From: Eric Botcazou <ebotca...@adacore.com>
Date: Mon, 27 Feb 2012 10:42:17 +0100
>> We probably want to do some nop'ish thing here which will yield the
>> cpu thread on Niagara cpus, I'd recommend something along the lines of
>> "rd %ccr, %g0" or "rd %y, %g0"
>
> libgomp has its own idea about cpu_relax:
>
> static inline void
> cpu_relax (void)
> {
> #if defined __arch64__ || defined __sparc_v9__
> __asm volatile ("membar #LoadLoad" : : : "memory");
> #else
> __asm volatile ("" : : : "memory");
> #endif
> }
>
> Maybe we can come up with a single implementation for libgomp and libitm?
I think that's a great idea.
We need a reliable way to test for v9/v8plus/whatever properly because
nobody is testing current gcc with real 32-bit pre-v9 sparc hardware and
not providing atomics and proper cpu_relax implementations is just silly.
