Merge pull request #74318 from nate-chandler/gh72615

[Test] Add regression test.

Author: nate-chandler

validation-test/SILOptimizer/issue-72615.swift

@@ -0,0 +1,29 @@
+// RUN: %target-swift-frontend \
+// RUN:     %s                 \
+// RUN:     -emit-sil -verify  \
+// RUN:     -sil-verify-all
+
+func doStuffUniquely(with value: consuming [Int]) {
+  // If we received the last remaining reference to `value`, we'd like
+  // to be able to efficiently update it without incurring more copies.
+  var newValue = consume value
+  newValue.append(42)
+}
+
+func test() {
+  var x: [Int] = [1,2,3]
+
+  // x is appended to. After this point, we know that x is unique. We want to
+  // preserve that property.
+  x.append(5)
+
+  // Pass the current value of x off to another function, that
+  doStuffUniquely(with: consume x)
+
+  // Reset x to a new value. Since we don't use the old value anymore,
+  x = []
+  doMoreStuff(with: &x)
+}
+
+func doMoreStuff(with value: inout [Int]) {
+}