[PATCH] libstdc++: remove the gnu++11 in check performance script
Jonathan Wakely
jwakely@redhat.com
Fri Aug 21 13:01:52 GMT 2026
On Fri, 21 Aug 2026 at 13:48, Yuao Ma <addr2line@gmail.com> wrote:
>
> On Fri, Aug 21, 2026 at 8:25 PM Jonathan Wakely <jwakely@redhat.com> wrote:
> >
> > On Fri, 21 Aug 2026 at 20:23 +0800, Yuao Ma wrote:
> > >On Thu, Aug 20, 2026 at 11:34 PM Jonathan Wakely <jwakely@redhat.com> wrote:
> > >>
> > >> On Thu, 20 Aug 2026 at 14:38, Yuao Ma <addr2line@gmail.com> wrote:
> > >> >
> > >> > Hi!
> > >> >
> > >> > Based on previous discussions, we could remove the gnu++11 flag in the
> > >> > check performance script. And the rebind logic removed in c++20 is
> > >> > also adjusted.
> > >>
> > >> This makes the pb_ds performance tests unable to run as C++98, because
> > >> that doesn't have std::allocator_traits. So if anybody wanted to
> > >> compare performance of those containers in C++98 and C++20 (or C++11),
> > >> maybe because they were adding move semantics to the pb_ds containers,
> > >> the performance tests would not work.
> > >>
> > >> Although I really don't care about the pb_ds tests (because pb_ds is
> > >> unmaintained and should be moved to a separate repo), you could make
> > >> it work for all versions of C++ by using __gnu_cxx::__alloc_traits
> > >> instead of std::allocator_traits.
> > >>
> > >
> > >Thanks for the review! Indeed when I made the change in the patch I
> > >did not think about the compatibility of c++98. Fixed in the new
> > >patch.
> > >
> > >> >
> > >> > Tested with make check-performance, ok for trunk?
> > >> >
> > >> > Thanks,
> > >> > Yuao
> > >>
> >
> > >From b243166201265b86491044b20bdba79116766ae6 Mon Sep 17 00:00:00 2001
> > >From: Yuao Ma <c8ef@outlook.com>
> > >Date: Fri, 21 Aug 2026 20:21:13 +0800
> > >Subject: [PATCH] libstdc++: remove the gnu++11 in check performance script
> > >
> > >Nowadays gcc's default c++ version is gnu++20, maybe we should just use
> > >this in performance check as well.
> > >
> > >libstdc++-v3/ChangeLog:
> > >
> > > * scripts/check_performance: Remove gnu++11 flag.
> > > * testsuite/util/native_type/native_hash_map.hpp: Adjust rebind
> > > usage.
> > > * testsuite/util/native_type/native_hash_multimap.hpp: Ditto.
> > > * testsuite/util/native_type/native_hash_set.hpp: Ditto.
> > > * testsuite/util/native_type/native_map.hpp: Ditto.
> > > * testsuite/util/native_type/native_multimap.hpp: Ditto.
> > > * testsuite/util/native_type/native_set.hpp: Ditto.
> > >---
> > > libstdc++-v3/scripts/check_performance | 2 +-
> > > .../testsuite/util/native_type/native_hash_map.hpp | 2 +-
> > > .../testsuite/util/native_type/native_hash_multimap.hpp | 4 +---
> > > .../testsuite/util/native_type/native_hash_set.hpp | 2 +-
> > > libstdc++-v3/testsuite/util/native_type/native_map.hpp | 4 ++--
> > > .../testsuite/util/native_type/native_multimap.hpp | 7 ++-----
> > > libstdc++-v3/testsuite/util/native_type/native_set.hpp | 2 +-
> > > 7 files changed, 9 insertions(+), 14 deletions(-)
> > >
> > >diff --git a/libstdc++-v3/scripts/check_performance b/libstdc++-v3/scripts/check_performance
> > >index 4831ed71b6f..eb6adbc5ec6 100755
> > >--- a/libstdc++-v3/scripts/check_performance
> > >+++ b/libstdc++-v3/scripts/check_performance
> > >@@ -32,7 +32,7 @@ SH_FLAG="-Wl,--rpath -Wl,$BUILD_DIR/../../gcc \
> > > -Wl,--rpath -Wl,$BUILD_DIR/src/.libs"
> > > ST_FLAG="-static"
> > > LINK=$SH_FLAG
> > >-CXX="$COMPILER $INCLUDES $FLAGS -std=gnu++11 $CXXFLAGS $LINK"
> > >+CXX="$COMPILER $INCLUDES $FLAGS $CXXFLAGS $LINK"
> > > LIBS="./libtestc++.a"
> > > TESTS_FILE="testsuite_files_performance"
> > >
> > >diff --git a/libstdc++-v3/testsuite/util/native_type/native_hash_map.hpp b/libstdc++-v3/testsuite/util/native_type/native_hash_map.hpp
> > >index 1eb9851c886..0c0ecaeaa6b 100644
> > >--- a/libstdc++-v3/testsuite/util/native_type/native_hash_map.hpp
> > >+++ b/libstdc++-v3/testsuite/util/native_type/native_hash_map.hpp
> > >@@ -50,7 +50,7 @@ namespace __gnu_pbds
> > > {
> > > #define PB_DS_BASE_C_DEC \
> > > std::tr1::__unordered_map<Key, Data, Hash_Fn, Eq_Fn, \
> > >- typename _Alloc::template rebind<std::pair<const Key, Data> >::other, Cache_Hash>
> > >+ typename __gnu_cxx::__alloc_traits<_Alloc>::template rebind_alloc<std::pair<const Key, Data>>, Cache_Hash>
> >
> > For C++98 compatibility we need a space between the >> tokens.
> >
> > >
> > > template<typename Key,
> > > typename Data,
> > >diff --git a/libstdc++-v3/testsuite/util/native_type/native_hash_multimap.hpp b/libstdc++-v3/testsuite/util/native_type/native_hash_multimap.hpp
> > >index 35f16de8a1c..f6808aab9d1 100644
> > >--- a/libstdc++-v3/testsuite/util/native_type/native_hash_multimap.hpp
> > >+++ b/libstdc++-v3/testsuite/util/native_type/native_hash_multimap.hpp
> > >@@ -70,9 +70,7 @@ namespace __gnu_pbds
> > > typedef typename base_type::iterator iterator;
> > > typedef typename base_type::const_iterator const_iterator;
> > >
> > >- typedef
> > >- typename allocator::template rebind<pair_type>::other::const_reference
> > >- const_reference;
> > >+ typedef const pair_type& const_reference;
> > >
> > > native_hash_multimap() : base_type(Init_Size)
> > > { }
> > >diff --git a/libstdc++-v3/testsuite/util/native_type/native_hash_set.hpp b/libstdc++-v3/testsuite/util/native_type/native_hash_set.hpp
> > >index 75ebed43110..27bc4d76d3d 100644
> > >--- a/libstdc++-v3/testsuite/util/native_type/native_hash_set.hpp
> > >+++ b/libstdc++-v3/testsuite/util/native_type/native_hash_set.hpp
> > >@@ -50,7 +50,7 @@ namespace __gnu_pbds
> > > {
> > > #define PB_DS_BASE_C_DEC \
> > > std::tr1::__unordered_set<Key, Hash_Fn, Eq_Fn, \
> > >- typename _Alloc::template rebind<Key>::other, Cache_Hash>
> > >+ typename __gnu_cxx::__alloc_traits<_Alloc>::template rebind_alloc<Key>, Cache_Hash>
> > >
> > > template<typename Key,
> > > size_t Init_Size = 8,
> > >diff --git a/libstdc++-v3/testsuite/util/native_type/native_map.hpp b/libstdc++-v3/testsuite/util/native_type/native_map.hpp
> > >index 958553951b4..1617ed27e20 100644
> > >--- a/libstdc++-v3/testsuite/util/native_type/native_map.hpp
> > >+++ b/libstdc++-v3/testsuite/util/native_type/native_map.hpp
> > >@@ -49,8 +49,8 @@ namespace __gnu_pbds
> > > namespace test
> > > {
> > > #define PB_DS_BASE_C_DEC \
> > >- std::map<Key, Data, Cmp_Fn, \
> > >-typename _Alloc::template rebind<std::pair<const Key, Data > >::other >
> > >+ std::map<Key, Data, Cmp_Fn, \
> > >+ typename __gnu_cxx::__alloc_traits<_Alloc>::template rebind_alloc<std::pair<const Key, Data>>>
> >
> > And here.
> >
> > >
> > > template<typename Key, typename Data, class Cmp_Fn = std::less<Key>,
> > > typename _Alloc = std::allocator<char> >
> > >diff --git a/libstdc++-v3/testsuite/util/native_type/native_multimap.hpp b/libstdc++-v3/testsuite/util/native_type/native_multimap.hpp
> > >index 3646de930b4..eea682131cd 100644
> > >--- a/libstdc++-v3/testsuite/util/native_type/native_multimap.hpp
> > >+++ b/libstdc++-v3/testsuite/util/native_type/native_multimap.hpp
> > >@@ -48,7 +48,7 @@ namespace __gnu_pbds
> > > {
> > > #define PB_DS_BASE_C_DEC \
> > > std::multimap<Key, Data, Less_Fn, \
> > >- typename _Alloc::template rebind<std::pair<const Key, Data> >::other>
> > >+ typename __gnu_cxx::__alloc_traits<_Alloc>::template rebind_alloc<std::pair<const Key, Data>>>
> >
> > And here.
> >
> > >
> > > template<typename Key, typename Data, class Less_Fn = std::less<Key>,
> > > typename _Alloc = std::allocator<char> >
> > >@@ -62,10 +62,7 @@ namespace __gnu_pbds
> > >
> > > typedef _Alloc allocator;
> > >
> > >- typedef
> > >- typename _Alloc::template rebind<
> > >- std::pair<Key, Data> >::other::const_reference
> > >- const_reference;
> > >+ typedef const std::pair<Key, Data>& const_reference;
> > >
> > > typedef typename base_type::iterator iterator;
> > > typedef typename base_type::const_iterator const_iterator;
> > >diff --git a/libstdc++-v3/testsuite/util/native_type/native_set.hpp b/libstdc++-v3/testsuite/util/native_type/native_set.hpp
> > >index d382a371226..d26e665843a 100644
> > >--- a/libstdc++-v3/testsuite/util/native_type/native_set.hpp
> > >+++ b/libstdc++-v3/testsuite/util/native_type/native_set.hpp
> > >@@ -48,7 +48,7 @@ namespace __gnu_pbds
> > > namespace test
> > > {
> > > #define PB_DS_BASE_C_DEC \
> > >- std::set<Key, Cmp_Fn, typename _Alloc::template rebind<Key>::other>
> > >+ std::set<Key, Cmp_Fn, typename __gnu_cxx::__alloc_traits<_Alloc>::template rebind_alloc<Key>>
> >
> > And here.
> >
> > OK for trunk with those changes, thanks.
> >
>
> After some checking it seems that __gnu_cxx::__alloc_traits does not
> support rebind_alloc in gnu++98 : (
Ah, it provides __alloc_traits::rebind not rebind_alloc.
(Because 'rebind_alloc' is not a reserved name in C++98, but 'rebind' is)
> So in the new patch I switch to conditional macros. Both 98 and 20 are
> verified now. And for c++11 and above we can simply use the standard
> traits.
>
> > >
> > > template<typename Key, class Cmp_Fn = std::less<Key>,
> > > typename _Alloc = std::allocator<char> >
> > >--
> > >2.54.0
> > >
> >
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