compiler: fix corner case

Author: mloubout

devito/ir/iet/nodes.py

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

devito/ir/iet/visitors.py

@@ -1331,7 +1331,7 @@ def visit_Node(self, o, **kwargs):
             handle = self.mapper[o]
             return self.transform(o, handle, **kwargs)
         children = [self._visit(i, **kwargs) for i in o.children]
-        if o._traversable and not any(children):
+        if o._traversable and not any(children) and not o.args_frozen:
             return None
         return o._rebuild(*children, **o.args_frozen)
 

examples/performance/01_gpu.ipynb

@@ -288,7 +288,6 @@
       "\n",
       "  const int x_fsz0 = u_vec->size[1];\n",
       "  const int y_fsz0 = u_vec->size[2];\n",
-      "\n",
       "  const int x_stride0 = x_fsz0*y_fsz0;\n",
       "  const int y_stride0 = y_fsz0;\n",
       "\n",