From 09b4000c7c5b359ec62b5d621daf6ab95233ce10 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Fri, 24 May 2019 16:39:35 +0100
Subject: [PATCH] Fix std::midpoint(T*, T*) for reversed arguments

	* include/std/numeric (midpoint(T*, T*)): Fix incorrect result.
	* testsuite/26_numerics/midpoint/pointer.cc: Change "compile" test
	to "run".

From-SVN: r271606
---
 libstdc++-v3/ChangeLog                                 | 4 ++++
 libstdc++-v3/include/std/numeric                       | 2 +-
 libstdc++-v3/testsuite/26_numerics/midpoint/pointer.cc | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 0a83bd3252c..ad97108fdb0 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,9 @@
 2019-05-24  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/numeric (midpoint(T*, T*)): Fix incorrect result.
+	* testsuite/26_numerics/midpoint/pointer.cc: Change "compile" test
+	to "run".
+
 	* testsuite/20_util/shared_ptr/cons/alias-rval.cc: Fix test.
 	* testsuite/20_util/shared_ptr/cons/alias.cc: Remove unused function.
 
diff --git a/libstdc++-v3/include/std/numeric b/libstdc++-v3/include/std/numeric
index 4858ad1aea3..9dff247538a 100644
--- a/libstdc++-v3/include/std/numeric
+++ b/libstdc++-v3/include/std/numeric
@@ -195,7 +195,7 @@ template<typename _Tp>
     enable_if_t<__and_v<is_object<_Tp>, bool_constant<sizeof(_Tp) != 0>>, _Tp*>
     midpoint(_Tp* __a, _Tp* __b) noexcept
     {
-      return __a > __b ? __b + (__a - __b) / 2 : __a + (__b - __a) / 2;
+      return __a  + (__b - __a) / 2;
     }
 #endif // C++20
 
diff --git a/libstdc++-v3/testsuite/26_numerics/midpoint/pointer.cc b/libstdc++-v3/testsuite/26_numerics/midpoint/pointer.cc
index bd586d28ba0..3d3aafc3ec8 100644
--- a/libstdc++-v3/testsuite/26_numerics/midpoint/pointer.cc
+++ b/libstdc++-v3/testsuite/26_numerics/midpoint/pointer.cc
@@ -16,7 +16,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-options "-std=gnu++2a" }
-// { dg-do compile { target c++2a } }
+// { dg-do run { target c++2a } }
 
 #include <numeric>
 #include <climits>
-- 
2.30.2