Reworked branch adding in prologue. Added check for infinite loops which are not modulo scheduled.

llvm-svn: 18419

llvm/lib/Target/SparcV9/ModuloScheduling/MSSchedule.cpp

@@ -164,8 +164,6 @@ bool MSSchedule::resourcesFree(MSchedGraphNode *node, int cycle) {
 }
 
 bool MSSchedule::constructKernel(int II) {
-  MSchedGraphNode *branchNode = 0;
-  MSchedGraphNode *branchANode = 0;
  
   int stageNum = (schedule.rbegin()->first)/ II;
   DEBUG(std::cerr << "Number of Stages: " << stageNum << "\n");
@@ -178,11 +176,8 @@ bool MSSchedule::constructKernel(int II) {
 	      E = schedule[i].end(); I != E; ++I) {
 	  //Check if its a branch
 	  if((*I)->isBranch()) {
-	    if((*I)->getInst()->getOpcode() == V9::BA)
-	      branchANode = *I;
-	    else
-	      branchNode = *I;
 	    assert(count == 0 && "Branch can not be from a previous iteration");
+	    kernel.push_back(std::make_pair(*I, count));
 	  }
 	  else
 	  //FIXME: Check if the instructions in the earlier stage conflict
@@ -193,13 +188,6 @@ bool MSSchedule::constructKernel(int II) {
     }
   }
   
-  //Add Branch to the end
-  kernel.push_back(std::make_pair(branchNode, 0));
-
-  //Add Branch Always to the end
-  kernel.push_back(std::make_pair(branchANode, 0));
-
-
   if(stageNum > 0)
     maxStage = stageNum;
   else

llvm/lib/Target/SparcV9/ModuloScheduling/ModuloScheduling.cpp

@@ -213,20 +213,20 @@ bool ModuloSchedulingPass::runOnFunction(Function &F) {
     });
     
     //Finally schedule nodes
-    computeSchedule();
+    bool haveSched = computeSchedule();
     
     //Print out final schedule
     DEBUG(schedule.print(std::cerr));
     
     //Final scheduling step is to reconstruct the loop only if we actual have
     //stage > 0
-    if(schedule.getMaxStage() != 0) {
+    if(schedule.getMaxStage() != 0 && haveSched) {
       reconstructLoop(*BI);
       ++MSLoops;
       Changed = true;
     }
     else
-      DEBUG(std::cerr << "Max stage is 0, so no change in loop\n");
+      DEBUG(std::cerr << "Max stage is 0, so no change in loop or reached cap\n");
 
     //Clear out our maps for the next basic block that is processed
     nodeToAttributesMap.clear();
@@ -293,6 +293,11 @@ bool ModuloSchedulingPass::MachineBBisValid(const MachineBasicBlock *BI) {
   if(!isLoop)
     return false;
 
+  //Check that we have a conditional branch (avoiding MS infinite loops)
+  if(BranchInst *b = dyn_cast<BranchInst>(((BasicBlock*) BI->getBasicBlock())->getTerminator()))
+    if(b->isUnconditional())
+      return false;
+
   //Check size of our basic block.. make sure we have more then just the terminator in it
   if(BI->getBasicBlock()->size() == 1)
     return false;
@@ -1139,13 +1144,13 @@ void ModuloSchedulingPass::orderNodes() {
   //return FinalNodeOrder;
 }
 
-void ModuloSchedulingPass::computeSchedule() {
+bool ModuloSchedulingPass::computeSchedule() {
 
   bool success = false;
   
   //FIXME: Should be set to max II of the original loop
   //Cap II in order to prevent infinite loop
-  int capII = 30;
+  int capII = 100;
 
   while(!success) {
 
@@ -1252,8 +1257,12 @@ void ModuloSchedulingPass::computeSchedule() {
       }
     }
     
+    if(II >= capII)
+      return false;
+
     assert(II < capII && "The II should not exceed the original loop number of cycles");
   } 
+  return true;
 }
 
 
@@ -1312,21 +1321,22 @@ void ModuloSchedulingPass::writePrologues(std::vector<MachineBasicBlock *> &prol
   std::map<int, std::set<const MachineInstr*> > inKernel;
   int maxStageCount = 0;
 
+  //Keep a map of new values we consumed in case they need to be added back
+  std::map<Value*, std::map<int, Value*> > consumedValues;
+
   MSchedGraphNode *branch = 0;
   MSchedGraphNode *BAbranch = 0;
 
   schedule.print(std::cerr);
 
+  std::vector<MSchedGraphNode*> branches;
+
   for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {
     maxStageCount = std::max(maxStageCount, I->second);
     
     //Ignore the branch, we will handle this separately
     if(I->first->isBranch()) {
-      if (I->first->getInst()->getOpcode() != V9::BA)
-	branch = I->first;
-      else
-	BAbranch = I->first;
-
+      branches.push_back(I->first);
       continue;
     }
 
@@ -1357,7 +1367,7 @@ void ModuloSchedulingPass::writePrologues(std::vector<MachineBasicBlock *> &prol
 	  //After cloning, we may need to save the value that this instruction defines
 	  for(unsigned opNum=0; opNum < MI->getNumOperands(); ++opNum) {
 	    //get machine operand
-	    const MachineOperand &mOp = instClone->getOperand(opNum);
+	    MachineOperand &mOp = instClone->getOperand(opNum);
 	    if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef()) {
 
 	      //Check if this is a value we should save
@@ -1386,13 +1396,24 @@ void ModuloSchedulingPass::writePrologues(std::vector<MachineBasicBlock *> &prol
 	    //We may also need to update the value that we use if its from an earlier prologue
 	    if(j != 0) {
 	      if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isUse()) {
-		if(newValues.count(mOp.getVRegValue()))
-		  if(newValues[mOp.getVRegValue()].count(j-1)) {
+		if(newValues.count(mOp.getVRegValue())) {
+		  if(newValues[mOp.getVRegValue()].count(i-1)) {
+		    Value *oldV =  mOp.getVRegValue();
 		    DEBUG(std::cerr << "Replaced this value: " << mOp.getVRegValue() << " With:" << (newValues[mOp.getVRegValue()][i-1]) << "\n");
 		    //Update the operand with the right value
-		    instClone->getOperand(opNum).setValueReg(newValues[mOp.getVRegValue()][i-1]);
+		    mOp.setValueReg(newValues[mOp.getVRegValue()][i-1]);
+
+		    //Remove this value since we have consumed it
+		    //NOTE: Should this only be done if j != maxStage?
+		    consumedValues[oldV][i-1] = (newValues[oldV][i-1]);
+		    DEBUG(std::cerr << "Deleted value: " << consumedValues[oldV][i-1] << "\n");
+		    newValues[oldV].erase(i-1);
 		  }
 		}
+		else
+		  if(consumedValues.count(mOp.getVRegValue()))
+		    assert(!consumedValues[mOp.getVRegValue()].count(i-1) && "Found a case where we need the value");
+	      }
 	    }
 	  }
 	}
@@ -1400,17 +1421,15 @@ void ModuloSchedulingPass::writePrologues(std::vector<MachineBasicBlock *> &prol
     }
 
 
+    for(std::vector<MSchedGraphNode*>::iterator BR = branches.begin(), BE = branches.end(); BR != BE; ++BR) {
+      
       //Stick in branch at the end
-    machineBB->push_back(branch->getInst()->clone());
+      machineBB->push_back((*BR)->getInst()->clone());
 
       //Add nop
       BuildMI(machineBB, V9::NOP, 0);
+    }
 
-    //Stick in branch at the end
-    machineBB->push_back(BAbranch->getInst()->clone());
-
-    //Add nop
-    BuildMI(machineBB, V9::NOP, 0);
 
   (((MachineBasicBlock*)origBB)->getParent())->getBasicBlockList().push_back(machineBB);  
     prologues.push_back(machineBB);

llvm/lib/Target/SparcV9/ModuloScheduling/ModuloScheduling.h

@@ -88,7 +88,7 @@ namespace llvm {
     void addReccurrence(std::vector<MSchedGraphNode*> &recurrence, int II, MSchedGraphNode*, MSchedGraphNode*);
 
     void computePartialOrder();
-    void computeSchedule();
+    bool computeSchedule();
     bool scheduleNode(MSchedGraphNode *node, 
 		      int start, int end);