pre RA scheduling failure

Failed to schedule the send pairs.
For SIMD32 send which is splitted into two SIMD16 or 4 SIMD8, Pressure
scheduling will try to schedule these instruction in bundle. However,
the clustering scheduling breaks the rule right now and will schedule
other send instruction between them. This fix is to prevent this
situation happen.

Author: bcheng0127

visa/LocalScheduler/G4_Sched.cpp

@@ -825,7 +825,8 @@ class SethiUllmanQueue : public QueueBase {
 private:
   // Initialize Sethi-Ullman numbers.
   void init();
-
+  // Check if the Tuple restriction is obeyed.
+  bool willNotBreakTupleRestriction(preNode *N) const;
   // Select next ready node to schedule.
   preNode *select();
   // In clustering mode
@@ -957,17 +958,19 @@ bool SethiUllmanQueue::compare(preNode *N1, preNode *N2) {
   return N1->getID() > N2->getID();
 }
 
-
+bool SethiUllmanQueue::willNotBreakTupleRestriction(preNode *N) const {
+  return (!N->getInst() || !N->getInst()->isSend() || !TheCurrTupleLead ||
+          (N->getTupleLead() == TheCurrTupleLead));
+};
 
 preNode *SethiUllmanQueue::select() {
   vASSERT(!Q.empty());
   auto TopIter = Q.end();
   for (auto I = Q.begin(), E = Q.end(); I != E; ++I) {
     preNode *N = *I;
     // If there's a node to be paired, skip send not in pair.
-    if (N->getInst() && N->getInst()->isSend())
-      if (TheCurrTupleLead && N->getTupleLead() != TheCurrTupleLead)
-        continue;
+    if (!willNotBreakTupleRestriction(N))
+      continue;
     if (TopIter == Q.end() || compare(*TopIter, *I))
       TopIter = I;
   }
@@ -997,6 +1000,7 @@ void SethiUllmanQueue::formWorkingSet(preNode *seed,
     W.push_back(seed);
     return;
   }
+
   std::vector<preNode *> Cluster;
   Cluster.push_back(seed);
   preNode *ClusterWait = nullptr;
@@ -1047,9 +1051,29 @@ void SethiUllmanQueue::formWorkingSet(preNode *seed,
     while (idx < Q.size()) {
       preNode *Tmp = Q[idx];
       if (std::find(Cluster.begin(), Cluster.end(), Tmp) != Cluster.end()) {
-        W.push_back(Tmp);
-        Q[idx] = Q.back();
-        Q.pop_back();
+        // For send instruction which is not part of TheCurrTupleLead, the send
+        // instruction cannot be inserted into W. Which will be scheduled before
+        // the other parts of TheCurrTupleLead.
+        // Such as in following 4 send instructions, first two and last two send
+        // instructions must be schedule together, cannot interleave between
+        // them.
+        //
+        // sample_l.RGB (M1, 16)  0x0:uw S31 %bss V0626.0 %null.0 V0628.0
+        // CCTuple_1.0 CCTuple_1.64
+        // sample_l.RGB(M5, 16) 0x0 : uw S31 %bss V0627.0 %null.0 V0629.0
+        // CCTuple_2.0 CCTuple_2.64
+        //
+        // sample_l.RGB(M1, 16) 0x0 : uw S31 %bss V0640.0 %null.0 V0642.0
+        // CCTuple_3.0 CCTuple_3.64
+        // sample_l.RGB(M5, 16) 0x0 : uw S31 %bss V0641.0 %null.0 V0643.0
+        // CCTuple_4.0 CCTuple_4.64
+        if (willNotBreakTupleRestriction(Tmp)) {
+          W.push_back(Tmp);
+          Q[idx] = Q.back();
+          Q.pop_back();
+        } else {
+          idx++;
+        }
       } else
         idx++;
     }
@@ -1067,7 +1091,7 @@ void SethiUllmanQueue::formWorkingSet(preNode *seed,
           Top = Node; // continue search
           Searching = true;
           break;
-        } else {
+        } else if (willNotBreakTupleRestriction(Node)) {
           if (Node != seed) {
             Q.erase(std::remove(Q.begin(), Q.end(), Node), Q.end());
             Q.push_back(seed);