1 files changed, 40 insertions, 5 deletions

diff --git a/lib/Target/SystemZ/SystemZHazardRecognizer.cpp b/lib/Target/SystemZ/SystemZHazardRecognizer.cpp
index d300d1d88abc7..b9e5788cf0187 100644
--- a/lib/Target/SystemZ/SystemZHazardRecognizer.cpp
+++ b/lib/Target/SystemZ/SystemZHazardRecognizer.cpp
@@ -55,7 +55,7 @@ getNumDecoderSlots(SUnit *SU) const {
     else
       return 3; // Expanded/group-alone instruction
   }
-    
+
   return 1; // Normal instruction
 }
 
@@ -81,6 +81,7 @@ getHazardType(SUnit *m, int Stalls) {
 
 void SystemZHazardRecognizer::Reset() {
   CurrGroupSize = 0;
+  CurrGroupHas4RegOps = false;
   clearProcResCounters();
   GrpCount = 0;
   LastFPdOpCycleIdx = UINT_MAX;
@@ -99,6 +100,12 @@ SystemZHazardRecognizer::fitsIntoCurrentGroup(SUnit *SU) const {
   if (SC->BeginGroup)
     return (CurrGroupSize == 0);
 
+  // An instruction with 4 register operands will not fit in last slot.
+  assert ((CurrGroupSize < 2 || !CurrGroupHas4RegOps) &&
+          "Current decoder group is already full!");
+  if (CurrGroupSize == 2 && has4RegOps(SU->getInstr()))
+    return false;
+
   // Since a full group is handled immediately in EmitInstruction(),
   // SU should fit into current group. NumSlots should be 1 or 0,
   // since it is not a cracked or expanded instruction.
@@ -108,6 +115,23 @@ SystemZHazardRecognizer::fitsIntoCurrentGroup(SUnit *SU) const {
   return true;
 }
 
+bool SystemZHazardRecognizer::has4RegOps(const MachineInstr *MI) const {
+  const MachineFunction &MF = *MI->getParent()->getParent();
+  const TargetRegisterInfo *TRI = &TII->getRegisterInfo();
+  const MCInstrDesc &MID = MI->getDesc();
+  unsigned Count = 0;
+  for (unsigned OpIdx = 0; OpIdx < MID.getNumOperands(); OpIdx++) {
+    const TargetRegisterClass *RC = TII->getRegClass(MID, OpIdx, TRI, MF);
+    if (RC == nullptr)
+      continue;
+    if (OpIdx >= MID.getNumDefs() &&
+        MID.getOperandConstraint(OpIdx, MCOI::TIED_TO) != -1)
+      continue;
+    Count++;
+  }
+  return Count >= 4;
+}
+
 void SystemZHazardRecognizer::nextGroup() {
   if (CurrGroupSize == 0)
     return;
@@ -119,6 +143,7 @@ void SystemZHazardRecognizer::nextGroup() {
 
   // Reset counter for next group.
   CurrGroupSize = 0;
+  CurrGroupHas4RegOps = false;
 
   // Decrease counters for execution units by one.
   for (unsigned i = 0; i < SchedModel->getNumProcResourceKinds(); ++i)
@@ -142,7 +167,7 @@ void SystemZHazardRecognizer::dumpSU(SUnit *SU, raw_ostream &OS) const {
   const MCSchedClassDesc *SC = getSchedClass(SU);
   if (!SC->isValid())
     return;
-  
+
   for (TargetSchedModel::ProcResIter
          PI = SchedModel->getWriteProcResBegin(SC),
          PE = SchedModel->getWriteProcResEnd(SC); PI != PE; ++PI) {
@@ -172,6 +197,8 @@ void SystemZHazardRecognizer::dumpSU(SUnit *SU, raw_ostream &OS) const {
     OS << "/EndsGroup";
   if (SU->isUnbuffered)
     OS << "/Unbuffered";
+  if (has4RegOps(SU->getInstr()))
+    OS << "/4RegOps";
 }
 
 void SystemZHazardRecognizer::dumpCurrGroup(std::string Msg) const {
@@ -184,6 +211,7 @@ void SystemZHazardRecognizer::dumpCurrGroup(std::string Msg) const {
     dbgs() << "{ " << CurGroupDbg << " }";
     dbgs() << " (" << CurrGroupSize << " decoder slot"
            << (CurrGroupSize > 1 ? "s":"")
+           << (CurrGroupHas4RegOps ? ", 4RegOps" : "")
            << ")\n";
   }
 }
@@ -294,11 +322,14 @@ EmitInstruction(SUnit *SU) {
   // Insert SU into current group by increasing number of slots used
   // in current group.
   CurrGroupSize += getNumDecoderSlots(SU);
-  assert (CurrGroupSize <= 3);
+  CurrGroupHas4RegOps |= has4RegOps(SU->getInstr());
+  unsigned GroupLim =
+    ((CurrGroupHas4RegOps && getNumDecoderSlots(SU) < 3) ? 2 : 3);
+  assert (CurrGroupSize <= GroupLim && "SU does not fit into decoder group!");
 
   // Check if current group is now full/ended. If so, move on to next
   // group to be ready to evaluate more candidates.
-  if (CurrGroupSize == 3 || SC->EndGroup)
+  if (CurrGroupSize == GroupLim || SC->EndGroup)
     nextGroup();
 }
 
@@ -306,7 +337,7 @@ int SystemZHazardRecognizer::groupingCost(SUnit *SU) const {
   const MCSchedClassDesc *SC = getSchedClass(SU);
   if (!SC->isValid())
     return 0;
-  
+
   // If SU begins new group, it can either break a current group early
   // or fit naturally if current group is empty (negative cost).
   if (SC->BeginGroup) {
@@ -325,6 +356,10 @@ int SystemZHazardRecognizer::groupingCost(SUnit *SU) const {
     return -1;
   }
 
+  // An instruction with 4 register operands will not fit in last slot.
+  if (CurrGroupSize == 2 && has4RegOps(SU->getInstr()))
+    return 1;
+
   // Most instructions can be placed in any decoder slot.
   return 0;
 }