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Re: inline asm constraints for conditions
On Mon, Sep 29, 2003 at 06:21:34PM +0100, Jamie Lokier wrote:
> If the flags register is killed, then "reloading" should be a simple
> matter of either redoing the comparison, as effectively happens all
> the time now, or saving the _particular_ comparison results that are
> wanted using setcc, sbbl etc. into an ordinary register.
In the case under discussion the compiler would not have access to the
instruction that set the flags -- it's hidden in an asm. If the insns
in question were exposed via __builtins, the flags might have been set
by an instruction like xaddl or cmpxchg which cannot be re-done.
So, no, this would not help at all.