r219770 - in /trunk/libstdc++-v3: ChangeLog con...

[torvald@gcc.gnu.org]

Author: torvald
Date: Fri Jan 16 19:50:43 2015
New Revision: 219770

URL: https://gcc.gnu.org/viewcvs?rev=219770&root=gcc&view=rev
Log:
libstdc++: Optimize synchronization in std::future if futexes are available.

	* src/c++11/futex.cc: New file.
	* include/bits/atomic_futex.h: New file.
	* include/std/future (__future_base::_State_baseV2): Use
	atomic_futex_unsigned instead of mutex+condvar.
	* src/c++11/futex.cc: Likewise.
	* include/Makefile.am: Add atomic_futex.h.
	* include/Makefile.in: Likewise.
	* src/c++11/Makefile.am: Add futex.cc.
	* src/c++11/Makefile.in: Likewise.

Added:
    trunk/libstdc++-v3/include/bits/atomic_futex.h
    trunk/libstdc++-v3/src/c++11/futex.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/config/abi/pre/gnu.ver
    trunk/libstdc++-v3/include/Makefile.am
    trunk/libstdc++-v3/include/Makefile.in
    trunk/libstdc++-v3/include/std/future
    trunk/libstdc++-v3/src/c++11/Makefile.am
    trunk/libstdc++-v3/src/c++11/Makefile.in
    trunk/libstdc++-v3/src/c++11/future.cc