From 22f30cb943543d093b0537091036d35c953dd209 Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2@gmail.com>
Date: Thu, 18 Sep 2025 10:17:00 -0400
Subject: [PATCH] [libc++] Remove obsolete locale-specific regex tests

After a recent macOS update, several of the locale-specific regex
tests started failing. These tests were mainly testing two locale
specific features of regular expressions:

- A character class like `[=x=]` matches any character that is considered
  equivalent to `x` according to the collation rules of the current locale.

- A character class like `[[.ch.]]` matches anything that is equivalent
  to `ch` (whether as two letters or as a single collation element)
  in the current locale.

However, these tests were relying on platform-specific localization data,
specifically they were only working with older macOS localization data.
As can be seen from the numerous XFAILs, most mainstream platforms didn't
actually pass this test. After the macOS update, macOS itself also doesn't
pass these tests anymore.

I looked at whether there are locales where these tests would still make
sense, and I couldn't find any. I am not a localization expert, but it
appears that only e.g. the traditional Spanish locale considers `[.ch.]`
to be a single collation element. Therefore, it seems that the locale
specific part of these tests is not relevant anymore, so this patch
removes them.

The patch also moves some tests for equivalence classes inside character
classes to their non locale-specific tests, since that feature was not
covered there.

Finally, the lookup_collatename.pass.cpp test was fixed by removing an
assertion that `ch` is a collation element in the CZ locale, which seems
to not be the case in recent localization data (and appears to be the
root cause for about half the failures in these tests).
---
 .../re.alg/re.alg.match/awk.locale.pass.cpp   | 136 ------------------
 .../std/re/re.alg/re.alg.match/awk.pass.cpp   |  46 ++++++
 .../re.alg/re.alg.match/basic.locale.pass.cpp | 125 ----------------
 .../std/re/re.alg/re.alg.match/basic.pass.cpp |  46 ++++++
 .../re.alg/re.alg.match/ecma.locale.pass.cpp  | 121 ----------------
 .../std/re/re.alg/re.alg.match/ecma.pass.cpp  |  42 ++++++
 .../re.alg.match/extended.locale.pass.cpp     | 125 ----------------
 .../re/re.alg/re.alg.match/extended.pass.cpp  |  46 ++++++
 .../re.alg/re.alg.search/awk.locale.pass.cpp  | 125 ----------------
 .../std/re/re.alg/re.alg.search/awk.pass.cpp  |  46 ++++++
 .../re.alg.search/basic.locale.pass.cpp       | 125 ----------------
 .../re/re.alg/re.alg.search/basic.pass.cpp    |  46 ++++++
 .../re.alg/re.alg.search/ecma.locale.pass.cpp | 121 ----------------
 .../std/re/re.alg/re.alg.search/ecma.pass.cpp |  42 ++++++
 .../re.alg.search/extended.locale.pass.cpp    | 125 ----------------
 .../re/re.alg/re.alg.search/extended.pass.cpp |  46 ++++++
 .../re/re.traits/lookup_collatename.pass.cpp  |  20 ---
 17 files changed, 360 insertions(+), 1023 deletions(-)
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.match/awk.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.match/basic.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.match/ecma.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.match/extended.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.search/awk.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.search/basic.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.search/ecma.locale.pass.cpp
 delete mode 100644 libcxx/test/std/re/re.alg/re.alg.search/extended.locale.pass.cpp

diff --git a/libcxx/test/std/re/re.alg/re.alg.match/awk.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/awk.locale.pass.cpp
deleted file mode 100644
index 8c2875de01c52..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.match/awk.locale.pass.cpp
+++ /dev/null
@@ -1,136 +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
-//
-//===----------------------------------------------------------------------===//
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT,
-//           class traits>
-//   bool regex_match(BidirectionalIterator first, BidirectionalIterator last,
-//                    match_results<BidirectionalIterator, Allocator>& m,
-//                    const basic_regex<charT, traits>& e,
-//                    regex_constants::match_flag_type flags
-//                                            = regex_constants::match_default);
-
-// TODO: investigation needed
-// TODO(netbsd): incomplete support for locales
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, netbsd, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-// AIX supports character equivalence classes. What the contents of the class are depends
-// on the locale and the standards do not specify any locale other than C/POSIX.
-#if defined(_AIX)
-        assert(std::regex_match(s, m,
-                      std::regex("[a[=m=]z]", std::regex_constants::awk)));
-#else
-        assert(std::regex_match(s, m,
-                      std::regex("[a[=M=]z]", std::regex_constants::awk)));
-#endif
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert((std::size_t)m.length(0) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_match(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::awk | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert((std::size_t)m.length(0) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-#if defined(_AIX)
-        assert(std::regex_match(s, m, std::wregex(L"[a[=m=]z]",
-                                                 std::regex_constants::awk)));
-#else
-        assert(std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-#endif
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert((std::size_t)m.length(0) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-//TODO: Need to be investigated for AIX OS
-#if !defined(_AIX)
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_match(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::awk | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert((std::size_t)m.length(0) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-#endif
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp
index 988beec15e644..024738258c050 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp
@@ -573,6 +573,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_match(s, m,
+                      std::regex("[a[=m=]z]", std::regex_constants::awk)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert((std::size_t)m.length(0) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_match(s, m,
+                      std::regex("[a[=M=]z]", std::regex_constants::awk)));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1215,6 +1238,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_match(s, m, std::wregex(L"[a[=m=]z]",
+                                                 std::regex_constants::awk)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert((std::size_t)m.length(0) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
+                                                 std::regex_constants::awk)));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/basic.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/basic.locale.pass.cpp
deleted file mode 100644
index 9002681547b8d..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.match/basic.locale.pass.cpp
+++ /dev/null
@@ -1,125 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_match(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_match(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_match(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::basic | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_match(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::basic | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp
index 9765a07f2e4fe..fd91866b9209b 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/basic.pass.cpp
@@ -575,6 +575,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_match(s, m, std::regex("[a[=m=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1203,6 +1226,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_match(s, m, std::wregex(L"[a[=m=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/ecma.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/ecma.locale.pass.cpp
deleted file mode 100644
index 2e6f7fd285ae4..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.match/ecma.locale.pass.cpp
+++ /dev/null
@@ -1,121 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_match(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_match(s, m, std::regex("[a[=M=]z]")));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_match(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]")));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_match(s, m, std::wregex(L"[a[=M=]z]")));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_match(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]")));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp
index a0699634c2bc9..799a362425ad5 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/ecma.pass.cpp
@@ -563,6 +563,27 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_match(s, m, std::regex("[a[=m=]z]")));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]")));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1226,6 +1247,27 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_match(s, m, std::wregex(L"[a[=m=]z]")));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]")));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/extended.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/extended.locale.pass.cpp
deleted file mode 100644
index 4948f68f3934c..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.match/extended.locale.pass.cpp
+++ /dev/null
@@ -1,125 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_match(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_match(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_match(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::extended | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_match(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::extended | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
index 73c1d8352ab2b..e800fa88d8300 100644
--- a/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
@@ -590,6 +590,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_match(s, m, std::regex("[a[=m=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_match(s, m, std::regex("[a[=M=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1234,6 +1257,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_match(s, m, std::wregex(L"[a[=m=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_match(s, m, std::wregex(L"[a[=M=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/awk.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/awk.locale.pass.cpp
deleted file mode 100644
index 4c883a1cf380f..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.search/awk.locale.pass.cpp
+++ /dev/null
@@ -1,125 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_search(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_search(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_search(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::awk | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_search(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::awk | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::awk)));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp
index 2c23cf0f70079..904ba066125ec 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/awk.pass.cpp
@@ -645,6 +645,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_search(s, m, std::regex("[a[=m=]z]",
+                                                 std::regex_constants::awk)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]",
+                                                 std::regex_constants::awk)));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1377,6 +1400,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_search(s, m, std::wregex(L"[a[=m=]z]",
+                                                 std::regex_constants::awk)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
+                                                 std::regex_constants::awk)));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/basic.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/basic.locale.pass.cpp
deleted file mode 100644
index 7bf28a27ea604..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.search/basic.locale.pass.cpp
+++ /dev/null
@@ -1,125 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_search(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_search(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_search(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::basic | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_search(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::basic | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::basic)));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp
index 99f94f26b32ae..74b4d6341e9de 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/basic.pass.cpp
@@ -647,6 +647,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_search(s, m, std::regex("[a[=m=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1365,6 +1388,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_search(s, m, std::wregex(L"[a[=m=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
+                                                 std::regex_constants::basic)));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/ecma.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/ecma.locale.pass.cpp
deleted file mode 100644
index 64365932bfe72..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.search/ecma.locale.pass.cpp
+++ /dev/null
@@ -1,121 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_search(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_search(s, m, std::regex("[a[=M=]z]")));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_search(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]")));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_search(s, m, std::wregex(L"[a[=M=]z]")));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_search(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]")));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp
index 518c27e424484..ee88d11385c8d 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/ecma.pass.cpp
@@ -630,6 +630,27 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_search(s, m, std::regex("[a[=m=]z]")));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]")));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1371,6 +1392,27 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_search(s, m, std::wregex(L"[a[=m=]z]")));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]")));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/extended.locale.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/extended.locale.pass.cpp
deleted file mode 100644
index 22a98c601de5a..0000000000000
--- a/libcxx/test/std/re/re.alg/re.alg.search/extended.locale.pass.cpp
+++ /dev/null
@@ -1,125 +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
-//
-//===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-// XFAIL: LIBCXX-AIX-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
-
-// <regex>
-
-// template <class BidirectionalIterator, class Allocator, class charT, class traits>
-//     bool
-//     regex_search(BidirectionalIterator first, BidirectionalIterator last,
-//                  match_results<BidirectionalIterator, Allocator>& m,
-//                  const basic_regex<charT, traits>& e,
-//                  regex_constants::match_flag_type flags = regex_constants::match_default);
-
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}, freebsd
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
-#include <regex>
-#include <cassert>
-#include "test_macros.h"
-#include "test_iterators.h"
-
-#include "platform_support.h" // locale name macros
-
-int main(int, char**)
-{
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(std::regex_search(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::cmatch m;
-        const char s[] = "Ch";
-        assert(std::regex_search(s, m, std::regex("[a[.ch.]z]",
-                   std::regex_constants::extended | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::cmatch m;
-        const char s[] = "m";
-        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 0);
-    }
-
-#ifndef TEST_HAS_NO_WIDE_CHARACTERS
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"Ch";
-        assert(std::regex_search(s, m, std::wregex(L"[a[.ch.]z]",
-                   std::regex_constants::extended | std::regex_constants::icase)));
-        assert(m.size() == 1);
-        assert(!m.prefix().matched);
-        assert(m.prefix().first == s);
-        assert(m.prefix().second == m[0].first);
-        assert(!m.suffix().matched);
-        assert(m.suffix().first == m[0].second);
-        assert(m.suffix().second == m[0].second);
-        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
-        assert(m.position(0) == 0);
-        assert(m.str(0) == s);
-    }
-    std::locale::global(std::locale("C"));
-    {
-        std::wcmatch m;
-        const wchar_t s[] = L"m";
-        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
-                                                 std::regex_constants::extended)));
-        assert(m.size() == 0);
-    }
-#endif // TEST_HAS_NO_WIDE_CHARACTERS
-
-    return 0;
-}
diff --git a/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp b/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
index 0ddb49d619a18..73c37267efe86 100644
--- a/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
+++ b/libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
@@ -663,6 +663,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(std::regex_search(s, m, std::regex("[a[=m=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::cmatch m;
+        const char s[] = "m";
+        assert(!std::regex_search(s, m, std::regex("[a[=M=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 0);
+    }
     {
         std::cmatch m;
         const char s[] = "-";
@@ -1397,6 +1420,29 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(std::regex_search(s, m, std::wregex(L"[a[=m=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 1);
+        assert(!m.prefix().matched);
+        assert(m.prefix().first == s);
+        assert(m.prefix().second == m[0].first);
+        assert(!m.suffix().matched);
+        assert(m.suffix().first == m[0].second);
+        assert(m.suffix().second == m[0].second);
+        assert(m.length(0) >= 0 && static_cast<std::size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"m";
+        assert(!std::regex_search(s, m, std::wregex(L"[a[=M=]z]",
+                                                 std::regex_constants::extended)));
+        assert(m.size() == 0);
+    }
     {
         std::wcmatch m;
         const wchar_t s[] = L"-";
diff --git a/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp b/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp
index 50434832ddfff..5c690d5cfa480 100644
--- a/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp
+++ b/libcxx/test/std/re/re.traits/lookup_collatename.pass.cpp
@@ -5,14 +5,6 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-//
-// NetBSD does not support LC_COLLATE at the moment
-// XFAIL: netbsd
-
-// XFAIL: LIBCXX-AIX-FIXME
-// XFAIL: LIBCXX-FREEBSD-FIXME
-
-// REQUIRES: locale.cs_CZ.ISO8859-2
 
 // <regex>
 
@@ -22,18 +14,12 @@
 //   string_type
 //   lookup_collatename(ForwardIterator first, ForwardIterator last) const;
 
-// TODO: investigation needed
-// XFAIL: target={{.*}}-linux-gnu{{.*}}
-// XFAIL: target={{.*}}-amazon-linux{{.*}}
-// XFAIL: target={{.*}}-apple-{{.*}}
-
 #include <regex>
 #include <iterator>
 #include <cassert>
 
 #include "test_macros.h"
 #include "test_iterators.h"
-#include "platform_support.h" // locale name macros
 
 template <class char_type>
 void
@@ -118,9 +104,6 @@ int main(int, char**)
 
     test("tild", std::string(""));
     test("ch", std::string(""));
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    test("ch", std::string("ch"));
-    std::locale::global(std::locale("C"));
 
 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
     test(L"NUL", std::wstring(L"\x00", 1));
@@ -195,9 +178,6 @@ int main(int, char**)
 
     test(L"tild", std::wstring(L""));
     test(L"ch", std::wstring(L""));
-    std::locale::global(std::locale(LOCALE_cs_CZ_ISO8859_2));
-    test(L"ch", std::wstring(L"ch"));
-    std::locale::global(std::locale("C"));
 #endif // TEST_HAS_NO_WIDE_CHARACTERS
 
   return 0;