ScheduleTreeElemBand::drop: change type of position and number to size_t

This is a more natural type for a position and a number.

Author: Sven Verdoolaege

tc/core/polyhedral/schedule_tree_elem.cc

@@ -151,9 +151,9 @@ size_t ScheduleTreeElemBand::nOuterCoincident() const {
   return i;
 }
 
-void ScheduleTreeElemBand::drop(int pos, int n) {
-  CHECK_LE(0, n) << "range out of bounds";
-  CHECK_LE(0, pos) << "range  out of bounds";
+void ScheduleTreeElemBand::drop(size_t pos, size_t n) {
+  CHECK_LE(0u, n) << "range out of bounds";
+  CHECK_LE(0u, pos) << "range  out of bounds";
   CHECK_GE(nMember(), pos + n) << "range out of bounds";
   int nBegin = nMember();
 

tc/core/polyhedral/schedule_tree_elem.h

@@ -270,7 +270,7 @@ struct ScheduleTreeElemBand : public ScheduleTreeElemBase {
   // We apply the transformation even if "n" is zero to ensure consistent
   // behavior with respect to changes in the schedule space.
   // The caller is responsible for updating the isolate option (Note: why?)
-  void drop(int pos, int n);
+  void drop(size_t pos, size_t n);
 
  public:
   bool permutable_{false};