commit d0279def2905a8950a5ef4502758c6be05009ffe
author zoecarver <z.zoelec2@gmail.com> Mon Sep 14 18:11:08 2020 -0400
committer Louis Dionne <ldionne@apple.com> Mon Sep 14 18:14:46 2020 -0400
tree 102fb5b24db8402240e2301bff35c022929b02e9
parent 3145fb838991dedbff0caac075b9e95d2680a5e2

[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

Cr-Mirrored-From: https://chromium.googlesource.com/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 3ed89b51da38f081fedb57727076262abb81d149

include/iterator

diff --git a/include/iterator b/include/iterator
index 36571a5..45516db 100644
--- a/include/iterator
+++ b/include/iterator
@@ -1393,13 +1393,13 @@
 
 template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 copy(_Ip, _Ip, _Op);
 template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 copy_backward(_B1, _B1, _B2);
-template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY move(_Ip, _Ip, _Op);
-template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY move_backward(_B1, _B1, _B2);
+template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 move(_Ip, _Ip, _Op);
+template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 move_backward(_B1, _B1, _B2);
 
 #if _LIBCPP_DEBUG_LEVEL < 2
 
 template <class _Tp>
-_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
 typename enable_if
 <
     is_trivially_copy_assignable<_Tp>::value,
@@ -1410,7 +1410,7 @@
 #else
 
 template <class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
 typename enable_if
 <
     is_trivially_copy_assignable<_Tp>::value,
@@ -1604,12 +1604,12 @@
 
     template <class _Ip, class _Op> friend _LIBCPP_CONSTEXPR_AFTER_CXX17 _Op copy(_Ip, _Ip, _Op);
     template <class _B1, class _B2> friend _LIBCPP_CONSTEXPR_AFTER_CXX17 _B2 copy_backward(_B1, _B1, _B2);
-    template <class _Ip, class _Op> friend _Op move(_Ip, _Ip, _Op);
-    template <class _B1, class _B2> friend _B2 move_backward(_B1, _B1, _B2);
+    template <class _Ip, class _Op> friend _LIBCPP_CONSTEXPR_AFTER_CXX17 _Op move(_Ip, _Ip, _Op);
+    template <class _B1, class _B2> friend _LIBCPP_CONSTEXPR_AFTER_CXX17 _B2 move_backward(_B1, _B1, _B2);
 
 #if _LIBCPP_DEBUG_LEVEL < 2
     template <class _Tp>
-    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
+    _LIBCPP_CONSTEXPR friend
     typename enable_if
     <
         is_trivially_copy_assignable<_Tp>::value,
@@ -1618,7 +1618,7 @@
     __unwrap_iter(__wrap_iter<_Tp*>);
 #else
   template <class _Tp>
-  inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+  inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
   typename enable_if
   <
       is_trivially_copy_assignable<_Tp>::value,