Add Theano flag conv.assert_shape to easily get rid of the abstract conv assert of shapes.

doc/library/config.txt

@@ -693,6 +693,13 @@ import theano and print the config variable, as in:
 
     If ``'False'``, do not use cuDNN or check if it is available.
 
+.. attribute:: config.conv.assert_shape
+
+    If False, AbstractConv* ops won't add assert that verify that
+    the user provided shapes are also the one at run time.
+
+    This can speed up compilation time and/or execution time.
+
 .. attribute:: config.dnn.conv.workmem
 
     Deprecated, use :attr:`config.dnn.conv.algo_fwd`.

theano/configdefaults.py

@@ -126,6 +126,13 @@ AddConfigVar(
     BoolParam(False, allow_override=False),
     in_c_key=False)
 
+AddConfigVar(
+    'conv.assert_shape',
+    "If False, AbstractConv* ops won't add assert that verify that"
+    " the user provided shapes are also the one at run time",
+    BoolParam(True),
+    in_c_key=False)
+
 AddConfigVar(
     'print_global_stats',
     "Print some global statistics (time spent) at the end",

theano/tensor/nnet/abstract_conv.py

@@ -493,7 +493,7 @@ def assert_shape(x, expected_shape, msg='Unexpected shape.'):
         will return `x` directly.
 
     """
-    if expected_shape is None:
+    if expected_shape is None or not theano.config.conv.assert_shape:
         return x
     shape = x.shape
     tests = []