1 //=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.cpp --------------===//
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 //
9 // This pass does combining of machine instructions at the generic MI level,
10 // before the legalizer.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MipsTargetMachine.h"
15 #include "llvm/CodeGen/GlobalISel/Combiner.h"
16 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
17 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
18 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
19 #include "llvm/CodeGen/TargetPassConfig.h"
20 #include "llvm/InitializePasses.h"
21 
22 #define DEBUG_TYPE "mips-prelegalizer-combiner"
23 
24 using namespace llvm;
25 
26 namespace {
27 class MipsPreLegalizerCombinerInfo : public CombinerInfo {
28 public:
29   MipsPreLegalizerCombinerInfo()
30       : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
31                      /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
32                      /*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
33   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
34                        MachineIRBuilder &B) const override;
35 };
36 
37 bool MipsPreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
38                                            MachineInstr &MI,
39                                            MachineIRBuilder &B) const {
40   CombinerHelper Helper(Observer, B);
41 
42   switch (MI.getOpcode()) {
43   default:
44     return false;
45   case TargetOpcode::G_LOAD:
46   case TargetOpcode::G_SEXTLOAD:
47   case TargetOpcode::G_ZEXTLOAD:
48     return Helper.tryCombineExtendingLoads(MI);
49   }
50   return false;
51 }
52 
53 // Pass boilerplate
54 // ================
55 
56 class MipsPreLegalizerCombiner : public MachineFunctionPass {
57 public:
58   static char ID;
59 
60   MipsPreLegalizerCombiner();
61 
62   StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
63 
64   bool runOnMachineFunction(MachineFunction &MF) override;
65 
66   void getAnalysisUsage(AnalysisUsage &AU) const override;
67 };
68 } // end anonymous namespace
69 
70 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
71   AU.addRequired<TargetPassConfig>();
72   AU.setPreservesCFG();
73   getSelectionDAGFallbackAnalysisUsage(AU);
74   MachineFunctionPass::getAnalysisUsage(AU);
75 }
76 
77 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
78   initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
79 }
80 
81 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
82   if (MF.getProperties().hasProperty(
83           MachineFunctionProperties::Property::FailedISel))
84     return false;
85   auto *TPC = &getAnalysis<TargetPassConfig>();
86   MipsPreLegalizerCombinerInfo PCInfo;
87   Combiner C(PCInfo, TPC);
88   return C.combineMachineInstrs(MF, nullptr);
89 }
90 
91 char MipsPreLegalizerCombiner::ID = 0;
92 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
93                       "Combine Mips machine instrs before legalization", false,
94                       false)
95 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
96 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
97                     "Combine Mips machine instrs before legalization", false,
98                     false)
99 
100 namespace llvm {
101 FunctionPass *createMipsPreLegalizeCombiner() {
102   return new MipsPreLegalizerCombiner();
103 }
104 } // end namespace llvm
105