diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ea4928f5a78..c307c1ff7ab 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,11 @@
 2018-10-19  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/regex_executor.tcc (_Backref_matcher::_M_apply): Use
+	_GLIBCXX_STD_A to refer to normal mode algorithms.
+	* testsuite/28_regex/headers/regex/parallel_mode.cc: New test.
+	* testsuite/28_regex/headers/regex/std_c++0x_neg.cc: Remove empty
+	whitespace.
+
 	* include/debug/map.h (map::erase(iterator)): Add abi-tag so that
 	C++11 version mangles differently from incompatible C++98 version.
 	* include/debug/multimap.h (multimap::erase(iterator)): Likewise.
diff --git a/libstdc++-v3/include/bits/regex_executor.tcc b/libstdc++-v3/include/bits/regex_executor.tcc
index b3238894f5d..68f1213cb64 100644
--- a/libstdc++-v3/include/bits/regex_executor.tcc
+++ b/libstdc++-v3/include/bits/regex_executor.tcc
@@ -366,11 +366,11 @@ namespace __detail
 	       _BiIter __actual_end)
       {
 	if (!_M_icase)
-	  return std::__equal4(__expected_begin, __expected_end,
+	  return _GLIBCXX_STD_A::__equal4(__expected_begin, __expected_end,
 			       __actual_begin, __actual_end);
 	typedef std::ctype<_CharT> __ctype_type;
 	const auto& __fctyp = use_facet<__ctype_type>(_M_traits.getloc());
-	return std::__equal4(__expected_begin, __expected_end,
+	return _GLIBCXX_STD_A::__equal4(__expected_begin, __expected_end,
 			     __actual_begin, __actual_end,
 			     [this, &__fctyp](_CharT __lhs, _CharT __rhs)
 			     {
diff --git a/libstdc++-v3/testsuite/28_regex/headers/regex/parallel_mode.cc b/libstdc++-v3/testsuite/28_regex/headers/regex/parallel_mode.cc
new file mode 100644
index 00000000000..d32df55c966
--- /dev/null
+++ b/libstdc++-v3/testsuite/28_regex/headers/regex/parallel_mode.cc
@@ -0,0 +1,22 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do compile { target c++11 } }
+// { dg-require-normal-mode "" }
+
+#define _GLIBCXX_PARALLEL
+#include <regex>
diff --git a/libstdc++-v3/testsuite/28_regex/headers/regex/std_c++0x_neg.cc b/libstdc++-v3/testsuite/28_regex/headers/regex/std_c++0x_neg.cc
index 44aa140eeea..85899aab0dd 100644
--- a/libstdc++-v3/testsuite/28_regex/headers/regex/std_c++0x_neg.cc
+++ b/libstdc++-v3/testsuite/28_regex/headers/regex/std_c++0x_neg.cc
@@ -21,6 +21,3 @@
 #include <regex>
 
 // { dg-error "ISO C.. 2011" "" { target *-*-* } 32 }
-
-
-