1 files changed, 134 insertions, 6 deletions

diff --git a/contrib/llvm-project/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp b/contrib/llvm-project/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp
index 5649d7d13966..ce615e554d94 100644
--- a/contrib/llvm-project/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp
+++ b/contrib/llvm-project/llvm/lib/Target/PowerPC/PPCMachineScheduler.cpp
@@ -49,10 +49,103 @@ bool PPCPreRASchedStrategy::biasAddiLoadCandidate(SchedCandidate &Cand,
 void PPCPreRASchedStrategy::tryCandidate(SchedCandidate &Cand,
                                          SchedCandidate &TryCand,
                                          SchedBoundary *Zone) const {
-  GenericScheduler::tryCandidate(Cand, TryCand, Zone);
+  // From GenericScheduler::tryCandidate
 
-  if (!Cand.isValid() || !Zone)
+  // Initialize the candidate if needed.
+  if (!Cand.isValid()) {
+    TryCand.Reason = NodeOrder;
     return;
+  }
+
+  // Bias PhysReg Defs and copies to their uses and defined respectively.
+  if (tryGreater(biasPhysReg(TryCand.SU, TryCand.AtTop),
+                 biasPhysReg(Cand.SU, Cand.AtTop), TryCand, Cand, PhysReg))
+    return;
+
+  // Avoid exceeding the target's limit.
+  if (DAG->isTrackingPressure() &&
+      tryPressure(TryCand.RPDelta.Excess, Cand.RPDelta.Excess, TryCand, Cand,
+                  RegExcess, TRI, DAG->MF))
+    return;
+
+  // Avoid increasing the max critical pressure in the scheduled region.
+  if (DAG->isTrackingPressure() &&
+      tryPressure(TryCand.RPDelta.CriticalMax, Cand.RPDelta.CriticalMax,
+                  TryCand, Cand, RegCritical, TRI, DAG->MF))
+    return;
+
+  // We only compare a subset of features when comparing nodes between
+  // Top and Bottom boundary. Some properties are simply incomparable, in many
+  // other instances we should only override the other boundary if something
+  // is a clear good pick on one boundary. Skip heuristics that are more
+  // "tie-breaking" in nature.
+  bool SameBoundary = Zone != nullptr;
+  if (SameBoundary) {
+    // For loops that are acyclic path limited, aggressively schedule for
+    // latency. Within an single cycle, whenever CurrMOps > 0, allow normal
+    // heuristics to take precedence.
+    if (Rem.IsAcyclicLatencyLimited && !Zone->getCurrMOps() &&
+        tryLatency(TryCand, Cand, *Zone))
+      return;
+
+    // Prioritize instructions that read unbuffered resources by stall cycles.
+    if (tryLess(Zone->getLatencyStallCycles(TryCand.SU),
+                Zone->getLatencyStallCycles(Cand.SU), TryCand, Cand, Stall))
+      return;
+  }
+
+  // Keep clustered nodes together to encourage downstream peephole
+  // optimizations which may reduce resource requirements.
+  //
+  // This is a best effort to set things up for a post-RA pass. Optimizations
+  // like generating loads of multiple registers should ideally be done within
+  // the scheduler pass by combining the loads during DAG postprocessing.
+  const SUnit *CandNextClusterSU =
+      Cand.AtTop ? DAG->getNextClusterSucc() : DAG->getNextClusterPred();
+  const SUnit *TryCandNextClusterSU =
+      TryCand.AtTop ? DAG->getNextClusterSucc() : DAG->getNextClusterPred();
+  if (tryGreater(TryCand.SU == TryCandNextClusterSU,
+                 Cand.SU == CandNextClusterSU, TryCand, Cand, Cluster))
+    return;
+
+  if (SameBoundary) {
+    // Weak edges are for clustering and other constraints.
+    if (tryLess(getWeakLeft(TryCand.SU, TryCand.AtTop),
+                getWeakLeft(Cand.SU, Cand.AtTop), TryCand, Cand, Weak))
+      return;
+  }
+
+  // Avoid increasing the max pressure of the entire region.
+  if (DAG->isTrackingPressure() &&
+      tryPressure(TryCand.RPDelta.CurrentMax, Cand.RPDelta.CurrentMax, TryCand,
+                  Cand, RegMax, TRI, DAG->MF))
+    return;
+
+  if (SameBoundary) {
+    // Avoid critical resource consumption and balance the schedule.
+    TryCand.initResourceDelta(DAG, SchedModel);
+    if (tryLess(TryCand.ResDelta.CritResources, Cand.ResDelta.CritResources,
+                TryCand, Cand, ResourceReduce))
+      return;
+    if (tryGreater(TryCand.ResDelta.DemandedResources,
+                   Cand.ResDelta.DemandedResources, TryCand, Cand,
+                   ResourceDemand))
+      return;
+
+    // Avoid serializing long latency dependence chains.
+    // For acyclic path limited loops, latency was already checked above.
+    if (!RegionPolicy.DisableLatencyHeuristic && TryCand.Policy.ReduceLatency &&
+        !Rem.IsAcyclicLatencyLimited && tryLatency(TryCand, Cand, *Zone))
+      return;
+
+    // Fall through to original instruction order.
+    if ((Zone->isTop() && TryCand.SU->NodeNum < Cand.SU->NodeNum) ||
+        (!Zone->isTop() && TryCand.SU->NodeNum > Cand.SU->NodeNum)) {
+      TryCand.Reason = NodeOrder;
+    }
+  }
+
+  // GenericScheduler::tryCandidate end
 
   // Add powerpc specific heuristic only when TryCand isn't selected or
   // selected as node order.
@@ -61,8 +154,10 @@ void PPCPreRASchedStrategy::tryCandidate(SchedCandidate &Cand,
 
   // There are some benefits to schedule the ADDI before the load to hide the
   // latency, as RA may create a true dependency between the load and addi.
-  if (biasAddiLoadCandidate(Cand, TryCand, *Zone))
-    return;
+  if (SameBoundary) {
+    if (biasAddiLoadCandidate(Cand, TryCand, *Zone))
+      return;
+  }
 }
 
 bool PPCPostRASchedStrategy::biasAddiCandidate(SchedCandidate &Cand,
@@ -79,11 +174,44 @@ bool PPCPostRASchedStrategy::biasAddiCandidate(SchedCandidate &Cand,
 
 void PPCPostRASchedStrategy::tryCandidate(SchedCandidate &Cand,
                                           SchedCandidate &TryCand) {
-  PostGenericScheduler::tryCandidate(Cand, TryCand);
+  // From PostGenericScheduler::tryCandidate
+
+  // Initialize the candidate if needed.
+  if (!Cand.isValid()) {
+    TryCand.Reason = NodeOrder;
+    return;
+  }
+
+  // Prioritize instructions that read unbuffered resources by stall cycles.
+  if (tryLess(Top.getLatencyStallCycles(TryCand.SU),
+              Top.getLatencyStallCycles(Cand.SU), TryCand, Cand, Stall))
+    return;
 
-  if (!Cand.isValid())
+  // Keep clustered nodes together.
+  if (tryGreater(TryCand.SU == DAG->getNextClusterSucc(),
+                 Cand.SU == DAG->getNextClusterSucc(), TryCand, Cand, Cluster))
     return;
 
+  // Avoid critical resource consumption and balance the schedule.
+  if (tryLess(TryCand.ResDelta.CritResources, Cand.ResDelta.CritResources,
+              TryCand, Cand, ResourceReduce))
+    return;
+  if (tryGreater(TryCand.ResDelta.DemandedResources,
+                 Cand.ResDelta.DemandedResources, TryCand, Cand,
+                 ResourceDemand))
+    return;
+
+  // Avoid serializing long latency dependence chains.
+  if (Cand.Policy.ReduceLatency && tryLatency(TryCand, Cand, Top)) {
+    return;
+  }
+
+  // Fall through to original instruction order.
+  if (TryCand.SU->NodeNum < Cand.SU->NodeNum)
+    TryCand.Reason = NodeOrder;
+
+  // PostGenericScheduler::tryCandidate end
+
   // Add powerpc post ra specific heuristic only when TryCand isn't selected or
   // selected as node order.
   if (TryCand.Reason != NodeOrder && TryCand.Reason != NoCand)