[llvm] [llvm][ADT] Add wrappers to `std::includes` (PR #143297)

[Jakub Kuderski via llvm-commits]

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@@ -1940,6 +1940,28 @@ template <typename R> bool is_sorted(R &&Range) {
   return std::is_sorted(adl_begin(Range), adl_end(Range));
 }
 
+/// Provide wrappers to std::includes which take ranges instead of having to
+/// pass begin/end explicitly.
+/// This function checks if the sorted range \p R2 is a subsequence of the
+/// sorted range \p R1. The ranges must be sorted in non-descending order.
+template <typename R1, typename R2> bool includes(R1 &&Range1, R2 &&Range2) {
+  assert(is_sorted(Range1) && "Range1 must be sorted in non-descending order");
+  assert(is_sorted(Range2) && "Range2 must be sorted in non-descending order");
+  return std::includes(adl_begin(Range1), adl_end(Range1), adl_begin(Range2),
+                       adl_end(Range2));
+}
+
+/// This function checks if the sorted range \p R2 is a subsequence of the
+/// sorted range \p R1. The ranges must be sorted with respect to a comparator
+/// \p C.
+template <typename R1, typename R2, typename Compare>
+bool includes(R1 &&Range1, R2 &&Range2, Compare &&C) {
+  assert(is_sorted(Range1, C) && "Range1 must be sorted with respect to C");
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kuhar wrote:

`includes` is already O(n) so checking if the ranges are sorted doesn't change the complexity -- I think that having this as an plain assertion is fair game. My understanding is that expensive checks are mainly for things that noticeable worsen performance.

https://github.com/llvm/llvm-project/pull/143297