diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 1e49d3a7d04ff7403971dfb43ce6b21e1ba5a2d5..4e822def3fe310dc08b427c06ed3d7115ab45370 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,21 @@
 2019-10-04  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/81091
+	PR libstdc++/91947
+	* configure.ac: Use AC_SYS_LARGEFILE to enable 64-bit file APIs.
+	* config.h.in: Regenerate:
+	* configure: Regenerate:
+	* include/Makefile.am (${host_builddir}/largefile-config.h): New
+	target to generate config header for filesystem library.
+	(${host_builddir}/c++config.h): Rename macros for large file support.
+	* include/Makefile.in: Regenerate.
+	* src/c++17/fs_dir.cc: Include new config header.
+	* src/c++17/fs_ops.cc: Likewise.
+	(filesystem::file_size): Use uintmax_t for size.
+	* src/filesystem/dir.cc: Include new config header.
+	* src/filesystem/ops.cc: Likewise.
+	(experimental::filesystem::file_size): Use uintmax_t for size.
+
 	* testsuite/util/testsuite_abi.h: Use std::unordered_map instead of
 	std::tr1::unordered_map.
 	* testsuite/util/testsuite_allocator.h: Likewise.
diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in
index 3d13402f9234fcdd23df82126947c236ffab5468..32f7863a85ef90083c29f466b84b95c54b0339a2 100644
--- a/libstdc++-v3/config.h.in
+++ b/libstdc++-v3/config.h.in
@@ -803,6 +803,14 @@
 /* Version number of package */
 #undef VERSION
 
+/* Enable large inode numbers on Mac OS X 10.5.  */
+#ifndef _DARWIN_USE_64_BIT_INODE
+# define _DARWIN_USE_64_BIT_INODE 1
+#endif
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+#undef _FILE_OFFSET_BITS
+
 /* Define if C99 functions in <complex.h> should be used in <complex> for
    C++11. Using compiler builtins for these functions requires corresponding
    C99 library functions to be present. */
@@ -1047,6 +1055,9 @@
 /* Define to 1 if mutex_timedlock is available. */
 #undef _GTHREAD_USE_MUTEX_TIMEDLOCK
 
+/* Define for large files, on AIX-style hosts. */
+#undef _LARGE_FILES
+
 /* Define if all C++11 floating point overloads are available in <math.h>.  */
 #if __cplusplus >= 201103L
 #undef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index e646c412f98941f1eb8e0b36307f8b41522b56cc..cb67581206d10f09b69171b53cc45a337e39749a 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -895,6 +895,7 @@ ac_user_opts='
 enable_option_checking
 enable_multilib
 enable_silent_rules
+enable_largefile
 with_target_subdir
 with_cross_host
 with_newlib
@@ -1579,6 +1580,7 @@ Optional Features:
   --enable-multilib       build many library versions (default)
   --enable-silent-rules   less verbose build output (undo: "make V=1")
   --disable-silent-rules  verbose build output (undo: "make V=0")
+  --disable-largefile     omit support for large files
   --enable-maintainer-mode
                           enable make rules and dependencies not useful (and
                           sometimes confusing) to the casual installer
@@ -4928,9 +4930,210 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 CXXFLAGS="$save_CXXFLAGS"
 
+
+# Check whether --enable-largefile was given.
+if test "${enable_largefile+set}" = set; then :
+  enableval=$enable_largefile;
+fi
+
+if test "$enable_largefile" != no; then
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for special C compiler options needed for large files" >&5
+$as_echo_n "checking for special C compiler options needed for large files... " >&6; }
+if ${ac_cv_sys_largefile_CC+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_sys_largefile_CC=no
+     if test "$GCC" != yes; then
+       ac_save_CC=$CC
+       while :; do
+	 # IRIX 6.2 and later do not support large files by default,
+	 # so use the C compiler's -n32 option if that helps.
+	 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+  int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
+		       && LARGE_OFF_T % 2147483647 == 1)
+		      ? 1 : -1];
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+	 if ac_fn_c_try_compile "$LINENO"; then :
+  break
+fi
+rm -f core conftest.err conftest.$ac_objext
+	 CC="$CC -n32"
+	 if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_sys_largefile_CC=' -n32'; break
+fi
+rm -f core conftest.err conftest.$ac_objext
+	 break
+       done
+       CC=$ac_save_CC
+       rm -f conftest.$ac_ext
+    fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sys_largefile_CC" >&5
+$as_echo "$ac_cv_sys_largefile_CC" >&6; }
+  if test "$ac_cv_sys_largefile_CC" != no; then
+    CC=$CC$ac_cv_sys_largefile_CC
+  fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for _FILE_OFFSET_BITS value needed for large files" >&5
+$as_echo_n "checking for _FILE_OFFSET_BITS value needed for large files... " >&6; }
+if ${ac_cv_sys_file_offset_bits+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  while :; do
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+  int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
+		       && LARGE_OFF_T % 2147483647 == 1)
+		      ? 1 : -1];
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_sys_file_offset_bits=no; break
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#define _FILE_OFFSET_BITS 64
+#include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+  int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
+		       && LARGE_OFF_T % 2147483647 == 1)
+		      ? 1 : -1];
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_sys_file_offset_bits=64; break
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  ac_cv_sys_file_offset_bits=unknown
+  break
+done
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sys_file_offset_bits" >&5
+$as_echo "$ac_cv_sys_file_offset_bits" >&6; }
+case $ac_cv_sys_file_offset_bits in #(
+  no | unknown) ;;
+  *)
+cat >>confdefs.h <<_ACEOF
+#define _FILE_OFFSET_BITS $ac_cv_sys_file_offset_bits
+_ACEOF
+;;
+esac
+rm -rf conftest*
+  if test $ac_cv_sys_file_offset_bits = unknown; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for _LARGE_FILES value needed for large files" >&5
+$as_echo_n "checking for _LARGE_FILES value needed for large files... " >&6; }
+if ${ac_cv_sys_large_files+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  while :; do
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+  int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
+		       && LARGE_OFF_T % 2147483647 == 1)
+		      ? 1 : -1];
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_sys_large_files=no; break
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#define _LARGE_FILES 1
+#include <sys/types.h>
+ /* Check that off_t can represent 2**63 - 1 correctly.
+    We can't simply define LARGE_OFF_T to be 9223372036854775807,
+    since some C++ compilers masquerading as C compilers
+    incorrectly reject 9223372036854775807.  */
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+  int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
+		       && LARGE_OFF_T % 2147483647 == 1)
+		      ? 1 : -1];
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_sys_large_files=1; break
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  ac_cv_sys_large_files=unknown
+  break
+done
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sys_large_files" >&5
+$as_echo "$ac_cv_sys_large_files" >&6; }
+case $ac_cv_sys_large_files in #(
+  no | unknown) ;;
+  *)
+cat >>confdefs.h <<_ACEOF
+#define _LARGE_FILES $ac_cv_sys_large_files
+_ACEOF
+;;
+esac
+rm -rf conftest*
+  fi
+
+
+fi
+
+
 # Runs configure.host, and assorted other critical bits.  Sets
 # up critical shell variables.
-
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
@@ -11850,7 +12053,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11853 "configure"
+#line 12056 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11956,7 +12159,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11959 "configure"
+#line 12162 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -15648,7 +15851,7 @@ $as_echo "$glibcxx_cv_atomic_long_long" >&6; }
   # Fake what AC_TRY_COMPILE does.
 
     cat > conftest.$ac_ext << EOF
-#line 15651 "configure"
+#line 15854 "configure"
 int main()
 {
   typedef bool atomic_type;
@@ -15683,7 +15886,7 @@ $as_echo "$glibcxx_cv_atomic_bool" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15686 "configure"
+#line 15889 "configure"
 int main()
 {
   typedef short atomic_type;
@@ -15718,7 +15921,7 @@ $as_echo "$glibcxx_cv_atomic_short" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15721 "configure"
+#line 15924 "configure"
 int main()
 {
   // NB: _Atomic_word not necessarily int.
@@ -15754,7 +15957,7 @@ $as_echo "$glibcxx_cv_atomic_int" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15757 "configure"
+#line 15960 "configure"
 int main()
 {
   typedef long long atomic_type;
@@ -15907,7 +16110,7 @@ $as_echo "mutex" >&6; }
   # unnecessary for this test.
 
     cat > conftest.$ac_ext << EOF
-#line 15910 "configure"
+#line 16113 "configure"
 int main()
 {
   _Decimal32 d1;
@@ -15949,7 +16152,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   # unnecessary for this test.
 
     cat > conftest.$ac_ext << EOF
-#line 15952 "configure"
+#line 16155 "configure"
 template<typename T1, typename T2>
   struct same
   { typedef T2 type; };
@@ -15983,7 +16186,7 @@ $as_echo "$enable_int128" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15986 "configure"
+#line 16189 "configure"
 template<typename T1, typename T2>
   struct same
   { typedef T2 type; };
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index ad4ae0c3b7d323413c122ee343963852a32fee6d..154819acefef3c6f62bf90e8bc04a2e0bb5ddbac 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -83,6 +83,8 @@ AC_PROG_CC
 AC_PROG_CXX
 CXXFLAGS="$save_CXXFLAGS"
 
+AC_SYS_LARGEFILE
+
 # Runs configure.host, and assorted other critical bits.  Sets
 # up critical shell variables.
 GLIBCXX_CONFIGURE
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index b8b786d9260b91b814c99358496d148be686539d..3e9540ca0470f968a300f9ce226dc626a0c72bc3 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -1014,6 +1014,7 @@ allstamped = \
 # catenation.
 allcreated = \
 	${host_builddir}/c++config.h \
+	${host_builddir}/largefile-config.h \
 	${thread_host_headers} \
 	${pch_build}
 
@@ -1237,10 +1238,29 @@ stamp-float128:
 	echo 'undef _GLIBCXX_USE_FLOAT128' > stamp-float128
 endif
 
+# This header is not installed, it's only used to build libstdc++ itself.
+${host_builddir}/largefile-config.h: ${CONFIG_HEADER} \
+				     ${glibcxx_srcdir}/include/bits/c++config
+	@echo '#if defined _GLIBCXX_CXX_CONFIG_H || defined _FEATURES_H' > $@
+	@echo '# error "This file must be included before any others"' >> $@
+	@echo '#endif' >> $@
+	@echo >> $@
+	@echo '/* Enable large inode numbers on Mac OS X 10.5.  */' >> $@
+	@echo '#ifndef _DARWIN_USE_64_BIT_INODE' >> $@
+	@echo '# define _DARWIN_USE_64_BIT_INODE 1' >> $@
+	@echo '#endif' >> $@
+	@echo >> $@
+	@echo '/* Number of bits in a file offset, on hosts where this is settable. */' >> $@
+	@grep '_FILE_OFFSET_BITS' ${CONFIG_HEADER} >> $@
+	@echo >> $@
+	@echo '/* Define for large files, on AIX-style hosts. */' >> $@
+	@grep '_LARGE_FILES' ${CONFIG_HEADER} >> $@
+
 # NB: The non-empty default ldbl_compat works around an AIX sed
 # oddity, see libstdc++/31957 for details.
 ${host_builddir}/c++config.h: ${CONFIG_HEADER} \
 			      ${glibcxx_srcdir}/include/bits/c++config \
+			      ${host_builddir}/largefile-config.h \
 			      stamp-${host_alias} \
 			      ${toplevel_srcdir}/gcc/DATESTAMP \
 			      stamp-namespace-version \
@@ -1278,6 +1298,9 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \
 	    -e 's/PACKAGE/_GLIBCXX_PACKAGE/g' \
 	    -e 's/VERSION/_GLIBCXX_VERSION/g' \
 	    -e 's/WORDS_/_GLIBCXX_WORDS_/g' \
+	    -e 's/_DARWIN_USE_64_BIT_INODE/_GLIBCXX_DARWIN_USE_64_BIT_INODE/g' \
+	    -e 's/_FILE_OFFSET_BITS/_GLIBCXX_FILE_OFFSET_BITS/g' \
+	    -e 's/_LARGE_FILES/_GLIBCXX_LARGE_FILES/g' \
 	    -e 's/ICONV_CONST/_GLIBCXX_ICONV_CONST/g' \
 	    -e '/[	 ]_GLIBCXX_LONG_DOUBLE_COMPAT[	 ]/d' \
 	    < ${CONFIG_HEADER} >> $@ ;\
diff --git a/libstdc++-v3/include/Makefile.in b/libstdc++-v3/include/Makefile.in
index cd1e9df5482a19e11fa7bcaf7960304535978c9d..24e1363951c8ab160e7eca2383b56aee810bed1d 100644
--- a/libstdc++-v3/include/Makefile.in
+++ b/libstdc++-v3/include/Makefile.in
@@ -1346,6 +1346,7 @@ allstamped = \
 # catenation.
 allcreated = \
 	${host_builddir}/c++config.h \
+	${host_builddir}/largefile-config.h \
 	${thread_host_headers} \
 	${pch_build}
 
@@ -1717,10 +1718,29 @@ stamp-host: ${host_headers} ${bits_host_headers} ${ext_host_headers} ${host_head
 @ENABLE_FLOAT128_FALSE@stamp-float128:
 @ENABLE_FLOAT128_FALSE@	echo 'undef _GLIBCXX_USE_FLOAT128' > stamp-float128
 
+# This header is not installed, it's only used to build libstdc++ itself.
+${host_builddir}/largefile-config.h: ${CONFIG_HEADER} \
+				     ${glibcxx_srcdir}/include/bits/c++config
+	@echo '#if defined _GLIBCXX_CXX_CONFIG_H || defined _FEATURES_H' > $@
+	@echo '# error "This file must be included before any others"' >> $@
+	@echo '#endif' >> $@
+	@echo >> $@
+	@echo '/* Enable large inode numbers on Mac OS X 10.5.  */' >> $@
+	@echo '#ifndef _DARWIN_USE_64_BIT_INODE' >> $@
+	@echo '# define _DARWIN_USE_64_BIT_INODE 1' >> $@
+	@echo '#endif' >> $@
+	@echo >> $@
+	@echo '/* Number of bits in a file offset, on hosts where this is settable. */' >> $@
+	@grep '_FILE_OFFSET_BITS' ${CONFIG_HEADER} >> $@
+	@echo >> $@
+	@echo '/* Define for large files, on AIX-style hosts. */' >> $@
+	@grep '_LARGE_FILES' ${CONFIG_HEADER} >> $@
+
 # NB: The non-empty default ldbl_compat works around an AIX sed
 # oddity, see libstdc++/31957 for details.
 ${host_builddir}/c++config.h: ${CONFIG_HEADER} \
 			      ${glibcxx_srcdir}/include/bits/c++config \
+			      ${host_builddir}/largefile-config.h \
 			      stamp-${host_alias} \
 			      ${toplevel_srcdir}/gcc/DATESTAMP \
 			      stamp-namespace-version \
@@ -1758,6 +1778,9 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \
 	    -e 's/PACKAGE/_GLIBCXX_PACKAGE/g' \
 	    -e 's/VERSION/_GLIBCXX_VERSION/g' \
 	    -e 's/WORDS_/_GLIBCXX_WORDS_/g' \
+	    -e 's/_DARWIN_USE_64_BIT_INODE/_GLIBCXX_DARWIN_USE_64_BIT_INODE/g' \
+	    -e 's/_FILE_OFFSET_BITS/_GLIBCXX_FILE_OFFSET_BITS/g' \
+	    -e 's/_LARGE_FILES/_GLIBCXX_LARGE_FILES/g' \
 	    -e 's/ICONV_CONST/_GLIBCXX_ICONV_CONST/g' \
 	    -e '/[	 ]_GLIBCXX_LONG_DOUBLE_COMPAT[	 ]/d' \
 	    < ${CONFIG_HEADER} >> $@ ;\
diff --git a/libstdc++-v3/src/c++17/fs_dir.cc b/libstdc++-v3/src/c++17/fs_dir.cc
index d8c48f6d6d861ef37466747a384393335dca69ee..bcbcd7ba6b3bdbe5f81d5c00832c32bc02e6939d 100644
--- a/libstdc++-v3/src/c++17/fs_dir.cc
+++ b/libstdc++-v3/src/c++17/fs_dir.cc
@@ -26,6 +26,7 @@
 # define _GLIBCXX_USE_CXX11_ABI 1
 #endif
 
+#include <bits/largefile-config.h>
 #include <filesystem>
 #include <utility>
 #include <stack>
diff --git a/libstdc++-v3/src/c++17/fs_ops.cc b/libstdc++-v3/src/c++17/fs_ops.cc
index d8064819d3611e85cd312b69ec24ec1d859e6ea8..2541530e784dcce28755f193bff918b0da041ce7 100644
--- a/libstdc++-v3/src/c++17/fs_ops.cc
+++ b/libstdc++-v3/src/c++17/fs_ops.cc
@@ -28,6 +28,7 @@
 # define NEED_DO_SPACE
 #endif
 
+#include <bits/largefile-config.h>
 #include <filesystem>
 #include <functional>
 #include <ostream>
@@ -950,7 +951,7 @@ fs::file_size(const path& p, error_code& ec) noexcept
     S(const stat_type& st) : type(make_file_type(st)), size(st.st_size) { }
     S() : type(file_type::not_found) { }
     file_type type;
-    size_t size;
+    uintmax_t size;
   };
   auto s = do_stat(p, ec, [](const auto& st) { return S{st}; }, S{});
   if (s.type == file_type::regular)
diff --git a/libstdc++-v3/src/filesystem/dir.cc b/libstdc++-v3/src/filesystem/dir.cc
index 3e6e598fa6423b201dbf1e349752a1bfffe792b0..ac3bd3aafb3457c91224247f5c5d9fe3ae0f6623 100644
--- a/libstdc++-v3/src/filesystem/dir.cc
+++ b/libstdc++-v3/src/filesystem/dir.cc
@@ -26,6 +26,7 @@
 # define _GLIBCXX_USE_CXX11_ABI 1
 #endif
 
+#include <bits/largefile-config.h>
 #include <experimental/filesystem>
 
 #ifndef _GLIBCXX_HAVE_DIRENT_H
diff --git a/libstdc++-v3/src/filesystem/ops.cc b/libstdc++-v3/src/filesystem/ops.cc
index 36b5d2c24f645c86feca02e92d44c6bbde889d30..8687fcdc297c8cfff070458c1909ad642f0159c4 100644
--- a/libstdc++-v3/src/filesystem/ops.cc
+++ b/libstdc++-v3/src/filesystem/ops.cc
@@ -28,6 +28,7 @@
 # define NEED_DO_SPACE
 #endif
 
+#include <bits/largefile-config.h>
 #include <experimental/filesystem>
 #include <functional>
 #include <ostream>
@@ -806,7 +807,7 @@ fs::file_size(const path& p, error_code& ec) noexcept
     S(const stat_type& st) : type(make_file_type(st)), size(st.st_size) { }
     S() : type(file_type::not_found) { }
     file_type type;
-    size_t size;
+    uintmax_t size;
   };
   auto s = do_stat(p, ec, [](const auto& st) { return S{st}; }, S{});
   if (s.type == file_type::regular)