Revert "Bug 39129: Speeding up partition_point/lower_bound/upper_bound/ by using unsigned division by 2 when possible."

This reverts r345525. I'm reverting because that patch apparently caused
a regression on certain platforms (see https://reviews.llvm.org/D53994).
Since we don't fully understand the reasons for the regression, I'm
reverting until we can provide a fix we understand.

llvm-svn: 345893

1 files changed, 0 insertions, 59 deletions

diff --git a/libcxx/test/libcxx/algorithms/half_positive.pass.cpp b/libcxx/test/libcxx/algorithms/half_positive.pass.cpp
deleted file mode 100644
index 178055cbbd0..00000000000
--- a/libcxx/test/libcxx/algorithms/half_positive.pass.cpp
+++ /dev/null
@@ -1,59 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-// <algorithm>
-
-// template <typename _Tp> _Tp __half_positive(const _Tp&);
-
-// __half_positive divide integer number by 2 as unsigned number
-// if it's safe to do so. It can be an important optimization for lower bound,
-// for example.
-
-#include <algorithm>
-#include <cassert>
-#include <limits>
-#include <type_traits>
-
-#include "test_macros.h"
-#include "user_defined_integral.hpp"
-
-namespace {
-
-template <class IntType, class UnderlyingType = IntType>
-TEST_CONSTEXPR bool test(IntType max_v = IntType(std::numeric_limits<UnderlyingType>::max())) {
-    return std::__half_positive(max_v) == max_v / 2;
-}
-
-}  // namespace
-
-int main()
-{
-    {
-        assert(test<char>());
-        assert(test<int>());
-        assert(test<long>());
-        assert((test<UserDefinedIntegral<int>, int>()));
-        assert(test<size_t>());
-#if !defined(_LIBCPP_HAS_NO_INT128)
-        assert(test<__int128_t>());
-#endif  // !defined(_LIBCPP_HAS_NO_INT128)
-    }
-
-#if TEST_STD_VER >= 11
-    {
-        static_assert(test<char>(), "");
-        static_assert(test<int>(), "");
-        static_assert(test<long>(), "");
-        static_assert(test<size_t>(), "");
-#if !defined(_LIBCPP_HAS_NO_INT128)
-        static_assert(test<__int128_t>(), "");
-#endif  // !defined(_LIBCPP_HAS_NO_INT128)
-    }
-#endif // TEST_STD_VER >= 11
-}