SwiftCompilerSources: add the InstructionRange.insert(borrowScopeOf:) utility

Adds the instruction range of a borrow-scope by transitively visiting all (potential) re-borrows.

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift

@@ -532,3 +532,25 @@ extension GlobalVariable {
     }
   }
 }
+
+extension InstructionRange {
+  /// Adds the instruction range of a borrow-scope by transitively visiting all (potential) re-borrows.
+  mutating func insert(borrowScopeOf borrow: BorrowIntroducingInstruction, _ context: some Context) {
+    var worklist = ValueWorklist(context)
+    defer { worklist.deinitialize() }
+
+    worklist.pushIfNotVisited(borrow)
+    while let value = worklist.pop() {
+      for use in value.uses {
+        switch use.instruction {
+        case let endBorrow as EndBorrowInst:
+          self.insert(endBorrow)
+        case let branch as BranchInst:
+          worklist.pushIfNotVisited(branch.getArgument(for: use))
+        default:
+          break
+        }
+      }
+    }
+  }
+}