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The current constexpr implementation of std::char_traits<C>::move relies on being able to compare the pointer parameters, which is not allowed for unrelated pointers. We can use __builtin_constant_p to determine whether it's safe to compare the pointers directly. If not, then we know the ranges must be disjoint and so we can use char_traits<C>::copy to copy forwards from the first character to the last. If the pointers can be compared directly, then we can simplify the condition for copying backwards to just two pointer comparisons. libstdc++-v3/ChangeLog: PR libstdc++/113200 * include/bits/char_traits.h (__gnu_cxx::char_traits::move): Use __builtin_constant_p to check for unrelated pointers that cannot be compared during constant evaluation. * testsuite/21_strings/char_traits/requirements/113200.cc: New test. |
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| config.h.in | ||
| configure | ||
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file: libstdc++-v3/README New users may wish to point their web browsers to the file index.html in the 'doc/html' subdirectory. It contains brief building instructions and notes on how to configure the library in interesting ways.