Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 24 Aug 2011 16:11:13 -0700 | Subject | Re: [PATCH 13/15] x86: add cmpxchg_flag() variant |
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On Wed, Aug 24, 2011 at 4:04 PM, H. Peter Anvin <hpa@zytor.com> wrote: > >> I was also thinking that using it reduces register pressure, since you >> don't need to keep the "old" value around, so it dies sooner. > > ... but you burn a register for the intermediate flag value, so you're > just as bad off.
But that register has much shorter liveness - so I do agree that it *can* help.
Whether it actually *does* help is unclear. I do agree that we might be better off without introducing yet another (questionable) interface.
Linus
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