[Mlir-commits] [mlir] [mlir][Python] downcast ir.Value to BlockArgument or OpResult (PR #175264)

[Maksim Levental]

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@@ -2012,26 +2006,23 @@ nb::typed<nb::object, PyValue> PyValue::maybeDownCast() {
       PyGlobals::get().lookupValueCaster(mlirTypeID, mlirTypeGetDialect(type));
   // nb::rv_policy::move means use std::move to move the return value
   // contents into a new instance that will be owned by Python.
-  nb::object thisObj = nb::cast(this, nb::rv_policy::move);
-  if (!valueCaster)
-    return thisObj;
-  return valueCaster.value()(thisObj);
+  nb::object thisObj;
+  if (mlirValueIsAOpResult(value))
+    thisObj = nb::cast<PyOpResult>(*this, nb::rv_policy::move);
+  else if (mlirValueIsABlockArgument(value))
+    thisObj = nb::cast<PyBlockArgument>(*this, nb::rv_policy::move);
+  else
+    assert(false && "Value must be an block arg or op result.");
+  if (valueCaster)
+    return valueCaster.value()(thisObj);
+  return thisObj;
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makslevental wrote:

this is the only significant part of the PR...

https://github.com/llvm/llvm-project/pull/175264