[Bug libstdc++/88466] New: Support std::hardware_destructive_interference_size and std:: hardware_constructive_interference_size

[duarte at scylladb dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88466

            Bug ID: 88466
           Summary: Support std::hardware_destructive_interference_size
                    and std:: hardware_constructive_interference_size
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: duarte at scylladb dot com
  Target Milestone: ---

The following should compile:

#include <new>

struct x {
    alignas(std::hardware_destructive_interference_size) int y;
    alignas(std::hardware_constructive_interference_size) int z;
};

It seems, however, that neither std::hardware_destructive_interference_size nor
std::hardware_constructive_interference_size have been included in libstdc++.