[llvm-branch-commits] [llvm] RegAlloc: Do not fatal error if there are no registers in the alloc order (PR #119640)

[Matt Arsenault via llvm-branch-commits]

arsenm wrote:

### Merge activity

* **Dec 15, 8:41 PM EST**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/119640).


https://github.com/llvm/llvm-project/pull/119640