1//===-------------- PPCVSXCopy.cpp - VSX Copy Legalization ----------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// A pass which deals with the complexity of generating legal VSX register 11// copies to/from register classes which partially overlap with the VSX 12// register file. 13// 14//===----------------------------------------------------------------------===// 15 16#include "PPCInstrInfo.h" 17#include "MCTargetDesc/PPCPredicates.h" 18#include "PPC.h" 19#include "PPCHazardRecognizers.h" 20#include "PPCInstrBuilder.h" 21#include "PPCMachineFunctionInfo.h" 22#include "PPCTargetMachine.h" 23#include "llvm/ADT/STLExtras.h" 24#include "llvm/ADT/Statistic.h" 25#include "llvm/CodeGen/MachineFrameInfo.h" 26#include "llvm/CodeGen/MachineFunctionPass.h" 27#include "llvm/CodeGen/MachineInstrBuilder.h" 28#include "llvm/CodeGen/MachineMemOperand.h" 29#include "llvm/CodeGen/MachineRegisterInfo.h" 30#include "llvm/MC/MCAsmInfo.h" 31#include "llvm/Support/CommandLine.h" 32#include "llvm/Support/Debug.h" 33#include "llvm/Support/ErrorHandling.h" 34#include "llvm/Support/TargetRegistry.h" 35#include "llvm/Support/raw_ostream.h" 36 37using namespace llvm; 38 39#define DEBUG_TYPE "ppc-vsx-copy" 40 41namespace llvm { 42 void initializePPCVSXCopyPass(PassRegistry&); 43} 44 45namespace { 46 // PPCVSXCopy pass - For copies between VSX registers and non-VSX registers 47 // (Altivec and scalar floating-point registers), we need to transform the 48 // copies into subregister copies with other restrictions. 49 struct PPCVSXCopy : public MachineFunctionPass { 50 static char ID; 51 PPCVSXCopy() : MachineFunctionPass(ID) { 52 initializePPCVSXCopyPass(*PassRegistry::getPassRegistry()); 53 } 54 55 const TargetInstrInfo *TII; 56 57 bool IsRegInClass(unsigned Reg, const TargetRegisterClass *RC, 58 MachineRegisterInfo &MRI) { 59 if (TargetRegisterInfo::isVirtualRegister(Reg)) { 60 return RC->hasSubClassEq(MRI.getRegClass(Reg)); 61 } else if (RC->contains(Reg)) { 62 return true; 63 } 64 65 return false; 66 } 67 68 bool IsVSReg(unsigned Reg, MachineRegisterInfo &MRI) { 69 return IsRegInClass(Reg, &PPC::VSRCRegClass, MRI); 70 } 71 72 bool IsVRReg(unsigned Reg, MachineRegisterInfo &MRI) { 73 return IsRegInClass(Reg, &PPC::VRRCRegClass, MRI); 74 } 75 76 bool IsF8Reg(unsigned Reg, MachineRegisterInfo &MRI) { 77 return IsRegInClass(Reg, &PPC::F8RCRegClass, MRI); 78 } 79 80protected: 81 bool processBlock(MachineBasicBlock &MBB) { 82 bool Changed = false; 83 84 MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo(); 85 for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end(); 86 I != IE; ++I) { 87 MachineInstr *MI = I; 88 if (!MI->isFullCopy()) 89 continue; 90 91 MachineOperand &DstMO = MI->getOperand(0); 92 MachineOperand &SrcMO = MI->getOperand(1); 93 94 if ( IsVSReg(DstMO.getReg(), MRI) && 95 !IsVSReg(SrcMO.getReg(), MRI)) { 96 // This is a copy *to* a VSX register from a non-VSX register. 97 Changed = true; 98 99 const TargetRegisterClass *SrcRC = 100 IsVRReg(SrcMO.getReg(), MRI) ? &PPC::VSHRCRegClass : 101 &PPC::VSLRCRegClass; 102 assert((IsF8Reg(SrcMO.getReg(), MRI) || 103 IsVRReg(SrcMO.getReg(), MRI)) && 104 "Unknown source for a VSX copy"); 105 106 unsigned NewVReg = MRI.createVirtualRegister(SrcRC); 107 BuildMI(MBB, MI, MI->getDebugLoc(), 108 TII->get(TargetOpcode::SUBREG_TO_REG), NewVReg) 109 .addImm(1) // add 1, not 0, because there is no implicit clearing 110 // of the high bits. 111 .addOperand(SrcMO) 112 .addImm(IsVRReg(SrcMO.getReg(), MRI) ? PPC::sub_128 : 113 PPC::sub_64); 114 115 // The source of the original copy is now the new virtual register. 116 SrcMO.setReg(NewVReg); 117 } else if (!IsVSReg(DstMO.getReg(), MRI) && 118 IsVSReg(SrcMO.getReg(), MRI)) { 119 // This is a copy *from* a VSX register to a non-VSX register. 120 Changed = true; 121 122 const TargetRegisterClass *DstRC = 123 IsVRReg(DstMO.getReg(), MRI) ? &PPC::VSHRCRegClass : 124 &PPC::VSLRCRegClass; 125 assert((IsF8Reg(DstMO.getReg(), MRI) || 126 IsVRReg(DstMO.getReg(), MRI)) && 127 "Unknown destination for a VSX copy"); 128 129 // Copy the VSX value into a new VSX register of the correct subclass. 130 unsigned NewVReg = MRI.createVirtualRegister(DstRC); 131 BuildMI(MBB, MI, MI->getDebugLoc(), 132 TII->get(TargetOpcode::COPY), NewVReg) 133 .addOperand(SrcMO); 134 135 // Transform the original copy into a subregister extraction copy. 136 SrcMO.setReg(NewVReg); 137 SrcMO.setSubReg(IsVRReg(DstMO.getReg(), MRI) ? PPC::sub_128 : 138 PPC::sub_64); 139 } 140 } 141 142 return Changed; 143 } 144 145public: 146 bool runOnMachineFunction(MachineFunction &MF) override { 147 // If we don't have VSX on the subtarget, don't do anything. 148 const PPCSubtarget &STI = MF.getSubtarget<PPCSubtarget>(); 149 if (!STI.hasVSX()) 150 return false; 151 TII = STI.getInstrInfo(); 152 153 bool Changed = false; 154 155 for (MachineFunction::iterator I = MF.begin(); I != MF.end();) { 156 MachineBasicBlock &B = *I++; 157 if (processBlock(B)) 158 Changed = true; 159 } 160 161 return Changed; 162 } 163 164 void getAnalysisUsage(AnalysisUsage &AU) const override { 165 MachineFunctionPass::getAnalysisUsage(AU); 166 } 167 }; 168} 169 170INITIALIZE_PASS(PPCVSXCopy, DEBUG_TYPE, 171 "PowerPC VSX Copy Legalization", false, false) 172 173char PPCVSXCopy::ID = 0; 174FunctionPass* 175llvm::createPPCVSXCopyPass() { return new PPCVSXCopy(); } 176 177