1 //=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.cpp --------------===//
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 // This pass does combining of machine instructions at the generic MI level,
11 // before the legalizer.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "MipsTargetMachine.h"
16 #include "llvm/CodeGen/GlobalISel/Combiner.h"
17 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
18 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
19 #include "llvm/CodeGen/TargetPassConfig.h"
20 
21 #define DEBUG_TYPE "mips-prelegalizer-combiner"
22 
23 using namespace llvm;
24 
25 namespace {
26 class MipsPreLegalizerCombinerInfo : public CombinerInfo {
27 public:
28   MipsPreLegalizerCombinerInfo()
29       : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
30                      /*LegalizerInfo*/ nullptr) {}
31   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
32                        MachineIRBuilder &B) const override;
33 };
34 
35 bool MipsPreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
36                                            MachineInstr &MI,
37                                            MachineIRBuilder &B) const {
38   return false;
39 }
40 
41 // Pass boilerplate
42 // ================
43 
44 class MipsPreLegalizerCombiner : public MachineFunctionPass {
45 public:
46   static char ID;
47 
48   MipsPreLegalizerCombiner();
49 
50   StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
51 
52   bool runOnMachineFunction(MachineFunction &MF) override;
53 
54   void getAnalysisUsage(AnalysisUsage &AU) const override;
55 };
56 } // end anonymous namespace
57 
58 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
59   AU.addRequired<TargetPassConfig>();
60   AU.setPreservesCFG();
61   getSelectionDAGFallbackAnalysisUsage(AU);
62   MachineFunctionPass::getAnalysisUsage(AU);
63 }
64 
65 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
66   initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
67 }
68 
69 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
70   if (MF.getProperties().hasProperty(
71           MachineFunctionProperties::Property::FailedISel))
72     return false;
73   auto *TPC = &getAnalysis<TargetPassConfig>();
74   MipsPreLegalizerCombinerInfo PCInfo;
75   Combiner C(PCInfo, TPC);
76   return C.combineMachineInstrs(MF, nullptr);
77 }
78 
79 char MipsPreLegalizerCombiner::ID = 0;
80 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
81                       "Combine Mips machine instrs before legalization", false,
82                       false)
83 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
84 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
85                     "Combine Mips machine instrs before legalization", false,
86                     false)
87 
88 namespace llvm {
89 FunctionPass *createMipsPreLegalizeCombiner() {
90   return new MipsPreLegalizerCombiner();
91 }
92 } // end namespace llvm
93