[Mlir-commits] [mlir] [mlir][memref] Add a new `ReifyResultShapes` pass (PR #145927)

[Fabian Mora]

fabianmcg wrote:

We might need to update the docs, because at least I cannot infer that from the docs:
```
def ReifyRankedShapedTypeOpInterface :
    OpInterface<"ReifyRankedShapedTypeOpInterface"> {
  let description = [{
    Interface to compute the shape of the result of an operation when
    the result is a ranked shape type, i.e. `RankedTensorType` or
    `MemRefType`.
  }];
  let cppNamespace = "::mlir";

  let methods = [
    InterfaceMethod<
      /*desc=*/[{
        Reify the shape of the result of an operation (typically in terms of the
        shape of its operands).

        `reifiedReturnShapes` is populated with one vector per op result. Each
        of those vectors contains an OpFoldResult for each dimension of the
        shaped type. The given builder may be used to insert ops that compute
        result shapes.

        If the shape of a particular result cannot be computed it must be empty.
      }],
      /*retTy=*/"::llvm::LogicalResult",
      /*methodName=*/"reifyResultShapes",
      /*args=*/(ins "::mlir::OpBuilder &":$builder,
        "::mlir::ReifiedRankedShapedTypeDims &":$reifiedReturnShapes)
    >
  ];
}
```

Also, there's no cast to fold into or from in this case. So no way to augment those patterns.

Finally, I'd argue that ir is reification because we are coming from dynamic dimensions and inferring that the output type is static.

https://github.com/llvm/llvm-project/pull/145927