[all-commits] [llvm/llvm-project] 3ed89b: [Take 2] [libc++] Make rotate a constexpr.

[Zoe Carver via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 3ed89b51da38f081fedb57727076262abb81d149
      https://github.com/llvm/llvm-project/commit/3ed89b51da38f081fedb57727076262abb81d149
  Author: zoecarver <z.zoelec2 at gmail.com>
  Date:   2020-09-14 (Mon, 14 Sep 2020)

  Changed paths:
    M libcxx/include/algorithm
    M libcxx/include/iterator
    M libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move.pass.cpp
    M libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp
    M libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
    M libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate_copy.pass.cpp
    M libcxx/test/std/algorithms/alg.sorting/alg.merge/merge.pass.cpp
    M libcxx/test/std/algorithms/alg.sorting/alg.merge/merge_comp.pass.cpp
    M libcxx/www/cxx2a_status.html

  Log Message:
  -----------
  [Take 2] [libc++] Make rotate a constexpr.

This patch makes `std::rotate` a constexpr. In doing so, this patch also
updates the internal `__move` and `__move_backward` funtions to be
constexpr.

This patch was previously reverted in ed653184ac63 because it was missing
some UNSUPPORTED markup for older compilers. This commit adds it.

Differential Revision: https://reviews.llvm.org/D65721