1 files changed, 10 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index cf75d53..d9d0a78 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -2724,7 +2724,11 @@ bool tryLatency(GenericSchedulerBase::SchedCandidate &TryCand,
                 GenericSchedulerBase::SchedCandidate &Cand,
                 SchedBoundary &Zone) {
   if (Zone.isTop()) {
-    if (Cand.SU->getDepth() > Zone.getScheduledLatency()) {
+    // Prefer the candidate with the lesser depth, but only if one of them has
+    // depth greater than the total latency scheduled so far, otherwise either
+    // of them could be scheduled now with no stall.
+    if (std::max(TryCand.SU->getDepth(), Cand.SU->getDepth()) >
+        Zone.getScheduledLatency()) {
       if (tryLess(TryCand.SU->getDepth(), Cand.SU->getDepth(),
                   TryCand, Cand, GenericSchedulerBase::TopDepthReduce))
         return true;
@@ -2733,7 +2737,11 @@ bool tryLatency(GenericSchedulerBase::SchedCandidate &TryCand,
                    TryCand, Cand, GenericSchedulerBase::TopPathReduce))
       return true;
   } else {
-    if (Cand.SU->getHeight() > Zone.getScheduledLatency()) {
+    // Prefer the candidate with the lesser height, but only if one of them has
+    // height greater than the total latency scheduled so far, otherwise either
+    // of them could be scheduled now with no stall.
+    if (std::max(TryCand.SU->getHeight(), Cand.SU->getHeight()) >
+        Zone.getScheduledLatency()) {
       if (tryLess(TryCand.SU->getHeight(), Cand.SU->getHeight(),
                   TryCand, Cand, GenericSchedulerBase::BotHeightReduce))
         return true;