Use isinstance() instead of equality.

theano/sandbox/gpuarray/opt.py

@@ -194,7 +194,7 @@ def local_cut_gpu_transfers(node):
     # gpu[ab] -> host -> gpub
     if (isinstance(node.op, GpuFromHost) and
             node.inputs[0].owner and
-            node.inputs[0].owner.op == host_from_gpu):
+            isinstance(node.inputs[0].owner.op, HostFromGpu)):
         other = node.inputs[0].owner.inputs[0]
         if node.op.context_name == other.type.context_name:
             return [other]
@@ -202,7 +202,7 @@ def local_cut_gpu_transfers(node):
             return [GpuToGpu(node.op.context_name)(other)]
 
     # ? -> gpua -> host
-    elif (node.op == host_from_gpu and
+    elif (isinstance(node.op, HostFromGpu) and
           node.inputs[0].owner):
         n2 = node.inputs[0].owner