diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index cfe58dae343c..2d8912b71f14 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -220,7 +220,7 @@ MCDwarfLineTableHeader::Emit(MCStreamer *MCOS,
       1  // DW_LNS_set_isa
   };
   assert(array_lengthof(StandardOpcodeLengths) >=
-         (Params.DWARF2LineOpcodeBase - 1));
+         (Params.DWARF2LineOpcodeBase - 1U));
   return Emit(MCOS, Params, ArrayRef<char>(StandardOpcodeLengths,
                                            Params.DWARF2LineOpcodeBase - 1));
 }