Seq type (#199)

* base implementation

* add example

* change table gen

* docs

* small change for review

Co-authored-by: Alexandre Eichenberger <alexe@us.ibm.com>
Co-authored-by: Tian Jin <tjingrant@gmail.com>

docs/Dialects/onnx.md

@@ -637,7 +637,7 @@ ONNX ConcatFromSequence operation
 
 | Operand | Description |
 | :-----: | ----------- |
-`input_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`input_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 #### Results:
 
@@ -4833,7 +4833,7 @@ ONNX SequenceAt operation
 
 | Operand | Description |
 | :-----: | ----------- |
-`input_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`input_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 `position` | tensor of 32-bit signless integer values or tensor of 64-bit signless integer values or memref of any type values
 
 #### Results:
@@ -4859,7 +4859,7 @@ ONNX SequenceConstruct operation
 
 | Result | Description |
 | :----: | ----------- |
-`output_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`output_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 ### `onnx.SequenceEmpty` (ONNXSequenceEmptyOp)
 
@@ -4877,7 +4877,7 @@ ONNX SequenceEmpty operation
 
 | Result | Description |
 | :----: | ----------- |
-`output` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`output` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 ### `onnx.SequenceErase` (ONNXSequenceEraseOp)
 
@@ -4892,14 +4892,14 @@ ONNX SequenceErase operation
 
 | Operand | Description |
 | :-----: | ----------- |
-`input_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`input_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 `position` | tensor of 32-bit signless integer values or tensor of 64-bit signless integer values or memref of any type values or none type
 
 #### Results:
 
 | Result | Description |
 | :----: | ----------- |
-`output_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`output_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 ### `onnx.SequenceInsert` (ONNXSequenceInsertOp)
 
@@ -4915,7 +4915,7 @@ ONNX SequenceInsert operation
 
 | Operand | Description |
 | :-----: | ----------- |
-`input_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`input_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 `tensor` | tensor of 8-bit unsigned integer values or tensor of 16-bit unsigned integer values or tensor of 32-bit unsigned integer values or tensor of 64-bit unsigned integer values or tensor of 8-bit signless integer values or tensor of 16-bit signless integer values or tensor of 32-bit signless integer values or tensor of 64-bit signless integer values or tensor of 16-bit float values or tensor of 32-bit float values or tensor of 64-bit float values or tensor of stirng type values or tensor of 1-bit signless integer values or tensor of complex type with 32-bit float elements values or tensor of complex type with 64-bit float elements values or memref of any type values
 `position` | tensor of 32-bit signless integer values or tensor of 64-bit signless integer values or memref of any type values or none type
 
@@ -4923,7 +4923,7 @@ ONNX SequenceInsert operation
 
 | Result | Description |
 | :----: | ----------- |
-`output_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`output_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 ### `onnx.SequenceLength` (ONNXSequenceLengthOp)
 
@@ -4935,7 +4935,7 @@ ONNX SequenceLength operation
 
 | Operand | Description |
 | :-----: | ----------- |
-`input_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`input_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 #### Results:
 
@@ -5298,7 +5298,7 @@ ONNX SplitToSequence operation
 
 | Result | Description |
 | :----: | ----------- |
-`output_sequence` | tensor of tensor of 8-bit unsigned integer values values or tensor of tensor of 16-bit unsigned integer values values or tensor of tensor of 32-bit unsigned integer values values or tensor of tensor of 64-bit unsigned integer values values or tensor of tensor of 8-bit signless integer values values or tensor of tensor of 16-bit signless integer values values or tensor of tensor of 32-bit signless integer values values or tensor of tensor of 64-bit signless integer values values or tensor of tensor of 16-bit float values values or tensor of tensor of 32-bit float values values or tensor of tensor of 64-bit float values values or tensor of tensor of stirng type values values or tensor of tensor of 1-bit signless integer values values or tensor of tensor of complex type with 32-bit float elements values values or tensor of tensor of complex type with 64-bit float elements values values or memref of any type values
+`output_sequence` | SeqType of tensor of 8-bit unsigned integer values values or SeqType of tensor of 16-bit unsigned integer values values or SeqType of tensor of 32-bit unsigned integer values values or SeqType of tensor of 64-bit unsigned integer values values or SeqType of tensor of 8-bit signless integer values values or SeqType of tensor of 16-bit signless integer values values or SeqType of tensor of 32-bit signless integer values values or SeqType of tensor of 64-bit signless integer values values or SeqType of tensor of 16-bit float values values or SeqType of tensor of 32-bit float values values or SeqType of tensor of 64-bit float values values or SeqType of tensor of stirng type values values or SeqType of tensor of 1-bit signless integer values values or SeqType of tensor of complex type with 32-bit float elements values values or SeqType of tensor of complex type with 64-bit float elements values values or memref of any type values
 
 ### `onnx.Sqrt` (ONNXSqrtOp)
 
@@ -5964,5 +5964,5 @@ ONNX ZipMap operation
 
 | Result | Description |
 | :----: | ----------- |
-`Z` | tensor of tuple with any combination of stirng type or 32-bit float values values or tensor of tuple with any combination of 64-bit signless integer or 32-bit float values values or memref of any type values
+`Z` | SeqType of tuple with any combination of stirng type or 32-bit float values values or SeqType of tuple with any combination of 64-bit signless integer or 32-bit float values values or memref of any type values
 

src/Dialect/ONNX/ONNXOps.cpp

@@ -484,18 +484,48 @@ ONNXOpsDialect::ONNXOpsDialect(mlir::MLIRContext *ctx)
 #include "src/Dialect/ONNX/ONNXOps.cpp.inc"
       >();
   addTypes<StringType>();
+  addTypes<SeqType>();
 }
 
 mlir::Type ONNXOpsDialect::parseType(mlir::DialectAsmParser &parser) const {
-  if (parser.parseKeyword("String"))
+  StringRef keyword;
+  if (parser.parseKeyword(&keyword))
     return Type();
 
-  return StringType::get(getContext());
+  if (keyword == "String")
+    return StringType::get(getContext());
+  if (keyword == "Seq") {
+    if (parser.parseLess())
+      return Type();
+
+    SmallVector<mlir::Type, 1> elementTypes;
+    do {
+      llvm::SMLoc typeLoc = parser.getCurrentLocation();
+      mlir::Type elementType;
+      if (parser.parseType(elementType))
+        return Type();
+
+      // TOFIX: type limitation for Seq? similar but different shape??
+      elementTypes.push_back(elementType);
+    } while (succeeded(parser.parseOptionalComma()));
+
+    if (parser.parseGreater())
+      return Type();
+    return SeqType::get(elementTypes);
+  }
 }
 
 void ONNXOpsDialect::printType(
     mlir::Type type, mlir::DialectAsmPrinter &printer) const {
-  printer << "String";
+  if (auto stringType = type.dyn_cast<StringType>()) {
+    printer << "String";
+  } else if (auto seqType = type.dyn_cast<SeqType>()) {
+    printer << "Seq<";
+    llvm::interleaveComma(seqType.getElementTypes(), printer);
+    printer << '>';
+  } else {
+    llvm_unreachable("Unexpected onnxmlir type");
+  }
 }
 
 void ONNXEntryPointOp::build(mlir::OpBuilder &builder,
@@ -2625,9 +2655,56 @@ LogicalResult ONNXSliceOp::inferShapes() {
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// ONNX type related code
+//===----------------------------------------------------------------------===//
+
+namespace mlir {
+namespace onnxmlir {
+namespace detail {
+struct SeqTypeStorage : public mlir::TypeStorage {
+  using KeyTy = llvm::ArrayRef<mlir::Type>;
+
+  SeqTypeStorage(llvm::ArrayRef<mlir::Type> elementTypes)
+      : elementTypes(elementTypes) {}
+
+  bool operator==(const KeyTy &key) const { return key == elementTypes; }
+  static llvm::hash_code hasKey(const KeyTy &key) {
+    return llvm::hash_value(key);
+  }
+
+  static KeyTy getKey(llvm::ArrayRef<mlir::Type> elementTypes) {
+    return KeyTy(elementTypes);
+  }
+
+  static SeqTypeStorage *construct(
+      mlir::TypeStorageAllocator &allocator, const KeyTy &key) {
+    llvm::ArrayRef<mlir::Type> elementTypes = allocator.copyInto(key);
+    return new (allocator.allocate<SeqTypeStorage>())
+        SeqTypeStorage(elementTypes);
+  }
+  llvm::ArrayRef<mlir::Type> elementTypes;
+};
+} // end namespace detail
+} // end namespace onnxmlir
+} // end namespace mlir
+
+SeqType SeqType::get(llvm::ArrayRef<mlir::Type> elementTypes) {
+  assert(!elementTypes.empty() && "expected non-empty seq");
+  mlir::MLIRContext *ctx = elementTypes.front().getContext();
+  return Base::get(ctx, ONNXTypes::SEQ, elementTypes);
+}
+
+llvm::ArrayRef<mlir::Type> SeqType::getElementTypes() {
+  return getImpl()->elementTypes;
+}
+
+mlir::Type SeqType::getElementType() { return getElementTypes()[0]; }
+
 //===----------------------------------------------------------------------===//
 // TableGen'd op method definitions
 //===----------------------------------------------------------------------===//
 
 #define GET_OP_CLASSES
+
 #include "src/Dialect/ONNX/ONNXOps.cpp.inc"

src/Dialect/ONNX/ONNXOps.hpp

@@ -79,6 +79,27 @@ public:
   }
 };
 
+namespace detail {
+struct SeqTypeStorage;
+} // namespace detail
+
+class SeqType
+    : public mlir::Type::TypeBase<SeqType, mlir::Type, detail::SeqTypeStorage> {
+public:
+  using Base::Base;
+  static bool kindof(unsigned kind) { return kind == ONNXTypes::SEQ; }
+
+  static unsigned getTypeKind() { return ONNXTypes::SEQ; }
+
+  static SeqType get(llvm::ArrayRef<mlir::Type> elementTypes);
+
+  llvm::ArrayRef<mlir::Type> getElementTypes();
+
+  mlir::Type getElementType();
+
+  size_t getNumElementTypes() { return getElementTypes().size(); }
+};
+
 } // end namespace onnxmlir
 
 } // end namespace mlir

src/Dialect/ONNX/ONNXOps.td

@@ -19,6 +19,12 @@ include "mlir/IR/OpBase.td"
 
 def StringType : Type<CPred<"$_self.isa<StringType>()">, "stirng type">;
 
+def IsSeqTypePred : CPred<"$_self.isa<SeqType>()">;
+
+class SeqOf<list<Type> allowedTypes> : 
+  ContainerType<AnyTypeOf<allowedTypes>, IsSeqTypePred,
+                "$_self.cast<SeqType>().getElementType()",  "SeqType">;
+
 #ifdef SHAPE_INFERENCE_INTERFACE
 #else
 include "src/Interface/ShapeInferenceInterface.td"

src/Dialect/ONNX/ONNXOps.td.inc

@@ -610,7 +610,7 @@ def ONNXConcatFromSequenceOp:ONNX_Op<"ConcatFromSequence",
   "By default 'new_axis' is 0, the behavior is similar to numpy.concatenate."
   "When 'new_axis' is 1, the behavior is similar to numpy.stack."
   }];
-  let arguments = (ins AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
+  let arguments = (ins AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
     I64Attr:$axis,
     DefaultValuedAttr<I64Attr, "0">:$new_axis);
   let results = (outs AnyTypeOf<[TensorOf<[UI8]>, TensorOf<[UI16]>, TensorOf<[UI32]>, TensorOf<[UI64]>, TensorOf<[I8]>, TensorOf<[I16]>, TensorOf<[I32]>, TensorOf<[I64]>, TensorOf<[F16]>, TensorOf<[F32]>, TensorOf<[F64]>, TensorOf<[StringType]>, TensorOf<[I1]>, TensorOf<[Complex<F32>]>, TensorOf<[Complex<F64>]>, AnyMemRef]>:$concat_result);
@@ -4582,7 +4582,7 @@ def ONNXSequenceAtOp:ONNX_Op<"SequenceAt",
   "Accepted range for 'position' is in `[-n, n - 1]`, where `n` is the number of tensors in 'input_sequence'."
   "Negative value means counting positions from the back."
   }];
-  let arguments = (ins AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
+  let arguments = (ins AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
     AnyTypeOf<[TensorOf<[I32]>, TensorOf<[I64]>, AnyMemRef]>:$position);
   let results = (outs AnyTypeOf<[TensorOf<[UI8]>, TensorOf<[UI16]>, TensorOf<[UI32]>, TensorOf<[UI64]>, TensorOf<[I8]>, TensorOf<[I16]>, TensorOf<[I32]>, TensorOf<[I64]>, TensorOf<[F16]>, TensorOf<[F32]>, TensorOf<[F64]>, TensorOf<[StringType]>, TensorOf<[I1]>, TensorOf<[Complex<F32>]>, TensorOf<[Complex<F64>]>, AnyMemRef]>:$tensor);
   let extraClassDeclaration = [{
@@ -4606,7 +4606,7 @@ def ONNXSequenceConstructOp:ONNX_Op<"SequenceConstruct",
   "All tensors in 'inputs' must have the same data type."
   }];
   let arguments = (ins Variadic<AnyTypeOf<[TensorOf<[UI8]>, TensorOf<[UI16]>, TensorOf<[UI32]>, TensorOf<[UI64]>, TensorOf<[I8]>, TensorOf<[I16]>, TensorOf<[I32]>, TensorOf<[I64]>, TensorOf<[F16]>, TensorOf<[F32]>, TensorOf<[F64]>, TensorOf<[StringType]>, TensorOf<[I1]>, TensorOf<[Complex<F32>]>, TensorOf<[Complex<F64>]>, AnyMemRef]>>:$inputs);
-  let results = (outs AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
+  let results = (outs AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
       return -1;
@@ -4627,7 +4627,7 @@ def ONNXSequenceEmptyOp:ONNX_Op<"SequenceEmpty",
   "Construct an empty tensor sequence, with given data type."
   }];
   let arguments = (ins OptionalAttr<I64Attr>:$dtype);
-  let results = (outs AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output);
+  let results = (outs AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
       return 0;
@@ -4650,9 +4650,9 @@ def ONNXSequenceEraseOp:ONNX_Op<"SequenceErase",
   "Negative value means counting positions from the back."
   "'position' is optional, by default it erases the last tensor from 'input_sequence'."
   }];
-  let arguments = (ins AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
+  let arguments = (ins AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
     AnyTypeOf<[TensorOf<[I32]>, TensorOf<[I64]>, AnyMemRef, NoneType]>:$position);
-  let results = (outs AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
+  let results = (outs AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
       return 2;
@@ -4676,10 +4676,10 @@ def ONNXSequenceInsertOp:ONNX_Op<"SequenceInsert",
   "Negative value means counting positions from the back."
   "'position' is optional, by default it inserts 'tensor' to the back of 'input_sequence'."
   }];
-  let arguments = (ins AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
+  let arguments = (ins AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence,
     AnyTypeOf<[TensorOf<[UI8]>, TensorOf<[UI16]>, TensorOf<[UI32]>, TensorOf<[UI64]>, TensorOf<[I8]>, TensorOf<[I16]>, TensorOf<[I32]>, TensorOf<[I64]>, TensorOf<[F16]>, TensorOf<[F32]>, TensorOf<[F64]>, TensorOf<[StringType]>, TensorOf<[I1]>, TensorOf<[Complex<F32>]>, TensorOf<[Complex<F64>]>, AnyMemRef]>:$tensor,
     AnyTypeOf<[TensorOf<[I32]>, TensorOf<[I64]>, AnyMemRef, NoneType]>:$position);
-  let results = (outs AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
+  let results = (outs AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
       return 3;
@@ -4699,7 +4699,7 @@ def ONNXSequenceLengthOp:ONNX_Op<"SequenceLength",
   let description = [{
   "Produces a scalar(tensor of empty shape) containing the number of tensors in 'input_sequence'."
   }];
-  let arguments = (ins AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence);
+  let arguments = (ins AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$input_sequence);
   let results = (outs AnyTypeOf<[TensorOf<[I64]>, AnyMemRef]>:$length);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
@@ -5074,7 +5074,7 @@ def ONNXSplitToSequenceOp:ONNX_Op<"SplitToSequence",
     AnyTypeOf<[TensorOf<[I32]>, TensorOf<[I64]>, AnyMemRef, NoneType]>:$split,
     DefaultValuedAttr<I64Attr, "0">:$axis,
     DefaultValuedAttr<I64Attr, "1">:$keepdims);
-  let results = (outs AnyTypeOf<[TensorOf<[TensorOf<[UI8]>]>, TensorOf<[TensorOf<[UI16]>]>, TensorOf<[TensorOf<[UI32]>]>, TensorOf<[TensorOf<[UI64]>]>, TensorOf<[TensorOf<[I8]>]>, TensorOf<[TensorOf<[I16]>]>, TensorOf<[TensorOf<[I32]>]>, TensorOf<[TensorOf<[I64]>]>, TensorOf<[TensorOf<[F16]>]>, TensorOf<[TensorOf<[F32]>]>, TensorOf<[TensorOf<[F64]>]>, TensorOf<[TensorOf<[StringType]>]>, TensorOf<[TensorOf<[I1]>]>, TensorOf<[TensorOf<[Complex<F32>]>]>, TensorOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
+  let results = (outs AnyTypeOf<[SeqOf<[TensorOf<[UI8]>]>, SeqOf<[TensorOf<[UI16]>]>, SeqOf<[TensorOf<[UI32]>]>, SeqOf<[TensorOf<[UI64]>]>, SeqOf<[TensorOf<[I8]>]>, SeqOf<[TensorOf<[I16]>]>, SeqOf<[TensorOf<[I32]>]>, SeqOf<[TensorOf<[I64]>]>, SeqOf<[TensorOf<[F16]>]>, SeqOf<[TensorOf<[F32]>]>, SeqOf<[TensorOf<[F64]>]>, SeqOf<[TensorOf<[StringType]>]>, SeqOf<[TensorOf<[I1]>]>, SeqOf<[TensorOf<[Complex<F32>]>]>, SeqOf<[TensorOf<[Complex<F64>]>]>, AnyMemRef]>:$output_sequence);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
       return 2;
@@ -6240,7 +6240,7 @@ def ONNXZipMapOp:ONNX_Op<"ZipMap",
   let arguments = (ins TensorOf<[F32]>:$X,
     OptionalAttr<I64ArrayAttr>:$classlabels_int64s,
     OptionalAttr<StrArrayAttr>:$classlabels_strings);
-  let results = (outs AnyTypeOf<[TensorOf<[TupleOf<[StringType, F32]>]>, TensorOf<[TupleOf<[I64, F32]>]>, AnyMemRef]>:$Z);
+  let results = (outs AnyTypeOf<[SeqOf<[TupleOf<[StringType, F32]>]>, SeqOf<[TupleOf<[I64, F32]>]>, AnyMemRef]>:$Z);
   let extraClassDeclaration = [{
     static int getNumberOfOperands() {
       return 1;

test/mlir/onnx/onnx_structure.mlir

@@ -14,3 +14,14 @@ func @check_string(%arg0: tensor<10x20x!onnx.String>) -> tensor<10x20x!onnx.Stri
   // CHECK-NEXT: return %arg0 : tensor<10x20x!onnx.String>
 }
 
+// CHECK-LABEL: @check_seq(%arg0: tensor<10x20xf32>, %arg1: tensor<5x20xf32>) -> tensor<*xf32> {
+func @check_seq(%arg0: tensor<10x20xf32>, %arg1: tensor<5x20xf32>) -> tensor<*xf32> {
+  %cst = "onnx.Constant"() {value = dense<[0]> : tensor<1xi32>} : () -> tensor<1xi32>
+  %0 = "onnx.SequenceConstruct"(%arg0, %arg1) : (tensor<10x20xf32>, tensor<5x20xf32>) -> !onnx.Seq<tensor<10x20xf32>, tensor<5x20xf32>>
+  %1 = "onnx.SequenceAt"(%0, %cst) : (!onnx.Seq<tensor<10x20xf32>, tensor<5x20xf32>>, tensor<1xi32>) -> tensor<*xf32>
+  return %1 : tensor<*xf32>
+  // CHECK-NEXT: %0 = "onnx.Constant"() {value = dense<0> : tensor<1xi32>} : () -> tensor<1xi32>
+  // CHECK-NEXT: %1 = "onnx.SequenceConstruct"(%arg0, %arg1) : (tensor<10x20xf32>, tensor<5x20xf32>) -> !onnx.Seq<tensor<10x20xf32>, tensor<5x20xf32>>
+  // CHECK-NEXT: %2 = "onnx.SequenceAt"(%1, %0) : (!onnx.Seq<tensor<10x20xf32>, tensor<5x20xf32>>, tensor<1xi32>) -> tensor<*xf32>
+}
+

utils/gen_onnx_mlir.py

@@ -728,7 +728,7 @@ def parse_type_str(allowedType):
     onnx_to_mlir_type_dict = { '(': '<[',
         ')': ']>',
         'tensor' : 'TensorOf',
-        'seq' : 'TensorOf',
+        'seq' : 'SeqOf',
         'map' : 'TupleOf',
         'bool': 'I1',
         #'uint8' : 'AnyI8',