compiler: prevent premature reducermap->dict conversion

Author: mloubout

devito/operator/operator.py

@@ -637,15 +637,16 @@ def _prepare_arguments(self, autotune=None, estimate_memory=False, **kwargs):
                     # E.g., given a ConditionalDimension `t_sub` with factor `fact`
                     # and a TimeFunction `usave(t_sub, x, y)`, an override for
                     # `fact` is supplied w/o overriding `usave`; that's legal
-                    args[k] = args.unique(k, candidate=v)
-                elif is_integer(args[k]) and not contains_val(args[k], v):
+                    continue
+                if is_integer(args[k]) and not contains_val(args[k], v):
                     raise InvalidArgument(
                         f"Default `{p}` is incompatible with other args as "
                         f"`{k}={v}`, while `{k}={args[k]}` is expected. Perhaps "
                         f"you forgot to override `{p}`?"
                     )
+                args[k] = args.unique(k, candidate=v)
 
-        args = kwargs['args'] = args.reduce_all()
+        kwargs['args'] = args.reduce_inplace()
 
         for i in discretizations:
             args.update(i._arg_values(**kwargs))

devito/tools/data_structures.py

@@ -223,6 +223,8 @@ def reduce_inplace(self):
         for k, v in self.reduce_all().items():
             self[k] = v
 
+        return self
+
 
 class DefaultOrderedDict(OrderedDict):
     # Source: http://stackoverflow.com/a/6190500/562769

devito/types/dimension.py

@@ -1042,7 +1042,8 @@ def _arg_defaults(self, _min=None, size=None, alias=None):
                                      f"{self.name}: {size} < {size0}")
             else:
                 # Given a factor the last time index is factor*(size - 1)
-                defaults[dim.parent.max_name] = range(d0, d0 + factor*(size - 1) + 1)
+                # The maximum allowed value is then factor*size - 1
+                defaults[dim.parent.max_name] = range(d0, d0 + factor*size)
 
         return defaults