[mlir] Deprecate NamedAttrList(std::nullopt_t) (NFC) (#149544)

This patch deprecates NamedAttrList(std::nullopt_t) to avoid use of
std::nullopt outside the context of std::optional.

Author: kazutakahirata

mlir/include/mlir/IR/OperationSupport.h

@@ -802,6 +802,7 @@ class NamedAttrList {
   using size_type = size_t;
 
   NamedAttrList() : dictionarySorted({}, true) {}
+  LLVM_DEPRECATED("Use NamedAttrList() instead", "NamedAttrList()")
   NamedAttrList(std::nullopt_t none) : NamedAttrList() {}
   NamedAttrList(ArrayRef<NamedAttribute> attributes);
   NamedAttrList(DictionaryAttr attributes);

mlir/lib/AsmParser/Parser.cpp

@@ -1198,8 +1198,8 @@ Value OperationParser::createForwardRefPlaceholder(SMLoc loc, Type type) {
   auto name = OperationName("builtin.unrealized_conversion_cast", getContext());
   auto *op = Operation::create(
       getEncodedSourceLocation(loc), name, type, /*operands=*/{},
-      /*attributes=*/std::nullopt, /*properties=*/nullptr, /*successors=*/{},
-      /*numRegions=*/0);
+      /*attributes=*/NamedAttrList(), /*properties=*/nullptr,
+      /*successors=*/{}, /*numRegions=*/0);
   forwardRefPlaceholders[op->getResult(0)] = loc;
   forwardRefOps.insert(op);
   return op->getResult(0);

mlir/unittests/Debug/FileLineColLocBreakpointManagerTest.cpp

@@ -24,7 +24,7 @@ static Operation *createOp(MLIRContext *context, Location loc,
                            unsigned int numRegions = 0) {
   context->allowUnregisteredDialects();
   return Operation::create(loc, OperationName(operationName, context), {}, {},
-                           std::nullopt, OpaqueProperties(nullptr), {},
+                           NamedAttrList(), OpaqueProperties(nullptr), {},
                            numRegions);
 }
 

mlir/unittests/IR/OperationSupportTest.cpp

@@ -24,7 +24,7 @@ static Operation *createOp(MLIRContext *context, ArrayRef<Value> operands = {},
   context->allowUnregisteredDialects();
   return Operation::create(UnknownLoc::get(context),
                            OperationName("foo.bar", context), resultTypes,
-                           operands, std::nullopt, nullptr, {}, numRegions);
+                           operands, NamedAttrList(), nullptr, {}, numRegions);
 }
 
 namespace {
@@ -236,7 +236,7 @@ TEST(OperationFormatPrintTest, CanPrintNameAsPrefix) {
   Operation *op = Operation::create(
       NameLoc::get(StringAttr::get(&context, "my_named_loc")),
       OperationName("t.op", &context), builder.getIntegerType(16), {},
-      std::nullopt, nullptr, {}, 0);
+      NamedAttrList(), nullptr, {}, 0);
 
   std::string str;
   OpPrintingFlags flags;

mlir/unittests/IR/ValueTest.cpp

@@ -22,7 +22,7 @@ static Operation *createOp(MLIRContext *context, ArrayRef<Value> operands = {},
   context->allowUnregisteredDialects();
   return Operation::create(UnknownLoc::get(context),
                            OperationName("foo.bar", context), resultTypes,
-                           operands, std::nullopt, nullptr, {}, numRegions);
+                           operands, NamedAttrList(), nullptr, {}, numRegions);
 }
 
 namespace {

mlir/unittests/Transforms/DialectConversion.cpp

@@ -15,7 +15,7 @@ static Operation *createOp(MLIRContext *context) {
   context->allowUnregisteredDialects();
   return Operation::create(UnknownLoc::get(context),
                            OperationName("foo.bar", context), {}, {},
-                           std::nullopt, /*properties=*/nullptr, {}, 0);
+                           NamedAttrList(), /*properties=*/nullptr, {}, 0);
 }
 
 namespace {