD::PTRADD for 64-bit AS by default (PR #146076)

[Fabian Ritter via llvm-commits]

ritter-x2a wrote:

### Merge activity

* **Oct 2, 8:04 AM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/146076).


https://github.com/llvm/llvm-project/pull/146076