Remove the last few llvm::Optional

include/swift/AST/IRGenOptions.h

@@ -25,13 +25,13 @@
 #include "swift/Basic/OptimizationMode.h"
 #include "swift/Config.h"
 #include "clang/Basic/PointerAuthOptions.h"
-#include "llvm/ADT/Optional.h"
 #include "llvm/IR/CallingConv.h"
 // FIXME: This include is just for llvm::SanitizerCoverageOptions. We should
 // split the header upstream so we don't include so much.
 #include "llvm/Transforms/Instrumentation.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/VersionTuple.h"
+#include <optional>
 #include <string>
 #include <vector>
 

include/swift/Driver/Driver.h

@@ -25,11 +25,11 @@
 #include "swift/Basic/Sanitizers.h"
 #include "swift/Driver/Util.h"
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
 
 #include <functional>
 #include <memory>
+#include <optional>
 #include <string>
 
 namespace llvm {

lib/IRGen/IRGenDebugInfo.cpp

@@ -1346,7 +1346,7 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
 
     SmallVector<llvm::Metadata *, 16> Elements;
     for (auto *ElemDecl : Decl->getAllElements()) {
-      llvm::Optional<DebugTypeInfo> ElemDbgTy;
+      std::optional<DebugTypeInfo> ElemDbgTy;
       if (auto ArgTy = ElemDecl->getArgumentInterfaceType()) {
         // A variant case which carries a payload.
         ArgTy = ElemDecl->getParentEnum()->mapTypeIntoContext(ArgTy);