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Re: disabling branch probability guessing (patch) [another patch]


On Sat, Jan 20, 2001 at 03:03:30AM -0400, Aldy Hernandez wrote:
>  > I agree that that would be a good heuristic. Assume goto as not taken. 
> 
> Alright.  I did some playing around to predict gotos as not taken
> (patch below).  It seems to work pretty good.

I don't necessarily agree that this is a good heuristic.  It assumes
a rather rigid adherence to one programming style.  One that doesn't
apply at all to machine generated code I might add.

Placed as this check is, we get no chance to make potentially better
guesses based on the shape of the CFG or other tell-tales.  I wouldn't
mind this test as one of several being combined, but on its own I'm
dubious.


r~

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