[Mlir-commits] [mlir] [MLIR] getBackwardSlice: don't bail on ops that are IsolatedFromAbove (PR #158135)

[Ian Wood]

IanWood1 wrote:

Does isolated from above carry any other meaning than the ops regions don't use values outside of the region?

For example if you assume `%2` is NOT isolated from above and you take a backwards slice from `%2` it would contain `{%2, %1, %0}`. But I think you are suggesting that if it were isolated from above it should just contain `{%2}`. I'm not sure what about the `IsolatedFromAbove` trait would cause this difference.

```mlir
%0 = op
%1 = op_with_region %0 {
^bb0(%in):
   %2 = op_in_body %in
}
```

I think that it would make sense to include all 3 ops even if it `%1` is `IsolatedFromAbove`. But also, I think this could be controlled by the user with `options.filter`.

https://github.com/llvm/llvm-project/pull/158135