do not try cudnn opt when it isn't available

theano/sandbox/cuda/dnn.py

@@ -1545,42 +1545,42 @@ if True:
     @register_opt('cudnn')
     @alpha_merge(GpuDnnConv, alpha_in=4, nd=4)
     def local_dnn_conv_alpha_merge(node, *inputs):
-        if version() == -1:
+        if not dnn_available() or version() == -1:
             return None
         return [GpuDnnConv(workmem=node.op.workmem)(*inputs)]
 
     @register_opt('cudnn')
     @alpha_merge(GpuDnnConvGradW, alpha_in=4, nd=4)
     def local_dnn_convw_alpha_merge(node, *inputs):
-        if version() == -1:
+        if not dnn_available() or version() == -1:
             return None
         return [GpuDnnConvGradW()(*inputs)]
 
     @register_opt('cudnn')
     @alpha_merge(GpuDnnConvGradI, alpha_in=4, nd=4)
     def local_dnn_convi_alpha_merge(node, *inputs):
-        if version() == -1:
+        if not dnn_available() or version() == -1:
             return None
         return [GpuDnnConvGradI()(*inputs)]
 
     @register_opt('cudnn')
     @output_merge(GpuDnnConv, alpha_in=4, out_in=2, nd=4)
     def local_dnn_conv_output_merge(node, *inputs):
-        if version() == -1:
+        if not dnn_available() or version() == -1:
             return None
         return [GpuDnnConv(workmem=node.op.workmem)(*inputs)]
 
     @register_opt('cudnn')
     @output_merge(GpuDnnConvGradW, alpha_in=4, out_in=2, nd=4)
     def local_dnn_convw_output_merge(node, *inputs):
-        if version() == -1:
+        if not dnn_available() or version() == -1:
             return None
         return [GpuDnnConvGradW()(*inputs)]
 
     @register_opt('cudnn')
     @output_merge(GpuDnnConvGradI, alpha_in=4, out_in=2, nd=4)
     def local_dnn_convi_output_merge(node, *inputs):
-        if version() == -1:
+        if not dnn_available() or version() == -1:
             return None
         return [GpuDnnConvGradI()(*inputs)]
 

theano/sandbox/cuda/tests/test_dnn.py

@@ -455,7 +455,10 @@ class TestDnnInferShapes(utt.InferShapeTester):
                 dnn.GpuDnnPoolGrad
             )
 
+
 def test_dnn_conv_merge():
+    if not cuda.dnn.dnn_available() or cuda.dnn.version() == -1:
+        raise SkipTest(cuda.dnn.dnn_available.msg)
     img = T.ftensor4()
     kern = T.ftensor4()
     out = T.ftensor4()
@@ -516,7 +519,7 @@ def test_dnn_conv_merge():
 
 
 def test_dnn_conv_grad():
-    if dnn.version() == -1:
+    if not cuda.dnn.dnn_available() or dnn.version() == -1:
         raise SkipTest('alpha != 1.0 not supported in cudnn v1')
 
     b = 1