diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 36212ba4d06..595a9149b38 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -246,6 +246,7 @@ MachineMemOperand::MachineMemOperand(const Value *v, unsigned int f,
   : 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!");
+  assert((isLoad() || isStore()) && "Not a load/store!");
 }
 
 //===----------------------------------------------------------------------===//