Make InputsToGpuOptimizer skip processing if all clients are transfers or…

theano/sandbox/gpuarray/opt.py

@@ -165,9 +165,9 @@ class InputToGpuOptimizer(Optimizer):
             if isinstance(input.type, GpuArrayType):
                 continue
 
-            if (len(input.clients) == 1 and
-                (input.clients[0][0] == 'output' or
-                 isinstance(input.clients[0][0].op, GpuFromHost))):
+            # If all clients are outputs or transfers don't do anything.
+            if (all(cl[0] == 'output' or isinstance(cl[0].op, GpuFromHost)
+                    for cl in input.clients)):
                 continue
 
             ctx_name = getattr(input.tag, 'context_name', None)
@@ -179,10 +179,10 @@ class InputToGpuOptimizer(Optimizer):
                 # This could fail if the inputs are not TensorTypes
                 pass
             except ContextNotDefined:
+                if hasattr(input.tag, 'context_name'):
+                    raise
                 # If there is no context tag and no default context
                 # then it stays on the CPU
-                if not hasattr(input.tag, 'context_name'):
-                    raise
                 pass