[NFC] OwnershipUtils: Factored out function.

For historical reasons, the existing function
(`areUsesWithinExtendedScope`) trafficked in operands rather than
instructions.  Now that PrunedLiveness has an API that deals with
instructions, add a function (`areWithinExtendedScope`) which does as
well.  Factor the existing function through this new function.

Author: nate-chandler

include/swift/SIL/OwnershipUtils.h

@@ -630,6 +630,21 @@ struct BorrowedValue {
   /// necessarilly dominated by the borrow scope.
   void computeTransitiveLiveness(MultiDefPrunedLiveness &liveness) const;
 
+  /// Whether \p insts are completely within this borrow introducer's local
+  /// scope.
+  ///
+  /// Precondition: \p insts are dominated by the local borrow introducer.
+  ///
+  /// This ignores reborrows. The assumption is that, since \p insts are
+  /// dominated by this local scope, checking the extended borrow scope should
+  /// not be necessary to determine they are within the scope.
+  ///
+  /// \p deadEndBlocks is optional during transition. It will be completely
+  /// removed in an upcoming commit.
+  template <typename Instructions>
+  bool areWithinExtendedScope(Instructions insts,
+                              DeadEndBlocks *deadEndBlocks) const;
+
   /// Returns true if \p uses are completely within this borrow introducer's
   /// local scope.
   ///

lib/SIL/Utils/OwnershipUtils.cpp

@@ -975,8 +975,9 @@ computeTransitiveLiveness(MultiDefPrunedLiveness &liveness) const {
   });
 }
 
-bool BorrowedValue::areUsesWithinExtendedScope(
-    ArrayRef<Operand *> uses, DeadEndBlocks *deadEndBlocks) const {
+template <typename Instructions>
+bool BorrowedValue::areWithinExtendedScope(Instructions insts,
+                                           DeadEndBlocks *deadEndBlocks) const {
   // First make sure that we actually have a local scope. If we have a non-local
   // scope, then we have something (like a SILFunctionArgument) where a larger
   // semantic construct (in the case of SILFunctionArgument, the function
@@ -988,7 +989,17 @@ bool BorrowedValue::areUsesWithinExtendedScope(
   // Compute the local scope's liveness.
   MultiDefPrunedLiveness liveness(value->getFunction());
   computeTransitiveLiveness(liveness);
-  return liveness.areUsesWithinBoundary(uses, deadEndBlocks);
+  return liveness.areWithinBoundary(insts, deadEndBlocks);
+}
+
+template bool
+BorrowedValue::areWithinExtendedScope<SILInstruction::OperandUserRange>(
+    SILInstruction::OperandUserRange insts, DeadEndBlocks *deadEndBlocks) const;
+
+bool BorrowedValue::areUsesWithinExtendedScope(
+    ArrayRef<Operand *> uses, DeadEndBlocks *deadEndBlocks) const {
+  SILInstruction::OperandUserRange users(uses, SILInstruction::OperandToUser());
+  return areWithinExtendedScope(users, deadEndBlocks);
 }
 
 // The visitor \p func is only called on final scope-ending uses, not reborrows.