[PATCH] D127115: [RFC][DAGCombine] Make sure combined nodes are added back to the worklist in topological order.

[Sergei Barannikov via Phabricator via llvm-commits]

barannikov88 added a comment.

@spatel 
I'm facing an issue which might be related to the work you are doing.
Suppose I have the following DAG:
A -> B -> C -> D
DAGCominer can optimize C -> D into E, and then A -> B -> E can be optimized further to just F.

If C precedes A in the visit order, this is just fine. However, if A is visited first and then C -> D is combined into E, then A will not be revisited (because it is not immediate successor or predecessor of C), and the pattern A -> B -> E will not be matched.
For this reason I have to match both A -> B -> C -> D and A -> B -> E. Will your patch help with this issue or is it something unrelated?


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