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From: Nicholas N. <nj...@cs...> - 2007-02-16 00:22:11
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On Thu, 15 Feb 2007, Josef Weidendorfer wrote:
>> Also, if we ever do more aggressive block formation which speculatively
>> chases across conditional branches ("trace formation"), then some branch
>> conditions will have to be inverted - it is unavoidable.
>
> Is such a speculative chasing useful? I assume that you take the
> outcome of the first execution, which does the translation. It is not
> clear to me why the first execution will stay a good speculation in
> the run of a program.
Systems that do this kind of thing normally do so after doing some run-time
profiling for a while -- eg. optimise the hot blocks after they've run
enough times.
Nick
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