[mlir][spirv] NFC: use Optional to replace SPV_Optional

Differential Revision: https://reviews.llvm.org/D78046

Author: antiagainst

mlir/include/mlir/Dialect/SPIRV/SPIRVBase.td

@@ -3040,9 +3040,6 @@ def SPV_IntVec4 : SPV_Vec4<SPV_Integer>;
 def SPV_IOrUIVec4 : SPV_Vec4<SPV_SignlessOrUnsignedInt>;
 def SPV_Int32Vec4 : SPV_Vec4<AnyI32>;
 
-// TODO(antiagainst): Use a more appropriate way to model optional operands
-class SPV_Optional<Type type> : Variadic<type>;
-
 // TODO(ravishankarm): From 1.4, this should also include Composite type.
 def SPV_SelectType : AnyTypeOf<[SPV_Scalar, SPV_Vector, SPV_AnyPtr]>;
 

mlir/include/mlir/Dialect/SPIRV/SPIRVControlFlowOps.td

@@ -240,7 +240,7 @@ def SPV_FunctionCallOp : SPV_Op<"FunctionCall", [
   );
 
   let results = (outs
-    SPV_Optional<SPV_Type>:$result
+    Optional<SPV_Type>:$result
   );
 
   let autogenSerialization = 0;

mlir/include/mlir/Dialect/SPIRV/SPIRVNonUniformOps.td

@@ -30,7 +30,7 @@ class SPV_GroupNonUniformArithmeticOp<string mnemonic, Type type,
     SPV_ScopeAttr:$execution_scope,
     SPV_GroupOperationAttr:$group_operation,
     SPV_ScalarOrVectorOf<type>:$value,
-    SPV_Optional<SPV_Integer>:$cluster_size
+    Optional<SPV_Integer>:$cluster_size
   );
 
   let results = (outs

mlir/include/mlir/Dialect/SPIRV/SPIRVOps.td

@@ -469,7 +469,7 @@ def SPV_VariableOp : SPV_Op<"Variable", []> {
 
   let arguments = (ins
     SPV_StorageClassAttr:$storage_class,
-    SPV_Optional<AnyType>:$initializer
+    Optional<AnyType>:$initializer
   );
 
   let results = (outs

mlir/lib/Conversion/LinalgToSPIRV/LinalgToSPIRV.cpp

@@ -155,7 +155,7 @@ LogicalResult SingleWorkgroupReduction::matchAndRewrite(
     groupOperation = rewriter.create<spirv::spvOp>(                            \
         loc, originalInputType.getElementType(), spirv::Scope::Subgroup,       \
         spirv::GroupOperation::Reduce, inputElement,                           \
-        /*cluster_size=*/ArrayRef<Value>());                                   \
+        /*cluster_size=*/nullptr);                                             \
   } break
   switch (*binaryOpKind) {
     CREATE_GROUP_NON_UNIFORM_BIN_OP(IAdd, GroupNonUniformIAddOp);

mlir/lib/Dialect/SPIRV/Serialization/Deserializer.cpp

@@ -2291,6 +2291,10 @@ Deserializer::processOp<spirv::FunctionCallOp>(ArrayRef<uint32_t> operands) {
            << operands[0];
   }
 
+  // Use null type to mean no result type.
+  if (isVoidType(resultType))
+    resultType = nullptr;
+
   auto resultID = operands[1];
   auto functionID = operands[2];
 
@@ -2306,18 +2310,12 @@ Deserializer::processOp<spirv::FunctionCallOp>(ArrayRef<uint32_t> operands) {
     arguments.push_back(value);
   }
 
-  SmallVector<Type, 1> resultTypes;
-  if (!isVoidType(resultType)) {
-    resultTypes.push_back(resultType);
-  }
-
   auto opFunctionCall = opBuilder.create<spirv::FunctionCallOp>(
-      unknownLoc, resultTypes, opBuilder.getSymbolRefAttr(functionName),
+      unknownLoc, resultType, opBuilder.getSymbolRefAttr(functionName),
       arguments);
 
-  if (!resultTypes.empty()) {
+  if (resultType)
     valueMap[resultID] = opFunctionCall.getResult(0);
-  }
   return success();
 }
 

mlir/test/Dialect/SPIRV/control-flow-ops.mlir

@@ -202,7 +202,7 @@ func @caller() {
 
 spv.module Logical GLSL450 {
   spv.func @f_invalid_result_type(%arg0 : i32, %arg1 : i32) -> () "None" {
-    // expected-error @+1 {{expected callee function to have 0 or 1 result, but provided 2}}
+    // expected-error @+1 {{result group starting at #0 requires 0 or 1 element, but found 2}}
     %0:2 = spv.FunctionCall @f_invalid_result_type(%arg0, %arg1) : (i32, i32) -> (i32, i32)
     spv.Return
   }

mlir/utils/spirv/gen_spirv_dialect.py

@@ -548,7 +548,7 @@ def map_spec_operand_to_ods_argument(operand):
     if quantifier == '':
       arg_type = 'SPV_Type'
     elif quantifier == '?':
-      arg_type = 'SPV_Optional<SPV_Type>'
+      arg_type = 'Optional<SPV_Type>'
     else:
       arg_type = 'Variadic<SPV_Type>'
   elif kind == 'IdMemorySemantics' or kind == 'IdScope':