compiler: patch efuncs graph

Author: mloubout

devito/finite_differences/derivative.py

@@ -2,6 +2,7 @@
 from collections.abc import Iterable
 from functools import cached_property
 from itertools import chain
+import numbers
 
 import sympy
 
@@ -158,11 +159,14 @@ def _validate_expr(expr):
         """
         if type(expr) is sympy.Derivative:
             raise ValueError("Cannot nest sympy.Derivative with devito.Derivative")
+        elif isinstance(expr, numbers.Number):
+            return sympy.S.Zero
         if not isinstance(expr, Differentiable):
             try:
                 expr = diffify(expr)
             except Exception as e:
-                raise ValueError("`expr` must be a `Differentiable` type object") from e
+                d = type(expr)
+                raise ValueError(f"`expr` must be a `Differentiable` type object not {d}") from e
         return expr
 
     @staticmethod

devito/passes/iet/engine.py

@@ -223,13 +223,15 @@ def create_call_graph(root, efuncs):
     """
     dag = DAG(nodes=[root])
     queue = [root]
+    defuncs = {root}
 
     while queue:
         caller = queue.pop(0)
         callees = FindNodes(Call).visit(efuncs[caller])
 
         for callee in filter_ordered([i.name for i in callees]):
             if callee in efuncs:  # Exclude foreign Calls, e.g., MPI calls
+                defuncs.add(callee)
                 try:
                     dag.add_node(callee)
                     queue.append(callee)
@@ -239,7 +241,7 @@ def create_call_graph(root, efuncs):
                 dag.add_edge(callee, caller)
 
     # Sanity check
-    assert dag.size == len(efuncs)
+    assert dag.size == len(defuncs)
 
     return dag