AMDGPU/SI: Remove double lookups in SI scheduler

[axeldavy]

Summary

Replace duplicated lookups for better efficiency.

[arsenm]

LGTM

llvm/trunk/lib/Target/AMDGPU/SIMachineScheduler.cpp

 
 void SIScheduleBlockCreator::colorMergeIfPossibleSmallGroupsToNextGroup() {
   unsigned DAGSize = DAG->SUnits.size();
   std::map<unsigned, unsigned> ColorCount;
 
   for (unsigned SUNum : DAG->BottomUpIndex2SU) {
     SUnit *SU = &DAG->SUnits[SUNum];
     unsigned color = CurrentColoring[SU->NodeNum];
-    std::map<unsigned, unsigned>::iterator Pos = ColorCount.find(color);
-      if (Pos != ColorCount.end()) {
-        ++ColorCount[color];
-      } else {
-        ColorCount[color] = 1;
-      }
   }
 
   for (unsigned SUNum : DAG->BottomUpIndex2SU) {
     SUnit *SU = &DAG->SUnits[SUNum];
     unsigned color = CurrentColoring[SU->NodeNum];
     std::set<unsigned> SUColors;
 
     if (CurrentColoring[SU->NodeNum] <= (int)DAGSize)
for (unsigned Reg : Block->getInRegs()) {
           }
         }
       }
 
       if (!Found)
         continue;
 
       int PredID = BlocksStruct.TopDownIndex2Block[topoInd];
-      std::map<unsigned, unsigned>::iterator RegPos =
-        LiveOutRegsNumUsages[PredID].find(Reg);
-      if (RegPos != LiveOutRegsNumUsages[PredID].end()) {
-        ++LiveOutRegsNumUsages[PredID][Reg];
-      } else {
-        LiveOutRegsNumUsages[PredID][Reg] = 1;
-      }
     }
   }
 
   LastPosHighLatencyParentScheduled.resize(Blocks.size(), 0);
   BlockNumPredsLeft.resize(Blocks.size());
   BlockNumSuccsLeft.resize(Blocks.size());
 
   for (unsigned i = 0, e = Blocks.size(); i != e; ++i) {
for (unsigned Reg : Block->getInRegs()) {
         std::set<unsigned>::iterator RegPos = PredOutRegs.find(Reg);
 
         if (RegPos != PredOutRegs.end()) {
           Found = true;
           break;
         }
       }
 
-      if (!Found) {
-        if (LiveRegsConsumers.find(Reg) == LiveRegsConsumers.end())
-          LiveRegsConsumers[Reg] = 1;
-        else
-          ++LiveRegsConsumers[Reg];
-      }
-    }
-  }
+      if (!Found)
 
   for (unsigned i = 0, e = Blocks.size(); i != e; ++i) {
     SIScheduleBlock *Block = Blocks[i];
     if (BlockNumPredsLeft[i] == 0) {
       ReadyBlocks.push_back(Block);
     }
   }
 

 void SIScheduleBlockScheduler::blockScheduled(SIScheduleBlock *Block) {
   decreaseLiveRegs(Block, Block->getInRegs());
   addLiveRegs(Block->getOutRegs());
   releaseBlockSuccs(Block);
   for (std::map<unsigned, unsigned>::iterator RegI =
        LiveOutRegsNumUsages[Block->getID()].begin(),
        E = LiveOutRegsNumUsages[Block->getID()].end(); RegI != E; ++RegI) {
     std::pair<unsigned, unsigned> RegP = *RegI;
-    if (LiveRegsConsumers.find(RegP.first) == LiveRegsConsumers.end())
-      LiveRegsConsumers[RegP.first] = RegP.second;
-    else {
-      assert(LiveRegsConsumers[RegP.first] == 0);
-      LiveRegsConsumers[RegP.first] += RegP.second;
-    }
-  }
+    // We produce this register, thus it must not be previously alive.
+    assert(LiveRegsConsumers.find(RegP.first) == LiveRegsConsumers.end() ||
+           LiveRegsConsumers[RegP.first] == 0);
   if (LastPosHighLatencyParentScheduled[Block->getID()] >
         (unsigned)LastPosWaitedHighLatency)
     LastPosWaitedHighLatency =
       LastPosHighLatencyParentScheduled[Block->getID()];
   ++NumBlockScheduled;
 }
 
 std::vector<int>