fix conditions and comment

theano/tensor/opt.py

@@ -1605,17 +1605,17 @@ def local_useless_elemwise(node):
 
             if isinstance(node.inputs[0], T.TensorConstant):
                 const_val = T.extract_constant(node.inputs[0])
-                if const_val == 1:
-                    return [node.inputs[1]]
-                elif const_val == 0:
+                if const_val == 0:
                     return zeros_like(node, 1)
+                else:
+                    return [node.inputs[1]]
 
             if isinstance(node.inputs[1], T.TensorConstant):
                 const_val = T.extract_constant(node.inputs[1])
-                if const_val == 1:
-                    return [node.inputs[0]]
-                elif const_val == 0:
+                if const_val == 0:
                     return zeros_like(node, 0)
+                else:
+                    return [node.inputs[0]]
 
         elif (isinstance(node.op.scalar_op, scalar.OR) and
               len(node.inputs) == 2):
@@ -1624,14 +1624,14 @@ def local_useless_elemwise(node):
                 const_val = T.extract_constant(node.inputs[0])
                 if const_val == 0:
                     return [node.inputs[1]]
-                elif const_val == 1:
+                else:
                     return ones_like(node, 1)
 
             if isinstance(node.inputs[1], T.TensorConstant):
                 const_val = T.extract_constant(node.inputs[1])
                 if const_val == 0:
                     return [node.inputs[0]]
-                if const_val == 1:
+                else:
                     return ones_like(node, 0)
 
         elif (isinstance(node.op.scalar_op, scalar.XOR) and
@@ -4216,8 +4216,7 @@ def local_useless_elemwise_comparison(node):
     """...
 
     :note: These cases appear in the graph generated by scan.
-           These optimizations will not reduce computation,
-           but will make the graph easier to read.
+           These optimizations will make the graph easier to read.
     # Comparing to itself is constant
     Elemwise[{LT,GT}](X, X) -> Elemwise[zeros](X)
     Elemwise[{LE,GE}](X, X) -> Elemwise[ones](X)