diff --git a/lib/DebugInfo/DWARFTypeUnit.cpp b/lib/DebugInfo/DWARFTypeUnit.cpp
index c81e2403b1d..303bf707067 100644
--- a/lib/DebugInfo/DWARFTypeUnit.cpp
+++ b/lib/DebugInfo/DWARFTypeUnit.cpp
@@ -28,7 +28,7 @@ void DWARFTypeUnit::dump(raw_ostream &OS) {
      << " version = " << format("0x%04x", getVersion())
      << " abbr_offset = " << format("0x%04x", getAbbreviations()->getOffset())
      << " addr_size = " << format("0x%02x", getAddressByteSize())
-     << " type_signature = " << format("0x%16lx", TypeHash)
+     << " type_signature = " << format("0x%16" PRIx64, TypeHash)
      << " type_offset = " << format("0x%04x", TypeOffset)
      << " (next unit at " << format("0x%08x", getNextUnitOffset())
      << ")\n";