[gcc r17-909] libstdc++: Fix availability of flat_meow::operator=(initializer_list)
Patrick Palka
ppalka@gcc.gnu.org
Thu May 28 14:39:54 GMT 2026
https://gcc.gnu.org/g:c345d6afd9a9b331cb679b82e89213deb8f8a69a
commit r17-909-gc345d6afd9a9b331cb679b82e89213deb8f8a69a
Author: Patrick Palka <ppalka@redhat.com>
Date: Thu May 28 10:39:32 2026 -0400
libstdc++: Fix availability of flat_meow::operator=(initializer_list)
This assignment operator was not being brought in from the private base
class causing assignments from {...} to be inefficiently treated as
construction + move assignment.
libstdc++-v3/ChangeLog:
* include/std/flat_map (flat_map): Bring in operator= from
_Flat_map_base.
(flat_multimap): Likewise.
* include/std/flat_set (flat_set): Bring in operator= from
_Flat_set_base.
(flat_multiset): Likewise.
* testsuite/23_containers/flat_map/1.cc (test11): Simplify by
using = {...}.
(test12): New test.
* testsuite/23_containers/flat_multimap/1.cc (test10): Simplify
by using = {...}.
(test11): New test.
* testsuite/23_containers/flat_multiset/1.cc (test10): Simplify
by using = {...}.
(test11): New test.
* testsuite/23_containers/flat_set/1.cc (test10): Simplify by
using = {...}.
(test11): New test.
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Diff:
---
libstdc++-v3/include/std/flat_map | 10 +++++++++
libstdc++-v3/include/std/flat_set | 10 +++++++++
libstdc++-v3/testsuite/23_containers/flat_map/1.cc | 23 +++++++++++++++------
.../testsuite/23_containers/flat_multimap/1.cc | 23 +++++++++++++++------
.../testsuite/23_containers/flat_multiset/1.cc | 24 ++++++++++++++++------
libstdc++-v3/testsuite/23_containers/flat_set/1.cc | 24 ++++++++++++++++------
6 files changed, 90 insertions(+), 24 deletions(-)
diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
index f06c75a16f65..b82d41b4f5e1 100644
--- a/libstdc++-v3/include/std/flat_map
+++ b/libstdc++-v3/include/std/flat_map
@@ -1275,6 +1275,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// constructors
using _Impl::_Impl;
+ // operator=(initializer_list<value_type>)
+ // Although this also brings in the base move/copy assignment operators,
+ // they will be hidden by our synthesized ones.
+ using _Impl::operator=;
+
// iterators
using _Impl::begin;
using _Impl::end;
@@ -1628,6 +1633,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// constructors
using _Impl::_Impl;
+ // operator=(initializer_list<value_type>)
+ // Although this also brings in the base move/copy assignment operators,
+ // they will be hidden by our synthesized ones.
+ using _Impl::operator=;
+
// iterators
using _Impl::begin;
using _Impl::end;
diff --git a/libstdc++-v3/include/std/flat_set b/libstdc++-v3/include/std/flat_set
index e92559949ebb..2f204cc08bf9 100644
--- a/libstdc++-v3/include/std/flat_set
+++ b/libstdc++-v3/include/std/flat_set
@@ -967,6 +967,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// constructors
using _Impl::_Impl;
+ // operator=(initializer_list<value_type>)
+ // Although this also brings in the base move/copy assignment operators,
+ // they will be hidden by our synthesized ones.
+ using _Impl::operator=;
+
// iterators
using _Impl::begin;
using _Impl::end;
@@ -1115,6 +1120,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// constructors
using _Impl::_Impl;
+ // operator=(initializer_list<value_type>)
+ // Although this also brings in the base move/copy assignment operators,
+ // they will be hidden by our synthesized ones.
+ using _Impl::operator=;
+
// iterators
using _Impl::begin;
using _Impl::end;
diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
index 7e22e0366ec2..0cd06b72e96c 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
@@ -351,8 +351,7 @@ test11()
}
// Verify invariant preservation upon throwing move assignment.
- source.clear();
- source.insert({{1, 100}, {2, 200}});
+ source = {{1, 100}, {2, 200}};
flat_map target;
target.insert({{3, 300}, {4, 400}});
try
@@ -367,10 +366,8 @@ test11()
}
// Verify invariant preservation upon throwing swap.
- source.clear();
- source.insert({{1, 100}, {2, 200}});
- target.clear();
- target.insert({{3, 300}, {4, 400}});
+ source = {{1, 100}, {2, 200}};
+ target = {{3, 300}, {4, 400}};
try
{
source.swap(target);
@@ -396,6 +393,18 @@ test12()
VERIFY( std::ranges::equal(m.values(), (int[]){100, 200, 300}) );
}
+void
+test13()
+{
+ // Verify usability of flat_map::operator=(initializer_list).
+ throwing_vector<int>::throw_on_move = true;
+ std::flat_map<int, int, std::less<int>, throwing_vector<int>> s;
+ std::initializer_list<std::pair<int, int>> il = {{2, 1}, {3, 2}, {1, 3}};
+ s = il;
+ VERIFY( std::ranges::equal(s.keys(), (int[]){1, 2, 3}) );
+ VERIFY( std::ranges::equal(s.values(), (int[]){3, 1, 2}) );
+}
+
void
test()
{
@@ -415,6 +424,7 @@ test()
test11<std::vector, throwing_vector>();
test11<throwing_vector, std::vector>();
test12();
+ test13();
}
constexpr
@@ -435,6 +445,7 @@ test_constexpr()
#endif
// test11() is non-constexpr
test12();
+ // test13() is non-constexpr
return true;
}
diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
index 48688b7583ed..a070c5ef0911 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
@@ -304,8 +304,7 @@ test10()
}
// Verify invariant preservation upon throwing move assignment.
- source.clear();
- source.insert({{1, 100}, {2, 200}});
+ source = {{1, 100}, {2, 200}};
flat_multimap target;
target.insert({{3, 300}, {4, 400}});
try
@@ -320,10 +319,8 @@ test10()
}
// Verify invariant preservation upon throwing swap.
- source.clear();
- source.insert({{1, 100}, {2, 200}});
- target.clear();
- target.insert({{3, 300}, {4, 400}});
+ source = {{1, 100}, {2, 200}};
+ target = {{3, 300}, {4, 400}};
try
{
source.swap(target);
@@ -349,6 +346,18 @@ test11()
VERIFY( std::ranges::equal(m.values(), (int[]){100, 200, 300}) );
}
+void
+test12()
+{
+ // Verify usability of flat_multimap::operator=(initializer_list).
+ throwing_vector<int>::throw_on_move = true;
+ std::flat_multimap<int, int, std::less<int>, throwing_vector<int>> s;
+ std::initializer_list<std::pair<int, int>> il = {{2, 1}, {3, 2}, {1, 3}};
+ s = il;
+ VERIFY( std::ranges::equal(s.keys(), (int[]){1, 2, 3}) );
+ VERIFY( std::ranges::equal(s.values(), (int[]){3, 1, 2}) );
+}
+
void
test()
{
@@ -366,6 +375,7 @@ test()
test10<std::vector, throwing_vector>();
test10<throwing_vector, std::vector>();
test11();
+ test12();
}
constexpr
@@ -382,6 +392,7 @@ test_constexpr()
test09();
// test10() is non-constexpr
test11();
+ // test12() is non-constexpr
return true;
}
diff --git a/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
index 4544adb50770..eea53733f6d2 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
@@ -289,6 +289,8 @@ struct throwing_vector : std::vector<T>
throw std::runtime_error("move assign");
return *this;
}
+
+ using std::vector<int>::operator=;
};
void
@@ -312,8 +314,7 @@ test10()
}
// Verify invariant preservation upon throwing move assignment.
- source.clear();
- source.insert({1, 2});
+ source = {1, 2};
flat_multiset target = {3, 4};
try
{
@@ -327,10 +328,8 @@ test10()
}
// Verify invariant preservation upon throwing swap.
- source.clear();
- source.insert({1, 2});
- target.clear();
- target.insert({3, 4});
+ source = {1, 2};
+ target = {3, 4};
try
{
source.swap(target);
@@ -355,6 +354,17 @@ test11()
VERIFY( std::ranges::equal(m, (int[]){1, 2, 3}) );
}
+void
+test12()
+{
+ // Verify usability of flat_multiset::operator=(initializer_list).
+ throwing_vector<int>::throw_on_move = true;
+ std::flat_multiset<int, std::less<int>, throwing_vector<int>> s;
+ std::initializer_list<int> il = {2, 3, 1};
+ s = il;
+ VERIFY( std::ranges::equal(s, (int[]){1, 2, 3}) );
+}
+
void
test()
{
@@ -370,6 +380,7 @@ test()
test09();
test10();
test11();
+ test12();
}
constexpr
@@ -386,6 +397,7 @@ test_constexpr()
test09();
// test10() is non-constexpr
test11();
+ // test12() is non-constexpr
return true;
}
diff --git a/libstdc++-v3/testsuite/23_containers/flat_set/1.cc b/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
index ac12815bd0d4..116ccdcb48d4 100644
--- a/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
@@ -301,6 +301,8 @@ struct throwing_vector : std::vector<T>
throw std::runtime_error("move assign");
return *this;
}
+
+ using std::vector<int>::operator=;
};
void
@@ -324,8 +326,7 @@ test10()
}
// Verify invariant preservation upon throwing move assignment.
- source.clear();
- source.insert({1, 2});
+ source = {1, 2};
flat_set target = {3, 4};
try
{
@@ -339,10 +340,8 @@ test10()
}
// Verify invariant preservation upon throwing swap.
- source.clear();
- source.insert({1, 2});
- target.clear();
- target.insert({3, 4});
+ source = {1, 2};
+ target = {3, 4};
try
{
source.swap(target);
@@ -367,6 +366,17 @@ test11()
VERIFY( std::ranges::equal(m, (int[]){1, 2, 3}) );
}
+void
+test12()
+{
+ // Verify usability of flat_set::operator=(initializer_list).
+ throwing_vector<int>::throw_on_move = true;
+ std::flat_set<int, std::less<int>, throwing_vector<int>> s;
+ std::initializer_list<int> il = {2, 3, 1};
+ s = il;
+ VERIFY( std::ranges::equal(s, (int[]){1, 2, 3}) );
+}
+
void
test()
{
@@ -382,6 +392,7 @@ test()
test09();
test10();
test11();
+ test12();
}
constexpr
@@ -398,6 +409,7 @@ test_constexpr()
test09();
// test10() is non-constexpr
test11();
+ // test12() is non-constexpr
return true;
}
More information about the Libstdc++-cvs
mailing list