[PATCH] D43620: [Pipeliner] Fixed node order issue related to zero latency edges

Brendon Cahoon via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Wed Feb 28 09:02:34 PST 2018

bcahoon added a comment.

Thanks for the detailed explanation. That make sense, and I agree that the ZLD/ZLH is a more general/better solution.

Comment at: lib/CodeGen/MachinePipeliner.cpp:1615
                                   getDistance(pred, SU, *IP) * MII));
+      if (getLatency(SU, *IP) == 0)
+        zeroLatencyDepth =
I think the zeroLatencyDepth (and Height) calculation needs to be done prior to the ignoreDependence() check. Otherwise, Anti dependence edges won't be considered in the ZLD/ZLH calculation.



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