On Wed, Apr 21, 2021 at 11:50:02AM -0400, David Edelsohn via Gcc-patches wrote:
> This patch broke bootstrap on AIX.
>
> std::thread is not provided in all instances. GCC is not compiled
> multi-threaded by default.
>
> error: `std::thread' has not been declared.
In addition to that, I'm not really convinced it is a good idea,
e.g. for Linux I believe the previous implementation was much better
(as it counted only the cores/threads available to gcc subprocesses,
rather than all available on the system, so e.g. when running some
compilation job under taskset with std::thread::hardware_concurrency it
will oversubscribe the available CPUs).
Sure, for some non-Linux targets you might want to copy what is done in
libstdc++-v3/src/c++11/thread.cc, but I think it is better to copy/adjust the
relevant configure bits and the thread.cc code is very short...
Jakub
