diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 8c65e95..1062011 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1551,8 +1551,15 @@
   Record.push_back(N->isDistinct());
   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
-  Record.push_back(N->getChecksumKind());
-  Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()));
+  if (N->getRawChecksum()) {
+    Record.push_back(N->getRawChecksum()->Kind);
+    Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
+  } else {
+    // Maintain backwards compatibility with the old internal representation of
+    // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
+    Record.push_back(0);
+    Record.push_back(VE.getMetadataOrNullID(nullptr));
+  }
 
   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
   Record.clear();