1. GNAT needs GCC 5.1 or later
2. Ubuntu 16.04 uses GCC 5.4
3. The propose is bump to GCC 5.5
4. Debian 9 uses GCC 6.3
5. D need GCC 9.4 or later
GCC 9.4 is obviously too new, and using GCC 5.5 rules out Ubuntu
16.04. So unless there is a strong reason to do so, it is recommended
to bump to GCC 5.4.
On Thu, Sep 19, 2024 at 12:59 AM Jason Merrill <ja...@redhat.com> wrote:
>
> On 9/18/24 6:36 PM, Iain Sandoe wrote:
> >
> >
> >> On 18 Sep 2024, at 17:18, Jason Merrill <ja...@redhat.com> wrote:
> >>
> >> Tested x86_64-pc-linux-gnu with 5.5.0 bootstrap compiler. Thoughts?
> >
> > Despite that adequate support is available in GCC-5.5/6, would it be
> > useful to jump to a version that allows a single toolchain to bootstrap
> > all the currently supported languages (currently we have 4.8.x for the
> > c-family+fortran, 5 for Ada and 9 for D which is somewhat unhelpful
> > for folks who test all supported langs).
>
> Hmm, people are certainly encouraged to bootstrap with GCC 9 if they
> want D support, but I wouldn't list it as a requirement for building GCC
> at all. The cost of unnecessarily cutting off older installations seems
> to me a poor tradeoff.
>
> >> -- 8< --
> >>
> >> This implements my proposal to update our bootstrap requirement to C++14.
> >> The big benefit of the change is the greater constexpr power, but C++14
> >> also
> >> added variable templates, generic lambdas, lambda init-capture, binary
> >> literals, and numeric literal digit separators.
> >>
> >> I'm not sure which GCC version to mention here. C++14 was feature-complete
> >> in GCC 5, and became the default in GCC 6. 5.5.0 builds trunk with no
> >> trouble, but of course trunk also doesn't use any C++14 features. Looking
> >> at bugzilla, I see only one C++14 fix (PR71630) in 5.5, and it doesn't seem
> >> important. In 5.4, PR69995 seems potentially significant, so shall we
> >> recommend 5.4 or later? Or just say 5.5 because people are unlikely to be
> >> stuck on an earlier minor release?
> >>
> >> gcc/ChangeLog:
> >>
> >> * doc/install.texi (Prerequisites): Update to C++14.
> >>
> >> ChangeLog:
> >>
> >> * configure.ac: Update requirement to C++14.
> >> * configure: Regenerate.
> >> ---
> >> gcc/doc/install.texi | 15 +-
> >> configure.ac | 12 +-
> >> configure | 832 ++++++++++++++++++++++++++++++++++++++++---
> >> 3 files changed, 790 insertions(+), 69 deletions(-)
> >>
> >> diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
> >> index e339d736969..87add0b6572 100644
> >> --- a/gcc/doc/install.texi
> >> +++ b/gcc/doc/install.texi
> >> @@ -222,17 +222,18 @@ described below.
> >>
> >> @heading Tools/packages necessary for building GCC
> >> @table @asis
> >> -@item ISO C++11 compiler
> >> -Necessary to bootstrap GCC. GCC 4.8.3 or newer has sufficient
> >> -support for used C++11 features.
> >> +@item ISO C++14 compiler
> >> +Necessary to bootstrap GCC. GCC 5.5 or newer has sufficient
> >> +support for used C++14 features.
> >>
> >> -Versions of GCC prior to 11 also allow bootstrapping with an ISO C++98
> >> -compiler, and versions of GCC prior to 4.8 also allow bootstrapping with
> >> -an ISO C89 compiler.
> >> +Versions of GCC prior to 15 allow bootstrapping with an ISO C++11
> >> +compiler, versions prior to 11 allow bootstrapping with an ISO C++98
> >> +compiler, and versions prior to 4.8 allow bootstrapping with an ISO
> >> +C89 compiler.
> >>
> >> To build all languages in a cross-compiler or other configuration where
> >> 3-stage bootstrap is not performed, you need to start with an existing
> >> -GCC binary (version 4.8.3 or later) because source code for language
> >> +GCC binary (version 5.5 or later) because source code for language
> >> frontends other than C might use GCC extensions.
> >>
> >> @item C standard library and headers
> >> diff --git a/configure.ac b/configure.ac
> >> index f61dbe64a94..91635d5368a 100644
> >> --- a/configure.ac
> >> +++ b/configure.ac
> >> @@ -1457,16 +1457,16 @@ case
> >> "$have_compiler:$host:$target:$enable_bootstrap" in
> >> ;;
> >> esac
> >>
> >> -# When bootstrapping with GCC, build stage 1 in C++11 mode to ensure that
> >> a
> >> -# C++11 compiler can still start the bootstrap. Otherwise, if building
> >> GCC,
> >> -# require C++11 (or higher).
> >> +# When bootstrapping with GCC, build stage 1 in C++14 mode to ensure that
> >> a
> >> +# C++14 compiler can still start the bootstrap. Otherwise, if building
> >> GCC,
> >> +# require C++14 (or higher).
> >> if test "$enable_bootstrap:$GXX" = "yes:yes"; then
> >> - CXX="$CXX -std=c++11"
> >> + CXX="$CXX -std=c++14"
> >> elif test "$have_compiler" = yes; then
> >> - AX_CXX_COMPILE_STDCXX(11)
> >> + AX_CXX_COMPILE_STDCXX(14)
> >>
> >> if test "${build}" != "${host}"; then
> >> - AX_CXX_COMPILE_STDCXX(11, [], [], [_FOR_BUILD])
> >> + AX_CXX_COMPILE_STDCXX(14, [], [], [_FOR_BUILD])
> >> fi
> >> fi
> >>
> >> diff --git a/configure b/configure
> >> index e9583f2ba0c..ab9719c6e93 100755
> >> --- a/configure
> >> +++ b/configure
> >> @@ -712,8 +712,8 @@ gmplibs
> >> PGO_BUILD_LTO_CFLAGS
> >> PGO_BUILD_USE_CFLAGS
> >> PGO_BUILD_GEN_CFLAGS
> >> -HAVE_CXX11_FOR_BUILD
> >> -HAVE_CXX11
> >> +HAVE_CXX14_FOR_BUILD
> >> +HAVE_CXX14
> >> do_compare
> >> CARGO
> >> GDC
> >> @@ -5914,13 +5914,13 @@ $as_echo "$as_me: WARNING: trying to bootstrap a
> >> cross compiler" >&2;}
> >> ;;
> >> esac
> >>
> >> -# When bootstrapping with GCC, build stage 1 in C++11 mode to ensure that
> >> a
> >> -# C++11 compiler can still start the bootstrap. Otherwise, if building
> >> GCC,
> >> -# require C++11 (or higher).
> >> +# When bootstrapping with GCC, build stage 1 in C++14 mode to ensure that
> >> a
> >> +# C++14 compiler can still start the bootstrap. Otherwise, if building
> >> GCC,
> >> +# require C++14 (or higher).
> >> if test "$enable_bootstrap:$GXX" = "yes:yes"; then
> >> - CXX="$CXX -std=c++11"
> >> + CXX="$CXX -std=c++14"
> >> elif test "$have_compiler" = yes; then
> >> - ax_cxx_compile_alternatives="11 0x"
> >> ax_cxx_compile_cxx11_required=true
> >> + ax_cxx_compile_alternatives="14 1y"
> >> ax_cxx_compile_cxx14_required=true
> >> ac_ext=cpp
> >> ac_cpp='$CXXCPP $CPPFLAGS'
> >> ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
> >> @@ -5928,9 +5928,9 @@ ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS
> >> $CPPFLAGS $LDFLAGS conftest.$ac_ex
> >> ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
> >> ac_success=no
> >>
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++11 features by default" >&5
> >> -$as_echo_n "checking whether $CXX supports C++11 features by default... "
> >> >&6; }
> >> -if ${ax_cv_cxx_compile_cxx11+:} false; then :
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++14 features by default" >&5
> >> +$as_echo_n "checking whether $CXX supports C++14 features by default... "
> >> >&6; }
> >> +if ${ax_cv_cxx_compile_cxx14+:} false; then :
> >> $as_echo_n "(cached) " >&6
> >> else
> >> cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> >> @@ -6223,26 +6223,146 @@ namespace cxx11
> >>
> >>
> >>
> >> +
> >> +// If the compiler admits that it is not ready for C++14, why torture it?
> >> +// Hopefully, this will speed up the test.
> >> +
> >> +#ifndef __cplusplus
> >> +
> >> +#error "This is not a C++ compiler"
> >> +
> >> +#elif __cplusplus < 201402L
> >> +
> >> +#error "This is not a C++14 compiler"
> >> +
> >> +#else
> >> +
> >> +namespace cxx14
> >> +{
> >> +
> >> + namespace test_polymorphic_lambdas
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + const auto lambda = [](auto&&... args){
> >> + const auto istiny = [](auto x){
> >> + return (sizeof(x) == 1UL) ? 1 : 0;
> >> + };
> >> + const int aretiny[] = { istiny(args)... };
> >> + return aretiny[0];
> >> + };
> >> + return lambda(1, 1L, 1.0f, '1');
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_binary_literals
> >> + {
> >> +
> >> + constexpr auto ivii = 0b0000000000101010;
> >> + static_assert(ivii == 42, "wrong value");
> >> +
> >> + }
> >> +
> >> + namespace test_generalized_constexpr
> >> + {
> >> +
> >> + template < typename CharT >
> >> + constexpr unsigned long
> >> + strlen_c(const CharT *const s) noexcept
> >> + {
> >> + auto length = 0UL;
> >> + for (auto p = s; *p; ++p)
> >> + ++length;
> >> + return length;
> >> + }
> >> +
> >> + static_assert(strlen_c("") == 0UL, "");
> >> + static_assert(strlen_c("x") == 1UL, "");
> >> + static_assert(strlen_c("test") == 4UL, "");
> >> + static_assert(strlen_c("another\0test") == 7UL, "");
> >> +
> >> + }
> >> +
> >> + namespace test_lambda_init_capture
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + const auto lambda1 = [a = x](int b){ return a + b; };
> >> + const auto lambda2 = [a = lambda1(x)](){ return a; };
> >> + return lambda2();
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_digit_separators
> >> + {
> >> +
> >> + constexpr auto ten_million = 100'000'000;
> >> + static_assert(ten_million == 100000000, "");
> >> +
> >> + }
> >> +
> >> + namespace test_return_type_deduction
> >> + {
> >> +
> >> + auto f(int& x) { return x; }
> >> + decltype(auto) g(int& x) { return x; }
> >> +
> >> + template < typename T1, typename T2 >
> >> + struct is_same
> >> + {
> >> + static constexpr auto value = false;
> >> + };
> >> +
> >> + template < typename T >
> >> + struct is_same<T, T>
> >> + {
> >> + static constexpr auto value = true;
> >> + };
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + static_assert(is_same<int, decltype(f(x))>::value, "");
> >> + static_assert(is_same<int&, decltype(g(x))>::value, "");
> >> + return x;
> >> + }
> >> +
> >> + }
> >> +
> >> +} // namespace cxx14
> >> +
> >> +#endif // __cplusplus >= 201402L
> >> +
> >> +
> >> +
> >> _ACEOF
> >> if ac_fn_cxx_try_compile "$LINENO"; then :
> >> - ax_cv_cxx_compile_cxx11=yes
> >> + ax_cv_cxx_compile_cxx14=yes
> >> else
> >> - ax_cv_cxx_compile_cxx11=no
> >> + ax_cv_cxx_compile_cxx14=no
> >> fi
> >> rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
> >> fi
> >> -{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
> >> $ax_cv_cxx_compile_cxx11" >&5
> >> -$as_echo "$ax_cv_cxx_compile_cxx11" >&6; }
> >> - if test x$ax_cv_cxx_compile_cxx11 = xyes; then
> >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
> >> $ax_cv_cxx_compile_cxx14" >&5
> >> +$as_echo "$ax_cv_cxx_compile_cxx14" >&6; }
> >> + if test x$ax_cv_cxx_compile_cxx14 = xyes; then
> >> ac_success=yes
> >> fi
> >>
> >> if test x$ac_success = xno; then
> >> for alternative in ${ax_cxx_compile_alternatives}; do
> >> switch="-std=gnu++${alternative}"
> >> - cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_$switch" | $as_tr_sh`
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++11 features with $switch" >&5
> >> -$as_echo_n "checking whether $CXX supports C++11 features with $switch...
> >> " >&6; }
> >> + cachevar=`$as_echo "ax_cv_cxx_compile_cxx14_$switch" | $as_tr_sh`
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++14 features with $switch" >&5
> >> +$as_echo_n "checking whether $CXX supports C++14 features with $switch...
> >> " >&6; }
> >> if eval \${$cachevar+:} false; then :
> >> $as_echo_n "(cached) " >&6
> >> else
> >> @@ -6538,6 +6658,126 @@ namespace cxx11
> >>
> >>
> >>
> >> +
> >> +// If the compiler admits that it is not ready for C++14, why torture it?
> >> +// Hopefully, this will speed up the test.
> >> +
> >> +#ifndef __cplusplus
> >> +
> >> +#error "This is not a C++ compiler"
> >> +
> >> +#elif __cplusplus < 201402L
> >> +
> >> +#error "This is not a C++14 compiler"
> >> +
> >> +#else
> >> +
> >> +namespace cxx14
> >> +{
> >> +
> >> + namespace test_polymorphic_lambdas
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + const auto lambda = [](auto&&... args){
> >> + const auto istiny = [](auto x){
> >> + return (sizeof(x) == 1UL) ? 1 : 0;
> >> + };
> >> + const int aretiny[] = { istiny(args)... };
> >> + return aretiny[0];
> >> + };
> >> + return lambda(1, 1L, 1.0f, '1');
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_binary_literals
> >> + {
> >> +
> >> + constexpr auto ivii = 0b0000000000101010;
> >> + static_assert(ivii == 42, "wrong value");
> >> +
> >> + }
> >> +
> >> + namespace test_generalized_constexpr
> >> + {
> >> +
> >> + template < typename CharT >
> >> + constexpr unsigned long
> >> + strlen_c(const CharT *const s) noexcept
> >> + {
> >> + auto length = 0UL;
> >> + for (auto p = s; *p; ++p)
> >> + ++length;
> >> + return length;
> >> + }
> >> +
> >> + static_assert(strlen_c("") == 0UL, "");
> >> + static_assert(strlen_c("x") == 1UL, "");
> >> + static_assert(strlen_c("test") == 4UL, "");
> >> + static_assert(strlen_c("another\0test") == 7UL, "");
> >> +
> >> + }
> >> +
> >> + namespace test_lambda_init_capture
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + const auto lambda1 = [a = x](int b){ return a + b; };
> >> + const auto lambda2 = [a = lambda1(x)](){ return a; };
> >> + return lambda2();
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_digit_separators
> >> + {
> >> +
> >> + constexpr auto ten_million = 100'000'000;
> >> + static_assert(ten_million == 100000000, "");
> >> +
> >> + }
> >> +
> >> + namespace test_return_type_deduction
> >> + {
> >> +
> >> + auto f(int& x) { return x; }
> >> + decltype(auto) g(int& x) { return x; }
> >> +
> >> + template < typename T1, typename T2 >
> >> + struct is_same
> >> + {
> >> + static constexpr auto value = false;
> >> + };
> >> +
> >> + template < typename T >
> >> + struct is_same<T, T>
> >> + {
> >> + static constexpr auto value = true;
> >> + };
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + static_assert(is_same<int, decltype(f(x))>::value, "");
> >> + static_assert(is_same<int&, decltype(g(x))>::value, "");
> >> + return x;
> >> + }
> >> +
> >> + }
> >> +
> >> +} // namespace cxx14
> >> +
> >> +#endif // __cplusplus >= 201402L
> >> +
> >> +
> >> +
> >> _ACEOF
> >> if ac_fn_cxx_try_compile "$LINENO"; then :
> >> eval $cachevar=yes
> >> @@ -6564,9 +6804,9 @@ $as_echo "$ac_res" >&6; }
> >> if test x$ac_success = xno; then
> >> for alternative in ${ax_cxx_compile_alternatives}; do
> >> for switch in -std=c++${alternative} +std=c++${alternative} "-h
> >> std=c++${alternative}"; do
> >> - cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_$switch" | $as_tr_sh`
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++11 features with $switch" >&5
> >> -$as_echo_n "checking whether $CXX supports C++11 features with $switch...
> >> " >&6; }
> >> + cachevar=`$as_echo "ax_cv_cxx_compile_cxx14_$switch" | $as_tr_sh`
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++14 features with $switch" >&5
> >> +$as_echo_n "checking whether $CXX supports C++14 features with $switch...
> >> " >&6; }
> >> if eval \${$cachevar+:} false; then :
> >> $as_echo_n "(cached) " >&6
> >> else
> >> @@ -6862,6 +7102,126 @@ namespace cxx11
> >>
> >>
> >>
> >> +
> >> +// If the compiler admits that it is not ready for C++14, why torture it?
> >> +// Hopefully, this will speed up the test.
> >> +
> >> +#ifndef __cplusplus
> >> +
> >> +#error "This is not a C++ compiler"
> >> +
> >> +#elif __cplusplus < 201402L
> >> +
> >> +#error "This is not a C++14 compiler"
> >> +
> >> +#else
> >> +
> >> +namespace cxx14
> >> +{
> >> +
> >> + namespace test_polymorphic_lambdas
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + const auto lambda = [](auto&&... args){
> >> + const auto istiny = [](auto x){
> >> + return (sizeof(x) == 1UL) ? 1 : 0;
> >> + };
> >> + const int aretiny[] = { istiny(args)... };
> >> + return aretiny[0];
> >> + };
> >> + return lambda(1, 1L, 1.0f, '1');
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_binary_literals
> >> + {
> >> +
> >> + constexpr auto ivii = 0b0000000000101010;
> >> + static_assert(ivii == 42, "wrong value");
> >> +
> >> + }
> >> +
> >> + namespace test_generalized_constexpr
> >> + {
> >> +
> >> + template < typename CharT >
> >> + constexpr unsigned long
> >> + strlen_c(const CharT *const s) noexcept
> >> + {
> >> + auto length = 0UL;
> >> + for (auto p = s; *p; ++p)
> >> + ++length;
> >> + return length;
> >> + }
> >> +
> >> + static_assert(strlen_c("") == 0UL, "");
> >> + static_assert(strlen_c("x") == 1UL, "");
> >> + static_assert(strlen_c("test") == 4UL, "");
> >> + static_assert(strlen_c("another\0test") == 7UL, "");
> >> +
> >> + }
> >> +
> >> + namespace test_lambda_init_capture
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + const auto lambda1 = [a = x](int b){ return a + b; };
> >> + const auto lambda2 = [a = lambda1(x)](){ return a; };
> >> + return lambda2();
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_digit_separators
> >> + {
> >> +
> >> + constexpr auto ten_million = 100'000'000;
> >> + static_assert(ten_million == 100000000, "");
> >> +
> >> + }
> >> +
> >> + namespace test_return_type_deduction
> >> + {
> >> +
> >> + auto f(int& x) { return x; }
> >> + decltype(auto) g(int& x) { return x; }
> >> +
> >> + template < typename T1, typename T2 >
> >> + struct is_same
> >> + {
> >> + static constexpr auto value = false;
> >> + };
> >> +
> >> + template < typename T >
> >> + struct is_same<T, T>
> >> + {
> >> + static constexpr auto value = true;
> >> + };
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + static_assert(is_same<int, decltype(f(x))>::value, "");
> >> + static_assert(is_same<int&, decltype(g(x))>::value, "");
> >> + return x;
> >> + }
> >> +
> >> + }
> >> +
> >> +} // namespace cxx14
> >> +
> >> +#endif // __cplusplus >= 201402L
> >> +
> >> +
> >> +
> >> _ACEOF
> >> if ac_fn_cxx_try_compile "$LINENO"; then :
> >> eval $cachevar=yes
> >> @@ -6895,41 +7255,41 @@ ac_compile='$CC -c $CFLAGS $CPPFLAGS
> >> conftest.$ac_ext >&5'
> >> ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS
> >> conftest.$ac_ext $LIBS >&5'
> >> ac_compiler_gnu=$ac_cv_c_compiler_gnu
> >>
> >> - if test x$ax_cxx_compile_cxx11_required = xtrue; then
> >> + if test x$ax_cxx_compile_cxx14_required = xtrue; then
> >> if test x$ac_success = xno; then
> >> - as_fn_error $? "*** A compiler with support for C++11 language
> >> features is required." "$LINENO" 5
> >> + as_fn_error $? "*** A compiler with support for C++14 language
> >> features is required." "$LINENO" 5
> >> fi
> >> fi
> >> if test x$ac_success = xno; then
> >> - HAVE_CXX11=0
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: No compiler with C++11
> >> support was found" >&5
> >> -$as_echo "$as_me: No compiler with C++11 support was found" >&6;}
> >> + HAVE_CXX14=0
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: No compiler with C++14
> >> support was found" >&5
> >> +$as_echo "$as_me: No compiler with C++14 support was found" >&6;}
> >> else
> >> - HAVE_CXX11=1
> >> + HAVE_CXX14=1
> >>
> >> -$as_echo "#define HAVE_CXX11 1" >>confdefs.h
> >> +$as_echo "#define HAVE_CXX14 1" >>confdefs.h
> >>
> >> fi
> >>
> >>
> >>
> >> if test "${build}" != "${host}"; then
> >> - ax_cxx_compile_alternatives="11 0x"
> >> ax_cxx_compile_cxx11_required=true
> >> + ax_cxx_compile_alternatives="14 1y"
> >> ax_cxx_compile_cxx14_required=true
> >> ac_ext=cpp
> >> ac_cpp='$CXXCPP $CPPFLAGS'
> >> ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
> >> ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS
> >> conftest.$ac_ext $LIBS >&5'
> >> ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
> >> ac_success=no
> >> - ax_cv_cxx_compile_cxx11_orig_cxx="$CXX"
> >> - ax_cv_cxx_compile_cxx11_orig_cxxflags="$CXXFLAGS"
> >> - ax_cv_cxx_compile_cxx11_orig_cppflags="$CPPFLAGS"
> >> + ax_cv_cxx_compile_cxx14_orig_cxx="$CXX"
> >> + ax_cv_cxx_compile_cxx14_orig_cxxflags="$CXXFLAGS"
> >> + ax_cv_cxx_compile_cxx14_orig_cppflags="$CPPFLAGS"
> >> CXX="$CXX_FOR_BUILD"
> >> CXXFLAGS="$CXXFLAGS_FOR_BUILD"
> >> CPPFLAGS="$CPPFLAGS_FOR_BUILD"
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++11 features by default" >&5
> >> -$as_echo_n "checking whether $CXX supports C++11 features by default... "
> >> >&6; }
> >> -if ${ax_cv_cxx_compile_cxx11_FOR_BUILD+:} false; then :
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++14 features by default" >&5
> >> +$as_echo_n "checking whether $CXX supports C++14 features by default... "
> >> >&6; }
> >> +if ${ax_cv_cxx_compile_cxx14_FOR_BUILD+:} false; then :
> >> $as_echo_n "(cached) " >&6
> >> else
> >> cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> >> @@ -7222,26 +7582,146 @@ namespace cxx11
> >>
> >>
> >>
> >> +
> >> +// If the compiler admits that it is not ready for C++14, why torture it?
> >> +// Hopefully, this will speed up the test.
> >> +
> >> +#ifndef __cplusplus
> >> +
> >> +#error "This is not a C++ compiler"
> >> +
> >> +#elif __cplusplus < 201402L
> >> +
> >> +#error "This is not a C++14 compiler"
> >> +
> >> +#else
> >> +
> >> +namespace cxx14
> >> +{
> >> +
> >> + namespace test_polymorphic_lambdas
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + const auto lambda = [](auto&&... args){
> >> + const auto istiny = [](auto x){
> >> + return (sizeof(x) == 1UL) ? 1 : 0;
> >> + };
> >> + const int aretiny[] = { istiny(args)... };
> >> + return aretiny[0];
> >> + };
> >> + return lambda(1, 1L, 1.0f, '1');
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_binary_literals
> >> + {
> >> +
> >> + constexpr auto ivii = 0b0000000000101010;
> >> + static_assert(ivii == 42, "wrong value");
> >> +
> >> + }
> >> +
> >> + namespace test_generalized_constexpr
> >> + {
> >> +
> >> + template < typename CharT >
> >> + constexpr unsigned long
> >> + strlen_c(const CharT *const s) noexcept
> >> + {
> >> + auto length = 0UL;
> >> + for (auto p = s; *p; ++p)
> >> + ++length;
> >> + return length;
> >> + }
> >> +
> >> + static_assert(strlen_c("") == 0UL, "");
> >> + static_assert(strlen_c("x") == 1UL, "");
> >> + static_assert(strlen_c("test") == 4UL, "");
> >> + static_assert(strlen_c("another\0test") == 7UL, "");
> >> +
> >> + }
> >> +
> >> + namespace test_lambda_init_capture
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + const auto lambda1 = [a = x](int b){ return a + b; };
> >> + const auto lambda2 = [a = lambda1(x)](){ return a; };
> >> + return lambda2();
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_digit_separators
> >> + {
> >> +
> >> + constexpr auto ten_million = 100'000'000;
> >> + static_assert(ten_million == 100000000, "");
> >> +
> >> + }
> >> +
> >> + namespace test_return_type_deduction
> >> + {
> >> +
> >> + auto f(int& x) { return x; }
> >> + decltype(auto) g(int& x) { return x; }
> >> +
> >> + template < typename T1, typename T2 >
> >> + struct is_same
> >> + {
> >> + static constexpr auto value = false;
> >> + };
> >> +
> >> + template < typename T >
> >> + struct is_same<T, T>
> >> + {
> >> + static constexpr auto value = true;
> >> + };
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + static_assert(is_same<int, decltype(f(x))>::value, "");
> >> + static_assert(is_same<int&, decltype(g(x))>::value, "");
> >> + return x;
> >> + }
> >> +
> >> + }
> >> +
> >> +} // namespace cxx14
> >> +
> >> +#endif // __cplusplus >= 201402L
> >> +
> >> +
> >> +
> >> _ACEOF
> >> if ac_fn_cxx_try_compile "$LINENO"; then :
> >> - ax_cv_cxx_compile_cxx11_FOR_BUILD=yes
> >> + ax_cv_cxx_compile_cxx14_FOR_BUILD=yes
> >> else
> >> - ax_cv_cxx_compile_cxx11_FOR_BUILD=no
> >> + ax_cv_cxx_compile_cxx14_FOR_BUILD=no
> >> fi
> >> rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
> >> fi
> >> -{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
> >> $ax_cv_cxx_compile_cxx11_FOR_BUILD" >&5
> >> -$as_echo "$ax_cv_cxx_compile_cxx11_FOR_BUILD" >&6; }
> >> - if test x$ax_cv_cxx_compile_cxx11_FOR_BUILD = xyes; then
> >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
> >> $ax_cv_cxx_compile_cxx14_FOR_BUILD" >&5
> >> +$as_echo "$ax_cv_cxx_compile_cxx14_FOR_BUILD" >&6; }
> >> + if test x$ax_cv_cxx_compile_cxx14_FOR_BUILD = xyes; then
> >> ac_success=yes
> >> fi
> >>
> >> if test x$ac_success = xno; then
> >> for alternative in ${ax_cxx_compile_alternatives}; do
> >> switch="-std=gnu++${alternative}"
> >> - cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_FOR_BUILD_$switch" |
> >> $as_tr_sh`
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++11 features with $switch" >&5
> >> -$as_echo_n "checking whether $CXX supports C++11 features with $switch...
> >> " >&6; }
> >> + cachevar=`$as_echo "ax_cv_cxx_compile_cxx14_FOR_BUILD_$switch" |
> >> $as_tr_sh`
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++14 features with $switch" >&5
> >> +$as_echo_n "checking whether $CXX supports C++14 features with $switch...
> >> " >&6; }
> >> if eval \${$cachevar+:} false; then :
> >> $as_echo_n "(cached) " >&6
> >> else
> >> @@ -7537,6 +8017,126 @@ namespace cxx11
> >>
> >>
> >>
> >> +
> >> +// If the compiler admits that it is not ready for C++14, why torture it?
> >> +// Hopefully, this will speed up the test.
> >> +
> >> +#ifndef __cplusplus
> >> +
> >> +#error "This is not a C++ compiler"
> >> +
> >> +#elif __cplusplus < 201402L
> >> +
> >> +#error "This is not a C++14 compiler"
> >> +
> >> +#else
> >> +
> >> +namespace cxx14
> >> +{
> >> +
> >> + namespace test_polymorphic_lambdas
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + const auto lambda = [](auto&&... args){
> >> + const auto istiny = [](auto x){
> >> + return (sizeof(x) == 1UL) ? 1 : 0;
> >> + };
> >> + const int aretiny[] = { istiny(args)... };
> >> + return aretiny[0];
> >> + };
> >> + return lambda(1, 1L, 1.0f, '1');
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_binary_literals
> >> + {
> >> +
> >> + constexpr auto ivii = 0b0000000000101010;
> >> + static_assert(ivii == 42, "wrong value");
> >> +
> >> + }
> >> +
> >> + namespace test_generalized_constexpr
> >> + {
> >> +
> >> + template < typename CharT >
> >> + constexpr unsigned long
> >> + strlen_c(const CharT *const s) noexcept
> >> + {
> >> + auto length = 0UL;
> >> + for (auto p = s; *p; ++p)
> >> + ++length;
> >> + return length;
> >> + }
> >> +
> >> + static_assert(strlen_c("") == 0UL, "");
> >> + static_assert(strlen_c("x") == 1UL, "");
> >> + static_assert(strlen_c("test") == 4UL, "");
> >> + static_assert(strlen_c("another\0test") == 7UL, "");
> >> +
> >> + }
> >> +
> >> + namespace test_lambda_init_capture
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + const auto lambda1 = [a = x](int b){ return a + b; };
> >> + const auto lambda2 = [a = lambda1(x)](){ return a; };
> >> + return lambda2();
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_digit_separators
> >> + {
> >> +
> >> + constexpr auto ten_million = 100'000'000;
> >> + static_assert(ten_million == 100000000, "");
> >> +
> >> + }
> >> +
> >> + namespace test_return_type_deduction
> >> + {
> >> +
> >> + auto f(int& x) { return x; }
> >> + decltype(auto) g(int& x) { return x; }
> >> +
> >> + template < typename T1, typename T2 >
> >> + struct is_same
> >> + {
> >> + static constexpr auto value = false;
> >> + };
> >> +
> >> + template < typename T >
> >> + struct is_same<T, T>
> >> + {
> >> + static constexpr auto value = true;
> >> + };
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + static_assert(is_same<int, decltype(f(x))>::value, "");
> >> + static_assert(is_same<int&, decltype(g(x))>::value, "");
> >> + return x;
> >> + }
> >> +
> >> + }
> >> +
> >> +} // namespace cxx14
> >> +
> >> +#endif // __cplusplus >= 201402L
> >> +
> >> +
> >> +
> >> _ACEOF
> >> if ac_fn_cxx_try_compile "$LINENO"; then :
> >> eval $cachevar=yes
> >> @@ -7563,9 +8163,9 @@ $as_echo "$ac_res" >&6; }
> >> if test x$ac_success = xno; then
> >> for alternative in ${ax_cxx_compile_alternatives}; do
> >> for switch in -std=c++${alternative} +std=c++${alternative} "-h
> >> std=c++${alternative}"; do
> >> - cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_FOR_BUILD_$switch" |
> >> $as_tr_sh`
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++11 features with $switch" >&5
> >> -$as_echo_n "checking whether $CXX supports C++11 features with $switch...
> >> " >&6; }
> >> + cachevar=`$as_echo "ax_cv_cxx_compile_cxx14_FOR_BUILD_$switch" |
> >> $as_tr_sh`
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX
> >> supports C++14 features with $switch" >&5
> >> +$as_echo_n "checking whether $CXX supports C++14 features with $switch...
> >> " >&6; }
> >> if eval \${$cachevar+:} false; then :
> >> $as_echo_n "(cached) " >&6
> >> else
> >> @@ -7861,6 +8461,126 @@ namespace cxx11
> >>
> >>
> >>
> >> +
> >> +// If the compiler admits that it is not ready for C++14, why torture it?
> >> +// Hopefully, this will speed up the test.
> >> +
> >> +#ifndef __cplusplus
> >> +
> >> +#error "This is not a C++ compiler"
> >> +
> >> +#elif __cplusplus < 201402L
> >> +
> >> +#error "This is not a C++14 compiler"
> >> +
> >> +#else
> >> +
> >> +namespace cxx14
> >> +{
> >> +
> >> + namespace test_polymorphic_lambdas
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + const auto lambda = [](auto&&... args){
> >> + const auto istiny = [](auto x){
> >> + return (sizeof(x) == 1UL) ? 1 : 0;
> >> + };
> >> + const int aretiny[] = { istiny(args)... };
> >> + return aretiny[0];
> >> + };
> >> + return lambda(1, 1L, 1.0f, '1');
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_binary_literals
> >> + {
> >> +
> >> + constexpr auto ivii = 0b0000000000101010;
> >> + static_assert(ivii == 42, "wrong value");
> >> +
> >> + }
> >> +
> >> + namespace test_generalized_constexpr
> >> + {
> >> +
> >> + template < typename CharT >
> >> + constexpr unsigned long
> >> + strlen_c(const CharT *const s) noexcept
> >> + {
> >> + auto length = 0UL;
> >> + for (auto p = s; *p; ++p)
> >> + ++length;
> >> + return length;
> >> + }
> >> +
> >> + static_assert(strlen_c("") == 0UL, "");
> >> + static_assert(strlen_c("x") == 1UL, "");
> >> + static_assert(strlen_c("test") == 4UL, "");
> >> + static_assert(strlen_c("another\0test") == 7UL, "");
> >> +
> >> + }
> >> +
> >> + namespace test_lambda_init_capture
> >> + {
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + const auto lambda1 = [a = x](int b){ return a + b; };
> >> + const auto lambda2 = [a = lambda1(x)](){ return a; };
> >> + return lambda2();
> >> + }
> >> +
> >> + }
> >> +
> >> + namespace test_digit_separators
> >> + {
> >> +
> >> + constexpr auto ten_million = 100'000'000;
> >> + static_assert(ten_million == 100000000, "");
> >> +
> >> + }
> >> +
> >> + namespace test_return_type_deduction
> >> + {
> >> +
> >> + auto f(int& x) { return x; }
> >> + decltype(auto) g(int& x) { return x; }
> >> +
> >> + template < typename T1, typename T2 >
> >> + struct is_same
> >> + {
> >> + static constexpr auto value = false;
> >> + };
> >> +
> >> + template < typename T >
> >> + struct is_same<T, T>
> >> + {
> >> + static constexpr auto value = true;
> >> + };
> >> +
> >> + int
> >> + test()
> >> + {
> >> + auto x = 0;
> >> + static_assert(is_same<int, decltype(f(x))>::value, "");
> >> + static_assert(is_same<int&, decltype(g(x))>::value, "");
> >> + return x;
> >> + }
> >> +
> >> + }
> >> +
> >> +} // namespace cxx14
> >> +
> >> +#endif // __cplusplus >= 201402L
> >> +
> >> +
> >> +
> >> _ACEOF
> >> if ac_fn_cxx_try_compile "$LINENO"; then :
> >> eval $cachevar=yes
> >> @@ -7890,28 +8610,28 @@ $as_echo "$ac_res" >&6; }
> >> CXX_FOR_BUILD="$CXX"
> >> CXXFLAGS_FOR_BUILD="$CXXFLAGS"
> >> CPPFLAGS_FOR_BUILD="$CPPFLAGS"
> >> - CXX="$ax_cv_cxx_compile_cxx11_orig_cxx"
> >> - CXXFLAGS="$ax_cv_cxx_compile_cxx11_orig_cxxflags"
> >> - CPPFLAGS="$ax_cv_cxx_compile_cxx11_orig_cppflags"
> >> + CXX="$ax_cv_cxx_compile_cxx14_orig_cxx"
> >> + CXXFLAGS="$ax_cv_cxx_compile_cxx14_orig_cxxflags"
> >> + CPPFLAGS="$ax_cv_cxx_compile_cxx14_orig_cppflags"
> >> ac_ext=c
> >> ac_cpp='$CPP $CPPFLAGS'
> >> ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
> >> ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS
> >> conftest.$ac_ext $LIBS >&5'
> >> ac_compiler_gnu=$ac_cv_c_compiler_gnu
> >>
> >> - if test x$ax_cxx_compile_cxx11_required = xtrue; then
> >> + if test x$ax_cxx_compile_cxx14_required = xtrue; then
> >> if test x$ac_success = xno; then
> >> - as_fn_error $? "*** A compiler with support for C++11 language
> >> features is required." "$LINENO" 5
> >> + as_fn_error $? "*** A compiler with support for C++14 language
> >> features is required." "$LINENO" 5
> >> fi
> >> fi
> >> if test x$ac_success = xno; then
> >> - HAVE_CXX11_FOR_BUILD=0
> >> - { $as_echo "$as_me:${as_lineno-$LINENO}: No compiler with C++11
> >> support was found" >&5
> >> -$as_echo "$as_me: No compiler with C++11 support was found" >&6;}
> >> + HAVE_CXX14_FOR_BUILD=0
> >> + { $as_echo "$as_me:${as_lineno-$LINENO}: No compiler with C++14
> >> support was found" >&5
> >> +$as_echo "$as_me: No compiler with C++14 support was found" >&6;}
> >> else
> >> - HAVE_CXX11_FOR_BUILD=1
> >> + HAVE_CXX14_FOR_BUILD=1
> >>
> >> -$as_echo "#define HAVE_CXX11_FOR_BUILD 1" >>confdefs.h
> >> +$as_echo "#define HAVE_CXX14_FOR_BUILD 1" >>confdefs.h
> >>
> >> fi
> >>
> >>
> >> base-commit: 5c8f9f4d4cebabf85e68c5bdbe2d4ee6646edc7c
> >> --
> >> 2.46.0
> >>
> >
>
