[Mlir-commits] [mlir] [mlir][PDL] Add support for native constraints with results (PR #82760)

[Matthias Gehre]

mgehre-amd wrote:

Open comments:
```
In any case, I think it makes more sense to map the ConstraintQuestion to the pdl_interp::ApplyConstraint operation and then retrieve the relevant results here, instead of relying on creating "placeholder" values.
```
https://reviews.llvm.org/D153245#inline-1481680

```
Do the types need to be encoded?
```
https://reviews.llvm.org/D153245#inline-1481699


```
It does make more sense to me to give constraint functions results by default, and current constraints will have "empty results". This means there will be a single consistent representation of constraint functions.
```
https://reviews.llvm.org/D153245#inline-1481674

```
This clobbering of using rewrite functions to contain constraints with results seems problematic. At this point I don't remember why rewrite functions are allowed to fail in the first place. In any case, please add results to regular constraint functions instead.`
```
https://reviews.llvm.org/D153245#inline-1481712

https://github.com/llvm/llvm-project/pull/82760