search for: __builtin_strlen

...isn't portably >> constexpr and std::char_traits<char>::length is only constexpr in >> C++17. > > Why don't we just create our own traits class that has a constexpr length, and then we can switch over to the standard one when we switch to C++17? GCC and Clang treat __builtin_strlen as constexpr. MSVC 2015 doesn't support C++14 extended constexpr. I don't know how well it optimises a recursive strlen. This works as an optimisation for GCC and Clang, and doesn't make things worse for MSVC: /// Construct a string ref from a cstring. LLVM_ATTRIBUTE_ALWAYS_...

...expr and std::char_traits<char>::length is only constexpr in > >> C++17. > > > > Why don't we just create our own traits class that has a constexpr > length, and then we can switch over to the standard one when we switch to > C++17? > > GCC and Clang treat __builtin_strlen as constexpr. > MSVC 2015 doesn't support C++14 extended constexpr. I don't know how well > it optimises a recursive strlen. > > This works as an optimisation for GCC and Clang, and doesn't make things > worse for MSVC: > > /// Construct a string ref from a cst...

...expr and std::char_traits<char>::length is only constexpr in > >> C++17. > > > > Why don't we just create our own traits class that has a constexpr > length, and then we can switch over to the standard one when we switch to > C++17? > > GCC and Clang treat __builtin_strlen as constexpr. > MSVC 2015 doesn't support C++14 extended constexpr. I don't know how well > it optimises a recursive strlen. > > This works as an optimisation for GCC and Clang, and doesn't make things > worse for MSVC: > > /// Construct a string ref from a cst...

On 29 November 2016 at 16:18, Zachary Turner <zturner at google.com> wrote: > I don't like the llvm_strlen approach as it is incompatible with > std::string_view which we may eventually move to. In what way is it incompatible? constexpr StringRef(const char* s) : Data(s), Length(llvm_strlen(s)) {} is equivalent to constexpr string_view(const char* s) : Data(s),

On 29 November 2016 at 17:38, Zachary Turner <zturner at google.com> wrote: > I see, but I looked over your proposed implementation from earlier in the > thread, and if I'm not mistaken I see this: That's a different suggestion. > That said, what did you think about my other proposal of the complicated UDL > with macro? > > #define LIT(x) x_string_ref_literal >

...expr and std::char_traits<char>::length is only constexpr in > >> C++17. > > > > Why don't we just create our own traits class that has a constexpr > length, and then we can switch over to the standard one when we switch to > C++17? > > GCC and Clang treat __builtin_strlen as constexpr. > MSVC 2015 doesn't support C++14 extended constexpr. I don't know how well > it optimises a recursive strlen. > > This works as an optimisation for GCC and Clang, and doesn't make things > worse for MSVC: > > /// Construct a string ref from a cst...

...expr and std::char_traits<char>::length is only constexpr in > >> C++17. > > > > Why don't we just create our own traits class that has a constexpr > length, and then we can switch over to the standard one when we switch to > C++17? > > GCC and Clang treat __builtin_strlen as constexpr. > MSVC 2015 doesn't support C++14 extended constexpr. I don't know how well > it optimises a recursive strlen. > > This works as an optimisation for GCC and Clang, and doesn't make things > worse for MSVC: > > /// Construct a string ref from a cst...

Hi all, There is a desire to be able to create constexpr StringRefs to avoid static initializers for global tables of/containing StringRefs. Creating constexpr StringRefs isn't trivial as strlen isn't portably constexpr and std::char_traits<char>::length is only constexpr in C++17. Alp Toker tried to create constexpr StringRefs for strings literals by subclassing StringRef: