Allow smi comparisons to have constant operands.

runtime/vm/flow_graph_compiler_ia32.cc

Index: runtime/vm/flow_graph_compiler_ia32.cc
diff --git a/runtime/vm/flow_graph_compiler_ia32.cc b/runtime/vm/flow_graph_compiler_ia32.cc
index 4f9dc6f3e03ca632b2fcef6ab2683fee562ca769..72c9e85e6eb91a18c81bf1f1525372719352c91f 100644
--- a/runtime/vm/flow_graph_compiler_ia32.cc
+++ b/runtime/vm/flow_graph_compiler_ia32.cc
@@ -1222,7 +1222,12 @@ void ParallelMoveResolver::EmitMove(int index) {
   } else {
     ASSERT(source.IsConstant());
     if (destination.IsRegister()) {
-      __ LoadObject(destination.reg(), source.constant());
+      const Object& constant = source.constant();
+      if (constant.IsSmi() && (Smi::Cast(constant).Value() == 0)) {
+        __ xorl(destination.reg(), destination.reg());
+      } else {
+        __ LoadObject(destination.reg(), constant);
+      }
     } else {
       ASSERT(destination.IsStackSlot());
       StoreObject(ToStackSlotAddress(destination), source.constant());