[Mlir-commits] [mlir] [mlir] Avoid rewriting unreachable blocks in the greedy driver (PR #225814)

[Matthias Springer]

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matthias-springer wrote:

Re: `Keys are the reachable blocks`

What happens if this op is inserted into an unreachable segment of the IR?

```mlir
scf.if {
  // REGION A
  scf.if {
    // REGION B
  }
}
```

Region A is invalidated during `notifyOperationInserted`, but Region B won't be invalidated. Will the driver keep processing ops in Region B?

https://github.com/llvm/llvm-project/pull/225814