[CRASH] Make GpuAdvancedSubtensor1 work with an empty list of indices.

theano/sandbox/cuda/cuda_ndarray.cu

@@ -1140,6 +1140,13 @@ CudaNdarray_TakeFrom(CudaNdarray * self, PyObject *args){
     }
 
     dim3 n_blocks(std::min(CudaNdarray_HOST_DIMS(out)[0],65535),1,1);
+    if(CudaNdarray_HOST_DIMS(out)[0] == 0){
+        // We take 0 elements, so no need for the rest of the code.
+        // This speed up that case AND fix crash otherwise.
+        free(dims);
+        Py_DECREF(indices);
+        return (PyObject *)out;
+    }
 
     switch (self->nd) {
         case 1:

theano/sandbox/cuda/tests/test_basic_ops.py

@@ -967,6 +967,8 @@ class T_subtensor(theano.tensor.tests.test_subtensor.T_subtensor):
         # version when we should. Users should not use it.
         for shape, idx, fast in [((70000,), range(70000), True),
                                  ((70000, 5), range(70000), True),
+                                 ((70000, 5),  numpy.zeros((0,), 'int64'),
+                                  True),
                                  ((70000, 2, 3), range(70000), True),
                                  ((1025, 1025), [5, 10], True),
                                  ((3, 1025, 1026), [1, 2], True),