diff --git a/lib/Bytecode/Writer/Writer.cpp b/lib/Bytecode/Writer/Writer.cpp
index 9ba475c9d3e..0441acbdca2 100644
--- a/lib/Bytecode/Writer/Writer.cpp
+++ b/lib/Bytecode/Writer/Writer.cpp
@@ -948,7 +948,7 @@ void BytecodeWriter::outputModuleInfoBlock(const Module *M) {
       
       // The extension word has this format: bit 0 = has initializer, bit 1-3 =
       // linkage, bit 4-8 = alignment (log2), bits 10+ = future use.
-      unsigned ExtWord = I->hasInitializer() | (getEncodedLinkage(I) << 1) |
+      unsigned ExtWord = (unsigned)I->hasInitializer() | (getEncodedLinkage(I) << 1) |
                          ((Log2_32(I->getAlignment())+1) << 4);
       output_vbr(ExtWord);
     }