lib/Target/Mips/MipsLegalizerInfo.cpp

   1 //===- MipsLegalizerInfo.cpp ------------------------------------*- C++ -*-===//
   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 /// \file
  10 /// This file implements the targeting of the Machinelegalizer class for Mips.
  11 /// \todo This should be generated by TableGen.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "MipsLegalizerInfo.h"
  15 #include "MipsTargetMachine.h"
  16 #include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
  17
  18 using namespace llvm;
  19
  20 MipsLegalizerInfo::MipsLegalizerInfo(const MipsSubtarget &ST) {
  21   using namespace TargetOpcode;
  22
  23   const LLT s32 = LLT::scalar(32);
  24   const LLT s64 = LLT::scalar(64);
  25   const LLT p0 = LLT::pointer(0, 32);
  26
  27   getActionDefinitionsBuilder(G_ADD)
  28       .legalFor({s32})
  29       .minScalar(0, s32)
  30       .customFor({s64});
  31
  32   getActionDefinitionsBuilder({G_LOAD, G_STORE})
  33       .legalForCartesianProduct({p0, s32}, {p0});
  34
  35   getActionDefinitionsBuilder({G_AND, G_OR, G_XOR, G_SHL, G_ASHR, G_LSHR})
  36       .legalFor({s32});
  37
  38   getActionDefinitionsBuilder(G_ICMP)
  39       .legalFor({{s32, s32}})
  40       .minScalar(0, s32);
  41
  42   getActionDefinitionsBuilder(G_CONSTANT)
  43       .legalFor({s32})
  44       .minScalar(0, s32)
  45       .customFor({s64});
  46
  47   getActionDefinitionsBuilder(G_GEP)
  48       .legalFor({{p0, s32}});
  49
  50   getActionDefinitionsBuilder(G_FRAME_INDEX)
  51       .legalFor({p0});
  52
  53   getActionDefinitionsBuilder(G_GLOBAL_VALUE)
  54       .legalFor({p0});
  55
  56   computeTables();
  57   verify(*ST.getInstrInfo());
  58 }
  59
  60 bool MipsLegalizerInfo::legalizeCustom(MachineInstr &MI,
  61                                        MachineRegisterInfo &MRI,
  62                                        MachineIRBuilder &MIRBuilder) const {
  63
  64   using namespace TargetOpcode;
  65
  66   MIRBuilder.setInstr(MI);
  67
  68   switch (MI.getOpcode()) {
  69   case G_ADD: {
  70     unsigned Size = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
  71
  72     const LLT sHalf = LLT::scalar(Size / 2);
  73
  74     unsigned RHSLow = MRI.createGenericVirtualRegister(sHalf);
  75     unsigned RHSHigh = MRI.createGenericVirtualRegister(sHalf);
  76     unsigned LHSLow = MRI.createGenericVirtualRegister(sHalf);
  77     unsigned LHSHigh = MRI.createGenericVirtualRegister(sHalf);
  78     unsigned ResLow = MRI.createGenericVirtualRegister(sHalf);
  79     unsigned ResHigh = MRI.createGenericVirtualRegister(sHalf);
  80     unsigned Carry = MRI.createGenericVirtualRegister(sHalf);
  81     unsigned TmpResHigh = MRI.createGenericVirtualRegister(sHalf);
  82
  83     MIRBuilder.buildUnmerge({RHSLow, RHSHigh}, MI.getOperand(2).getReg());
  84     MIRBuilder.buildUnmerge({LHSLow, LHSHigh}, MI.getOperand(1).getReg());
  85
  86     MIRBuilder.buildAdd(TmpResHigh, LHSHigh, RHSHigh);
  87     MIRBuilder.buildAdd(ResLow, LHSLow, RHSLow);
  88     MIRBuilder.buildICmp(CmpInst::ICMP_ULT, Carry, ResLow, LHSLow);
  89     MIRBuilder.buildAdd(ResHigh, TmpResHigh, Carry);
  90
  91     MIRBuilder.buildMerge(MI.getOperand(0).getReg(), {ResLow, ResHigh});
  92
  93     MI.eraseFromParent();
  94     break;
  95   }
  96   case G_CONSTANT: {
  97
  98     unsigned Size = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
  99     const LLT sHalf = LLT::scalar(Size / 2);
 100
 101     const APInt &CImmValue = MI.getOperand(1).getCImm()->getValue();
 102
 103     unsigned ResLow = MRI.createGenericVirtualRegister(sHalf);
 104     unsigned ResHigh = MRI.createGenericVirtualRegister(sHalf);
 105     MIRBuilder.buildConstant(
 106         ResLow, *ConstantInt::get(MI.getMF()->getFunction().getContext(),
 107                                   CImmValue.trunc(Size / 2)));
 108     MIRBuilder.buildConstant(
 109         ResHigh, *ConstantInt::get(MI.getMF()->getFunction().getContext(),
 110                                    CImmValue.lshr(Size / 2).trunc(Size / 2)));
 111
 112     MIRBuilder.buildMerge(MI.getOperand(0).getReg(), {ResLow, ResHigh});
 113
 114     MI.eraseFromParent();
 115     break;
 116   }
 117   default:
 118     return false;
 119   }
 120
 121   return true;
 122 }