Silence warning C4324: structure was padded due to alignment specifier (#4426)

Co-authored-by: Alex Guteniev <[email protected]>

Author: StephanTLavavej

stl/inc/execution

@@ -571,8 +571,6 @@ struct alignas(_Ty) alignas(size_t) alignas(_Atomic_counter_t) _Circular_buffer
     }
 };
 
-#pragma warning(push)
-#pragma warning(disable : 4324) // structure was padded due to alignment specifier
 template <class _Ty>
 class alignas(hardware_destructive_interference_size) _Work_stealing_deque {
     // thread-local work-stealing deque, which allows efficient access from a single owner thread at the "bottom"
@@ -686,7 +684,6 @@ private:
     _Guarded_by_(_Segment_lock) _Circular_buffer<_Ty>* _Segment{_Circular_buffer<_Ty>::_New_circular_buffer()};
     mutex _Segment_lock{};
 };
-#pragma warning(pop)
 
 enum class _Steal_result { _Success, _Abort, _Done };
 
@@ -2524,13 +2521,10 @@ struct _Static_partitioned_remove_if2 {
         // may transition from _Serial directly to _Done, doing the moving step implicitly.
     };
 
-#pragma warning(push)
-#pragma warning(disable : 4324) // structure was padded due to alignment specifier
     struct alignas(hardware_destructive_interference_size) alignas(_FwdIt) _Chunk_local_data {
         atomic<_Chunk_state> _State;
         _FwdIt _New_end;
     };
-#pragma warning(pop)
 
     _Static_partition_team<_Iter_diff_t<_FwdIt>> _Team;
     _Static_partition_range<_FwdIt> _Basis;
@@ -3486,14 +3480,11 @@ struct _Static_partitioned_partition2 {
         _Done // when a chunk becomes _Done, it is complete / will never need to touch _Results again
     };
 
-#pragma warning(push)
-#pragma warning(disable : 4324) // structure was padded due to alignment specifier
     struct alignas(hardware_destructive_interference_size) alignas(_FwdIt) _Chunk_local_data {
         atomic<_Chunk_state> _State;
         _FwdIt _Beginning_of_falses;
         _Diff _Chunk_trues;
     };
-#pragma warning(pop)
 
     _Static_partition_team<_Diff> _Team;
     _Static_partition_range<_FwdIt> _Basis;

stl/inc/xutility

@@ -3865,10 +3865,6 @@ namespace ranges {
         constexpr explicit _Subrange_base(const _Size_type& _Size_) noexcept : _Size(_Size_) {}
     };
 
-#if 1 // TRANSITION, VSO-1695918 - Warning C4324 incorrectly firing in the presence of `pragma pack`
-#pragma warning(push)
-#pragma warning(disable : 4324) // structure was padded due to alignment specifier
-#endif // ^^^ workaround ^^^
     _EXPORT_STD template <input_or_output_iterator _It, sentinel_for<_It> _Se, subrange_kind _Ki>
         requires (_Ki == subrange_kind::sized || !sized_sentinel_for<_Se, _It>)
     class subrange : public _Subrange_base<_It, _Se, _Ki> {
@@ -4032,9 +4028,6 @@ namespace ranges {
             return *this;
         }
     };
-#if 1 // TRANSITION, VSO-1695918 - Warning C4324 incorrectly firing in the presence of `pragma pack`
-#pragma warning(pop)
-#endif // ^^^ workaround ^^^
 
     template <input_or_output_iterator _It, sentinel_for<_It> _Se>
     subrange(_It, _Se) -> subrange<_It, _Se>;

stl/inc/yvals_core.h

@@ -778,6 +778,7 @@
 #endif // !defined(_STL_EXTRA_DISABLED_WARNINGS)
 
 // warning C4180: qualifier applied to function type has no meaning; ignored
+// warning C4324: structure was padded due to alignment specifier
 // warning C4412: function signature contains type 'meow'; C++ objects are unsafe to pass between pure code
 //                and mixed or native. (/Wall)
 // warning C4455: literal suffix identifiers that do not start with an underscore are reserved
@@ -809,9 +810,9 @@
 #ifndef _STL_DISABLED_WARNINGS
 // clang-format off
 #define _STL_DISABLED_WARNINGS                        \
-    4180 4412 4455 4494 4514 4574 4582 4583 4587 4588 \
-    4619 4623 4625 4626 4643 4648 4702 4793 4820 4868 \
-    4988 5026 5027 5045 5220 6294                     \
+    4180 4324 4412 4455 4494 4514 4574 4582 4583 4587 \
+    4588 4619 4623 4625 4626 4643 4648 4702 4793 4820 \
+    4868 4988 5026 5027 5045 5220 6294                \
     _STL_DISABLED_WARNING_C4577                       \
     _STL_DISABLED_WARNING_C4984                       \
     _STL_DISABLED_WARNING_C5053                       \

tests/std/tests/P2374R4_views_cartesian_product/test.cpp

@@ -934,6 +934,20 @@ constexpr void test_gh_3733() {
     assert(as_const(cart).size() == 0);
 }
 
+// GH-4425 <ranges>: views::cartesian_product and views::filter emit
+// spurious warning C4324 'structure was padded due to alignment specifier'
+constexpr void test_gh_4425() {
+    const vector<int> vec{11, 22, 33, 44};
+
+    const auto strictly_ascending = [](const auto& t) { return get<0>(t) < get<1>(t); };
+
+    const auto result = ranges::to<vector>(views::cartesian_product(vec, vec) | views::filter(strictly_ascending));
+
+    const vector<tuple<int, int>> correct{{11, 22}, {11, 33}, {11, 44}, {22, 33}, {22, 44}, {33, 44}};
+
+    assert(result == correct);
+}
+
 int main() {
     // Check views
 #ifndef __EDG__ // TRANSITION, VSO-1900293
@@ -997,4 +1011,7 @@ int main() {
 
     STATIC_ASSERT((test_gh_3733(), true));
     test_gh_3733();
+
+    STATIC_ASSERT((test_gh_4425(), true));
+    test_gh_4425();
 }