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[libc++] Add GCC workaround in std::char_traits<char>::length() 

GCC currently does not allow `__builtin_strlen()` during constant evaluation. This PR adds a workaround in `std::char_traits<char>::length()`

Reviewed By: Quuxplusone, ldionne, #libc, Mordante

Spies: Mordante, libcxx-commits

Differential Revision: https://reviews.llvm.org/D115795
This commit is contained in:
Nikolas Klauser 2021-12-15 21:12:24 +01:00
parent 9198d04c06
commit 148ef80f89
2 changed files with 15 additions and 5 deletions
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17
libcxx/include/__string
View File

@ -337,8 +337,21 @@ struct _LIBCPP_TEMPLATE_VIS char_traits<char>
static _LIBCPP_CONSTEXPR_AFTER_CXX14
int compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
static inline size_t _LIBCPP_CONSTEXPR_AFTER_CXX14
length(const char_type* __s) _NOEXCEPT {return __builtin_strlen(__s);}
static inline size_t _LIBCPP_CONSTEXPR_AFTER_CXX14 length(const char_type* __s) _NOEXCEPT {
// GCC currently does not support __builtin_strlen during constant evaluation.
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70816
#ifdef _LIBCPP_COMPILER_GCC
if (__libcpp_is_constant_evaluated()) {
size_t __i = 0;
for (; __s[__i] != char_type('\0'); ++__i)
;
return __i;
}
#endif
return __builtin_strlen(__s);
}
static _LIBCPP_CONSTEXPR_AFTER_CXX14
const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT;
static inline _LIBCPP_CONSTEXPR_AFTER_CXX17

3
libcxx/test/std/strings/string.view/string.view.ops/copy.pass.cpp
View File

@ -6,9 +6,6 @@
//
//===----------------------------------------------------------------------===//
// GCC's __builtin_strlen isn't constexpr yet
// XFAIL: gcc-11 && !(c++11 || c++14 || c++17)
// <string_view>
// size_type copy(charT* s, size_type n, size_type pos = 0) const;