insertExtensionAbove: make it more obvious that root argument can be relative

Author: Sven Verdoolaege

tc/core/polyhedral/schedule_transforms.cc

@@ -505,10 +505,10 @@ ScheduleTree* insertSequenceAbove(ScheduleTree* root, ScheduleTree* tree) {
 }
 
 ScheduleTree* insertExtensionAbove(
-    ScheduleTree* root,
+    ScheduleTree* relativeRoot,
     ScheduleTree* tree,
     isl::union_map extension) {
-  auto parent = tree->ancestor(root, 1);
+  auto parent = tree->ancestor(relativeRoot, 1);
   auto childPos = tree->positionInParent(parent);
   auto child = parent->detachChild(childPos);
   parent->insertChild(

tc/core/polyhedral/schedule_transforms.h

@@ -167,14 +167,14 @@ detail::ScheduleTree* insertSequenceAbove(
     detail::ScheduleTree* root,
     detail::ScheduleTree* tree);
 
-// In a tree starting at a (relative) "root", insert an extension node with the
+// In a tree starting at a "relativeRoot", insert an extension node with the
 // given extension above the node identified by "tree".
 //
 // The tree is modified in place.
 // Return a non-owning pointer to the inserted extension node
 // for call chaining purposes.
 detail::ScheduleTree* insertExtensionAbove(
-    detail::ScheduleTree* root,
+    detail::ScheduleTree* relativeRoot,
     detail::ScheduleTree* tree,
     isl::union_map extension);