Index: libcxx/include/regex
===================================================================
--- libcxx/include/regex
+++ libcxx/include/regex
@@ -3537,6 +3537,15 @@
                 default:
                     if (__get_grammar(__flags_) == awk)
                         __first = __parse_awk_escape(++__first, __last);
+                    else
+                    {
+                        unsigned __val = __traits_.value(*__temp, 10);
+                        if (__val >= 1 && __val <= 9)
+                        {
+                          __push_back_ref(__val);
+                          __first = ++__temp;
+                        }
+                    }
                     break;
                 }
             }
Index: libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
===================================================================
--- libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
+++ libcxx/test/std/re/re.alg/re.alg.match/extended.pass.cpp
@@ -432,6 +432,24 @@
     {
         std::cmatch m;
         const char s[] = "-ab,ab-";
+        assert(std::regex_match(s, m, std::regex("-(.*),\\1-", std::regex_constants::extended)));
+        assert(m.size() == 2);
+        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<size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+        assert(m.length(1) == 2);
+        assert(m.position(1) == 1);
+        assert(m.str(1) == "ab");
+    }
+    {
+        std::cmatch m;
+        const char s[] = "-ab,ab-";
         assert(std::regex_match(s, m, std::regex("-.*,.*-", std::regex_constants::extended)));
         assert(m.size() == 1);
         assert(!m.prefix().matched);
@@ -1100,6 +1118,24 @@
     {
         std::wcmatch m;
         const wchar_t s[] = L"-ab,ab-";
+        assert(std::regex_match(s, m, std::wregex(L"-(.*),\\1-", std::regex_constants::extended)));
+        assert(m.size() == 2);
+        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<size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+        assert(m.length(1) == 2);
+        assert(m.position(1) == 1);
+        assert(m.str(1) == L"ab");
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"-ab,ab-";
         assert(std::regex_match(s, m, std::wregex(L"-.*,.*-", std::regex_constants::extended)));
         assert(m.size() == 1);
         assert(!m.prefix().matched);
Index: libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
===================================================================
--- libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
+++ libcxx/test/std/re/re.alg/re.alg.search/extended.pass.cpp
@@ -495,6 +495,24 @@
     {
         std::cmatch m;
         const char s[] = "-ab,ab-";
+        assert(std::regex_search(s, m, std::regex("-(.*),\\1-", std::regex_constants::extended)));
+        assert(m.size() == 2);
+        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<size_t>(m.length(0)) == std::char_traits<char>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+        assert(m.length(1) == 2);
+        assert(m.position(1) == 1);
+        assert(m.str(1) == "ab");
+    }
+    {
+        std::cmatch m;
+        const char s[] = "-ab,ab-";
         assert(std::regex_search(s, m, std::regex("-.*,.*-", std::regex_constants::extended)));
         assert(m.size() == 1);
         assert(!m.prefix().matched);
@@ -1253,6 +1271,24 @@
     {
         std::wcmatch m;
         const wchar_t s[] = L"-ab,ab-";
+        assert(std::regex_search(s, m, std::wregex(L"-(.*),\\1-", std::regex_constants::extended)));
+        assert(m.size() == 2);
+        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<size_t>(m.length(0)) == std::char_traits<wchar_t>::length(s));
+        assert(m.position(0) == 0);
+        assert(m.str(0) == s);
+        assert(m.length(1) == 2);
+        assert(m.position(1) == 1);
+        assert(m.str(1) == L"ab");
+    }
+    {
+        std::wcmatch m;
+        const wchar_t s[] = L"-ab,ab-";
         assert(std::regex_search(s, m, std::wregex(L"-.*,.*-", std::regex_constants::extended)));
         assert(m.size() == 1);
         assert(!m.prefix().matched);