llvm/lib/Target/X86/GISel/X86RegisterBankInfo.cpp

   1 //===- X86RegisterBankInfo.cpp -----------------------------------*- C++ -*-==//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 /// \file
   9 /// This file implements the targeting of the RegisterBankInfo class for X86.
  10 /// \todo This should be generated by TableGen.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "X86RegisterBankInfo.h"
  14 #include "X86InstrInfo.h"
  15 #include "llvm/CodeGen/MachineRegisterInfo.h"
  16 #include "llvm/CodeGen/RegisterBank.h"
  17 #include "llvm/CodeGen/RegisterBankInfo.h"
  18 #include "llvm/CodeGen/TargetRegisterInfo.h"
  19
  20 #define GET_TARGET_REGBANK_IMPL
  21 #include "X86GenRegisterBank.inc"
  22
  23 using namespace llvm;
  24 // This file will be TableGen'ed at some point.
  25 #define GET_TARGET_REGBANK_INFO_IMPL
  26 #include "X86GenRegisterBankInfo.def"
  27
  28 X86RegisterBankInfo::X86RegisterBankInfo(const TargetRegisterInfo &TRI) {
  29
  30   // validate RegBank initialization.
  31   const RegisterBank &RBGPR = getRegBank(X86::GPRRegBankID);
  32   (void)RBGPR;
  33   assert(&X86::GPRRegBank == &RBGPR && "Incorrect RegBanks inizalization.");
  34
  35   // The GPR register bank is fully defined by all the registers in
  36   // GR64 + its subclasses.
  37   assert(RBGPR.covers(*TRI.getRegClass(X86::GR64RegClassID)) &&
  38          "Subclass not added?");
  39   assert(getMaximumSize(RBGPR.getID()) == 64 &&
  40          "GPRs should hold up to 64-bit");
  41 }
  42
  43 const RegisterBank &
  44 X86RegisterBankInfo::getRegBankFromRegClass(const TargetRegisterClass &RC,
  45                                             LLT) const {
  46
  47   if (X86::GR8RegClass.hasSubClassEq(&RC) ||
  48       X86::GR16RegClass.hasSubClassEq(&RC) ||
  49       X86::GR32RegClass.hasSubClassEq(&RC) ||
  50       X86::GR64RegClass.hasSubClassEq(&RC) ||
  51       X86::LOW32_ADDR_ACCESSRegClass.hasSubClassEq(&RC) ||
  52       X86::LOW32_ADDR_ACCESS_RBPRegClass.hasSubClassEq(&RC))
  53     return getRegBank(X86::GPRRegBankID);
  54
  55   if (X86::FR32XRegClass.hasSubClassEq(&RC) ||
  56       X86::FR64XRegClass.hasSubClassEq(&RC) ||
  57       X86::VR128XRegClass.hasSubClassEq(&RC) ||
  58       X86::VR256XRegClass.hasSubClassEq(&RC) ||
  59       X86::VR512RegClass.hasSubClassEq(&RC))
  60     return getRegBank(X86::VECRRegBankID);
  61
  62   llvm_unreachable("Unsupported register kind yet.");
  63 }
  64
  65 X86GenRegisterBankInfo::PartialMappingIdx
  66 X86GenRegisterBankInfo::getPartialMappingIdx(const LLT &Ty, bool isFP) {
  67   if ((Ty.isScalar() && !isFP) || Ty.isPointer()) {
  68     switch (Ty.getSizeInBits()) {
  69     case 1:
  70     case 8:
  71       return PMI_GPR8;
  72     case 16:
  73       return PMI_GPR16;
  74     case 32:
  75       return PMI_GPR32;
  76     case 64:
  77       return PMI_GPR64;
  78     case 128:
  79       return PMI_VEC128;
  80       break;
  81     default:
  82       llvm_unreachable("Unsupported register size.");
  83     }
  84   } else if (Ty.isScalar()) {
  85     switch (Ty.getSizeInBits()) {
  86     case 32:
  87       return PMI_FP32;
  88     case 64:
  89       return PMI_FP64;
  90     case 128:
  91       return PMI_VEC128;
  92     default:
  93       llvm_unreachable("Unsupported register size.");
  94     }
  95   } else {
  96     switch (Ty.getSizeInBits()) {
  97     case 128:
  98       return PMI_VEC128;
  99     case 256:
 100       return PMI_VEC256;
 101     case 512:
 102       return PMI_VEC512;
 103     default:
 104       llvm_unreachable("Unsupported register size.");
 105     }
 106   }
 107
 108   return PMI_None;
 109 }
 110
 111 void X86RegisterBankInfo::getInstrPartialMappingIdxs(
 112     const MachineInstr &MI, const MachineRegisterInfo &MRI, const bool isFP,
 113     SmallVectorImpl<PartialMappingIdx> &OpRegBankIdx) {
 114
 115   unsigned NumOperands = MI.getNumOperands();
 116   for (unsigned Idx = 0; Idx < NumOperands; ++Idx) {
 117     auto &MO = MI.getOperand(Idx);
 118     if (!MO.isReg() || !MO.getReg())
 119       OpRegBankIdx[Idx] = PMI_None;
 120     else
 121       OpRegBankIdx[Idx] = getPartialMappingIdx(MRI.getType(MO.getReg()), isFP);
 122   }
 123 }
 124
 125 bool X86RegisterBankInfo::getInstrValueMapping(
 126     const MachineInstr &MI,
 127     const SmallVectorImpl<PartialMappingIdx> &OpRegBankIdx,
 128     SmallVectorImpl<const ValueMapping *> &OpdsMapping) {
 129
 130   unsigned NumOperands = MI.getNumOperands();
 131   for (unsigned Idx = 0; Idx < NumOperands; ++Idx) {
 132     if (!MI.getOperand(Idx).isReg())
 133       continue;
 134     if (!MI.getOperand(Idx).getReg())
 135       continue;
 136
 137     auto Mapping = getValueMapping(OpRegBankIdx[Idx], 1);
 138     if (!Mapping->isValid())
 139       return false;
 140
 141     OpdsMapping[Idx] = Mapping;
 142   }
 143   return true;
 144 }
 145
 146 const RegisterBankInfo::InstructionMapping &
 147 X86RegisterBankInfo::getSameOperandsMapping(const MachineInstr &MI,
 148                                             bool isFP) const {
 149   const MachineFunction &MF = *MI.getParent()->getParent();
 150   const MachineRegisterInfo &MRI = MF.getRegInfo();
 151
 152   unsigned NumOperands = MI.getNumOperands();
 153   LLT Ty = MRI.getType(MI.getOperand(0).getReg());
 154
 155   if (NumOperands != 3 || (Ty != MRI.getType(MI.getOperand(1).getReg())) ||
 156       (Ty != MRI.getType(MI.getOperand(2).getReg())))
 157     llvm_unreachable("Unsupported operand mapping yet.");
 158
 159   auto Mapping = getValueMapping(getPartialMappingIdx(Ty, isFP), 3);
 160   return getInstructionMapping(DefaultMappingID, 1, Mapping, NumOperands);
 161 }
 162
 163 const RegisterBankInfo::InstructionMapping &
 164 X86RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
 165   const MachineFunction &MF = *MI.getParent()->getParent();
 166   const MachineRegisterInfo &MRI = MF.getRegInfo();
 167   unsigned Opc = MI.getOpcode();
 168
 169   // Try the default logic for non-generic instructions that are either copies
 170   // or already have some operands assigned to banks.
 171   if (!isPreISelGenericOpcode(Opc) || Opc == TargetOpcode::G_PHI) {
 172     const InstructionMapping &Mapping = getInstrMappingImpl(MI);
 173     if (Mapping.isValid())
 174       return Mapping;
 175   }
 176
 177   switch (Opc) {
 178   case TargetOpcode::G_ADD:
 179   case TargetOpcode::G_SUB:
 180   case TargetOpcode::G_MUL:
 181     return getSameOperandsMapping(MI, false);
 182   case TargetOpcode::G_FADD:
 183   case TargetOpcode::G_FSUB:
 184   case TargetOpcode::G_FMUL:
 185   case TargetOpcode::G_FDIV:
 186     return getSameOperandsMapping(MI, true);
 187   case TargetOpcode::G_SHL:
 188   case TargetOpcode::G_LSHR:
 189   case TargetOpcode::G_ASHR: {
 190     unsigned NumOperands = MI.getNumOperands();
 191     LLT Ty = MRI.getType(MI.getOperand(0).getReg());
 192
 193     auto Mapping = getValueMapping(getPartialMappingIdx(Ty, false), 3);
 194     return getInstructionMapping(DefaultMappingID, 1, Mapping, NumOperands);
 195
 196   }
 197   default:
 198     break;
 199   }
 200
 201   unsigned NumOperands = MI.getNumOperands();
 202   SmallVector<PartialMappingIdx, 4> OpRegBankIdx(NumOperands);
 203
 204   switch (Opc) {
 205   case TargetOpcode::G_FPEXT:
 206   case TargetOpcode::G_FPTRUNC:
 207   case TargetOpcode::G_FCONSTANT:
 208     // Instruction having only floating-point operands (all scalars in VECRReg)
 209     getInstrPartialMappingIdxs(MI, MRI, /* isFP */ true, OpRegBankIdx);
 210     break;
 211   case TargetOpcode::G_SITOFP:
 212   case TargetOpcode::G_FPTOSI: {
 213     // Some of the floating-point instructions have mixed GPR and FP operands:
 214     // fine-tune the computed mapping.
 215     auto &Op0 = MI.getOperand(0);
 216     auto &Op1 = MI.getOperand(1);
 217     const LLT Ty0 = MRI.getType(Op0.getReg());
 218     const LLT Ty1 = MRI.getType(Op1.getReg());
 219
 220     bool FirstArgIsFP = Opc == TargetOpcode::G_SITOFP;
 221     bool SecondArgIsFP = Opc == TargetOpcode::G_FPTOSI;
 222     OpRegBankIdx[0] = getPartialMappingIdx(Ty0, /* isFP */ FirstArgIsFP);
 223     OpRegBankIdx[1] = getPartialMappingIdx(Ty1, /* isFP */ SecondArgIsFP);
 224     break;
 225   }
 226   case TargetOpcode::G_FCMP: {
 227     LLT Ty1 = MRI.getType(MI.getOperand(2).getReg());
 228     LLT Ty2 = MRI.getType(MI.getOperand(3).getReg());
 229     (void)Ty2;
 230     assert(Ty1.getSizeInBits() == Ty2.getSizeInBits() &&
 231            "Mismatched operand sizes for G_FCMP");
 232
 233     unsigned Size = Ty1.getSizeInBits();
 234     (void)Size;
 235     assert((Size == 32 || Size == 64) && "Unsupported size for G_FCMP");
 236
 237     auto FpRegBank = getPartialMappingIdx(Ty1, /* isFP */ true);
 238     OpRegBankIdx = {PMI_GPR8,
 239                     /* Predicate */ PMI_None, FpRegBank, FpRegBank};
 240     break;
 241   }
 242   case TargetOpcode::G_TRUNC:
 243   case TargetOpcode::G_ANYEXT: {
 244     auto &Op0 = MI.getOperand(0);
 245     auto &Op1 = MI.getOperand(1);
 246     const LLT Ty0 = MRI.getType(Op0.getReg());
 247     const LLT Ty1 = MRI.getType(Op1.getReg());
 248
 249     bool isFPTrunc = (Ty0.getSizeInBits() == 32 || Ty0.getSizeInBits() == 64) &&
 250                      Ty1.getSizeInBits() == 128 && Opc == TargetOpcode::G_TRUNC;
 251     bool isFPAnyExt =
 252         Ty0.getSizeInBits() == 128 &&
 253         (Ty1.getSizeInBits() == 32 || Ty1.getSizeInBits() == 64) &&
 254         Opc == TargetOpcode::G_ANYEXT;
 255
 256     getInstrPartialMappingIdxs(MI, MRI, /* isFP */ isFPTrunc || isFPAnyExt,
 257                                OpRegBankIdx);
 258   } break;
 259   default:
 260     // Track the bank of each register, use NotFP mapping (all scalars in GPRs)
 261     getInstrPartialMappingIdxs(MI, MRI, /* isFP */ false, OpRegBankIdx);
 262     break;
 263   }
 264
 265   // Finally construct the computed mapping.
 266   SmallVector<const ValueMapping *, 8> OpdsMapping(NumOperands);
 267   if (!getInstrValueMapping(MI, OpRegBankIdx, OpdsMapping))
 268     return getInvalidInstructionMapping();
 269
 270   return getInstructionMapping(DefaultMappingID, /* Cost */ 1,
 271                                getOperandsMapping(OpdsMapping), NumOperands);
 272 }
 273
 274 void X86RegisterBankInfo::applyMappingImpl(
 275     MachineIRBuilder &Builder, const OperandsMapper &OpdMapper) const {
 276   return applyDefaultMapping(OpdMapper);
 277 }
 278
 279 RegisterBankInfo::InstructionMappings
 280 X86RegisterBankInfo::getInstrAlternativeMappings(const MachineInstr &MI) const {
 281
 282   const MachineFunction &MF = *MI.getParent()->getParent();
 283   const TargetSubtargetInfo &STI = MF.getSubtarget();
 284   const TargetRegisterInfo &TRI = *STI.getRegisterInfo();
 285   const MachineRegisterInfo &MRI = MF.getRegInfo();
 286
 287   switch (MI.getOpcode()) {
 288   case TargetOpcode::G_LOAD:
 289   case TargetOpcode::G_STORE:
 290   case TargetOpcode::G_IMPLICIT_DEF: {
 291     // we going to try to map 32/64 bit to PMI_FP32/PMI_FP64
 292     unsigned Size = getSizeInBits(MI.getOperand(0).getReg(), MRI, TRI);
 293     if (Size != 32 && Size != 64)
 294       break;
 295
 296     unsigned NumOperands = MI.getNumOperands();
 297
 298     // Track the bank of each register, use FP mapping (all scalars in VEC)
 299     SmallVector<PartialMappingIdx, 4> OpRegBankIdx(NumOperands);
 300     getInstrPartialMappingIdxs(MI, MRI, /* isFP */ true, OpRegBankIdx);
 301
 302     // Finally construct the computed mapping.
 303     SmallVector<const ValueMapping *, 8> OpdsMapping(NumOperands);
 304     if (!getInstrValueMapping(MI, OpRegBankIdx, OpdsMapping))
 305       break;
 306
 307     const RegisterBankInfo::InstructionMapping &Mapping = getInstructionMapping(
 308         /*ID*/ 1, /*Cost*/ 1, getOperandsMapping(OpdsMapping), NumOperands);
 309     InstructionMappings AltMappings;
 310     AltMappings.push_back(&Mapping);
 311     return AltMappings;
 312   }
 313   default:
 314     break;
 315   }
 316   return RegisterBankInfo::getInstrAlternativeMappings(MI);
 317 }