[PATCH] D79037: [StructurizeCFG] Fix region nodes ordering

[Ehud Katz via Phabricator via llvm-commits]

ekatz added a comment.

In D79037#2024574 <https://reviews.llvm.org/D79037#2024574>, @sameerds wrote:

> Actually, I take that back. Consider the following CFG:
>
> A -> H1, H2
>  H1->B, C
>  B->H1
>  C->B, H2
>  H2->E
>  E->H2, F
> 
>  A is the entry and F is the exit. The loops (H1, B, C) and (H2, E) are siblings with backedges B->H1 and E->H2 respectively. C is an exiting block in the first loop that branches to H2. One POT would be "B, F, E, H2, C, H1, A". When iterating in reverse, the loop with H1 is started first, but H2 from the second loop is encountered before the first loop is completed. 


In this case, those loops are in different regions, and as this is a region pass, they won't appear in the same POT.


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  https://reviews.llvm.org/D79037/new/

https://reviews.llvm.org/D79037