{"id":2226327,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2226327/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhubrmqub2.gcc.gcc-TEST.redi.31.1.8@forge-stage.sourceware.org/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.2/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,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"","list_archive_url":null,"date":"2026-04-22T10:44:23","name":"[v1,08/16] libstdc++: Remove reinterpret_cast uses in atomic wait/notify","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"b9ea9be85e745684672574fe75db00ebacf321fd","submitter":{"id":93210,"url":"http://patchwork.ozlabs.org/api/1.2/people/93210/?format=json","name":"Jonathan Wakely via Sourceware Forge","email":"forge-bot+redi@forge-stage.sourceware.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhubrmqub2.gcc.gcc-TEST.redi.31.1.8@forge-stage.sourceware.org/mbox/","series":[{"id":500987,"url":"http://patchwork.ozlabs.org/api/1.2/series/500987/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=500987","date":"2026-04-22T10:44:17","name":"atomic wait/notify ABI stabilization","version":1,"mbox":"http://patchwork.ozlabs.org/series/500987/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2226327/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2226327/checks/","tags":{},"related":[],"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 spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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server2.sourceware.org","From":"Jonathan Wakely via Sourceware Forge\n ","Date":"Wed, 22 Apr 2026 10:44:23 +0000","Subject":"[PATCH v1 08/16] libstdc++: Remove reinterpret_cast uses in atomic\n wait/notify","To":"gcc-patches mailing list ","Message-ID":"\n ","X-Mailer":"batrachomyomachia","X-Pull-Request-Organization":"gcc","X-Pull-Request-Repository":"gcc-TEST","X-Pull-Request":"https://forge.sourceware.org/gcc/gcc-TEST/pulls/31","References":"\n ","In-Reply-To":"\n ","X-Patch-URL":"\n https://forge.sourceware.org/redi/gcc/commit/b1f8b965c96462353d813f09a864976fc66b8ca2","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 ","Reply-To":"gcc-patches mailing list , redi@gcc.gnu.org","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"From: Jonathan Wakely \n\nWe can pass around void* instead of casting incompatible pointers to\n__platform_wait_t*, and then only static_cast to __platform_wait_t* when\nwe know that's valid.\n\nlibstdc++-v3/ChangeLog:\n\n\t* include/bits/atomic_timed_wait.h (__wait_until_impl): Change\n\tfirst parameter to const void* and then static_cast to const\n\t__platform_wait_t* when not using proxied wait.\n\t(__wait_until): Change first parameter to const void*.\n\t(__wait_for): Likewise.\n\t(__atomic_wait_address_until): Remove reinterpret_cast and allow\n\taddress to implicitly convert to const void* instead.\n\t(__atomic_wait_address_for): Likewise.\n\t* include/bits/atomic_wait.h: (__wait_impl, __notify_impl):\n\tChange first parameter to const void* and then static_cast to\n\tconst __platform_wait_t* when not using proxied wait.\n\t(__atomic_wait_address, __atomic_notify_address) Remove\n\treinterpret_cast and allow address to implicitly convert to\n\tconst void* instead.\n---\n libstdc++-v3/include/bits/atomic_timed_wait.h | 17 ++++++-----------\n libstdc++-v3/include/bits/atomic_wait.h | 16 ++++++----------\n 2 files changed, 12 insertions(+), 21 deletions(-)","diff":"diff --git a/libstdc++-v3/include/bits/atomic_timed_wait.h b/libstdc++-v3/include/bits/atomic_timed_wait.h\nindex a916c10879b7..cbf9187f2bb8 100644\n--- a/libstdc++-v3/include/bits/atomic_timed_wait.h\n+++ b/libstdc++-v3/include/bits/atomic_timed_wait.h\n@@ -170,8 +170,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n }\n \n inline __wait_result_type\n- __wait_until_impl(const __platform_wait_t* __addr,\n-\t\t const __wait_args_base& __a,\n+ __wait_until_impl(const void* __addr, const __wait_args_base& __a,\n \t\t const __wait_clock_t::time_point& __atime)\n {\n __wait_args_base __args = __a;\n@@ -184,7 +183,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t __atomic_load(__wait_addr, &__args._M_old, __args._M_order);\n \t}\n else\n-\t__wait_addr = __addr;\n+\t__wait_addr = static_cast(__addr);\n \n if (__args & __wait_flags::__do_spin)\n \t{\n@@ -222,7 +221,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n // Returns {true, val} if wait ended before a timeout.\n template\n __wait_result_type\n- __wait_until(const __platform_wait_t* __addr, const __wait_args_base& __args,\n+ __wait_until(const void* __addr, const __wait_args_base& __args,\n \t\t const chrono::time_point<_Clock, _Dur>& __atime) noexcept\n {\n \tauto __at = __detail::__to_wait_clock(__atime);\n@@ -243,7 +242,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n // Returns {true, val} if wait ended before a timeout.\n template\n __wait_result_type\n- __wait_for(const __platform_wait_t* __addr, const __wait_args_base& __args,\n+ __wait_for(const void* __addr, const __wait_args_base& __args,\n \t\t const chrono::duration<_Rep, _Period>& __rtime) noexcept\n {\n \tif (!__rtime.count())\n@@ -270,13 +269,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t\t\t\tconst chrono::time_point<_Clock, _Dur>& __atime,\n \t\t\t\tbool __bare_wait = false) noexcept\n {\n- const auto __wait_addr =\n-\treinterpret_cast(__addr);\n __detail::__wait_args __args{ __addr, __bare_wait };\n _Tp __val = __vfn();\n while (!__pred(__val))\n \t{\n-\t auto __res = __detail::__wait_until(__wait_addr, __args, __atime);\n+\t auto __res = __detail::__wait_until(__addr, __args, __atime);\n \t if (!__res.first)\n \t // timed out\n \t return __res.first; // C++26 will also return last observed __val\n@@ -320,13 +317,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t\t\t const chrono::duration<_Rep, _Period>& __rtime,\n \t\t\t bool __bare_wait = false) noexcept\n {\n- const auto __wait_addr =\n-\t reinterpret_cast(__addr);\n __detail::__wait_args __args{ __addr, __bare_wait };\n _Tp __val = __vfn();\n while (!__pred(__val))\n \t{\n-\t auto __res = __detail::__wait_for(__wait_addr, __args, __rtime);\n+\t auto __res = __detail::__wait_for(__addr, __args, __rtime);\n \t if (!__res.first)\n \t // timed out\n \t return __res.first; // C++26 will also return last observed __val\ndiff --git a/libstdc++-v3/include/bits/atomic_wait.h b/libstdc++-v3/include/bits/atomic_wait.h\nindex 5fd00c22565b..cfda323a3ab6 100644\n--- a/libstdc++-v3/include/bits/atomic_wait.h\n+++ b/libstdc++-v3/include/bits/atomic_wait.h\n@@ -355,7 +355,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n }\n \n inline __wait_result_type\n- __wait_impl(const __platform_wait_t* __addr, const __wait_args_base& __a)\n+ __wait_impl(const void* __addr, const __wait_args_base& __a)\n {\n __wait_args_base __args = __a;\n __waiter_pool_impl* __pool = nullptr;\n@@ -368,7 +368,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t __atomic_load(__wait_addr, &__args._M_old, __args._M_order);\n \t}\n else\n-\t__wait_addr = __addr;\n+\t__wait_addr = static_cast(__addr);\n \n if (__args & __wait_flags::__do_spin)\n \t{\n@@ -401,7 +401,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n }\n \n inline void\n- __notify_impl(const __platform_wait_t* __addr, [[maybe_unused]] bool __all,\n+ __notify_impl(const void* __addr, [[maybe_unused]] bool __all,\n \t\t const __wait_args_base& __args)\n {\n __waiter_pool_impl* __pool = nullptr;\n@@ -420,7 +420,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t __all = true;\n \t}\n else // Use the atomic variable's own address.\n-\t__wait_addr = __addr;\n+\t__wait_addr = static_cast(__addr);\n \n if (__args & __wait_flags::__track_contention)\n \t{\n@@ -449,8 +449,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n __atomic_wait_address(const _Tp* __addr, _Pred&& __pred, _ValFn&& __vfn,\n \t\t\t bool __bare_wait = false) noexcept\n {\n- const auto __wait_addr =\n-\t reinterpret_cast(__addr);\n __detail::__wait_args __args{ __addr, __bare_wait };\n _Tp __val = __vfn();\n while (!__pred(__val))\n@@ -462,7 +460,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t\t\t\t\t __val);\n \t // Otherwise, it's a proxy wait and the proxy's _M_ver is used.\n \n-\t __detail::__wait_impl(__wait_addr, __args);\n+\t __detail::__wait_impl(__addr, __args);\n \t __val = __vfn();\n \t}\n // C++26 will return __val\n@@ -494,10 +492,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n __atomic_notify_address(const _Tp* __addr, bool __all,\n \t\t\t bool __bare_wait = false) noexcept\n {\n- const auto __wait_addr =\n-\t reinterpret_cast(__addr);\n __detail::__wait_args __args{ __addr, __bare_wait };\n- __detail::__notify_impl(__wait_addr, __all, __args);\n+ __detail::__notify_impl(__addr, __all, __args);\n }\n _GLIBCXX_END_NAMESPACE_VERSION\n } // namespace std\n","prefixes":["v1","08/16"]}