[PATCH] D30633: [BPI] Reduce the probability of unreachable edge to minimal value greater than 0

Chandler Carruth via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue May 16 09:12:24 PDT 2017


chandlerc added a comment.

In https://reviews.llvm.org/D30633#756192, @davidxl wrote:

> It is known that BFI can not handle zero weight and it will add 1 to zero weight when it sees it.
>
> Here the  unreachable Branch prob is not zero (without the change).  Where does it get changed to zero?


This patch doesn't.

In my response I suggested that *if* the author wants to go beyond the current patch (which keeps unreachable at >0) they should discuss it more broadly. I don't think you need to worry about that today, they'll send email if they want to go there.

I added you to this patch to make sure the technique of dropping to 1 and maxing out the other side makes sense (now that we factor in when metadata has more precise information).


https://reviews.llvm.org/D30633





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