[llvm] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/TableGen/Parser.cpp b/llvm/lib/TableGen/Parser.cpp
index fd98a53..73a3362 100644
--- a/llvm/lib/TableGen/Parser.cpp
+++ b/llvm/lib/TableGen/Parser.cpp
@@ -28,7 +28,7 @@ bool llvm::TableGenParseFile(SourceMgr &InputSrcMgr, RecordKeeper &Records) {
   auto *MainFileBuffer = SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID());
   Records.saveInputFilename(MainFileBuffer->getBufferIdentifier().str());
 
-  TGParser Parser(SrcMgr, /*Macros=*/None, Records,
+  TGParser Parser(SrcMgr, /*Macros=*/std::nullopt, Records,
                   /*NoWarnOnUnusedTemplateArgs=*/false,
                   /*TrackReferenceLocs=*/true);
   bool ParseResult = Parser.ParseFile();