Revert r372777: [libc++] Implement LWG 2510 and its follow-ups

This also reverts:
 - r372778: [libc++] Implement LWG 3158
 - r372782: [libc++] Try fixing tests that fail on GCC 5 and older
 - r372787: Purge mentions of GCC 4 from the test suite

Reason: the change breaks compilation of LLVM with libc++, for details see
http://lists.llvm.org/pipermail/libcxx-dev/2019-September/000599.html

llvm-svn: 372832

3 files changed, 3 insertions, 32 deletions

diff --git a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.fail.cpp b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.fail.cpp
deleted file mode 100644
index fb991d425f1..00000000000
--- a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.fail.cpp
+++ /dev/null
@@ -1,29 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++98, c++03
-
-// Before GCC 6, aggregate initialization kicks in.
-// See https://stackoverflow.com/q/41799015/627587.
-// UNSUPPORTED: gcc-5
-
-// <memory>
-
-// struct allocator_arg_t { explicit allocator_arg_t() = default; };
-// const allocator_arg_t allocator_arg = allocator_arg_t();
-
-// This test checks for LWG 2510.
-
-#include <memory>
-
-
-std::allocator_arg_t f() { return {}; } // expected-error 1 {{chosen constructor is explicit in copy-initialization}}
-
-int main(int, char**) {
-    return 0;
-}
diff --git a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
index e22bec1e514..0253243319a 100644
--- a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
@@ -8,7 +8,7 @@
 
 // <memory>
 
-// struct allocator_arg_t { explicit allocator_arg_t() = default; };
+// struct allocator_arg_t { };
 // const allocator_arg_t allocator_arg = allocator_arg_t();
 
 #include <memory>
@@ -21,5 +21,5 @@ int main(int, char**)
 {
     test(std::allocator_arg);
 
-    return 0;
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
index ae8a162ef2f..2aabf812a75 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++98, c++03, c++11, c++14
-// XFAIL: gcc-5, gcc-6
+// XFAIL: gcc-4, gcc-5, gcc-6
 
 // <memory>