[gcc r14-3308] libstdc++: Reuse double overload of __convert_to_v if possible

[gcc r14-3308] libstdc++: Reuse double overload of __convert_to_v if possible

[Jonathan Wakely]

https://gcc.gnu.org/g:aad83d61d2e92b168688f7b6bd00b8604d11fc9f

commit r14-3308-gaad83d61d2e92b168688f7b6bd00b8604d11fc9f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Jul 24 11:38:32 2023 +0100

    libstdc++: Reuse double overload of __convert_to_v if possible
    
    For targets where double and long double have the same representation we
    can reuse the same __convert_to_v code for both types. This will
    slightly reduce the size of the compiled code in the library.
    
    libstdc++-v3/ChangeLog:
    
            * config/locale/generic/c_locale.cc (__convert_to_v): Reuse
            double overload for long double if possible.

Diff:
---
 libstdc++-v3/config/locale/generic/c_locale.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libstdc++-v3/config/locale/generic/c_locale.cc b/libstdc++-v3/config/locale/generic/c_locale.cc
index 8849d78fdfac..866ba0361dc4 100644
--- a/libstdc++-v3/config/locale/generic/c_locale.cc
+++ b/libstdc++-v3/config/locale/generic/c_locale.cc
@@ -187,6 +187,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     __convert_to_v(const char* __s, long double& __v,
 		   ios_base::iostate& __err, const __c_locale&) throw()
     {
+#if __DBL_MANT_DIG__ == __LDBL_MANT_DIG__
+      double __d;
+      __convert_to_v(__s, __d, __err, __c_locale);
+      __v = __d;
+#else
       // Assumes __s formatted for "C" locale.
       const char* __sav = __set_C_locale();
       if (!__sav)
@@ -233,6 +238,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       setlocale(LC_ALL, __sav);
       delete [] __sav;
+#endif // __DBL_MANT_DIG__ == __LDBL_MANT_DIG__
     }
 
   void