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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/99306] cross compiler bootstrap failure on
 msdosdjgpp: error: alignment of 'm' is greater than maximum object file
 alignment 16
Date: Mon, 01 Mar 2021 09:26:19 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99306

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-03-01
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
  __gnu_cxx::__mutex&
  get_mutex(unsigned char i)
  {
    // increase alignment to put each lock on a separate cache line
    struct alignas(64) M : __gnu_cxx::__mutex { };
    static M m[mask + 1];
    return m[i];

there's __BIGGEST_ALIGNMENT__ one could use as bound but that will usually
be lower than the max ofile alignment and on most targets likely less
than 64.  That value (64) looks like it should be target dependent anyway
(configury?)=