diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index da8101f..38176b0 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -246,6 +246,7 @@
                                      int64_t o, uint64_t s, unsigned int a)
   : Offset(o), Size(s), V(v),
     Flags((f & 7) | ((Log2_32(a) + 1) << 3)) {
+  assert(isPowerOf2_32(a) && "Alignment is not a power of 2!");
 }
 
 //===----------------------------------------------------------------------===//