[libcxx-commits] [PATCH] D101674: [libc++] [LIBCXX-DEBUG-FIXME] Constexpr char_traits::copy mustn't compare unrelated pointers.

[Arthur O'Dwyer via Phabricator via libcxx-commits]

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  We could arrange to skip the UB-inducing assert in the case where the computation
  might be happening at constexpr time; but we have no existing way to check for
  computation that *might be* happening at constexpr time. We only have a way
  to check for computation that is *definitely* happening at constexpr time
  (versus *might be* happening at runtime). __libcpp_is_constant_evaluated()
  returns true only if we KNOW it's constexpr-time; it returns false both at runtime
  and on compilers that don't support the builtin.
  Come to think of it, maybe this is the wrong default for __libcpp_is_constant_evaluated().


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D101674

Files:
  libcxx/include/__string
  libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/copy.pass.cpp
  libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/copy.pass.cpp
  libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/copy.pass.cpp
  libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/copy.pass.cpp
  libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/copy.pass.cpp
  libcxx/test/std/strings/string.view/string.view.ops/copy.pass.cpp

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