[mlir] Use std::optional instead of llvm::Optional (NFC)

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

diff --git a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
index 79f339d..38d91f6 100644 (file)
--- a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
+++ b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/TypeSwitch.h"
 #include "llvm/Frontend/OpenMP/OMPConstants.h"
 #include <cstddef>
+#include <optional>
 
 #include "mlir/Dialect/OpenMP/OpenMPOpsDialect.cpp.inc"
 #include "mlir/Dialect/OpenMP/OpenMPOpsEnums.cpp.inc"
@@ -512,7 +513,7 @@ static void printDependVarList(OpAsmPrinter &p, Operation *op,
 
 /// Verifies Depend clause
 static LogicalResult verifyDependVarList(Operation *op,
-                                         Optional<ArrayAttr> depends,
+                                         std::optional<ArrayAttr> depends,
                                          OperandRange dependVars) {
   if (!dependVars.empty()) {
     if (!depends || depends->size() != dependVars.size())