From b43f17c835df5d4ffa94f1902fe7af88206d7521 Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Mon, 16 Jan 2017 21:15:08 +0000
Subject: Fix std::tuples EBO when targeting the MSVC ABI.

MSVC/clang-cl doesn't do a full EBO unless __declspec(empty_bases)
is applied to the derived type. This causes certain tuple tests
to fail.

This patch adds the empty_bases attribute to __tuple_impl in order
for tuple to fully provide the EBO.

llvm-svn: 292159
---
 libcxx/include/tuple | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'libcxx/include/tuple')

diff --git a/libcxx/include/tuple b/libcxx/include/tuple
index cddb70954ee..a17ea01f102 100644
--- a/libcxx/include/tuple
+++ b/libcxx/include/tuple
@@ -366,7 +366,7 @@ struct __all_default_constructible<__tuple_types<_Tp...>>
 template<class _Indx, class ..._Tp> struct __tuple_impl;
 
 template<size_t ..._Indx, class ..._Tp>
-struct __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
+struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
     : public __tuple_leaf<_Indx, _Tp>...
 {
     _LIBCPP_INLINE_VISIBILITY
-- 
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