VirtRegMap.cpp revision ed41f1bb1981a98eea63f00c5988cf62bbdd7c59
134d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos//===-- llvm/CodeGen/VirtRegMap.cpp - Virtual Register Map ----------------===// 234d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// 334d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// The LLVM Compiler Infrastructure 434d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// 534d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// This file was developed by the LLVM research group and is distributed under 634d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// the University of Illinois Open Source License. See LICENSE.TXT for details. 734d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// 834d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos//===----------------------------------------------------------------------===// 934d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// 108c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// This file implements the VirtRegMap class. 118c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// 128c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// It also contains implementations of the the Spiller interface, which, given a 138c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// virtual register map and a machine function, eliminates all virtual 148c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// references by replacing them with physical register references - adding spill 150d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos// code as necessary. 1634d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos// 1734d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos//===----------------------------------------------------------------------===// 1834d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos 198c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner#define DEBUG_TYPE "spiller" 2034d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos#include "VirtRegMap.h" 210d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos#include "llvm/Function.h" 2234d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos#include "llvm/CodeGen/MachineFrameInfo.h" 238c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner#include "llvm/CodeGen/MachineFunction.h" 248c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner#include "llvm/CodeGen/SSARegMap.h" 2534d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos#include "llvm/Target/TargetMachine.h" 260d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos#include "llvm/Target/TargetInstrInfo.h" 27551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/CommandLine.h" 28551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 29f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattner#include "llvm/Support/Visibility.h" 30551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/Statistic.h" 31551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/STLExtras.h" 3227f291600b04c382c390b16fdacd52b910b9164dChris Lattner#include <algorithm> 332c2c6c61f100bc7c3df873b11203fcea1b5e18feChris Lattner#include <iostream> 3434d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenosusing namespace llvm; 3534d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos 3634d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenosnamespace { 37ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static Statistic<> NumSpills("spiller", "Number of register spills"); 38ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static Statistic<> NumStores("spiller", "Number of stores added"); 39ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static Statistic<> NumLoads ("spiller", "Number of loads added"); 40ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static Statistic<> NumReused("spiller", "Number of values reused"); 41ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static Statistic<> NumDSE ("spiller", "Number of dead stores elided"); 42ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static Statistic<> NumDCE ("spiller", "Number of copies elided"); 438c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 448c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner enum SpillerName { simple, local }; 458c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 46ed41f1bb1981a98eea63f00c5988cf62bbdd7c59Andrew Lenharth static cl::opt<SpillerName> 478c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner SpillerOpt("spiller", 487fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner cl::desc("Spiller to use: (default: local)"), 498c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner cl::Prefix, 508c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner cl::values(clEnumVal(simple, " simple spiller"), 518c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner clEnumVal(local, " local spiller"), 528c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner clEnumValEnd), 537fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner cl::init(local)); 548c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 558c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 568c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner//===----------------------------------------------------------------------===// 578c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// VirtRegMap implementation 588c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner//===----------------------------------------------------------------------===// 598c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 608c4d88d3697835371ecf6823f4142af13603ad2dChris Lattnervoid VirtRegMap::grow() { 617f690e625807b9320bf4ae437b8f35258acc99deChris Lattner Virt2PhysMap.grow(MF.getSSARegMap()->getLastVirtReg()); 627f690e625807b9320bf4ae437b8f35258acc99deChris Lattner Virt2StackSlotMap.grow(MF.getSSARegMap()->getLastVirtReg()); 6334d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos} 6434d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos 658c4d88d3697835371ecf6823f4142af13603ad2dChris Lattnerint VirtRegMap::assignVirt2StackSlot(unsigned virtReg) { 668c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner assert(MRegisterInfo::isVirtualRegister(virtReg)); 677f690e625807b9320bf4ae437b8f35258acc99deChris Lattner assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT && 688c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner "attempt to assign stack slot to already spilled register"); 697f690e625807b9320bf4ae437b8f35258acc99deChris Lattner const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(virtReg); 707f690e625807b9320bf4ae437b8f35258acc99deChris Lattner int frameIndex = MF.getFrameInfo()->CreateStackObject(RC->getSize(), 717f690e625807b9320bf4ae437b8f35258acc99deChris Lattner RC->getAlignment()); 727f690e625807b9320bf4ae437b8f35258acc99deChris Lattner Virt2StackSlotMap[virtReg] = frameIndex; 738c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner ++NumSpills; 748c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner return frameIndex; 7534d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos} 7634d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos 778c4d88d3697835371ecf6823f4142af13603ad2dChris Lattnervoid VirtRegMap::assignVirt2StackSlot(unsigned virtReg, int frameIndex) { 788c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner assert(MRegisterInfo::isVirtualRegister(virtReg)); 797f690e625807b9320bf4ae437b8f35258acc99deChris Lattner assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT && 808c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner "attempt to assign stack slot to already spilled register"); 817f690e625807b9320bf4ae437b8f35258acc99deChris Lattner Virt2StackSlotMap[virtReg] = frameIndex; 8238af59a43c4176d8f34bd26faeb18b23080a1d9bAlkis Evlogimenos} 8338af59a43c4176d8f34bd26faeb18b23080a1d9bAlkis Evlogimenos 84bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattnervoid VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *OldMI, 8535f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner unsigned OpNo, MachineInstr *NewMI) { 86bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner // Move previous memory references folded to new instruction. 87bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner MI2VirtMapTy::iterator IP = MI2VirtMap.lower_bound(NewMI); 88edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman for (MI2VirtMapTy::iterator I = MI2VirtMap.lower_bound(OldMI), 89bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner E = MI2VirtMap.end(); I != E && I->first == OldMI; ) { 90bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner MI2VirtMap.insert(IP, std::make_pair(NewMI, I->second)); 91dbea9731b12e62f70d9da40cf273cdd9105f987cChris Lattner MI2VirtMap.erase(I++); 928c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 93dbea9731b12e62f70d9da40cf273cdd9105f987cChris Lattner 94bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner ModRef MRInfo; 95bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner if (!OldMI->getOperand(OpNo).isDef()) { 96bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner assert(OldMI->getOperand(OpNo).isUse() && "Operand is not use or def?"); 97bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner MRInfo = isRef; 98bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner } else { 99bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner MRInfo = OldMI->getOperand(OpNo).isUse() ? isModRef : isMod; 100bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner } 1018c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 1028c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner // add new memory reference 103bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner MI2VirtMap.insert(IP, std::make_pair(NewMI, std::make_pair(VirtReg, MRInfo))); 1048c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 1055f37502bfbadfa65de087627bd67fd58bb03725cAlkis Evlogimenos 1067f690e625807b9320bf4ae437b8f35258acc99deChris Lattnervoid VirtRegMap::print(std::ostream &OS) const { 1077f690e625807b9320bf4ae437b8f35258acc99deChris Lattner const MRegisterInfo* MRI = MF.getTarget().getRegisterInfo(); 1088c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 1097f690e625807b9320bf4ae437b8f35258acc99deChris Lattner OS << "********** REGISTER MAP **********\n"; 1108c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner for (unsigned i = MRegisterInfo::FirstVirtualRegister, 1117f690e625807b9320bf4ae437b8f35258acc99deChris Lattner e = MF.getSSARegMap()->getLastVirtReg(); i <= e; ++i) { 1127f690e625807b9320bf4ae437b8f35258acc99deChris Lattner if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG) 1137f690e625807b9320bf4ae437b8f35258acc99deChris Lattner OS << "[reg" << i << " -> " << MRI->getName(Virt2PhysMap[i]) << "]\n"; 114edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 1158c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 1168c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 1178c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner for (unsigned i = MRegisterInfo::FirstVirtualRegister, 1187f690e625807b9320bf4ae437b8f35258acc99deChris Lattner e = MF.getSSARegMap()->getLastVirtReg(); i <= e; ++i) 1197f690e625807b9320bf4ae437b8f35258acc99deChris Lattner if (Virt2StackSlotMap[i] != VirtRegMap::NO_STACK_SLOT) 1207f690e625807b9320bf4ae437b8f35258acc99deChris Lattner OS << "[reg" << i << " -> fi#" << Virt2StackSlotMap[i] << "]\n"; 1217f690e625807b9320bf4ae437b8f35258acc99deChris Lattner OS << '\n'; 1225f37502bfbadfa65de087627bd67fd58bb03725cAlkis Evlogimenos} 1235f37502bfbadfa65de087627bd67fd58bb03725cAlkis Evlogimenos 1248c4d88d3697835371ecf6823f4142af13603ad2dChris Lattnervoid VirtRegMap::dump() const { print(std::cerr); } 12534d9bc9f168d17c52eb57e024580bd9499695f91Alkis Evlogimenos 1260d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 1278c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner//===----------------------------------------------------------------------===// 1288c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// Simple Spiller Implementation 1298c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner//===----------------------------------------------------------------------===// 130dd420e060accd1d773c731e77335cff65ca34013Alkis Evlogimenos 1318c4d88d3697835371ecf6823f4142af13603ad2dChris LattnerSpiller::~Spiller() {} 132dd420e060accd1d773c731e77335cff65ca34013Alkis Evlogimenos 1330d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenosnamespace { 134f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattner struct VISIBILITY_HIDDEN SimpleSpiller : public Spiller { 13535f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner bool runOnMachineFunction(MachineFunction& mf, VirtRegMap &VRM); 1368c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner }; 1378c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 1380d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 13935f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattnerbool SimpleSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) { 1408c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner DEBUG(std::cerr << "********** REWRITE MACHINE CODE **********\n"); 1418c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner DEBUG(std::cerr << "********** Function: " 1428c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner << MF.getFunction()->getName() << '\n'); 143b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner const TargetMachine &TM = MF.getTarget(); 144b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner const MRegisterInfo &MRI = *TM.getRegisterInfo(); 145b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner bool *PhysRegsUsed = MF.getUsedPhysregs(); 1468c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 1474ea1b828ebc5d2e8711acf13c2a3fdd7c14fe339Chris Lattner // LoadedRegs - Keep track of which vregs are loaded, so that we only load 1484ea1b828ebc5d2e8711acf13c2a3fdd7c14fe339Chris Lattner // each vreg once (in the case where a spilled vreg is used by multiple 1494ea1b828ebc5d2e8711acf13c2a3fdd7c14fe339Chris Lattner // operands). This is always smaller than the number of operands to the 1504ea1b828ebc5d2e8711acf13c2a3fdd7c14fe339Chris Lattner // current machine instr, so it should be small. 1514ea1b828ebc5d2e8711acf13c2a3fdd7c14fe339Chris Lattner std::vector<unsigned> LoadedRegs; 1528c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 1530fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner for (MachineFunction::iterator MBBI = MF.begin(), E = MF.end(); 1540fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner MBBI != E; ++MBBI) { 1550fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner DEBUG(std::cerr << MBBI->getBasicBlock()->getName() << ":\n"); 1560fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner MachineBasicBlock &MBB = *MBBI; 1570fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner for (MachineBasicBlock::iterator MII = MBB.begin(), 1580fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner E = MBB.end(); MII != E; ++MII) { 1590fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner MachineInstr &MI = *MII; 1600fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { 1617fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MachineOperand &MO = MI.getOperand(i); 162886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner if (MO.isRegister() && MO.getReg()) 163886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner if (MRegisterInfo::isVirtualRegister(MO.getReg())) { 164886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner unsigned VirtReg = MO.getReg(); 165886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner unsigned PhysReg = VRM.getPhys(VirtReg); 166886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner if (VRM.hasStackSlot(VirtReg)) { 167886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner int StackSlot = VRM.getStackSlot(VirtReg); 168bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner const TargetRegisterClass* RC = 169bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner MF.getSSARegMap()->getRegClass(VirtReg); 170edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 171886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner if (MO.isUse() && 172886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner std::find(LoadedRegs.begin(), LoadedRegs.end(), VirtReg) 173886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner == LoadedRegs.end()) { 174bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner MRI.loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC); 175886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner LoadedRegs.push_back(VirtReg); 176886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner ++NumLoads; 177886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner DEBUG(std::cerr << '\t' << *prior(MII)); 178886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner } 179edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 180886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner if (MO.isDef()) { 181bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner MRI.storeRegToStackSlot(MBB, next(MII), PhysReg, StackSlot, RC); 182886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner ++NumStores; 183886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner } 1840fc27ccdd374799c8d65b61e89db53ba1ea47358Chris Lattner } 185886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner PhysRegsUsed[PhysReg] = true; 186e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(PhysReg); 187886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner } else { 188886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner PhysRegsUsed[MO.getReg()] = true; 1898c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 1908c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 191886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner 192477e4555de341c5de780de3720d6f115ec133c4eChris Lattner DEBUG(std::cerr << '\t' << MI); 1934ea1b828ebc5d2e8711acf13c2a3fdd7c14fe339Chris Lattner LoadedRegs.clear(); 1948c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 1958c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 1968c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner return true; 1978c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 1980d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 1998c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner//===----------------------------------------------------------------------===// 2008c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner// Local Spiller Implementation 2018c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner//===----------------------------------------------------------------------===// 2020d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 2038c4d88d3697835371ecf6823f4142af13603ad2dChris Lattnernamespace { 2047fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner /// LocalSpiller - This spiller does a simple pass over the machine basic 2057fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner /// block to attempt to keep spills in registers as much as possible for 2067fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner /// blocks that have low register pressure (the vreg may be spilled due to 2077fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner /// register pressure in other blocks). 208f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattner class VISIBILITY_HIDDEN LocalSpiller : public Spiller { 2098c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner const MRegisterInfo *MRI; 2107fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner const TargetInstrInfo *TII; 2118c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner public: 21235f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) { 2137fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MRI = MF.getTarget().getRegisterInfo(); 2147fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner TII = MF.getTarget().getInstrInfo(); 2157fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner DEBUG(std::cerr << "\n**** Local spiller rewriting function '" 2167fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner << MF.getFunction()->getName() << "':\n"); 2177fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 2187fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner for (MachineFunction::iterator MBB = MF.begin(), E = MF.end(); 2197fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MBB != E; ++MBB) 2207fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner RewriteMBB(*MBB, VRM); 2217fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner return true; 2228c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 2237fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner private: 22435f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner void RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM); 2257fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner void ClobberPhysReg(unsigned PR, std::map<int, unsigned> &SpillSlots, 22607cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner std::multimap<unsigned, int> &PhysRegs); 2277fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner void ClobberPhysRegOnly(unsigned PR, std::map<int, unsigned> &SpillSlots, 22807cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner std::multimap<unsigned, int> &PhysRegs); 22907cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner void ModifyStackSlot(int Slot, std::map<int, unsigned> &SpillSlots, 23007cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner std::multimap<unsigned, int> &PhysRegs); 2318c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner }; 2328c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 2338c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 23466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// AvailableSpills - As the local spiller is scanning and rewriting an MBB from 23566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// top down, keep track of which spills slots are available in each register. 236593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// 237593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// Note that not all physregs are created equal here. In particular, some 238593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// physregs are reloads that we are allowed to clobber or ignore at any time. 239593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// Other physregs are values that the register allocated program is using that 240593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// we cannot CHANGE, but we can read if we like. We keep track of this on a 241593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// per-stack-slot basis as the low bit in the value of the SpillSlotsAvailable 242593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// entries. The predicate 'canClobberPhysReg()' checks this bit and 243593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner/// addAvailable sets it if. 244f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattnernamespace { 245f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattnerclass VISIBILITY_HIDDEN AvailableSpills { 24666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner const MRegisterInfo *MRI; 24766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner const TargetInstrInfo *TII; 24866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 24966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // SpillSlotsAvailable - This map keeps track of all of the spilled virtual 25066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // register values that are still available, due to being loaded or stored to, 25166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // but not invalidated yet. 25266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner std::map<int, unsigned> SpillSlotsAvailable; 25366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 25466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // PhysRegsAvailable - This is the inverse of SpillSlotsAvailable, indicating 25566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // which stack slot values are currently held by a physreg. This is used to 25666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // invalidate entries in SpillSlotsAvailable when a physreg is modified. 25766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner std::multimap<unsigned, int> PhysRegsAvailable; 25866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 25966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner void ClobberPhysRegOnly(unsigned PhysReg); 26066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattnerpublic: 26166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner AvailableSpills(const MRegisterInfo *mri, const TargetInstrInfo *tii) 26266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner : MRI(mri), TII(tii) { 26366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner } 26466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 26566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// getSpillSlotPhysReg - If the specified stack slot is available in a 26666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// physical register, return that PhysReg, otherwise return 0. 26766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner unsigned getSpillSlotPhysReg(int Slot) const { 26866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner std::map<int, unsigned>::const_iterator I = SpillSlotsAvailable.find(Slot); 26966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner if (I != SpillSlotsAvailable.end()) 270593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner return I->second >> 1; // Remove the CanClobber bit. 27166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner return 0; 27266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner } 273540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 274540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner const MRegisterInfo *getRegInfo() const { return MRI; } 27566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 27666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// addAvailable - Mark that the specified stack slot is available in the 277593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner /// specified physreg. If CanClobber is true, the physreg can be modified at 278593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner /// any time without changing the semantics of the program. 279593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner void addAvailable(int Slot, unsigned Reg, bool CanClobber = true) { 2808666249ad6eca27d267f251495545bca132a9a5cChris Lattner // If this stack slot is thought to be available in some other physreg, 2818666249ad6eca27d267f251495545bca132a9a5cChris Lattner // remove its record. 2828666249ad6eca27d267f251495545bca132a9a5cChris Lattner ModifyStackSlot(Slot); 2838666249ad6eca27d267f251495545bca132a9a5cChris Lattner 28466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner PhysRegsAvailable.insert(std::make_pair(Reg, Slot)); 285003cecbc9d210fa23f0ba68ac288748d20780cc7Jeff Cohen SpillSlotsAvailable[Slot] = (Reg << 1) | (unsigned)CanClobber; 28666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 28766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner DEBUG(std::cerr << "Remembering SS#" << Slot << " in physreg " 28866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner << MRI->getName(Reg) << "\n"); 28966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner } 29066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 291593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner /// canClobberPhysReg - Return true if the spiller is allowed to change the 292593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner /// value of the specified stackslot register if it desires. The specified 293593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner /// stack slot must be available in a physreg for this query to make sense. 294593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner bool canClobberPhysReg(int Slot) const { 295593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner assert(SpillSlotsAvailable.count(Slot) && "Slot not available!"); 296593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner return SpillSlotsAvailable.find(Slot)->second & 1; 297593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner } 29866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 29966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// ClobberPhysReg - This is called when the specified physreg changes 30066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// value. We use this to invalidate any info about stuff we thing lives in 30166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// it and any of its aliases. 30266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner void ClobberPhysReg(unsigned PhysReg); 30366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 30466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// ModifyStackSlot - This method is called when the value in a stack slot 30566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// changes. This removes information about which register the previous value 30666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner /// for this slot lives in (as the previous value is dead now). 30766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner void ModifyStackSlot(int Slot); 30866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner}; 309f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattner} 31066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 31166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// ClobberPhysRegOnly - This is called when the specified physreg changes 31266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// value. We use this to invalidate any info about stuff we thing lives in it. 31366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattnervoid AvailableSpills::ClobberPhysRegOnly(unsigned PhysReg) { 31466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner std::multimap<unsigned, int>::iterator I = 31566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner PhysRegsAvailable.lower_bound(PhysReg); 31607cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner while (I != PhysRegsAvailable.end() && I->first == PhysReg) { 3177fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner int Slot = I->second; 31807cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner PhysRegsAvailable.erase(I++); 319593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner assert((SpillSlotsAvailable[Slot] >> 1) == PhysReg && 32066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner "Bidirectional map mismatch!"); 32166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner SpillSlotsAvailable.erase(Slot); 3227fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner DEBUG(std::cerr << "PhysReg " << MRI->getName(PhysReg) 32307cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner << " clobbered, invalidating SS#" << Slot << "\n"); 3248c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 3258c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 3260d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 32766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// ClobberPhysReg - This is called when the specified physreg changes 32866cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// value. We use this to invalidate any info about stuff we thing lives in 32966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner/// it and any of its aliases. 33066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattnervoid AvailableSpills::ClobberPhysReg(unsigned PhysReg) { 3317fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner for (const unsigned *AS = MRI->getAliasSet(PhysReg); *AS; ++AS) 33266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner ClobberPhysRegOnly(*AS); 33366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner ClobberPhysRegOnly(PhysReg); 33407cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner} 33507cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner 33607cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner/// ModifyStackSlot - This method is called when the value in a stack slot 33707cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner/// changes. This removes information about which register the previous value 33807cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner/// for this slot lives in (as the previous value is dead now). 33966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattnervoid AvailableSpills::ModifyStackSlot(int Slot) { 34066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner std::map<int, unsigned>::iterator It = SpillSlotsAvailable.find(Slot); 34166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner if (It == SpillSlotsAvailable.end()) return; 342593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner unsigned Reg = It->second >> 1; 34366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner SpillSlotsAvailable.erase(It); 34407cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner 34507cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner // This register may hold the value of multiple stack slots, only remove this 34607cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner // stack slot from the set of values the register contains. 34707cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner std::multimap<unsigned, int>::iterator I = PhysRegsAvailable.lower_bound(Reg); 34807cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner for (; ; ++I) { 34907cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner assert(I != PhysRegsAvailable.end() && I->first == Reg && 35007cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner "Map inverse broken!"); 35107cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner if (I->second == Slot) break; 35207cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner } 35307cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner PhysRegsAvailable.erase(I); 3548c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner} 3558c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 3568c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 35707cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner 3587fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner// ReusedOp - For each reused operand, we keep track of a bit of information, in 3597fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner// case we need to rollback upon processing a new operand. See comments below. 3607fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattnernamespace { 3617fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner struct ReusedOp { 3627fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // The MachineInstr operand that reused an available value. 3637fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner unsigned Operand; 364edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 3657fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // StackSlot - The spill slot of the value being reused. 3667fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner unsigned StackSlot; 367edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 3687fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // PhysRegReused - The physical register the value was available in. 3697fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner unsigned PhysRegReused; 370edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 3717fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // AssignedPhysReg - The physreg that was assigned for use by the reload. 3727fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner unsigned AssignedPhysReg; 3738a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner 3748a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner // VirtReg - The virtual register itself. 3758a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner unsigned VirtReg; 3768a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner 3778a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner ReusedOp(unsigned o, unsigned ss, unsigned prr, unsigned apr, 3788a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner unsigned vreg) 3798a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner : Operand(o), StackSlot(ss), PhysRegReused(prr), AssignedPhysReg(apr), 3808a61a7524af19d67bd11f8e7d868ca75efbf5c91Chris Lattner VirtReg(vreg) {} 3817fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner }; 382540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 383540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// ReuseInfo - This maintains a collection of ReuseOp's for each operand that 384540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// is reused instead of reloaded. 385f8c68f694c25b1ae8c0e5adb2a19432cb405d232Chris Lattner class VISIBILITY_HIDDEN ReuseInfo { 386540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner MachineInstr &MI; 387540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner std::vector<ReusedOp> Reuses; 388540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner public: 389540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner ReuseInfo(MachineInstr &mi) : MI(mi) {} 390540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 391540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner bool hasReuses() const { 392540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner return !Reuses.empty(); 393540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } 394540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 395540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// addReuse - If we choose to reuse a virtual register that is already 396540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// available instead of reloading it, remember that we did so. 397540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner void addReuse(unsigned OpNo, unsigned StackSlot, 398540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner unsigned PhysRegReused, unsigned AssignedPhysReg, 399540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner unsigned VirtReg) { 400540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // If the reload is to the assigned register anyway, no undo will be 401540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // required. 402540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner if (PhysRegReused == AssignedPhysReg) return; 403540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 404540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // Otherwise, remember this. 405540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner Reuses.push_back(ReusedOp(OpNo, StackSlot, PhysRegReused, 406540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner AssignedPhysReg, VirtReg)); 407540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } 408540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 409540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// GetRegForReload - We are about to emit a reload into PhysReg. If there 410540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// is some other operand that is using the specified register, either pick 411540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// a new register to use, or evict the previous reload and use this reg. 412540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner unsigned GetRegForReload(unsigned PhysReg, MachineInstr *MI, 413540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner AvailableSpills &Spills, 414540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner std::map<int, MachineInstr*> &MaybeDeadStores) { 415540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner if (Reuses.empty()) return PhysReg; // This is most often empty. 416540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 417540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner for (unsigned ro = 0, e = Reuses.size(); ro != e; ++ro) { 418540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner ReusedOp &Op = Reuses[ro]; 419540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // If we find some other reuse that was supposed to use this register 420540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // exactly for its reload, we can change this reload to use ITS reload 421540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // register. 422540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner if (Op.PhysRegReused == PhysReg) { 423540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // Yup, use the reload register that we didn't use before. 42447cb7173ea48691343b1046a0228a87c03b4167eChris Lattner unsigned NewReg = Op.AssignedPhysReg; 42547cb7173ea48691343b1046a0228a87c03b4167eChris Lattner 42647cb7173ea48691343b1046a0228a87c03b4167eChris Lattner // Remove the record for the previous reuse. We know it can never be 42747cb7173ea48691343b1046a0228a87c03b4167eChris Lattner // invalidated now. 42847cb7173ea48691343b1046a0228a87c03b4167eChris Lattner Reuses.erase(Reuses.begin()+ro); 42947cb7173ea48691343b1046a0228a87c03b4167eChris Lattner return GetRegForReload(NewReg, MI, Spills, MaybeDeadStores); 430540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } else { 431540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // Otherwise, we might also have a problem if a previously reused 432540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // value aliases the new register. If so, codegen the previous reload 433540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // and use this one. 434540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner unsigned PRRU = Op.PhysRegReused; 435540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner const MRegisterInfo *MRI = Spills.getRegInfo(); 436540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner if (MRI->areAliases(PRRU, PhysReg)) { 437540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // Okay, we found out that an alias of a reused register 438540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // was used. This isn't good because it means we have 439540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // to undo a previous reuse. 440540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner MachineBasicBlock *MBB = MI->getParent(); 441540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner const TargetRegisterClass *AliasRC = 44228bad084118a9746df95084364d7d95de00c3b67Chris Lattner MBB->getParent()->getSSARegMap()->getRegClass(Op.VirtReg); 44328bad084118a9746df95084364d7d95de00c3b67Chris Lattner 44428bad084118a9746df95084364d7d95de00c3b67Chris Lattner // Copy Op out of the vector and remove it, we're going to insert an 44528bad084118a9746df95084364d7d95de00c3b67Chris Lattner // explicit load for it. 44628bad084118a9746df95084364d7d95de00c3b67Chris Lattner ReusedOp NewOp = Op; 44728bad084118a9746df95084364d7d95de00c3b67Chris Lattner Reuses.erase(Reuses.begin()+ro); 44828bad084118a9746df95084364d7d95de00c3b67Chris Lattner 44928bad084118a9746df95084364d7d95de00c3b67Chris Lattner // Ok, we're going to try to reload the assigned physreg into the 45028bad084118a9746df95084364d7d95de00c3b67Chris Lattner // slot that we were supposed to in the first place. However, that 45128bad084118a9746df95084364d7d95de00c3b67Chris Lattner // register could hold a reuse. Check to see if it conflicts or 45228bad084118a9746df95084364d7d95de00c3b67Chris Lattner // would prefer us to use a different register. 45328bad084118a9746df95084364d7d95de00c3b67Chris Lattner unsigned NewPhysReg = GetRegForReload(NewOp.AssignedPhysReg, 45428bad084118a9746df95084364d7d95de00c3b67Chris Lattner MI, Spills, MaybeDeadStores); 45528bad084118a9746df95084364d7d95de00c3b67Chris Lattner 45628bad084118a9746df95084364d7d95de00c3b67Chris Lattner MRI->loadRegFromStackSlot(*MBB, MI, NewPhysReg, 45728bad084118a9746df95084364d7d95de00c3b67Chris Lattner NewOp.StackSlot, AliasRC); 45828bad084118a9746df95084364d7d95de00c3b67Chris Lattner Spills.ClobberPhysReg(NewPhysReg); 45928bad084118a9746df95084364d7d95de00c3b67Chris Lattner Spills.ClobberPhysReg(NewOp.PhysRegReused); 460540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 461540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner // Any stores to this stack slot are not dead anymore. 46228bad084118a9746df95084364d7d95de00c3b67Chris Lattner MaybeDeadStores.erase(NewOp.StackSlot); 463540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 464e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI->getOperand(NewOp.Operand).setReg(NewPhysReg); 465540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 46628bad084118a9746df95084364d7d95de00c3b67Chris Lattner Spills.addAvailable(NewOp.StackSlot, NewPhysReg); 467540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner ++NumLoads; 468540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner DEBUG(MachineBasicBlock::iterator MII = MI; 469540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner std::cerr << '\t' << *prior(MII)); 470540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 471540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner DEBUG(std::cerr << "Reuse undone!\n"); 472540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner --NumReused; 47328bad084118a9746df95084364d7d95de00c3b67Chris Lattner 47428bad084118a9746df95084364d7d95de00c3b67Chris Lattner // Finally, PhysReg is now available, go ahead and use it. 475540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner return PhysReg; 476540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } 477540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } 478540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } 479540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner return PhysReg; 480540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner } 481540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner }; 4827fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner} 4837fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 4847fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 4857fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner/// rewriteMBB - Keep track of which spills are available even after the 4867fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner/// register allocator is done with them. If possible, avoid reloading vregs. 48735f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattnervoid LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { 4887fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 4897fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner DEBUG(std::cerr << MBB.getBasicBlock()->getName() << ":\n"); 4907fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 49166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // Spills - Keep track of which spilled values are available in physregs so 49266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner // that we can choose to reuse the physregs instead of emitting reloads. 49366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner AvailableSpills Spills(MRI, TII); 49466cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner 4957fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // DefAndUseVReg - When we see a def&use operand that is spilled, keep track 4967fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // of it. ".first" is the machine operand index (should always be 0 for now), 4977fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // and ".second" is the virtual register that is spilled. 4987fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner std::vector<std::pair<unsigned, unsigned> > DefAndUseVReg; 4997fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 50052b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner // MaybeDeadStores - When we need to write a value back into a stack slot, 50152b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner // keep track of the inserted store. If the stack slot value is never read 50252b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner // (because the value was used from some available register, for example), and 50352b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner // subsequently stored to, the original store is dead. This map keeps track 50452b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner // of inserted stores that are not used. If we see a subsequent store to the 50552b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner // same stack slot, the original store is deleted. 50652b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner std::map<int, MachineInstr*> MaybeDeadStores; 50752b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner 508b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner bool *PhysRegsUsed = MBB.getParent()->getUsedPhysregs(); 509b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner 5107fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner for (MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end(); 5117fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MII != E; ) { 5127fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MachineInstr &MI = *MII; 5137fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MachineBasicBlock::iterator NextMII = MII; ++NextMII; 5147fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 515540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// ReusedOperands - Keep track of operand reuse in case we need to undo 516540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner /// reuse. 517540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner ReuseInfo ReusedOperands(MI); 518540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 5197fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner DefAndUseVReg.clear(); 5207fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 5217fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // Process all of the spilled uses and all non spilled reg references. 5227fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { 5237fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MachineOperand &MO = MI.getOperand(i); 52450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner if (!MO.isRegister() || MO.getReg() == 0) 52550ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner continue; // Ignore non-register operands. 52650ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 52750ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner if (MRegisterInfo::isPhysicalRegister(MO.getReg())) { 52850ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // Ignore physregs for spilling, but remember that it is used by this 52950ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // function. 530886dd9136f4c5b4523a0958e726955272eb9dfb2Chris Lattner PhysRegsUsed[MO.getReg()] = true; 53150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner continue; 53250ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner } 53350ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 53450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner assert(MRegisterInfo::isVirtualRegister(MO.getReg()) && 53550ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner "Not a virtual or a physical register?"); 53650ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 53750ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner unsigned VirtReg = MO.getReg(); 53850ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner if (!VRM.hasStackSlot(VirtReg)) { 53950ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // This virtual register was assigned a physreg! 54050ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner unsigned Phys = VRM.getPhys(VirtReg); 54150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner PhysRegsUsed[Phys] = true; 542e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(Phys); 54350ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner continue; 54450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner } 54550ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 54650ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // This virtual register is now known to be a spilled value. 54750ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner if (!MO.isUse()) 54850ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner continue; // Handle defs in the loop below (handle use&def here though) 54950ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 55050ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // If this is both a def and a use, we need to emit a store to the 55150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // stack slot after the instruction. Keep track of D&U operands 55250ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // because we are about to change it to a physreg here. 55350ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner if (MO.isDef()) { 55450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // Remember that this was a def-and-use operand, and that the 55550ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // stack slot is live after this instruction executes. 55650ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner DefAndUseVReg.push_back(std::make_pair(i, VirtReg)); 55750ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner } 55850ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 55950ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner int StackSlot = VRM.getStackSlot(VirtReg); 56050ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner unsigned PhysReg; 56150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 56250ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // Check to see if this stack slot is available. 563addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner if ((PhysReg = Spills.getSpillSlotPhysReg(StackSlot))) { 564addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 565addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // Don't reuse it for a def&use operand if we aren't allowed to change 566addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // the physreg! 567addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner if (!MO.isDef() || Spills.canClobberPhysReg(StackSlot)) { 568addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // If this stack slot value is already available, reuse it! 569addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner DEBUG(std::cerr << "Reusing SS#" << StackSlot << " from physreg " 570addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner << MRI->getName(PhysReg) << " for vreg" 571addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner << VirtReg <<" instead of reloading into physreg " 572addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner << MRI->getName(VRM.getPhys(VirtReg)) << "\n"); 573e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(PhysReg); 574addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 575addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // The only technical detail we have is that we don't know that 576addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // PhysReg won't be clobbered by a reloaded stack slot that occurs 577addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // later in the instruction. In particular, consider 'op V1, V2'. 578addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // If V1 is available in physreg R0, we would choose to reuse it 579addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // here, instead of reloading it into the register the allocator 580addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // indicated (say R1). However, V2 might have to be reloaded 581addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // later, and it might indicate that it needs to live in R0. When 582addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // this occurs, we need to have information available that 583addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // indicates it is safe to use R1 for the reload instead of R0. 584addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // 585addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // To further complicate matters, we might conflict with an alias, 586addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // or R0 and R1 might not be compatible with each other. In this 587addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // case, we actually insert a reload for V1 in R1, ensuring that 588addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // we can get at R0 or its alias. 589addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner ReusedOperands.addReuse(i, StackSlot, PhysReg, 590addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner VRM.getPhys(VirtReg), VirtReg); 591addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner ++NumReused; 592addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner continue; 593addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner } 594addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 595addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // Otherwise we have a situation where we have a two-address instruction 596addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // whose mod/ref operand needs to be reloaded. This reload is already 597addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // available in some register "PhysReg", but if we used PhysReg as the 598addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // operand to our 2-addr instruction, the instruction would modify 599addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // PhysReg. This isn't cool if something later uses PhysReg and expects 600addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // to get its initial value. 60150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // 602addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // To avoid this problem, and to avoid doing a load right after a store, 603addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // we emit a copy from PhysReg into the designated register for this 604addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // operand. 605addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner unsigned DesignatedReg = VRM.getPhys(VirtReg); 606addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner assert(DesignatedReg && "Must map virtreg to physreg!"); 607addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 608addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // Note that, if we reused a register for a previous operand, the 609addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // register we want to reload into might not actually be 610addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // available. If this occurs, use the register indicated by the 611addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // reuser. 612addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner if (ReusedOperands.hasReuses()) 613addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner DesignatedReg = ReusedOperands.GetRegForReload(DesignatedReg, &MI, 614addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner Spills, MaybeDeadStores); 615addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 616ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner // If the mapped designated register is actually the physreg we have 617ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner // incoming, we don't need to inserted a dead copy. 618ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner if (DesignatedReg == PhysReg) { 619ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner // If this stack slot value is already available, reuse it! 620ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner DEBUG(std::cerr << "Reusing SS#" << StackSlot << " from physreg " 621ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner << MRI->getName(PhysReg) << " for vreg" 622ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner << VirtReg 623ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner << " instead of reloading into same physreg.\n"); 624e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(PhysReg); 625ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner ++NumReused; 626ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner continue; 627ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner } 628ba1fc3daf757c8f880c3069eed20218c91f2c3a8Chris Lattner 629addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner const TargetRegisterClass* RC = 630addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner MBB.getParent()->getSSARegMap()->getRegClass(VirtReg); 631addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 632addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner PhysRegsUsed[DesignatedReg] = true; 633addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner MRI->copyRegToReg(MBB, &MI, DesignatedReg, PhysReg, RC); 634addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 635addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner // This invalidates DesignatedReg. 636addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner Spills.ClobberPhysReg(DesignatedReg); 637addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner 638addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner Spills.addAvailable(StackSlot, DesignatedReg); 639e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(DesignatedReg); 640addc55af6c7f8b71eedd68d48f6a93ceecff2840Chris Lattner DEBUG(std::cerr << '\t' << *prior(MII)); 64150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner ++NumReused; 64250ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner continue; 64350ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner } 64450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 64550ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // Otherwise, reload it and remember that we have it. 64650ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner PhysReg = VRM.getPhys(VirtReg); 647172c362fefe3d6e762ada119d4084ed4ed31595bChris Lattner assert(PhysReg && "Must map virtreg to physreg!"); 648bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner const TargetRegisterClass* RC = 649bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner MBB.getParent()->getSSARegMap()->getRegClass(VirtReg); 65050ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 65150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // Note that, if we reused a register for a previous operand, the 65250ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // register we want to reload into might not actually be 65350ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // available. If this occurs, use the register indicated by the 65450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // reuser. 655540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner if (ReusedOperands.hasReuses()) 656540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner PhysReg = ReusedOperands.GetRegForReload(PhysReg, &MI, 657540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner Spills, MaybeDeadStores); 658540fec6b38c8107161a0db4f8a6b7cc50be38b4aChris Lattner 65950ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner PhysRegsUsed[PhysReg] = true; 660bf9716b9c48d3b0370c715cd79540945f73dc296Chris Lattner MRI->loadRegFromStackSlot(MBB, &MI, PhysReg, StackSlot, RC); 66150ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // This invalidates PhysReg. 66266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.ClobberPhysReg(PhysReg); 66350ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner 66450ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner // Any stores to this stack slot are not dead anymore. 66550ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner MaybeDeadStores.erase(StackSlot); 66666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.addAvailable(StackSlot, PhysReg); 66750ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner ++NumLoads; 668e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(PhysReg); 66950ea01ed5ba23c8988af9fed0b91178e69140a80Chris Lattner DEBUG(std::cerr << '\t' << *prior(MII)); 6708c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 6710d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 6727fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // Loop over all of the implicit defs, clearing them from our available 6737fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // sets. 674b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner for (const unsigned *ImpDef = TII->getImplicitDefs(MI.getOpcode()); 675b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner *ImpDef; ++ImpDef) { 676b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner PhysRegsUsed[*ImpDef] = true; 67766cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.ClobberPhysReg(*ImpDef); 678b0f31bf19b9cd0107900728123d4848eae462e6cChris Lattner } 6797fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 6807fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner DEBUG(std::cerr << '\t' << MI); 6817fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 6827fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // If we have folded references to memory operands, make sure we clear all 6837fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // physical registers that may contain the value of the spilled virtual 6847fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // register 6858f1d6402ba73b96993ffd1eb9434b28c828d8856Chris Lattner VirtRegMap::MI2VirtMapTy::const_iterator I, End; 6868f1d6402ba73b96993ffd1eb9434b28c828d8856Chris Lattner for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ++I) { 687bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner DEBUG(std::cerr << "Folded vreg: " << I->second.first << " MR: " 688bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner << I->second.second); 689bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner unsigned VirtReg = I->second.first; 690bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner VirtRegMap::ModRef MR = I->second.second; 691cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner if (!VRM.hasStackSlot(VirtReg)) { 692cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner DEBUG(std::cerr << ": No stack slot!\n"); 693cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner continue; 694cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner } 695cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner int SS = VRM.getStackSlot(VirtReg); 696cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner DEBUG(std::cerr << " - StackSlot: " << SS << "\n"); 697cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner 698cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // If this folded instruction is just a use, check to see if it's a 699cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // straight load from the virt reg slot. 700cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner if ((MR & VirtRegMap::isRef) && !(MR & VirtRegMap::isMod)) { 701cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner int FrameIdx; 702408396014742a05cad1c91949d2226169e3f9d80Chris Lattner if (unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx)) { 703408396014742a05cad1c91949d2226169e3f9d80Chris Lattner // If this spill slot is available, turn it into a copy (or nothing) 704408396014742a05cad1c91949d2226169e3f9d80Chris Lattner // instead of leaving it as a load! 70566cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner unsigned InReg; 70666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner if (FrameIdx == SS && (InReg = Spills.getSpillSlotPhysReg(SS))) { 707cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner DEBUG(std::cerr << "Promoted Load To Copy: " << MI); 708cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner MachineFunction &MF = *MBB.getParent(); 70966cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner if (DestReg != InReg) { 71066cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner MRI->copyRegToReg(MBB, &MI, DestReg, InReg, 711cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner MF.getSSARegMap()->getRegClass(VirtReg)); 71222480c43504eca3092f79d9b42bdbb1b413e8e53Chris Lattner // Revisit the copy so we make sure to notice the effects of the 71322480c43504eca3092f79d9b42bdbb1b413e8e53Chris Lattner // operation on the destreg (either needing to RA it if it's 71422480c43504eca3092f79d9b42bdbb1b413e8e53Chris Lattner // virtual or needing to clobber any values if it's physical). 71522480c43504eca3092f79d9b42bdbb1b413e8e53Chris Lattner NextMII = &MI; 71622480c43504eca3092f79d9b42bdbb1b413e8e53Chris Lattner --NextMII; // backtrack to the copy. 717cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner } 7188a18c13fa5d226e60a875eff5ae66cefe4093bc9Chris Lattner VRM.RemoveFromFoldedVirtMap(&MI); 719cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner MBB.erase(&MI); 720cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner goto ProcessNextInst; 721bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner } 722bec6a9ea1281a0b3b37aece91ab0df21e086af61Chris Lattner } 723cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner } 72452b25db3ef9390271bbfa0b5c6efe0a72ce7cb8eChris Lattner 725cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // If this reference is not a use, any previous store is now dead. 726cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // Otherwise, the store to this stack slot is not dead anymore. 727cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner std::map<int, MachineInstr*>::iterator MDSI = MaybeDeadStores.find(SS); 728cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner if (MDSI != MaybeDeadStores.end()) { 729cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner if (MR & VirtRegMap::isRef) // Previous store is not dead. 730cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner MaybeDeadStores.erase(MDSI); 731cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner else { 732cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // If we get here, the store is dead, nuke it now. 73335f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner assert(VirtRegMap::isMod && "Can't be modref!"); 73435f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner DEBUG(std::cerr << "Removed dead store:\t" << *MDSI->second); 73535f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner MBB.erase(MDSI->second); 736229924a79f9a3b33b767527b9d4249e1133ceedaChris Lattner VRM.RemoveFromFoldedVirtMap(MDSI->second); 73735f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner MaybeDeadStores.erase(MDSI); 73835f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner ++NumDSE; 739cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner } 740cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner } 741cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner 742cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // If the spill slot value is available, and this is a new definition of 743cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner // the value, the value is not available anymore. 744cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner if (MR & VirtRegMap::isMod) { 74507cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner // Notice that the value in this stack slot has been modified. 74666cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.ModifyStackSlot(SS); 747cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner 748cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // If this is *just* a mod of the value, check to see if this is just a 749cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // store to the spill slot (i.e. the spill got merged into the copy). If 750cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // so, realize that the vreg is available now, and add the store to the 751cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // MaybeDeadStore info. 752cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner int StackSlot; 753cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner if (!(MR & VirtRegMap::isRef)) { 754cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner if (unsigned SrcReg = TII->isStoreToStackSlot(&MI, StackSlot)) { 755cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner assert(MRegisterInfo::isPhysicalRegister(SrcReg) && 756cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner "Src hasn't been allocated yet?"); 75707cf14112dcdb9c6b20a4f8e17de717b5219dad8Chris Lattner // Okay, this is certainly a store of SrcReg to [StackSlot]. Mark 758cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // this as a potentially dead store in case there is a subsequent 759cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // store into the stack slot without a read from it. 760cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner MaybeDeadStores[StackSlot] = &MI; 761cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner 762cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // If the stack slot value was previously available in some other 763cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // register, change it now. Otherwise, make the register available, 764cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner // in PhysReg. 765593c95878b089388f9c82b8c7b1f4731af86c792Chris Lattner Spills.addAvailable(StackSlot, SrcReg, false /*don't clobber*/); 766cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner } 767cd81639d2e3705ee13b1869d6c166b5f5b4c29c4Chris Lattner } 7687fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner } 7698c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 7700d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 7717fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // Process all of the spilled defs. 7727fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { 7737fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MachineOperand &MO = MI.getOperand(i); 7747fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner if (MO.isRegister() && MO.getReg() && MO.isDef()) { 7757fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner unsigned VirtReg = MO.getReg(); 7767fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 7777fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner if (!MRegisterInfo::isVirtualRegister(VirtReg)) { 7787fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // Check to see if this is a def-and-use vreg operand that we do need 7797fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner // to insert a store for. 7807fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner bool OpTakenCareOf = false; 7817fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner if (MO.isUse() && !DefAndUseVReg.empty()) { 7827fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner for (unsigned dau = 0, e = DefAndUseVReg.size(); dau != e; ++dau) 7837fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner if (DefAndUseVReg[dau].first == i) { 7847fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner VirtReg = DefAndUseVReg[dau].second; 7857fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner OpTakenCareOf = true; 7867fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner break; 7877fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner } 7887fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner } 789edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman 7907fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner if (!OpTakenCareOf) { 791109afed40bec552e4d37115c971e082e79eb0093Chris Lattner // Check to see if this is a noop copy. If so, eliminate the 792109afed40bec552e4d37115c971e082e79eb0093Chris Lattner // instruction before considering the dest reg to be changed. 793109afed40bec552e4d37115c971e082e79eb0093Chris Lattner unsigned Src, Dst; 794109afed40bec552e4d37115c971e082e79eb0093Chris Lattner if (TII->isMoveInstr(MI, Src, Dst) && Src == Dst) { 795109afed40bec552e4d37115c971e082e79eb0093Chris Lattner ++NumDCE; 796109afed40bec552e4d37115c971e082e79eb0093Chris Lattner DEBUG(std::cerr << "Removing now-noop copy: " << MI); 797109afed40bec552e4d37115c971e082e79eb0093Chris Lattner MBB.erase(&MI); 798229924a79f9a3b33b767527b9d4249e1133ceedaChris Lattner VRM.RemoveFromFoldedVirtMap(&MI); 799109afed40bec552e4d37115c971e082e79eb0093Chris Lattner goto ProcessNextInst; 800109afed40bec552e4d37115c971e082e79eb0093Chris Lattner } 80166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.ClobberPhysReg(VirtReg); 80284e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner continue; 8037fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner } 804edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman } 8057fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 80684e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // The only vregs left are stack slot definitions. 80784e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner int StackSlot = VRM.getStackSlot(VirtReg); 80884e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner const TargetRegisterClass *RC = 80984e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner MBB.getParent()->getSSARegMap()->getRegClass(VirtReg); 81084e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner unsigned PhysReg; 81184e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner 81284e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // If this is a def&use operand, and we used a different physreg for 81384e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // it than the one assigned, make sure to execute the store from the 81484e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // correct physical register. 81584e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner if (MO.getReg() == VirtReg) 81684e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner PhysReg = VRM.getPhys(VirtReg); 81784e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner else 81884e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner PhysReg = MO.getReg(); 81984e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner 82084e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner PhysRegsUsed[PhysReg] = true; 82184e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner MRI->storeRegToStackSlot(MBB, next(MII), PhysReg, StackSlot, RC); 82284e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner DEBUG(std::cerr << "Store:\t" << *next(MII)); 823e53f4a055f74bded20d6129b4724ddd17fd199f6Chris Lattner MI.getOperand(i).setReg(PhysReg); 82484e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner 825109afed40bec552e4d37115c971e082e79eb0093Chris Lattner // Check to see if this is a noop copy. If so, eliminate the 826109afed40bec552e4d37115c971e082e79eb0093Chris Lattner // instruction before considering the dest reg to be changed. 827109afed40bec552e4d37115c971e082e79eb0093Chris Lattner { 828109afed40bec552e4d37115c971e082e79eb0093Chris Lattner unsigned Src, Dst; 829109afed40bec552e4d37115c971e082e79eb0093Chris Lattner if (TII->isMoveInstr(MI, Src, Dst) && Src == Dst) { 830109afed40bec552e4d37115c971e082e79eb0093Chris Lattner ++NumDCE; 831109afed40bec552e4d37115c971e082e79eb0093Chris Lattner DEBUG(std::cerr << "Removing now-noop copy: " << MI); 832109afed40bec552e4d37115c971e082e79eb0093Chris Lattner MBB.erase(&MI); 833229924a79f9a3b33b767527b9d4249e1133ceedaChris Lattner VRM.RemoveFromFoldedVirtMap(&MI); 834109afed40bec552e4d37115c971e082e79eb0093Chris Lattner goto ProcessNextInst; 835109afed40bec552e4d37115c971e082e79eb0093Chris Lattner } 836109afed40bec552e4d37115c971e082e79eb0093Chris Lattner } 837109afed40bec552e4d37115c971e082e79eb0093Chris Lattner 83884e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // If there is a dead store to this stack slot, nuke it now. 83984e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner MachineInstr *&LastStore = MaybeDeadStores[StackSlot]; 84084e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner if (LastStore) { 84135f2705e3de4600c3621b883eed9b22e4607ddf4Chris Lattner DEBUG(std::cerr << "Removed dead store:\t" << *LastStore); 84284e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner ++NumDSE; 84384e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner MBB.erase(LastStore); 844229924a79f9a3b33b767527b9d4249e1133ceedaChris Lattner VRM.RemoveFromFoldedVirtMap(LastStore); 8450d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos } 84684e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner LastStore = next(MII); 84784e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner 84884e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // If the stack slot value was previously available in some other 84984e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // register, change it now. Otherwise, make the register available, 85084e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner // in PhysReg. 85166cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.ModifyStackSlot(StackSlot); 85266cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.ClobberPhysReg(PhysReg); 85366cf80f226e04e6704a78da83e08c7b0af944ef1Chris Lattner Spills.addAvailable(StackSlot, PhysReg); 85484e752a8129e7a02ee6e3c6d356a8fd68fbdf698Chris Lattner ++NumStores; 8557fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner } 8568c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 857cea8688ee4637e0f3cffc75e47f15be756f043bfChris Lattner ProcessNextInst: 8587fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner MII = NextMII; 8598c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 8600d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos} 8610d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos 8628c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner 8637fb64347d7d1310b5f3f06f7ae97031c73a21797Chris Lattner 8648c4d88d3697835371ecf6823f4142af13603ad2dChris Lattnerllvm::Spiller* llvm::createSpiller() { 8658c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner switch (SpillerOpt) { 8668c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner default: assert(0 && "Unreachable!"); 8678c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner case local: 8688c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner return new LocalSpiller(); 8698c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner case simple: 8708c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner return new SimpleSpiller(); 8718c4d88d3697835371ecf6823f4142af13603ad2dChris Lattner } 8720d6c5b6489b9abb634a1506d183ba47f1bf4d1f0Alkis Evlogimenos} 873