diff --git a/mlir/include/mlir-c/IR.h b/mlir/include/mlir-c/IR.h
--- a/mlir/include/mlir-c/IR.h
+++ b/mlir/include/mlir-c/IR.h
@@ -618,6 +618,19 @@
 /// Returns 1 if the value is an operation result, 0 otherwise.
 MLIR_CAPI_EXPORTED bool mlirValueIsAOpResult(MlirValue value);
 
+/// Replaces all uses of a value with a new value.
+MLIR_CAPI_EXPORTED void mlirValueReplaceAllUsesWith(MlirValue value,
+                                                    MlirValue newValue);
+
+/// Replaces uses of a value with a new value if a predicate returns true.
+/// The predicate takes a user operation and the index into its operands of the
+/// use.
+MLIR_CAPI_EXPORTED void mlirValueReplaceUsesWithIf(
+    MlirValue value, MlirValue newValue,
+    bool (*shouldReplace)(MlirOperation operation, intptr_t operandIndex,
+                          void *userData),
+    void *userData);
+
 /// Returns the block in which this value is defined as an argument. Asserts if
 /// the value is not a block argument.
 MLIR_CAPI_EXPORTED MlirBlock mlirBlockArgumentGetOwner(MlirValue value);
diff --git a/mlir/lib/Bindings/Python/IRCore.cpp b/mlir/lib/Bindings/Python/IRCore.cpp
--- a/mlir/lib/Bindings/Python/IRCore.cpp
+++ b/mlir/lib/Bindings/Python/IRCore.cpp
@@ -467,9 +467,13 @@
   return forContext(rawContext).releaseObject();
 }
 
-PyMlirContext *PyMlirContext::createNewContextForInit() {
+PyMlirContext *
+PyMlirContext::createNewContextForInit(bool registerAllDialects) {
   MlirContext context = mlirContextCreate();
-  mlirRegisterAllDialects(context);
+  // TODO: Remove implicit registration of dialects.
+  if (registerAllDialects) {
+    mlirRegisterAllDialects(context);
+  }
   return new PyMlirContext(context);
 }
 
@@ -1204,12 +1208,17 @@
 
 py::object PyOperation::createOpView() {
   checkValid();
-  MlirIdentifier ident = mlirOperationGetName(get());
-  MlirStringRef identStr = mlirIdentifierStr(ident);
-  auto opViewClass = PyGlobals::get().lookupRawOpViewClass(
-      StringRef(identStr.data, identStr.length));
-  if (opViewClass)
-    return (*opViewClass)(getRef().getObject());
+  MlirOperation cOp = get();
+  MlirTypeID registeredTypeID = mlirOperationGetTypeID(cOp);
+  // For registered ops, lookup an appropriate, generated op view.
+  if (!mlirTypeIDIsNull(registeredTypeID)) {
+    MlirIdentifier ident = mlirOperationGetName(cOp);
+    MlirStringRef identStr = mlirIdentifierStr(ident);
+    auto opViewClass = PyGlobals::get().lookupRawOpViewClass(
+        StringRef(identStr.data, identStr.length));
+    if (opViewClass)
+      return (*opViewClass)(getRef().getObject());
+  }
   return py::cast(PyOpView(getRef().getObject()));
 }
 
@@ -2181,7 +2190,8 @@
   // Mapping of MlirContext.
   //----------------------------------------------------------------------------
   py::class_<PyMlirContext>(m, "Context", py::module_local())
-      .def(py::init<>(&PyMlirContext::createNewContextForInit))
+      .def(py::init<>(&PyMlirContext::createNewContextForInit),
+           py::arg("register_all_dialects") = true)
       .def_static("_get_live_count", &PyMlirContext::getLiveCount)
       .def("_get_context_again",
            [](PyMlirContext &self) {
@@ -2569,30 +2579,48 @@
            py::arg("use_local_scope") = false,
            py::arg("assume_verified") = false, kOperationGetAsmDocstring)
       .def(
-          "verify",
+          "detach_from_parent",
           [](PyOperationBase &self) {
-            return mlirOperationVerify(self.getOperation());
+            PyOperation &operation = self.getOperation();
+            operation.checkValid();
+            if (!operation.isAttached())
+              throw py::value_error("Detached operation has no parent.");
+
+            operation.detachFromParent();
+            return operation.createOpView();
           },
-          "Verify the operation and return true if it passes, false if it "
-          "fails.")
+          "Detaches the operation from its parent block.")
+      .def("erase", [](PyOperationBase &self) { self.getOperation().erase(); })
       .def("move_after", &PyOperationBase::moveAfter, py::arg("other"),
            "Puts self immediately after the other operation in its parent "
            "block.")
       .def("move_before", &PyOperationBase::moveBefore, py::arg("other"),
            "Puts self immediately before the other operation in its parent "
            "block.")
+      .def_property_readonly("name",
+                             [](PyOperationBase &self) {
+                               PyOperation &operation = self.getOperation();
+                               operation.checkValid();
+                               MlirStringRef name = mlirIdentifierStr(
+                                   mlirOperationGetName(operation.get()));
+                               return py::str(name.data, name.length);
+                             })
+      .def_property_readonly("parent",
+                             [](PyOperationBase &self) -> py::object {
+                               PyOperation &operation = self.getOperation();
+                               operation.checkValid();
+                               auto parent = operation.getParentOperation();
+                               if (parent)
+                                 return parent->getObject();
+                               return py::none();
+                             })
       .def(
-          "detach_from_parent",
+          "verify",
           [](PyOperationBase &self) {
-            PyOperation &operation = self.getOperation();
-            operation.checkValid();
-            if (!operation.isAttached())
-              throw py::value_error("Detached operation has no parent.");
-
-            operation.detachFromParent();
-            return operation.createOpView();
+            return mlirOperationVerify(self.getOperation());
           },
-          "Detaches the operation from its parent block.");
+          "Verify the operation and return true if it passes, false if it "
+          "fails.");
 
   py::class_<PyOperation, PyOperationBase>(m, "Operation", py::module_local())
       .def_static("create", &PyOperation::create, py::arg("name"),
@@ -2602,25 +2630,9 @@
                   py::arg("successors") = py::none(), py::arg("regions") = 0,
                   py::arg("loc") = py::none(), py::arg("ip") = py::none(),
                   kOperationCreateDocstring)
-      .def_property_readonly("parent",
-                             [](PyOperation &self) -> py::object {
-                               auto parent = self.getParentOperation();
-                               if (parent)
-                                 return parent->getObject();
-                               return py::none();
-                             })
-      .def("erase", &PyOperation::erase)
       .def_property_readonly(MLIR_PYTHON_CAPI_PTR_ATTR,
                              &PyOperation::getCapsule)
       .def(MLIR_PYTHON_CAPI_FACTORY_ATTR, &PyOperation::createFromCapsule)
-      .def_property_readonly("name",
-                             [](PyOperation &self) {
-                               self.checkValid();
-                               MlirOperation operation = self.get();
-                               MlirStringRef name = mlirIdentifierStr(
-                                   mlirOperationGetName(operation));
-                               return py::str(name.data, name.length);
-                             })
       .def_property_readonly(
           "context",
           [](PyOperation &self) {
@@ -3026,6 +3038,10 @@
                    "the IR");
             return self.getParentOperation().getObject();
           })
+      .def("replace_all_uses_with",
+           [](PyValue &self, PyValue &newValue) {
+             mlirValueReplaceAllUsesWith(self.get(), newValue.get());
+           })
       .def("__eq__",
            [](PyValue &self, PyValue &other) {
              return self.get().ptr == other.get().ptr;
diff --git a/mlir/lib/Bindings/Python/IRModule.h b/mlir/lib/Bindings/Python/IRModule.h
--- a/mlir/lib/Bindings/Python/IRModule.h
+++ b/mlir/lib/Bindings/Python/IRModule.h
@@ -168,7 +168,7 @@
   /// that is also not supported by pybind11. Instead, we use this entry
   /// point which always constructs a fresh context (which cannot alias an
   /// existing one because it is fresh).
-  static PyMlirContext *createNewContextForInit();
+  static PyMlirContext *createNewContextForInit(bool registerAllDialects);
 
   /// Returns a context reference for the singleton PyMlirContext wrapper for
   /// the given context.
diff --git a/mlir/lib/Bindings/Python/IRTypes.cpp b/mlir/lib/Bindings/Python/IRTypes.cpp
--- a/mlir/lib/Bindings/Python/IRTypes.cpp
+++ b/mlir/lib/Bindings/Python/IRTypes.cpp
@@ -555,6 +555,18 @@
           return mlirTupleTypeGetNumTypes(self);
         },
         "Returns the number of types contained in a tuple.");
+    c.def_property_readonly(
+        "types",
+        [](PyTupleType &self) {
+          py::list result;
+          auto &context = self.getContext();
+          intptr_t n = mlirTupleTypeGetNumTypes(self);
+          for (intptr_t i = 0; i < n; ++i) {
+            result.append(PyType(context, mlirTupleTypeGetType(self, i)));
+          }
+          return result;
+        },
+        "Returns a sequence of the contained types.");
   }
 };
 
diff --git a/mlir/lib/CAPI/IR/IR.cpp b/mlir/lib/CAPI/IR/IR.cpp
--- a/mlir/lib/CAPI/IR/IR.cpp
+++ b/mlir/lib/CAPI/IR/IR.cpp
@@ -648,6 +648,21 @@
   return unwrap(value).isa<OpResult>();
 }
 
+void mlirValueReplaceAllUsesWith(MlirValue value, MlirValue newValue) {
+  unwrap(value).replaceAllUsesWith(unwrap(newValue));
+}
+
+void mlirValueReplaceUsesWithIf(MlirValue value, MlirValue newValue,
+                                bool (*shouldReplace)(MlirOperation operation,
+                                                      intptr_t operandIndex,
+                                                      void *userData),
+                                void *userData) {
+  unwrap(value).replaceUsesWithIf(unwrap(newValue), [&](OpOperand &operand) {
+    return shouldReplace(wrap(operand.getOwner()), operand.getOperandNumber(),
+                         userData);
+  });
+}
+
 MlirBlock mlirBlockArgumentGetOwner(MlirValue value) {
   return wrap(unwrap(value).cast<BlockArgument>().getOwner());
 }
diff --git a/mlir/python/mlir/_mlir_libs/_mlir/ir.pyi b/mlir/python/mlir/_mlir_libs/_mlir/ir.pyi
--- a/mlir/python/mlir/_mlir_libs/_mlir/ir.pyi
+++ b/mlir/python/mlir/_mlir_libs/_mlir/ir.pyi
@@ -110,11 +110,16 @@
     def _CAPIPtr(self) -> object: ...
     @property
     def attributes(self) -> "OpAttributeMap": ...
+    def erase(self) -> None: ...
     @property
     def location(self) -> "Location": ...
     @property
+    def name(self) -> str: ...
+    @property
     def operands(self) -> "OpOperandList": ...
     @property
+    def parent(self) -> Optional["_OperationBase"]: ...
+    @property
     def regions(self) -> "RegionSequence": ...
     @property
     def result(self) -> "OpResult": ...
@@ -421,7 +426,7 @@
 class Context:
     current: ClassVar["Context"] = ...  # read-only
     allow_unregistered_dialects: bool
-    def __init__(self) -> None: ...
+    def __init__(self, register_all_dialects: bool = True) -> None: ...
     def _CAPICreate(self) -> object: ...
     def _get_context_again(self) -> "Context": ...
     @staticmethod
@@ -807,17 +812,12 @@
         regions: int = 0,
         loc: Optional["Location"] = None,
         ip: Optional["InsertionPoint"] = None) -> "_OperationBase": ...
-    def erase(self) -> None: ...
     @property
     def _CAPIPtr(self) -> object: ...
     @property
     def context(self) -> "Context": ...
     @property
-    def name(self) -> str: ...
-    @property
     def opview(self) -> "OpView": ...
-    @property
-    def parent(self) -> Optional["_OperationBase"]: ...
 
 class OperationIterator:
     def __iter__(self) -> "OperationIterator": ...