silence vc++ warning.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75394 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/AsmParser.cpp b/tools/llvm-mc/AsmParser.cpp
index 1d9e1b6..a2cdea4 100644
--- a/tools/llvm-mc/AsmParser.cpp
+++ b/tools/llvm-mc/AsmParser.cpp
@@ -850,7 +850,7 @@
   // Compute alignment in bytes.
   if (IsPow2) {
     // FIXME: Diagnose overflow.
-    Alignment = 1 << Alignment;
+    Alignment = 1LL << Alignment;
   }
 
   // Diagnose non-sensical max bytes to fill.