diff --git a/mlir/test/Conversion/OneToNTypeConversion/one-to-n-type-conversion.mlir b/mlir/test/Conversion/OneToNTypeConversion/one-to-n-type-conversion.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/Conversion/OneToNTypeConversion/one-to-n-type-conversion.mlir
@@ -0,0 +1,140 @@
+// RUN: mlir-opt %s -split-input-file \
+// RUN:   -test-one-to-n-type-conversion="convert-tuple-ops" \
+// RUN: | FileCheck --check-prefix=CHECK-TUP %s
+
+// RUN: mlir-opt %s -split-input-file \
+// RUN:   -test-one-to-n-type-conversion="convert-func-ops" \
+// RUN: | FileCheck --check-prefix=CHECK-FUNC %s
+
+// RUN: mlir-opt %s -split-input-file \
+// RUN:   -test-one-to-n-type-conversion="convert-func-ops convert-tuple-ops" \
+// RUN: | FileCheck --check-prefix=CHECK-BOTH %s
+
+// Test case: Matching nested packs and unpacks just disappear.
+
+// CHECK-TUP-LABEL: func.func @pack_unpack(
+// CHECK-TUP-SAME:                          %[[ARG0:.*]]: i1,
+// CHECK-TUP-SAME:                          %[[ARG1:.*]]: i2) -> (i1, i2) {
+// CHECK-TUP-NEXT:    return %[[ARG0]], %[[ARG1]] : i1, i2
+func.func @pack_unpack(%arg0: i1, %arg1: i2) -> (i1, i2) {
+  %0 = "test.make_tuple"() : () -> tuple<>
+  %1 = "test.make_tuple"(%arg1) : (i2) -> tuple<i2>
+  %2 = "test.make_tuple"(%1) : (tuple<i2>) -> tuple<tuple<i2>>
+  %3 = "test.make_tuple"(%0, %arg0, %2) : (tuple<>, i1, tuple<tuple<i2>>) -> tuple<tuple<>, i1, tuple<tuple<i2>>>
+  %4 = "test.get_tuple_element"(%3) {index = 0 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<>
+  %5 = "test.get_tuple_element"(%3) {index = 1 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> i1
+  %6 = "test.get_tuple_element"(%3) {index = 2 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<tuple<i2>>
+  %7 = "test.get_tuple_element"(%6) {index = 0 : i32} : (tuple<tuple<i2>>) -> tuple<i2>
+  %8 = "test.get_tuple_element"(%7) {index = 0 : i32} : (tuple<i2>) -> i2
+  return %5, %8 : i1, i2
+}
+
+// -----
+
+// Test case: Appropriate materializations are created depending on which ops
+// are converted.
+
+// If we only convert the tuple ops, the original `get_tuple_element` ops will
+// disappear but one target materialization will be inserted from the
+// unconverted function arguments to each of the return values (which have
+// redundancy among themselves).
+//
+// CHECK-TUP-LABEL: func.func @materializations(
+// CHECK-TUP-SAME:                              %[[ARG0:.*]]: tuple<tuple<>, i1, tuple<tuple<i2>>>) -> (i1, i2) {
+// CHECK-TUP-NEXT:    %0 = "test.get_tuple_element"(%arg0) {index = 0 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<>
+// CHECK-TUP-NEXT:    %1 = "test.get_tuple_element"(%arg0) {index = 1 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> i1
+// CHECK-TUP-NEXT:    %2 = "test.get_tuple_element"(%arg0) {index = 2 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<tuple<i2>>
+// CHECK-TUP-NEXT:    %3 = "test.get_tuple_element"(%2) {index = 0 : i32} : (tuple<tuple<i2>>) -> tuple<i2>
+// CHECK-TUP-NEXT:    %4 = "test.get_tuple_element"(%3) {index = 0 : i32} : (tuple<i2>) -> i2
+// CHECK-TUP-NEXT:    %5 = "test.get_tuple_element"(%arg0) {index = 0 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<>
+// CHECK-TUP-NEXT:    %6 = "test.get_tuple_element"(%arg0) {index = 1 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> i1
+// CHECK-TUP-NEXT:    %7 = "test.get_tuple_element"(%arg0) {index = 2 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<tuple<i2>>
+// CHECK-TUP-NEXT:    %8 = "test.get_tuple_element"(%7) {index = 0 : i32} : (tuple<tuple<i2>>) -> tuple<i2>
+// CHECK-TUP-NEXT:    %9 = "test.get_tuple_element"(%8) {index = 0 : i32} : (tuple<i2>) -> i2
+// CHECK-TUP-NEXT:    return %1, %9 : i1, i2
+
+// If we only convert the func ops, argument materializations are created from
+// the converted tuple elements back to the tuples that the `get_tuple_element`
+// ops expect.
+//
+// CHECK-FUNC-LABEL: func.func @materializations(
+// CHECK-FUNC-SAME:                              %[[ARG0:.*]]: i1,
+// CHECK-FUNC-SAME:                              %[[ARG1:.*]]: i2) -> (i1, i2) {
+// CHECK-FUNC-NEXT:    %0 = "test.make_tuple"() : () -> tuple<>
+// CHECK-FUNC-NEXT:    %1 = "test.make_tuple"(%arg1) : (i2) -> tuple<i2>
+// CHECK-FUNC-NEXT:    %2 = "test.make_tuple"(%1) : (tuple<i2>) -> tuple<tuple<i2>>
+// CHECK-FUNC-NEXT:    %3 = "test.make_tuple"(%0, %arg0, %2) : (tuple<>, i1, tuple<tuple<i2>>) -> tuple<tuple<>, i1, tuple<tuple<i2>>>
+// CHECK-FUNC-NEXT:    %4 = "test.get_tuple_element"(%3) {index = 0 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<>
+// CHECK-FUNC-NEXT:    %5 = "test.get_tuple_element"(%3) {index = 1 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> i1
+// CHECK-FUNC-NEXT:    %6 = "test.get_tuple_element"(%3) {index = 2 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<tuple<i2>>
+// CHECK-FUNC-NEXT:    %7 = "test.get_tuple_element"(%6) {index = 0 : i32} : (tuple<tuple<i2>>) -> tuple<i2>
+// CHECK-FUNC-NEXT:    %8 = "test.get_tuple_element"(%7) {index = 0 : i32} : (tuple<i2>) -> i2
+// CHECK-FUNC-NEXT:    return %5, %8 : i1, i2
+
+// If we convert both tuple and func ops, basically everything disappears.
+//
+// CHECK-BOTH-LABEL: func.func @materializations(
+// CHECK-BOTH-SAME:                              %[[ARG0:.*]]: i1,
+// CHECK-BOTH-SAME:                              %[[ARG1:.*]]: i2) -> (i1, i2) {
+// CHECK-BOTH-NEXT:    return %arg0, %arg1 : i1, i2
+
+func.func @materializations(%arg0: tuple<tuple<>, i1, tuple<tuple<i2>>>) -> (i1, i2) {
+  %0 = "test.get_tuple_element"(%arg0) {index = 0 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<>
+  %1 = "test.get_tuple_element"(%arg0) {index = 1 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> i1
+  %2 = "test.get_tuple_element"(%arg0) {index = 2 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<tuple<i2>>
+  %3 = "test.get_tuple_element"(%2) {index = 0 : i32} : (tuple<tuple<i2>>) -> tuple<i2>
+  %4 = "test.get_tuple_element"(%3) {index = 0 : i32} : (tuple<i2>) -> i2
+  return %1, %4 : i1, i2
+}
+// -----
+
+// Test case: Appropriate materializations are created depending on which ops
+// are converted.
+
+// If we only convert the tuple ops, the original `make_tuple` ops will
+// disappear but a source materialization will be inserted from the result of
+// conversion (which, for `make_tuple`, are the original ops that get forwarded)
+// to the operands of the unconverted op with the original type (i.e.,
+// `return`).
+
+// CHECK-TUP-LABEL: func.func @materializations(
+// CHECK-TUP-SAME:                              %[[ARG0:.*]]: i1,
+// CHECK-TUP-SAME:                              %[[ARG1:.*]]: i2) -> tuple<tuple<>, i1, tuple<tuple<i2>>> {
+// CHECK-TUP-NEXT:    %[[V0:.*]] = "test.make_tuple"() : () -> tuple<>
+// CHECK-TUP-NEXT:    %[[V1:.*]] = "test.make_tuple"(%[[ARG1]]) : (i2) -> tuple<i2>
+// CHECK-TUP-NEXT:    %[[V2:.*]] = "test.make_tuple"(%[[V1]]) : (tuple<i2>) -> tuple<tuple<i2>>
+// CHECK-TUP-NEXT:    %[[V3:.*]] = "test.make_tuple"(%[[V0]], %[[ARG0]], %[[V2]]) : (tuple<>, i1, tuple<tuple<i2>>) -> tuple<tuple<>, i1, tuple<tuple<i2>>>
+// CHECK-TUP-NEXT:    return %[[V3]] : tuple<tuple<>, i1, tuple<tuple<i2>>>
+
+// If we only convert the func ops, target materializations are created from
+// original tuples produced by `make_tuple` to its constituent elements that the
+// converted op (i.e., `return`) expect.
+//
+// CHECK-FUNC-LABEL: func.func @materializations(
+// CHECK-FUNC-SAME:                              %[[ARG0:.*]]: i1,
+// CHECK-FUNC-SAME:                              %[[ARG1:.*]]: i2) -> (i1, i2) {
+// CHECK-FUNC-NEXT:    %0 = "test.make_tuple"() : () -> tuple<>
+// CHECK-FUNC-NEXT:    %1 = "test.make_tuple"(%arg1) : (i2) -> tuple<i2>
+// CHECK-FUNC-NEXT:    %2 = "test.make_tuple"(%1) : (tuple<i2>) -> tuple<tuple<i2>>
+// CHECK-FUNC-NEXT:    %3 = "test.make_tuple"(%0, %arg0, %2) : (tuple<>, i1, tuple<tuple<i2>>) -> tuple<tuple<>, i1, tuple<tuple<i2>>>
+// CHECK-FUNC-NEXT:    %4 = "test.get_tuple_element"(%3) {index = 0 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<>
+// CHECK-FUNC-NEXT:    %5 = "test.get_tuple_element"(%3) {index = 1 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> i1
+// CHECK-FUNC-NEXT:    %6 = "test.get_tuple_element"(%3) {index = 2 : i32} : (tuple<tuple<>, i1, tuple<tuple<i2>>>) -> tuple<tuple<i2>>
+// CHECK-FUNC-NEXT:    %7 = "test.get_tuple_element"(%6) {index = 0 : i32} : (tuple<tuple<i2>>) -> tuple<i2>
+// CHECK-FUNC-NEXT:    %8 = "test.get_tuple_element"(%7) {index = 0 : i32} : (tuple<i2>) -> i2
+// CHECK-FUNC-NEXT:    return %5, %8 : i1, i2
+
+// If we convert both tuple and func ops, basically everything disappears.
+//
+// CHECK-BOTH-LABEL: func.func @materializations(
+// CHECK-BOTH-SAME:                              %[[ARG0:.*]]: i1,
+// CHECK-BOTH-SAME:                              %[[ARG1:.*]]: i2) -> (i1, i2) {
+// CHECK-BOTH-NEXT:    return %arg0, %arg1 : i1, i2
+
+func.func @materializations(%arg0: i1, %arg1: i2) -> tuple<tuple<>, i1, tuple<tuple<i2>>> {
+  %0 = "test.make_tuple"() : () -> tuple<>
+  %1 = "test.make_tuple"(%arg1) : (i2) -> tuple<i2>
+  %2 = "test.make_tuple"(%1) : (tuple<i2>) -> tuple<tuple<i2>>
+  %3 = "test.make_tuple"(%0, %arg0, %2) : (tuple<>, i1, tuple<tuple<i2>>) -> tuple<tuple<>, i1, tuple<tuple<i2>>>
+  return %3 : tuple<tuple<>, i1, tuple<tuple<i2>>>
+}