[TableGen] Add a non-default constructor to CodeGenSchedClass and use it via emplace_back to create new SchedClasses instead of using resize(size+1)

llvm-svn: 328183
diff --git a/llvm/utils/TableGen/CodeGenSchedule.cpp b/llvm/utils/TableGen/CodeGenSchedule.cpp
index a21e44b..1f812fd 100644
--- a/llvm/utils/TableGen/CodeGenSchedule.cpp
+++ b/llvm/utils/TableGen/CodeGenSchedule.cpp
@@ -557,10 +557,9 @@
 void CodeGenSchedModels::collectSchedClasses() {
 
   // NoItinerary is always the first class at Idx=0
-  SchedClasses.resize(1);
-  SchedClasses.back().Index = 0;
-  SchedClasses.back().Name = "NoInstrModel";
-  SchedClasses.back().ItinClassDef = Records.getDef("NoItinerary");
+  assert(SchedClasses.empty() && "Expected empty sched class");
+  SchedClasses.emplace_back(0, "NoInstrModel",
+                            Records.getDef("NoItinerary"));
   SchedClasses.back().ProcIndices.push_back(0);
 
   // Create a SchedClass for each unique combination of itinerary class and
@@ -572,9 +571,7 @@
       findRWs(Inst->TheDef->getValueAsListOfDefs("SchedRW"), Writes, Reads);
 
     // ProcIdx == 0 indicates the class applies to all processors.
-    IdxVec ProcIndices(1, 0);
-
-    unsigned SCIdx = addSchedClass(ItinDef, Writes, Reads, ProcIndices);
+    unsigned SCIdx = addSchedClass(ItinDef, Writes, Reads, /*ProcIndices*/{0});
     InstrClassMap[Inst->TheDef] = SCIdx;
   }
   // Create classes for InstRW defs.
@@ -716,11 +713,11 @@
     return Idx;
   }
   Idx = SchedClasses.size();
-  SchedClasses.resize(Idx+1);
+  SchedClasses.emplace_back(Idx,
+                            createSchedClassName(ItinClassDef, OperWrites,
+                                                 OperReads),
+                            ItinClassDef);
   CodeGenSchedClass &SC = SchedClasses.back();
-  SC.Index = Idx;
-  SC.Name = createSchedClassName(ItinClassDef, OperWrites, OperReads);
-  SC.ItinClassDef = ItinClassDef;
   SC.Writes = OperWrites;
   SC.Reads = OperReads;
   SC.ProcIndices = ProcIndices;
@@ -788,10 +785,8 @@
       }
     }
     unsigned SCIdx = SchedClasses.size();
-    SchedClasses.resize(SCIdx+1);
+    SchedClasses.emplace_back(SCIdx, createSchedClassName(InstDefs), nullptr);
     CodeGenSchedClass &SC = SchedClasses.back();
-    SC.Index = SCIdx;
-    SC.Name = createSchedClassName(InstDefs);
     DEBUG(dbgs() << "InstRW: New SC " << SCIdx << ":" << SC.Name << " on "
           << InstRWDef->getValueAsDef("SchedModel")->getName() << "\n");