Fix after P0600.

gcc/testsuite/ChangeLog
2019-02-20  Ulrich Drepper  <drepper@redhat.com>

	Fix after P0600.
	* g++.dg/init/new39.C: Don't just ignore result of new.

libstdc++/ChangeLog
2019-02-20  Ulrich Drepper  <drepper@redhat.com>

	Implement C++20 P0600r1.
	* include/backward/hash_map: Add nodiscard attribute to empty.
	* include/backward/hash_set: Likewise.
	* backward/hashtable.h: Likewise.
	* include/bits/basic_string.h: Likewise.
	* include/bits/forward_list.h: Likewise.
	* include/bits/hashtable.h: Likewise.
	* include/bits/regex.h: Likewise.
	* include/bits/stl_deque.h: Likewise.
	* include/bits/stl_list.h: Likewise.
	* include/bits/stl_map.h: Likewise.
	* include/bits/stl_multimap.h: Likewise.
	* include/bits/stl_multiset.h: Likewise.
	* include/bits/stl_queue.h: Likewise.
	* include/bits/stl_set.h: Likewise.
	* include/bits/stl_stack.h: Likewise.
	* include/bits/stl_tree.h: Likewise.
	* include/bits/stl_vector.h: Likewise.
	* include/bits/unordered_map.h: Likewise.
	* include/bits/unordered_set.h: Likewise.
	* include/debug/array: Likewise.
	* include/experimental/any: Likewise.
	* include/experimental/bits/fs_path.h: Likewise.
	* include/experimental/internet: Likewise.
	* include/experimental/string_view: Likewise.
	* include/ext/pb_ds/detail/bin_search_tree_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/binary_heap_/binary_heap_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/binary_heap_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/cc_hash_table_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/cc_hash_table_map_/size_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/gp_hash_table_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/left_child_next_sibling_heap_/info_fn_imps.hpp:
	Likewise.
	*
include/ext/pb_ds/detail/left_child_next_sibling_heap_/left_child_next_sibling_heap_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/list_update_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/list_update_map_/lu_map_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/ov_tree_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/ov_tree_map_/ov_tree_map_.hp:
	Likewise.
	* include/ext/pb_ds/detail/pat_trie_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/pat_trie_/pat_trie_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/rc_binomial_heap_/rc.hpp:
	Likewise.
	* include/ext/pb_ds/detail/tree_trace_base.hpp: Likewise.
	* include/ext/pb_ds/trie_policy.hpp: Likewise.
	* include/ext/rope: Likewise.
	* include/ext/slist: Likewise.
	* include/ext/vstring.h: Likewise.
	* include/profile/array: Likewise.
	* include/std/array: Likewise.
	* include/tr1/array: Likewise.
	* include/tr1/hashtable.h: Likewise.
	* include/tr1/regex: Likewise.
	* include/tr2/dynamic_bitset: Likewise.
	* include/bits/alloc_traits.h: Add nodiscard attribute to
	allocate.
	* include/experimental/memory_resource: Likewise.
	* include/ext/alloc_traits.h: Likewise.
	* include/ext/array_allocator.h: Likewise.
	* include/ext/bitmap_allocator.h: Likewise.
	* include/ext/debug_allocator.h: Likewise.
	* include/ext/extptr_allocator.h: Likewise.
	* include/ext/mt_allocator.h: Likewise.
	* include/ext/new_allocator.h: Likewise.
	* include/ext/pool_allocator.h: Likewise.
	* include/ext/throw_allocator.h: Likewise.
	* include/std/scoped_allocator: Likewise.
	* libsupc++/eh_alloc.cc: Likewise.
	* include/std/future: Add nodiscard attribute to async.
	* libsupc++/new: Add nodiscard attribute to new.

From-SVN: r268111

5 files changed, 8 insertions, 8 deletions

diff --git a/libstdc++-v3/include/experimental/any b/libstdc++-v3/include/experimental/any
index f8cd4a78821..ed7a115f6b2 100644
--- a/libstdc++-v3/include/experimental/any
+++ b/libstdc++-v3/include/experimental/any
@@ -266,7 +266,7 @@ inline namespace fundamentals_v1
     // observers
 
     /// Reports whether there is a contained object or not.
-    bool empty() const noexcept { return _M_manager == nullptr; }
+    _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_manager == nullptr; }
 
 #if __cpp_rtti
     /// The @c typeid of the contained object, or @c typeid(void) if empty.
diff --git a/libstdc++-v3/include/experimental/bits/fs_path.h b/libstdc++-v3/include/experimental/bits/fs_path.h
index e9d6619876a..239776df313 100644
--- a/libstdc++-v3/include/experimental/bits/fs_path.h
+++ b/libstdc++-v3/include/experimental/bits/fs_path.h
@@ -365,7 +365,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 
     // query
 
-    bool empty() const noexcept { return _M_pathname.empty(); }
+    _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_pathname.empty(); }
     bool has_root_name() const;
     bool has_root_directory() const;
     bool has_root_path() const;
diff --git a/libstdc++-v3/include/experimental/internet b/libstdc++-v3/include/experimental/internet
index 07c62e697cd..80682efed53 100644
--- a/libstdc++-v3/include/experimental/internet
+++ b/libstdc++-v3/include/experimental/internet
@@ -1049,7 +1049,7 @@ namespace ip
 
     iterator begin() const noexcept { return _M_begin; }
     iterator end() const noexcept { return _M_end; }
-    bool empty() const noexcept { return _M_begin == _M_end; }
+    _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_begin == _M_end; }
 
     size_t
     size() const noexcept { return _M_end->to_uint() - _M_begin->to_uint(); }
@@ -1093,7 +1093,7 @@ namespace ip
 
     iterator begin() const noexcept { return _M_begin; }
     iterator end() const noexcept { return _M_end; }
-    bool empty() const noexcept { return _M_begin == _M_end; }
+    _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_begin == _M_end; }
 
     iterator
     find(const address_v6& __addr) const noexcept
@@ -1721,7 +1721,7 @@ namespace ip
       // size:
       size_type size() const noexcept { return _M_size; }
       size_type max_size() const noexcept { return _M_results.max_size(); }
-      bool empty() const noexcept { return _M_results.empty(); }
+      _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_results.empty(); }
 
       // element access:
       const_iterator begin() const { return _M_results.begin(); }
diff --git a/libstdc++-v3/include/experimental/memory_resource b/libstdc++-v3/include/experimental/memory_resource
index 4d96466f218..e9fece55cd0 100644
--- a/libstdc++-v3/include/experimental/memory_resource
+++ b/libstdc++-v3/include/experimental/memory_resource
@@ -88,7 +88,7 @@ namespace pmr {
 
     memory_resource& operator=(const memory_resource&) = default;
 
-    void*
+    _GLIBCXX_NODISCARD void*
     allocate(size_t __bytes, size_t __alignment = _S_max_align)
     { return do_allocate(__bytes, __alignment); }
 
@@ -145,7 +145,7 @@ namespace pmr {
       polymorphic_allocator&
 	operator=(const polymorphic_allocator& __rhs) = default;
 
-      _Tp* allocate(size_t __n)
+      _GLIBCXX_NODISCARD _Tp* allocate(size_t __n)
       { return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp),
 						       alignof(_Tp))); }
 
diff --git a/libstdc++-v3/include/experimental/string_view b/libstdc++-v3/include/experimental/string_view
index d233ecc743b..8cc0e90246b 100644
--- a/libstdc++-v3/include/experimental/string_view
+++ b/libstdc++-v3/include/experimental/string_view
@@ -169,7 +169,7 @@ inline namespace fundamentals_v1
 		/ sizeof(value_type) / 4;
       }
 
-      constexpr bool
+      _GLIBCXX_NODISCARD constexpr bool
       empty() const noexcept
       { return this->_M_len == 0; }