From 6af8d8e618ed27dae3432c96484de4360bd893ab Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 11 Jun 2024 15:52:30 +0100
Subject: [PATCH] libstdc++: Make std::type_info::operator== always_inline for
C++23 [PR110572]
Commit r12-6266-g3633cc54284450 implemented P1328 for C++23, making
std::type_info::operator== usable in constant expressions. For targets
such as mingw-w64 where that function was not previously inline, making
it constexpr required making it inline for C++23 and later. For
statically linked programs this can result in multiple definition
errors, because there's a non-inline definition in libstdc++.a as well.
For those targets make it always_inline for C++23, so that there is no
symbol generated for the inline definition, and the non-inline
definition in libstdc++.a will be the only definition.
libstdc++-v3/ChangeLog:
PR libstdc++/110572
* libsupc++/typeinfo (type_info::operator==): Add always_inline
attribute for targets where the ABI requries equality to be
non-inline.
* testsuite/18_support/type_info/110572.cc: New test.
---
libstdc++-v3/libsupc++/typeinfo | 3 +++
libstdc++-v3/testsuite/18_support/type_info/110572.cc | 11 +++++++++++
2 files changed, 14 insertions(+)
create mode 100644 libstdc++-v3/testsuite/18_support/type_info/110572.cc
diff --git a/libstdc++-v3/libsupc++/typeinfo b/libstdc++-v3/libsupc++/typeinfo
index fcc3077d0609..35e72bb18ee5 100644
--- a/libstdc++-v3/libsupc++/typeinfo
+++ b/libstdc++-v3/libsupc++/typeinfo
@@ -188,6 +188,9 @@ namespace std
#endif
#if __GXX_TYPEINFO_EQUALITY_INLINE || __cplusplus > 202002L
+# if ! __GXX_TYPEINFO_EQUALITY_INLINE
+ [[__gnu__::__always_inline__]]
+# endif
_GLIBCXX23_CONSTEXPR inline bool
type_info::operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT
{
diff --git a/libstdc++-v3/testsuite/18_support/type_info/110572.cc b/libstdc++-v3/testsuite/18_support/type_info/110572.cc
new file mode 100644
index 000000000000..64081879b77d
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/type_info/110572.cc
@@ -0,0 +1,11 @@
+// { dg-options "-static-libstdc++" }
+// { dg-require-static-libstdcxx }
+// { dg-require-cpp-feature-test __cpp_rtti }
+// { dg-do link }
+
+#include <typeinfo>
+
+int main()
+{
+ return typeid(0) == typeid(0u);
+}
--
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