[libcxx-commits] [libcxx] [libc++] Optimize the two range overload of mismatch (PR #86853)

[Louis Dionne via libcxx-commits]

================
@@ -107,17 +108,42 @@ mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __fi
 }
 
 #if _LIBCPP_STD_VER >= 14
+template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter1, _Iter2> __mismatch(
+    _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
+  while (__first1 != __last1 && __first2 != __last2) {
+    if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+      break;
+    ++__first1;
+    ++__first2;
+  }
+  return {std::move(__first1), std::move(__first2)};
+}
+
+template <class _Tp, class _Pred, class _Proj1, class _Proj2>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Tp*, _Tp*>
+__mismatch(_Tp* __first1, _Tp* __last1, _Tp* __first2, _Tp* __last2, _Pred& __pred, _Proj1 __proj1, _Proj2 __proj2) {
----------------
ldionne wrote:

You're not taking the projection by reference here. Seems like a test should be failing.

https://github.com/llvm/llvm-project/pull/86853