compiler: cleanup transformer

Author: mloubout

devito/ir/iet/nodes.py

@@ -407,7 +407,10 @@ def reads(self):
     @cached_property
     def write(self):
         """The Function written by the Expression."""
-        return self.expr.lhs.base.function
+        try:
+            return self.expr.rhs.writes[0]
+        except (AttributeError, IndexError):
+            return self.expr.lhs.base.function
 
     @cached_property
     def dimensions(self):

devito/ir/iet/visitors.py

@@ -1326,24 +1326,17 @@ def visit_tuple(self, o, **kwargs):
 
     visit_list = visit_tuple
 
-    def visit_ExpressionBundle(self, o, **kwargs):
-        if o in self.mapper:
-            handle = self.mapper[o]
-            return self.transform(o, handle, **kwargs)
-        children = [self._visit(i) for i in o.children]
-        if not [i for i in children if i]:
-            return None
-        return o._rebuild(*children, **o.args_frozen)
-
     def visit_Iteration(self, o, **kwargs):
         if o in self.mapper:
             handle = self.mapper[o]
             return self.transform(o, handle, **kwargs)
         children = [self._visit(i) for i in o.children]
-        if not [i for i in children if i]:
+        if not any(children):
             return None
         return o._rebuild(*children, **o.args_frozen)
 
+    visit_ExpressionBundle = visit_Iteration
+
     def visit_Node(self, o, **kwargs):
         if o in self.mapper:
             handle = self.mapper[o]