diff --git a/tools/llvm-mc/AsmParser.cpp b/tools/llvm-mc/AsmParser.cpp
index a782561..f51f43a 100644
--- a/tools/llvm-mc/AsmParser.cpp
+++ b/tools/llvm-mc/AsmParser.cpp
@@ -1111,7 +1111,7 @@
       Alignment = 31;
     }
 
-    Alignment = 1 << Alignment;
+    Alignment = 1ULL << Alignment;
   }
 
   // Diagnose non-sensical max bytes to align.