Weight variables by their number of uses for register allocation.

src/IceCfgNode.cpp

 //===- subzero/src/IceCfgNode.cpp - Basic block (node) implementation -----===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 682 matching lines @@
     // i1<i2, then i1's live range begins at instruction IBB->second
     // and extends through the end of the block.  If i1>i2, then i2's
     // live range begins at the first instruction of the block and
     // ends at IEB->second.  In any case, we choose the lesser of i1
     // and i2 and proceed accordingly.
     InstNumberT LB = i == i1 ? IBB->second : FirstInstNum;
     InstNumberT LE = i == i2 ? IEB->second : LastInstNum + 1;
 
     Variable *Var = Liveness->getVariable(i, this);
     if (LB > LE) {
-      Var->addLiveRange(FirstInstNum, LE, 1);
-      Var->addLiveRange(LB, LastInstNum + 1, 1);
+      Var->addLiveRange(FirstInstNum, LE);
+      Var->addLiveRange(LB, LastInstNum + 1);
       // Assert that Var is a global variable by checking that its
       // liveness index is less than the number of globals.  This
       // ensures that the LiveInAndOut[] access is valid.
       assert(i < Liveness->getNumGlobalVars());
       LiveInAndOut[i] = false;
     } else {
-      Var->addLiveRange(LB, LE, 1);
+      Var->addLiveRange(LB, LE);
     }
     if (i == i1)
       ++IBB;
     if (i == i2)
       ++IEB;
   }
   // Process the variables that are live across the entire block.
   for (int i = LiveInAndOut.find_first(); i != -1;
        i = LiveInAndOut.find_next(i)) {
     Variable *Var = Liveness->getVariable(i, this);
     if (Liveness->getRangeMask(Var->getIndex()))
-      Var->addLiveRange(FirstInstNum, LastInstNum + 1, 1);
+      Var->addLiveRange(FirstInstNum, LastInstNum + 1);
   }
 }
 
 // If this node contains only deleted instructions, and ends in an
 // unconditional branch, contract the node by repointing all its
 // in-edges to its successor.
 void CfgNode::contractIfEmpty() {
   if (InEdges.empty())
     return;
   Inst *Branch = nullptr;
@@ skipping 543 matching lines @@
   InstIntrinsicCall *Inst = InstIntrinsicCall::create(
       Func, 5, Func->makeVariable(IceType_i64), RMWI64Name, Info->Info);
   Inst->addArg(AtomicRMWOp);
   Inst->addArg(Counter);
   Inst->addArg(One);
   Inst->addArg(OrderAcquireRelease);
   Insts.push_front(Inst);
 }
 
 } // end of namespace Ice