{"id":2221469,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2221469/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/20260409132833.451634-1-tkaminsk@redhat.com/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.1/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260409132833.451634-1-tkaminsk@redhat.com>","date":"2026-04-09T13:09:14","name":"libstdc++: Remove span constructor from initializer_list.","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"86d681ea7ad524ff97acfbd61af948eed27b6f3f","submitter":{"id":90409,"url":"http://patchwork.ozlabs.org/api/1.1/people/90409/?format=json","name":"Tomasz Kamiński","email":"tkaminsk@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/20260409132833.451634-1-tkaminsk@redhat.com/mbox/","series":[{"id":499301,"url":"http://patchwork.ozlabs.org/api/1.1/series/499301/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=499301","date":"2026-04-09T13:09:14","name":"libstdc++: Remove span constructor from initializer_list.","version":1,"mbox":"http://patchwork.ozlabs.org/series/499301/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2221469/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2221469/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=fGMln4yq;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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charset=UTF-8","Content-Transfer-Encoding":"8bit","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"Following LWG4520 resolution from paper\nP4144R1 Remove span’s initializer_list constructor for C++26.\n\nlibstdc++-v3/ChangeLog:\n\n\t* include/bits/version.def (span_initializer_list): Remove.\n\t* include/bits/version.h: Regenerate.\n\t* include/std/span (span::span(initializer_list)):\n\tRemove.\n\t* testsuite/23_containers/span/init_list_cons.cc: Removed.\n\t* testsuite/23_containers/span/init_list_cons_neg.cc: Removed.\n\t* testsuite/23_containers/inplace_vector/copy.cc: Replace span\n\twith initializer_list in eq helper.\n\t* testsuite/23_containers/inplace_vector/erasure.cc: Likewise.\n\t* testsuite/23_containers/inplace_vector/move.cc: Likewise.\n---\nOf course I have managed to use this constructor in inplace_vector test,\nreplaced it with initializer_list.\n\nTested on x86_64-linux. OK for trunk?\n\n libstdc++-v3/include/bits/version.def | 8 ---\n libstdc++-v3/include/bits/version.h | 10 ---\n libstdc++-v3/include/std/span | 16 +----\n .../23_containers/inplace_vector/copy.cc | 2 +-\n .../23_containers/inplace_vector/erasure.cc | 11 +---\n .../23_containers/inplace_vector/move.cc | 2 +-\n .../23_containers/span/init_list_cons.cc | 65 -------------------\n .../23_containers/span/init_list_cons_neg.cc | 36 ----------\n 8 files changed, 6 insertions(+), 144 deletions(-)\n delete mode 100644 libstdc++-v3/testsuite/23_containers/span/init_list_cons.cc\n delete mode 100644 libstdc++-v3/testsuite/23_containers/span/init_list_cons_neg.cc","diff":"diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def\nindex cfb90533ce4..bdc282ab123 100644\n--- a/libstdc++-v3/include/bits/version.def\n+++ b/libstdc++-v3/include/bits/version.def\n@@ -2168,14 +2168,6 @@ ftms = {\n };\n };\n \n-ftms = {\n- name = span_initializer_list;\n- values = {\n- v = 202311;\n- cxxmin = 26;\n- };\n-};\n-\n ftms = {\n name = text_encoding;\n values = {\ndiff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h\nindex 22dd31b9d32..1278725cfa2 100644\n--- a/libstdc++-v3/include/bits/version.h\n+++ b/libstdc++-v3/include/bits/version.h\n@@ -2426,16 +2426,6 @@\n #endif /* !defined(__cpp_lib_saturation_arithmetic) */\n #undef __glibcxx_want_saturation_arithmetic\n \n-#if !defined(__cpp_lib_span_initializer_list)\n-# if (__cplusplus > 202302L)\n-# define __glibcxx_span_initializer_list 202311L\n-# if defined(__glibcxx_want_all) || defined(__glibcxx_want_span_initializer_list)\n-# define __cpp_lib_span_initializer_list 202311L\n-# endif\n-# endif\n-#endif /* !defined(__cpp_lib_span_initializer_list) */\n-#undef __glibcxx_want_span_initializer_list\n-\n #if !defined(__cpp_lib_text_encoding)\n # if (__cplusplus > 202302L) && _GLIBCXX_HOSTED && (_GLIBCXX_USE_NL_LANGINFO_L)\n # define __glibcxx_text_encoding 202306L\ndiff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span\nindex a2f338449c8..a5f5bf48f90 100644\n--- a/libstdc++-v3/include/std/span\n+++ b/libstdc++-v3/include/std/span\n@@ -47,9 +47,7 @@\n #include \n #include \n #include \n-#ifdef __cpp_lib_span_initializer_list\n-# include \n-#endif\n+\n namespace std _GLIBCXX_VISIBILITY(default)\n {\n _GLIBCXX_BEGIN_NAMESPACE_VERSION\n@@ -232,18 +230,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t: _M_ptr(ranges::data(__range)), _M_extent(ranges::size(__range))\n \t{ }\n \n-#if __cpp_lib_span_initializer_list >= 202311L // >= C++26\n-#pragma GCC diagnostic push\n-#pragma GCC diagnostic ignored \"-Winit-list-lifetime\"\n- constexpr\n- explicit(extent != dynamic_extent)\n- span(initializer_list __il)\n- requires (is_const_v<_Type>)\n- : _M_ptr(__il.begin()), _M_extent(__il.size())\n- { }\n-#pragma GCC diagnostic pop\n-#endif\n-\n constexpr\n span(const span&) noexcept = default;\n \ndiff --git a/libstdc++-v3/testsuite/23_containers/inplace_vector/copy.cc b/libstdc++-v3/testsuite/23_containers/inplace_vector/copy.cc\nindex 917eebd80f7..11260c63313 100644\n--- a/libstdc++-v3/testsuite/23_containers/inplace_vector/copy.cc\n+++ b/libstdc++-v3/testsuite/23_containers/inplace_vector/copy.cc\n@@ -138,7 +138,7 @@ static_assert(std::is_trivially_copy_assignable_v>);\n \n template\n constexpr bool\n-eq(const std::inplace_vector& s, std::span o)\n+eq(const std::inplace_vector& s, std::initializer_list> o)\n { return std::ranges::equal(s, o); }\n \n constexpr void\ndiff --git a/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc b/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc\nindex 8fb56e90623..a019dc0a1f1 100644\n--- a/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc\n+++ b/libstdc++-v3/testsuite/23_containers/inplace_vector/erasure.cc\n@@ -1,18 +1,13 @@\n // { dg-do run { target c++26 } }\n \n #include \n+#include \n #include \n-#include \n \n template\n constexpr bool\n-eq(const std::inplace_vector& l, std::span r) {\n- if (l.size() != r.size())\n- return false;\n- for (auto i = 0u; i < l.size(); ++i)\n- if (l[i] != r[i])\n- return false;\n- return true;\n+eq(const std::inplace_vector& l, std::initializer_list> r) {\n+ return std::ranges::equal(l, r);\n };\n \n constexpr void\ndiff --git a/libstdc++-v3/testsuite/23_containers/inplace_vector/move.cc b/libstdc++-v3/testsuite/23_containers/inplace_vector/move.cc\nindex e8703e027fe..8b5c3e9f247 100644\n--- a/libstdc++-v3/testsuite/23_containers/inplace_vector/move.cc\n+++ b/libstdc++-v3/testsuite/23_containers/inplace_vector/move.cc\n@@ -177,7 +177,7 @@ static_assert(std::is_nothrow_swappable_v>);\n \n template\n constexpr bool\n-eq(const std::inplace_vector& s, std::span o)\n+eq(const std::inplace_vector& s, std::initializer_list> o)\n { return std::ranges::equal(s, o); }\n \n constexpr void\ndiff --git a/libstdc++-v3/testsuite/23_containers/span/init_list_cons.cc b/libstdc++-v3/testsuite/23_containers/span/init_list_cons.cc\ndeleted file mode 100644\nindex 1dc30ab1a50..00000000000\n--- a/libstdc++-v3/testsuite/23_containers/span/init_list_cons.cc\n+++ /dev/null\n@@ -1,65 +0,0 @@\n-// { dg-do compile { target c++26 } }\n-\n-#include \n-#include \n-\n-#if !defined(__cpp_lib_span_initializer_list)\n-# error \"__cpp_lib_span_initializer_list should be defined\"\n-#elif __cpp_lib_span_initializer_list < 202311L\n-# error \"Wrong value for __cpp_lib_span_initializer_list (should be >= 202311L)\"\n-#endif\n-\n-// Check the constraint on the initializer_list constructor\n-static_assert( std::is_const_v::element_type>);\n-static_assert(!std::is_const_v::element_type>);\n-\n-static_assert( std::is_constructible_v, std::initializer_list< int>>);\n-static_assert( std::is_constructible_v, std::initializer_list>);\n-static_assert( std::is_constructible_v, std::initializer_list< int>>);\n-static_assert( std::is_constructible_v, std::initializer_list>);\n-static_assert(!std::is_constructible_v, std::initializer_list< int>>);\n-static_assert(!std::is_constructible_v, std::initializer_list>);\n-static_assert(!std::is_constructible_v, std::initializer_list< int>>);\n-static_assert(!std::is_constructible_v, std::initializer_list>);\n-\n-// Check the explicit-ness on the initializer_list constructor\n-static_assert( std::is_convertible_v, std::span>);\n-static_assert( std::is_convertible_v, std::span>);\n-static_assert(!std::is_convertible_v, std::span>);\n-static_assert(!std::is_convertible_v, std::span>);\n-static_assert(!std::is_convertible_v, std::span< int >>);\n-static_assert(!std::is_convertible_v, std::span< int >>);\n-static_assert(!std::is_convertible_v, std::span< int, 42>>);\n-static_assert(!std::is_convertible_v, std::span< int, 42>>);\n-\n-constexpr size_t fun1(std::span s)\n-{\n- return s.size();\n-}\n-\n-static_assert(fun1({}) == 0);\n-static_assert(fun1({1, 2, 3}) == 3);\n-static_assert(fun1(std::initializer_list{1, 2, 3}) == 3);\n-\n-// Stress-test array->pointer decays\n-struct decayer {\n- constexpr decayer() = default;\n- constexpr decayer(decayer *) {}\n-};\n-\n-constexpr size_t fun2(std::span s)\n-{\n- return s.size();\n-}\n-\n-void test01()\n-{\n- int intArray[42];\n- static_assert(fun1(intArray) == 42);\n-\n- decayer decArray[42];\n- static_assert(fun2(decArray) == 42);\n- static_assert(fun2({decArray}) == 1); // decayer[] -> decayer* -> decayer(decayer*) -> init_list of 1 element\n- static_assert(fun2({decArray, decArray + 42}) == 2); // does not select span(iterator, iterator)\n- static_assert(fun2({decArray, decArray, decArray}) == 3);\n-}\ndiff --git a/libstdc++-v3/testsuite/23_containers/span/init_list_cons_neg.cc b/libstdc++-v3/testsuite/23_containers/span/init_list_cons_neg.cc\ndeleted file mode 100644\nindex 6b78156ad5d..00000000000\n--- a/libstdc++-v3/testsuite/23_containers/span/init_list_cons_neg.cc\n+++ /dev/null\n@@ -1,36 +0,0 @@\n-// { dg-do run { target { c++20 && c++23_down } } }\n-// { dg-do compile { target c++26 } }\n-\n-#include \n-#include \n-\n-#include \n-\n-struct Any {\n- constexpr Any() { }\n- template constexpr Any(T) { }\n-};\n-\n-// Examples from P2447R4\n-void one(std::pair) {}\n-void one(std::span) {}\n-void two(std::span) {}\n-constexpr std::size_t three(std::span v) { return v.size(); }\n-constexpr std::size_t four(std::span v) { return v.size(); }\n-\n-void *array3[10];\n-Any array4[10];\n-\n-int main()\n-{\n- one({1, 2}); // { dg-error \"call of overloaded\" \"should be ambiguous with the one(std::pair) overload\" { target c++26 } }\n- two({{1, 2}}); // { dg-error \"would use explicit constructor\" \"should prefer the initializer_list constructor, which is explicit\" { target c++26 } }\n-\n-#if __cpp_lib_span_initializer_list\n- static_assert(three({array3, 0}) == 2);\n- static_assert(four({array4, array4 + 10}) == 2);\n-#else\n- static_assert(three({array3, 0}) == 0);\n- static_assert(four({array4, array4 + 10}) == 10);\n-#endif\n-}\n","prefixes":[]}