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

[Chandler Carruth via Phabricator via llvm-commits]

chandlerc added a comment.

In https://reviews.llvm.org/D30633#756248, @davidxl wrote:

> That is not my question :)
>
> My question is that without the patch, the probability of UR branch is actually lower (1, 0x8000....).   Looks like it gets truncated somewhere? In other words, the fix can be put to where the truncation happens.


I think I must be missing something ... Where is the probability of the UR branch lower before this patch? At least, the test cases updated, the probability of the UR branch is *higher* before this patch.

>From the comments in the review thread, the goal here is to avoid the case where the UR branch probability ends up *higher* than the loop exit branch probability.


https://reviews.llvm.org/D30633