Constrain fill_n -> memset operations to include implicit convertibility to unsigned char. This fixes http://llvm.org/bugs/show_bug.cgi?id=16764. Also a drive-by fix on a chrono test suite bug.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@187552 91177308-0d34-0410-b5e6-96231b3b80d8

include/algorithm

@@ -2012,6 +2012,7 @@ fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
    return _VSTD::__fill_n(__first, __n, __value_, integral_constant<bool,
                                               is_pointer<_OutputIterator>::value &&
                                               is_trivially_assignable<typename remove_pointer<_OutputIterator>::type, _Tp>::value &&
+                                              is_convertible<_Tp, unsigned char>::value &&
                                               sizeof(typename remove_pointer<_OutputIterator>::type) == 1>());
 }
 

test/utilities/time/time.duration/time.duration.cons/default.pass.cpp

@@ -27,7 +27,7 @@ test()
     D d;
     assert(d.count() == typename D::rep());
 #ifndef _LIBCPP_HAS_NO_CONSTEXPR
-    constexpr D d2;
+    constexpr D d2 = D();
     static_assert(d2.count() == typename D::rep(), "");
 #endif
 }