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({RHSHigh, RHSLow}, MI.getOperand(2).getReg());
84     MIRBuilder.buildUnmerge({LHSHigh, LHSLow}, 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(), {ResHigh, ResLow});
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(), {ResHigh, ResLow});
113 
114     MI.eraseFromParent();
115     break;
116   }
117   default:
118     return false;
119   }
120 
121   return true;
122 }
123