mirror of
https://github.com/c64scene-ar/llvm-6502.git
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9eb59ec548
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22520 91177308-0d34-0410-b5e6-96231b3b80d8
252 lines
8.6 KiB
C++
252 lines
8.6 KiB
C++
//===-- RegClass.cpp -----------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// class RegClass for coloring-based register allocation for LLVM.
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//
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//===----------------------------------------------------------------------===//
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#include "IGNode.h"
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#include "RegAllocCommon.h"
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#include "RegClass.h"
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#include "../SparcV9RegInfo.h"
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#include <iostream>
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namespace llvm {
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//----------------------------------------------------------------------------
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// This constructor inits IG. The actual matrix is created by a call to
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// createInterferenceGraph() above.
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//----------------------------------------------------------------------------
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RegClass::RegClass(const Function *M,
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const SparcV9RegInfo *_MRI_,
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const TargetRegClassInfo *_MRC_)
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: Meth(M), MRI(_MRI_), MRC(_MRC_),
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RegClassID( _MRC_->getRegClassID() ),
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IG(this), IGNodeStack() {
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if (DEBUG_RA >= RA_DEBUG_Interference)
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std::cerr << "Created Reg Class: " << RegClassID << "\n";
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IsColorUsedArr.resize(MRC->getNumOfAllRegs());
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}
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//----------------------------------------------------------------------------
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// Main entry point for coloring a register class.
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//----------------------------------------------------------------------------
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void RegClass::colorAllRegs()
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{
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if (DEBUG_RA >= RA_DEBUG_Coloring)
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std::cerr << "Coloring IG of reg class " << RegClassID << " ...\n";
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// pre-color IGNodes
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pushAllIGNodes(); // push all IG Nodes
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unsigned int StackSize = IGNodeStack.size();
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IGNode *CurIGNode;
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// for all LRs on stack
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for (unsigned int IGN=0; IGN < StackSize; IGN++) {
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CurIGNode = IGNodeStack.top(); // pop the IGNode on top of stack
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IGNodeStack.pop();
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colorIGNode (CurIGNode); // color it
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}
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}
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//----------------------------------------------------------------------------
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// The method for pushing all IGNodes on to the stack.
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//----------------------------------------------------------------------------
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void RegClass::pushAllIGNodes()
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{
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bool NeedMoreSpills;
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IG.setCurDegreeOfIGNodes(); // calculate degree of IGNodes
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// push non-constrained IGNodes
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bool PushedAll = pushUnconstrainedIGNodes();
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if (DEBUG_RA >= RA_DEBUG_Coloring) {
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std::cerr << " Puhsed all-unconstrained IGNodes. ";
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if( PushedAll ) std::cerr << " No constrained nodes left.";
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std::cerr << "\n";
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}
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if (PushedAll) // if NO constrained nodes left
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return;
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// now, we have constrained nodes. So, push one of them (the one with min
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// spill cost) and try to push the others as unConstrained nodes.
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// Repeat this.
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do {
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//get node with min spill cost
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IGNode *IGNodeSpill = getIGNodeWithMinSpillCost();
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// push that node on to stack
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IGNodeStack.push(IGNodeSpill);
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// set its OnStack flag and decrement degree of neighs
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IGNodeSpill->pushOnStack();
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// now push NON-constrained ones, if any
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NeedMoreSpills = !pushUnconstrainedIGNodes();
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if (DEBUG_RA >= RA_DEBUG_Coloring)
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std::cerr << "\nConstrained IG Node found !@!" << IGNodeSpill->getIndex();
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} while(NeedMoreSpills); // repeat until we have pushed all
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}
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//--------------------------------------------------------------------------
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// This method goes thru all IG nodes in the IGNodeList of an IG of a
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// register class and push any unconstrained IG node left (that is not
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// already pushed)
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//--------------------------------------------------------------------------
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bool RegClass::pushUnconstrainedIGNodes()
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{
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// # of LRs for this reg class
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unsigned int IGNodeListSize = IG.getIGNodeList().size();
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bool pushedall = true;
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// a pass over IGNodeList
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for (unsigned i =0; i < IGNodeListSize; i++) {
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// get IGNode i from IGNodeList
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IGNode *IGNode = IG.getIGNodeList()[i];
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if (!IGNode ) // can be null due to merging
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continue;
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// if already pushed on stack, continue. This can happen since this
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// method can be called repeatedly until all constrained nodes are
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// pushed
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if (IGNode->isOnStack() )
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continue;
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// if the degree of IGNode is lower
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if ((unsigned) IGNode->getCurDegree() < MRC->getNumOfAvailRegs()) {
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IGNodeStack.push( IGNode ); // push IGNode on to the stack
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IGNode->pushOnStack(); // set OnStack and dec deg of neighs
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if (DEBUG_RA >= RA_DEBUG_Coloring) {
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std::cerr << " pushed un-constrained IGNode " << IGNode->getIndex()
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<< " on to stack\n";
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}
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}
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else pushedall = false; // we didn't push all live ranges
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} // for
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// returns true if we pushed all live ranges - else false
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return pushedall;
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}
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//----------------------------------------------------------------------------
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// Get the IGNode with the minimum spill cost
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//----------------------------------------------------------------------------
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IGNode * RegClass::getIGNodeWithMinSpillCost() {
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unsigned int IGNodeListSize = IG.getIGNodeList().size();
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double MinSpillCost = 0;
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IGNode *MinCostIGNode = NULL;
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bool isFirstNode = true;
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// pass over IGNodeList to find the IGNode with minimum spill cost
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// among all IGNodes that are not yet pushed on to the stack
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for (unsigned int i =0; i < IGNodeListSize; i++) {
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IGNode *IGNode = IG.getIGNodeList()[i];
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if (!IGNode) // can be null due to merging
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continue;
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if (!IGNode->isOnStack()) {
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double SpillCost = (double) IGNode->getParentLR()->getSpillCost() /
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(double) (IGNode->getCurDegree() + 1);
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if (isFirstNode) { // for the first IG node
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MinSpillCost = SpillCost;
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MinCostIGNode = IGNode;
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isFirstNode = false;
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} else if (MinSpillCost > SpillCost) {
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MinSpillCost = SpillCost;
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MinCostIGNode = IGNode;
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}
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}
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}
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assert (MinCostIGNode && "No IGNode to spill");
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return MinCostIGNode;
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}
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//----------------------------------------------------------------------------
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// Color the IGNode using the machine specific code.
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//----------------------------------------------------------------------------
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void RegClass::colorIGNode(IGNode *const Node) {
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if (! Node->hasColor()) { // not colored as an arg etc.
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// init all elements of to IsColorUsedAr false;
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clearColorsUsed();
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// initialize all colors used by neighbors of this node to true
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V9LiveRange *LR = Node->getParentLR();
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unsigned NumNeighbors = Node->getNumOfNeighbors();
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for (unsigned n=0; n < NumNeighbors; n++) {
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IGNode *NeighIGNode = Node->getAdjIGNode(n);
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V9LiveRange *NeighLR = NeighIGNode->getParentLR();
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// Don't use a color if it is in use by the neighbor,
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// or is suggested for use by the neighbor,
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// markColorsUsed() should be given the color and the reg type for
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// LR, not for NeighLR, because it should mark registers used based on
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// the type we are looking for, not on the regType for the neighbour.
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if (NeighLR->hasColor())
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this->markColorsUsed(NeighLR->getColor(),
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MRI->getRegTypeForLR(NeighLR),
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MRI->getRegTypeForLR(LR)); // use LR, not NeighLR
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else if (NeighLR->hasSuggestedColor() &&
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NeighLR->isSuggestedColorUsable())
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this->markColorsUsed(NeighLR->getSuggestedColor(),
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MRI->getRegTypeForLR(NeighLR),
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MRI->getRegTypeForLR(LR)); // use LR, not NeighLR
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}
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// call the target specific code for coloring
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//
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MRC->colorIGNode(Node, IsColorUsedArr);
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} else {
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if (DEBUG_RA >= RA_DEBUG_Coloring) {
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std::cerr << " Node " << Node->getIndex();
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std::cerr << " already colored with color " << Node->getColor() << "\n";
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}
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}
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if (!Node->hasColor() ) {
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if (DEBUG_RA >= RA_DEBUG_Coloring) {
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std::cerr << " Node " << Node->getIndex();
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std::cerr << " - could not find a color (needs spilling)\n";
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}
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}
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}
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void RegClass::printIGNodeList() const {
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std::cerr << "IG Nodes for Register Class " << RegClassID << ":" << "\n";
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IG.printIGNodeList();
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}
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void RegClass::printIG() {
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std::cerr << "IG for Register Class " << RegClassID << ":" << "\n";
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IG.printIG();
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}
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} // End llvm namespace
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