[llvm] [MISched] Use right boundary when trying latency heuristics (PR #116592)

[Pengcheng Wang via llvm-commits]

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@@ -3969,9 +3969,14 @@ bool PostGenericScheduler::tryCandidate(SchedCandidate &Cand,
                  TryCand, Cand, ResourceDemand))
     return TryCand.Reason != NoCand;
 
-  // Avoid serializing long latency dependence chains.
-  if (Cand.Policy.ReduceLatency && tryLatency(TryCand, Cand, Top)) {
-    return TryCand.Reason != NoCand;
+  // We only compare a subset of features when comparing nodes between
+  // Top and Bottom boundary.
+  if (Cand.AtTop == TryCand.AtTop) {
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wangpc-pp wrote:

Yes. This is the same logic as the pre-ra scheduling. And, theoretically, I think we can't compare latencies from different directions, right?

https://github.com/llvm/llvm-project/pull/116592