From 9f3eb93e72703f6ea30aa27d0b6fc6db62cb4a04 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 3 Jan 2024 12:23:32 +0000
Subject: [PATCH] libstdc++: Use if-constexpr in std::__try_use_facet
[PR113099]
As noted in the PR, we can use if-constexpr for the explicit
instantantiation definitions that are compiled with -std=gnu++11. We
just need to disable the -Wc++17-extensions diagnostics.
libstdc++-v3/ChangeLog:
PR libstdc++/113099
* include/bits/locale_classes.tcc (__try_use_facet): Use
if-constexpr for C++11 and up.
---
libstdc++-v3/include/bits/locale_classes.tcc | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/bits/locale_classes.tcc b/libstdc++-v3/include/bits/locale_classes.tcc
index 2a6176fb4de4..63097582decf 100644
--- a/libstdc++-v3/include/bits/locale_classes.tcc
+++ b/libstdc++-v3/include/bits/locale_classes.tcc
@@ -87,6 +87,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__s2.data(), __s2.data() + __s2.length()) < 0);
}
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wc++17-extensions"
template<typename _Facet>
inline const _Facet*
__try_use_facet(const locale& __loc) _GLIBCXX_NOTHROW
@@ -97,7 +99,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// We know these standard facets are always installed in every locale
// so dynamic_cast always succeeds, just use static_cast instead.
#define _GLIBCXX_STD_FACET(...) \
- if _GLIBCXX17_CONSTEXPR (__is_same(_Facet, __VA_ARGS__)) \
+ if _GLIBCXX_CONSTEXPR (__is_same(_Facet, __VA_ARGS__)) \
return static_cast<const _Facet*>(__facets[__i])
_GLIBCXX_STD_FACET(ctype<char>);
@@ -145,6 +147,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return static_cast<const _Facet*>(__facets[__i]);
#endif
}
+#pragma GCC diagnostic pop
/**
* @brief Test for the presence of a facet.
--
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