Merge pull request #21813 from xedin/rdar-46939892

[TypeChecker] NFC: Add a test-case for rdar://problem/46939892

Author: xedin

validation-test/Sema/type_checker_perf/fast/rdar46939892.swift

@@ -0,0 +1,19 @@
+// RUN: %target-typecheck-verify-swift
+
+struct S {
+  let a: Int
+  let b: Int
+  let c: Int
+  let d: Int
+
+  init(_ a: Int, _ b: Int, _ c: Int, _ d: Int) {
+    self.a = a
+    self.b = b
+    self.c = c
+    self.d = d
+  }
+}
+
+func foo(_ lhs: S, _ rhs: S) -> Int {
+  return abs(lhs.a - rhs.a) + abs(lhs.b - rhs.b) + abs(lhs.c - rhs.c) + abs(lhs.d - rhs.d)
+}