Make is_empty() and propagate_subset() not unnecessarily rely on …

…the `src` and `dst` (#1699)

dace/memlet.py

@@ -230,7 +230,7 @@ def is_empty(self) -> bool:
         primarily used for connecting nodes to scopes without transferring 
         data to them. 
         """
-        return (self.data is None and self.src_subset is None and self.dst_subset is None)
+        return (self.data is None and self.subset is None and self.other_subset is None)
 
     @property
     def num_accesses(self):
@@ -561,20 +561,18 @@ def used_symbols(self, all_symbols: bool, edge=None) -> Set[str]:
                 view_edge = True
 
         if not view_edge:
-            if self.src_subset:
-                result |= self.src_subset.free_symbols
-
-            if self.dst_subset:
-                result |= self.dst_subset.free_symbols
+            if self.subset:
+                result |= self.subset.free_symbols
+            if self.other_subset:
+                result |= self.other_subset.free_symbols
         else:
             # View edges do not require the end of the range nor strides
-            if self.src_subset:
-                for rb, _, _ in self.src_subset.ndrange():
+            if self.subset:
+                for rb, _, _ in self.subset.ndrange():
                     if symbolic.issymbolic(rb):
                         result |= set(map(str, rb.free_symbols))
-
-            if self.dst_subset:
-                for rb, _, _ in self.dst_subset.ndrange():
+            if self.other_subset:
+                for rb, _, _ in self.other_subset.ndrange():
                     if symbolic.issymbolic(rb):
                         result |= set(map(str, rb.free_symbols))
 

dace/sdfg/propagation.py

@@ -1430,10 +1430,15 @@ def propagate_subset(memlets: List[Memlet],
         tmp_subset = None
 
         subset = None
-        if use_dst and md.dst_subset is not None:
-            subset = md.dst_subset
-        elif not use_dst and md.src_subset is not None:
-            subset = md.src_subset
+        src, dst = md.subset, md.other_subset
+        if md._is_data_src is not None:
+            # Ideally, this should always be the case. In practice, it is not always so. So, if the memlet is uninitialized
+            # for some reason, we just explicitly fallback to `subset` and `other_subset` to retain the prior behaviour.
+            src, dst = md.src_subset, md.dst_subset
+        if use_dst and dst is not None:
+            subset = dst
+        elif not use_dst and src is not None:
+            subset = src
         else:
             subset = md.subset