diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index 569931ff698..33b28017e58 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -526,5 +526,7 @@ void Emitter::emitInstruction(const MachineInstr &MI) {
     ++CurOp;
     break;
   }
-  assert(CurOp == MI.getNumOperands() && "Unknown encoding!");
+
+  if ((Desc.Flags & M_VARIABLE_OPS) == 0)
+    assert(CurOp == MI.getNumOperands() && "Unknown encoding!");
 }