defeat gcc's (over?) eager optimizer with std::launder

NVIDIA · Nov 2, 2023 · 4db236c · 4db236c
1 parent da9815f
commit 4db236c
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/include/stdexec/__detail/__memory.hpp b/include/stdexec/__detail/__memory.hpp
@@ -20,6 +20,7 @@
 
 #include <memory>
 #include <new>
+#include <utility> // for std::launder
 
 namespace stdexec {
   namespace __mem {
@@ -63,22 +64,22 @@ namespace stdexec {
         auto __alloc = _GetAllocator(__data);
         _Derived* __ptr = __alloc.__allocate();
         [[maybe_unused]] __scope_guard __g{[&]() noexcept { __alloc.__deallocate(__ptr); }};
-        ::new(&__ptr->__data_) _Data((_Data&&) __data);
+        ::new(&std::launder(__ptr)->__data_) _Data((_Data&&) __data);
         __g.__dismiss();
         return __ptr;
       }
 
       static void operator delete(void* __self, _Data&&) {
         _Derived* __ptr = static_cast<_Derived*>(__self);
         auto __alloc = _GetAllocator(__ptr->__data_);
-        __ptr->__data_.~_Data();
+        std::launder(__ptr)->__data_.~_Data();
         __alloc.__deallocate(__ptr);
       }
 
       static void operator delete(__with_allocator_provider* __self, std::destroying_delete_t) noexcept {
         _Derived* __ptr = static_cast<_Derived*>(__self);
         auto __alloc = _GetAllocator(__ptr->__data_);
-        __ptr->__data_.~_Data();
+        std::launder(__ptr)->__data_.~_Data();
         __alloc.__destroy(__ptr);
         __alloc.__deallocate(__ptr);
       }