[PATCH] D75341: [BFI] Use CallbackVH to notify BFI about deletion of basic blocks

[Daniil Suchkov via Phabricator via llvm-commits]

DaniilSuchkov added a comment.

In D75341#1904797 <https://reviews.llvm.org/D75341#1904797>, @davidxl wrote:

> I think we should explicitly fix the real problems that new blocks are not updated frequency information instead of just letting them get a known default value. Doing it later can make it harder to find those problems, right?


Cases when we don't properly set frequencies are inefficiencies, which are unfortunate, but they aren't critical, to catch them there is already a CheckBFIUnknownBlockQueries option. This patch, on the other hand, not about mere inefficiencies, it's about non-deterministic behavior of compiler, which is a pretty nasty thing, I find even possibility of this happening a real problem. What I here propose would protect us from such issues and it won't cover cases CheckBFIUnknownBlockQueries is made to detect, so it won't make finding such cases any harder.


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https://reviews.llvm.org/D75341