Re: [RS6000] atomic tweaks

2012-06-21 Thread Alan Modra
On Thu, Jun 21, 2012 at 12:08:42PM -0400, David Edelsohn wrote: > 4) Later loads and stores to which a dependency is carried from the > initial load (see 1.10p9 and 1.10p10 in the standard) cannot be > reordered to precede the load(memory_order_consume). Other loads and > stores following the load

Re: [RS6000] atomic tweaks

2012-06-21 Thread David Edelsohn
On Thu, Jun 21, 2012 at 6:55 AM, Alan Modra wrote: > A couple of small tweaks to PowerPc atomic operations.  The first > omits the "cmp; bc; isync" barrier on atomic_load with mem model > __ATOMIC_CONSUME.  PowerPC pointer loads don't need a barrier.  Ref > http://www.rdrop.com/users/paulmck/scala

[RS6000] atomic tweaks

2012-06-21 Thread Alan Modra
A couple of small tweaks to PowerPc atomic operations. The first omits the "cmp; bc; isync" barrier on atomic_load with mem model __ATOMIC_CONSUME. PowerPC pointer loads don't need a barrier. Ref http://www.rdrop.com/users/paulmck/scalability/paper/N2745r.2011.03.04a.html As best I can see, mem_