[PATCH] D84763: DomTree: Make PostDomTree immune to block successors swap

[Jakub Kuderski via Phabricator via llvm-commits]

kuhar added a comment.

In D84763#2179546 <https://reviews.llvm.org/D84763#2179546>, @lebedev.ri wrote:

> In D84763#2179475 <https://reviews.llvm.org/D84763#2179475>, @kuhar wrote:
>
>> Given that you want to fix InstCombine not to swap successors and move this to SimplifyCFG, does this patch improve anything in the current pass pipeline?
>
> I don't believe that is the correct fix, because it literally says "nope, there is no way to update PDT after swapping successors other than full domtree recomputation", that is why i'm pushing for fixing PDT.

This patch doesn't allow for updating PDT either, it just makes it insensitive to that order. I guess this is consistent with saying that domtrees should be compared by checking if they are isomorphic, such that we don't have to care about updating forward dominators after successor swaps either.


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https://reviews.llvm.org/D84763