[mlir][irdl] Add Variadicity to IRDL operations

[math-fehr]

Summary

This patch adds optional and variadic operands and results
to IRDL. These are added using the irdl.variadicity attribute,
which has to be attached to every irdl.operands and irdl.results
operations.

For instance:

mlir
irdl.operands(%0, single %1, optional %2, variadic %3)

has 4 operand definitions. The first two are single operands,
the second one is optional, and the last one is variadic.

Note that this patch only adds the variadicities to the definition,
but does not consider them when loading a dialect at runtime. This
will be done in the next patch.

[Mogball]

mlir/include/mlir/Dialect/IRDL/IR/IRDLAttributes.td

54

Check out ArrayOfAttr in AttrTypeBase.td for a stronger-typed array of attributes thing

mlir/include/mlir/Dialect/IRDL/IR/IRDLOps.td

276

nice

mlir/lib/Dialect/IRDL/IR/IRDL.cpp

92

please drop the consts around here

[unterumarmung]

Thanks for inviting to review :)
Shared my thoughts below

mlir/include/mlir/Dialect/IRDL/IR/IRDLAttributes.td

20–23

It is not used anywhere, if I'm not mistaken
Is it intentional?

28–30

I've checked the code and it seems like the third parameter for I32EnumAttrCase is optional and is defaulted to the first one. So, I think it's better to avoid the unnecessary repetition.

mlir/lib/Dialect/IRDL/IR/IRDL.cpp

139

To me, as an MLIR novice, it was not obvious that "parse" functions return true when the parsing is failed. To be exact, that the result of ParseResult conversion to bool.
I don't ask to change anything, just sharing my thoughts.

157

Optional thing

173–197

It seems like the docs are not relevant for the functions
The one for the parseAttributesOp should be actually for the printValuesWithVariadicity function

mlir/test/Dialect/IRDL/variadics.irdl.mlir

15–52

Minor thing: I wonder if the single variadicity should be tested inside operands op? Since the operands and result ops use the same parser, it's not as big of a deal

[unterumarmung]

mlir/include/mlir/Dialect/IRDL/IR/IRDLOps.td

290

What do the backticks in the beginning mean?

[unterumarmung]

mlir/test/Dialect/IRDL/variadics.irdl.mlir

15–52

I'm sorry, I missed the @single_operand test when I was reviewing the first time

[math-fehr]

Address comments

mlir/include/mlir/Dialect/IRDL/IR/IRDLOps.td

290

It means that no space should be added after the operation name.

mlir/lib/Dialect/IRDL/IR/IRDL.cpp

173–197

Oh good catch, thanks!

[unterumarmung]

LGTM but I'm not sure that my vote is enough

[math-fehr]

@Mogball, is that good to merge?

[math-fehr]

Update to main

[math-fehr]

Update to main

[math-fehr]

Update to main

mlir/include/mlir/Dialect/IRDL/IR/CMakeLists.txt

 add_dependencies(mlir-generic-headers MLIRIRDLOpsIncGen)
 
 # Add IRDL types
 set(LLVM_TARGET_DEFINITIONS IRDLTypes.td)
 mlir_tablegen(IRDLTypesGen.h.inc -gen-typedef-decls)
 mlir_tablegen(IRDLTypesGen.cpp.inc -gen-typedef-defs)
 add_public_tablegen_target(MLIRIRDLTypesIncGen)
 add_dependencies(mlir-generic-headers MLIRIRDLTypesIncGen)
+
+# Add IRDL attributes
+set(LLVM_TARGET_DEFINITIONS IRDLAttributes.td)
+mlir_tablegen(IRDLEnums.h.inc -gen-enum-decls)
+mlir_tablegen(IRDLEnums.cpp.inc -gen-enum-defs)
+mlir_tablegen(IRDLAttributes.h.inc -gen-attrdef-decls)
+mlir_tablegen(IRDLAttributes.cpp.inc -gen-attrdef-defs)
+add_public_tablegen_target(MLIRIRDLAttributesIncGen)
+add_dependencies(mlir-generic-headers MLIRIRDLAttributesIncGen)

mlir/include/mlir/Dialect/IRDL/IR/IRDL.h

 // IRDL Dialect
 //===----------------------------------------------------------------------===//
 
 #include "mlir/Dialect/IRDL/IR/IRDLDialect.h.inc"
 
 #define GET_TYPEDEF_CLASSES
 #include "mlir/Dialect/IRDL/IR/IRDLTypesGen.h.inc"
 
+#include "mlir/Dialect/IRDL/IR/IRDLEnums.h.inc"
+
+#define GET_ATTRDEF_CLASSES
+#include "mlir/Dialect/IRDL/IR/IRDLAttributes.h.inc"
+
 #define GET_OP_CLASSES
 #include "mlir/Dialect/IRDL/IR/IRDLOps.h.inc"
 
 #endif // MLIR_DIALECT_IRDL_IR_IRDL_H_

mlir/include/mlir/Dialect/IRDL/IR/IRDL.td

let description = [{
     both operands and the result of `mul` must be of equal type (and not just
     satisfy the same constraint).
 
     IRDL variables are handle over `mlir::Attribute`. In order to support
     manipulating `mlir::Type`, IRDL wraps all types in an `mlir::TypeAttr`
     attribute. The rationale of this is to simplify the dialect.
   }];
 
+  let useDefaultAttributePrinterParser = 1;
   let useDefaultTypePrinterParser = 1;
   let usePropertiesForAttributes = 1;
 
   let name = "irdl";
   let cppNamespace = "::mlir::irdl";
 }
 
 #endif // MLIR_DIALECT_IRDL_IR_IRDL

mlir/include/mlir/Dialect/IRDL/IR/IRDLAttributes.td

+//===- IRDLAttributes.td - IR Definition Language Dialect --*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the attributes used in IRDL.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_IRDL_IR_IRDLATTRIBUTES
+#define MLIR_DIALECT_IRDL_IR_IRDLATTRIBUTES
+
+include "IRDL.td"
+include "mlir/IR/AttrTypeBase.td"
+include "mlir/IR/EnumAttr.td"
+
+class IRDL_AttrDef<string name, string attrMnemonic, list<Trait> traits = []>
+  : AttrDef<IRDL_Dialect, name, traits, "::mlir::Attribute"> {
+  let mnemonic = attrMnemonic;
+}
+
+def Variadicity : I32EnumAttr<
+    "Variadicity", "variadicity kind",
+    [
+      I32EnumAttrCase<"single",  0, "single">,
+      I32EnumAttrCase<"optional",  1, "optional">,
+      I32EnumAttrCase<"variadic", 2, "variadic">,
+    ]> {
+  let cppNamespace = "::mlir::irdl";
+  let genSpecializedAttr = 0;
+}
+
+def VariadicityAttr : EnumAttr<IRDL_Dialect, Variadicity, "variadicity"> {
+  let summary =
+    "A variadicity kind. Can be either 'single', 'optional', or 'variadic'";
+  let description = [{
+    A `irdl.variadicity` attribute specifies that the associated operand or
+    result definition is either a single definition (the default), an
+    optional definition, or a variadic definition.
+
+    For instance:
+    ```mlir
+    irdl.operands (%arg1, single %arg2, optional %arg3, variadic %arg4)
+    ```
+
+    In this example, both %arg1 and %arg2 are single operands, %arg3 is an
+    optional operand, and %arg4 is a variadic operand.
+  }];
+}
+
+def VariadicityArrayAttr : TypedArrayAttrBase<VariadicityAttr,
+                                              "variadicity kind array"> {}
+
+#endif // MLIR_DIALECT_IRDL_IR_IRDLATTRIBUTES

mlir/include/mlir/Dialect/IRDL/IR/IRDLOps.td

 //===- IRDLOps.td - IR Definition Language Dialect ---------*- tablegen -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the IRDL dialect ops.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef MLIR_DIALECT_IRDL_IR_IRDLOPS
 #define MLIR_DIALECT_IRDL_IR_IRDLOPS
 
 include "IRDL.td"
+include "IRDLAttributes.td"
 include "IRDLTypes.td"
 include "IRDLInterfaces.td"
 include "mlir/Interfaces/SideEffectInterfaces.td"
 include "mlir/Interfaces/InferTypeOpInterface.td"
 include "mlir/IR/SymbolInterfaces.td"
 
 class IRDL_Op<string mnemonic, list<Trait> traits = []>
     : Op<IRDL_Dialect, mnemonic, traits>;
irdl.dialect @cmath {
         irdl.results(%1)
         irdl.operands(%1, %1)
       }
     }
     ```
 
     The `mul` operation will expect two operands of type `cmath.complex`, that
     have the same type, and return a result of the same type.
+
+    The operands can also be marked as variadic or optional:
+    ```mlir
+    irdl.operands(%0, single %1, optional %2, variadic %3)
+    ```
+    
+    Here, %0 and %1 are required single operands, %2 is an optional operand,
+    and %3 is a variadic operand.
+
+    When more than one operand is marked as optional or variadic, the operation
+    will expect a 'operand_segment_sizes' attribute that defines the number of
+    operands in each segment.
   }];
 
-  let arguments = (ins Variadic<IRDL_AttributeType>:$args);
-  let assemblyFormat = " `(` $args `)` attr-dict ";
+  let arguments = (ins Variadic<IRDL_AttributeType>:$args, 
+                        VariadicityArrayAttr:$variadicity);
+  let assemblyFormat =
+    "`` custom<ValuesWithVariadicity>($args, $variadicity) attr-dict";
+  let hasVerifier = true;
 }
 
 def IRDL_ResultsOp : IRDL_Op<"results", [HasParent<"OperationOp">]> {
   let summary = "Define the results of an operation";
   let description = [{
     `irdl.results` define the results of the `irdl.operation` parent operation
     definition.
 
irdl.dialect @cmath {
         irdl.results(%0, %0)
         irdl.operands(%1)
       }
     }
     ```
 
     The operation will expect one operand of the `cmath.complex` type, and two
     results that have the underlying type of the `cmath.complex`.
+
+    The results can also be marked as variadic or optional:
+    ```mlir
+    irdl.results(%0, single %1, optional %2, variadic %3)
+    ```
+    
+    Here, %0 and %1 are required single results, %2 is an optional result,
+    and %3 is a variadic result.
+
+    When more than one result is marked as optional or variadic, the operation
+    will expect a 'result_segment_sizes' attribute that defines the number of
+    results in each segment.
   }];
 
-  let arguments = (ins Variadic<IRDL_AttributeType>:$args);
-  let assemblyFormat = " `(` $args `)` attr-dict ";
+  let arguments = (ins Variadic<IRDL_AttributeType>:$args, 
+                        VariadicityArrayAttr:$variadicity);
+  let assemblyFormat =
+    " `` custom<ValuesWithVariadicity>($args, $variadicity) attr-dict";
+  let hasVerifier = true;
 }
 
 def IRDL_AttributesOp : IRDL_Op<"attributes", [HasParent<"OperationOp">]> {
   let summary = "Define the attributes of an operation";
 
   let description = [{
     `irdl.attributes` defines the attributes of the `irdl.operation` parent 
     operation definition.

mlir/lib/Dialect/IRDL/IR/IRDL.cpp

void IRDLDialect::initialize() {
   addOperations<
 #define GET_OP_LIST
 #include "mlir/Dialect/IRDL/IR/IRDLOps.cpp.inc"
       >();
   addTypes<
 #define GET_TYPEDEF_LIST
 #include "mlir/Dialect/IRDL/IR/IRDLTypesGen.cpp.inc"
       >();
+  addAttributes<
+#define GET_ATTRDEF_LIST
+#include "mlir/Dialect/IRDL/IR/IRDLAttributes.cpp.inc"
+      >();
 }
 
 //===----------------------------------------------------------------------===//
 // Parsing/Printing
 //===----------------------------------------------------------------------===//
 
 /// Parse a region, and add a single block if the region is empty.
 /// If no region is parsed, create a new region with a single empty block.

 }
 
 LogicalResult DialectOp::verify() {
   if (!Dialect::isValidNamespace(getName()))
     return emitOpError("invalid dialect name");
   return success();
 }
 
+LogicalResult OperandsOp::verify() {
+  const size_t numVariadicities = getVariadicity().size();
+  const size_t numOperands = getNumOperands();
+
+  if (numOperands != numVariadicities)
+    return emitOpError()
+           << "the number of operands and their variadicities must be "
+              "the same, but got "
+           << numOperands << " and " << numVariadicities << " respectively";
+
+  return success();
+}
+
+LogicalResult ResultsOp::verify() {
+  const size_t numVariadicities = getVariadicity().size();
+  const size_t numOperands = this->getNumOperands();
+
+  if (numOperands != numVariadicities)
+    return emitOpError()
+           << "the number of operands and their variadicities must be "
+              "the same, but got "
+           << numOperands << " and " << numVariadicities << " respectively";
+
+  return success();
+}
+
 LogicalResult AttributesOp::verify() {
   const size_t namesSize = getAttributeValueNames().size();
   const size_t valuesSize = getAttributeValues().size();
 
   if (namesSize != valuesSize)
     return emitOpError()
            << "the number of attribute names and their constraints must be "
               "the same but got "
            << namesSize << " and " << valuesSize << " respectively";
 
   return success();
 }
 
+/// Parse a value with its variadicity first. By default, the variadicity is
+/// single.
+///
+/// value-with-variadicity ::= ("single" | "optional" | "variadic")? ssa-value
+static ParseResult
+parseValueWithVariadicity(OpAsmParser &p,
+                          OpAsmParser::UnresolvedOperand &operand,
+                          VariadicityAttr &variadicityAttr) {
+  MLIRContext *ctx = p.getBuilder().getContext();
+
+  // Parse the variadicity, if present
+  if (p.parseOptionalKeyword("single").succeeded()) {
+    variadicityAttr = VariadicityAttr::get(ctx, Variadicity::single);
+  } else if (p.parseOptionalKeyword("optional").succeeded()) {
+    variadicityAttr = VariadicityAttr::get(ctx, Variadicity::optional);
+  } else if (p.parseOptionalKeyword("variadic").succeeded()) {
+    variadicityAttr = VariadicityAttr::get(ctx, Variadicity::variadic);
+  } else {
+    variadicityAttr = VariadicityAttr::get(ctx, Variadicity::single);
+  }
+
+  // Parse the value
+  if (p.parseOperand(operand))
+    return failure();
+  return success();
+}
+
+/// Parse a list of values with their variadicities first. By default, the
+/// variadicity is single.
+///
+/// values-with-variadicity ::=
+///   `(` (value-with-variadicity (`,` value-with-variadicity)*)? `)`
+/// value-with-variadicity ::= ("single" | "optional" | "variadic")? ssa-value
+static ParseResult parseValuesWithVariadicity(
+    OpAsmParser &p, SmallVectorImpl<OpAsmParser::UnresolvedOperand> &operands,
+    ArrayAttr &variadicityAttr) {
+  Builder &builder = p.getBuilder();
+  SmallVector<Attribute> variadicities;
+
+  // Parse a single value with its variadicity
+  auto parseOne = [&]() {
+    OpAsmParser::UnresolvedOperand operand;
+    VariadicityAttr variadicity;
+    if (parseValueWithVariadicity(p, operand, variadicity))
+      return failure();
+    operands.push_back(operand);
+    variadicities.push_back(variadicity);
+    return success();
+  };
+
+  if (p.parseCommaSeparatedList(OpAsmParser::Delimiter::Paren, parseOne))
+    return failure();
+  variadicityAttr = builder.getArrayAttr(variadicities);
+  return success();
+}
+
+/// Print a value with its variadicity first. By default, the variadicity is
+/// single.
+///
+/// value-with-variadicity ::= ("single" | "optional" | "variadic")? ssa-value
+static void printValuesWithVariadicity(OpAsmPrinter &p, Operation *op,
+                                       OperandRange operands,
+                                       ArrayAttr variadicityAttr) {
+  p << "(";
+  interleaveComma(llvm::seq<int>(0, operands.size()), p, [&](int i) {
+    Variadicity variadicity =
+        llvm::cast<VariadicityAttr>(variadicityAttr[i]).getValue();
+    if (variadicity != Variadicity::single) {
+      p << stringifyVariadicity(variadicity) << " ";
+    }
+    p << operands[i];
+  });
+  p << ")";
+}
+
+/// Print a list of values with their variadicities first. By default, the
+/// variadicity is single.
+///
+/// values-with-variadicity ::=
+///   `(` (value-with-variadicity (`,` value-with-variadicity)*)? `)`
+/// value-with-variadicity ::= ("single" | "optional" | "variadic")? ssa-value
 static ParseResult
 parseAttributesOp(OpAsmParser &p,
                   SmallVectorImpl<OpAsmParser::UnresolvedOperand> &attrOperands,
                   ArrayAttr &attrNamesAttr) {
   Builder &builder = p.getBuilder();
   SmallVector<Attribute> attrNames;
   if (succeeded(p.parseOptionalLBrace())) {
     auto parseOperands = [&]() {
static void printAttributesOp(OpAsmPrinter &p, AttributesOp op,
   p << '}';
 }
 
 #include "mlir/Dialect/IRDL/IR/IRDLInterfaces.cpp.inc"
 
 #define GET_TYPEDEF_CLASSES
 #include "mlir/Dialect/IRDL/IR/IRDLTypesGen.cpp.inc"
 
+#include "mlir/Dialect/IRDL/IR/IRDLEnums.cpp.inc"
+
+#define GET_ATTRDEF_CLASSES
+#include "mlir/Dialect/IRDL/IR/IRDLAttributes.cpp.inc"
+
 #define GET_OP_CLASSES
 #include "mlir/Dialect/IRDL/IR/IRDLOps.cpp.inc"

mlir/test/Dialect/IRDL/variadics-error.irdl.mlir

+// RUN: mlir-opt %s -verify-diagnostics -split-input-file
+
+irdl.dialect @errors {
+  irdl.operation @operands {
+    %0 = irdl.is i32
+
+    // expected-error@+1 {{'irdl.operands' op the number of operands and their variadicities must be the same, but got 2 and 1 respectively}}
+    "irdl.operands"(%0, %0) <{variadicity = [#irdl<variadicity single>]}> : (!irdl.attribute, !irdl.attribute) -> ()
+  }
+}
+
+// -----
+
+irdl.dialect @errors {
+  irdl.operation @operands2 {
+    %0 = irdl.is i32
+   
+    // expected-error@+1 {{'irdl.operands' op the number of operands and their variadicities must be the same, but got 1 and 2 respectively}}
+    "irdl.operands"(%0) <{variadicity = [#irdl<variadicity single>, #irdl<variadicity single>]}> : (!irdl.attribute) -> ()
+  }
+}
+
+// -----
+
+irdl.dialect @errors {
+  irdl.operation @results {
+    %0 = irdl.is i32
+
+    // expected-error@+1 {{'irdl.results' op the number of operands and their variadicities must be the same, but got 2 and 1 respectively}}
+    "irdl.results"(%0, %0) <{variadicity = [#irdl<variadicity single>]}> : (!irdl.attribute, !irdl.attribute) -> ()
+  }
+}
+
+// -----
+
+irdl.dialect @errors {
+  irdl.operation @results2 {
+    %0 = irdl.is i32
+   
+    // expected-error@+1 {{'irdl.results' op the number of operands and their variadicities must be the same, but got 1 and 2 respectively}}
+    "irdl.results"(%0) <{variadicity = [#irdl<variadicity single>, #irdl<variadicity single>]}> : (!irdl.attribute) -> ()
+  }
+}

mlir/test/Dialect/IRDL/variadics.irdl.mlir

+// RUN: mlir-opt %s | mlir-opt | FileCheck %s
+
+// CHECK: irdl.dialect @testvar {
+irdl.dialect @testvar {
+
+  // CHECK-LABEL: irdl.operation @single_operand {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i32
+  // CHECK-NEXT:    irdl.operands(%[[v0]])
+  // CHECK-NEXT:  }
+  irdl.operation @single_operand {
+    %0 = irdl.is i32
+    irdl.operands(single %0)
+  }
+
+  // CHECK-LABEL: irdl.operation @var_operand {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i16 
+  // CHECK-NEXT:    %[[v1:[^ ]*]] = irdl.is i32 
+  // CHECK-NEXT:    %[[v2:[^ ]*]] = irdl.is i64 
+  // CHECK-NEXT:    irdl.operands(%[[v0]], variadic %[[v1]], %[[v2]])
+  // CHECK-NEXT:  }
+  irdl.operation @var_operand {
+    %0 = irdl.is i16
+    %1 = irdl.is i32
+    %2 = irdl.is i64
+    irdl.operands(%0, variadic %1, %2)
+  }
+
+  // CHECK-LABEL: irdl.operation @opt_operand {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i16 
+  // CHECK-NEXT:    %[[v1:[^ ]*]] = irdl.is i32 
+  // CHECK-NEXT:    %[[v2:[^ ]*]] = irdl.is i64 
+  // CHECK-NEXT:    irdl.operands(%[[v0]], variadic %[[v1]], %[[v2]])
+  // CHECK-NEXT:  }
+  irdl.operation @opt_operand {
+    %0 = irdl.is i16
+    %1 = irdl.is i32
+    %2 = irdl.is i64
+    irdl.operands(%0, variadic %1, %2)
+  }
+
+  // CHECK-LABEL: irdl.operation @var_and_opt_operand {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i16 
+  // CHECK-NEXT:    %[[v1:[^ ]*]] = irdl.is i32 
+  // CHECK-NEXT:    %[[v2:[^ ]*]] = irdl.is i64 
+  // CHECK-NEXT:    irdl.operands(variadic %[[v0]], optional %[[v1]], %[[v2]])
+  // CHECK-NEXT:  }
+  irdl.operation @var_and_opt_operand {
+    %0 = irdl.is i16
+    %1 = irdl.is i32
+    %2 = irdl.is i64
+    irdl.operands(variadic %0, optional %1, %2)
+  }
+
+
+  // CHECK-LABEL: irdl.operation @single_result {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i32
+  // CHECK-NEXT:    irdl.results(%[[v0]])
+  // CHECK-NEXT:  }
+  irdl.operation @single_result {
+    %0 = irdl.is i32
+    irdl.results(single %0)
+  }
+
+  // CHECK-LABEL: irdl.operation @var_result {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i16 
+  // CHECK-NEXT:    %[[v1:[^ ]*]] = irdl.is i32 
+  // CHECK-NEXT:    %[[v2:[^ ]*]] = irdl.is i64 
+  // CHECK-NEXT:    irdl.results(%[[v0]], variadic %[[v1]], %[[v2]])
+  // CHECK-NEXT:  }
+  irdl.operation @var_result {
+    %0 = irdl.is i16
+    %1 = irdl.is i32
+    %2 = irdl.is i64
+    irdl.results(%0, variadic %1, %2)
+  }
+
+  // CHECK-LABEL: irdl.operation @opt_result {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i16 
+  // CHECK-NEXT:    %[[v1:[^ ]*]] = irdl.is i32 
+  // CHECK-NEXT:    %[[v2:[^ ]*]] = irdl.is i64 
+  // CHECK-NEXT:    irdl.results(%[[v0]], variadic %[[v1]], %[[v2]])
+  // CHECK-NEXT:  }
+  irdl.operation @opt_result {
+    %0 = irdl.is i16
+    %1 = irdl.is i32
+    %2 = irdl.is i64
+    irdl.results(%0, variadic %1, %2)
+  }
+
+  // CHECK-LABEL: irdl.operation @var_and_opt_result {
+  // CHECK-NEXT:    %[[v0:[^ ]*]] = irdl.is i16 
+  // CHECK-NEXT:    %[[v1:[^ ]*]] = irdl.is i32 
+  // CHECK-NEXT:    %[[v2:[^ ]*]] = irdl.is i64 
+  // CHECK-NEXT:    irdl.results(variadic %[[v0]], optional %[[v1]], %[[v2]])
+  // CHECK-NEXT:  }
+  irdl.operation @var_and_opt_result {
+    %0 = irdl.is i16
+    %1 = irdl.is i32
+    %2 = irdl.is i64
+    irdl.results(variadic %0, optional %1, %2)
+  }
+}