diff --git a/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp b/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp
index 6715f3d3fa1f..1a0503fcbde7 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp
@@ -122,7 +122,8 @@ Error PDBFileBuilder::commit(const msf::WritableStream &Buffer) {
   auto DirStream =
       WritableMappedBlockStream::createDirectoryStream(Layout, Buffer);
   StreamWriter DW(*DirStream);
-  if (auto EC = DW.writeInteger(Layout.StreamSizes.size()))
+  if (auto EC =
+          DW.writeInteger(static_cast<uint32_t>(Layout.StreamSizes.size())))
     return EC;
 
   if (auto EC = DW.writeArray(Layout.StreamSizes))