Index: lib/MC/MCAsmStreamer.cpp
===================================================================
--- lib/MC/MCAsmStreamer.cpp
+++ lib/MC/MCAsmStreamer.cpp
@@ -303,7 +303,7 @@
 }
 
 static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
-  assert(Bytes && "Invalid size!");
+  assert(Bytes > 0 && Bytes <= 8 && "Invalid size!");
   return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
 }