[Bug libstdc++/77691] [7/8/9 regression] experimental/memory_resource/resource_adaptor.cc FAILs

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77691

--- Comment #30 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Created attachment 45940
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45940&action=edit
Patch to fix resource_adaptor failures due to max_align_t bugs

Could you please try this patch on Soalris and HP-UX?

Commit log:

    Remove the hardcoded whitelist of allocators expected to return memory
    aligned to alignof(max_align_t), because that doesn't work when the
    platform's malloc() and GCC's max_align_t do not agree what the largest
    fundamental alignment is.

    Instead use a hardcoded list of fundamental types that will definitely
    be supported by the platform malloc, and use a copy of the allocator
    rebound to the first type that matches the requested alignment.

    This means allocations for alignof(__float128) might use additional
    memory to store the token, because we can't assume the platform malloc
    will return memory aligned to alignof(__float128). Ideally we'd be able
    to add __float128 to the list of fundamental types when we know it works
    for a given target.