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 "MipsLegalizerInfo.h"
15 #include "MipsTargetMachine.h"
16 #include "llvm/CodeGen/GlobalISel/Combiner.h"
17 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
18 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
19 #include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
20 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
21 #include "llvm/CodeGen/MachineFunctionPass.h"
22 #include "llvm/CodeGen/TargetPassConfig.h"
23 #include "llvm/InitializePasses.h"
24
25 #define DEBUG_TYPE "mips-prelegalizer-combiner"
26
27 using namespace llvm;
28
29 namespace {
30 struct MipsPreLegalizerCombinerInfo : public CombinerInfo {
31 public:
MipsPreLegalizerCombinerInfo__anonb65b3b5c0111::MipsPreLegalizerCombinerInfo32 MipsPreLegalizerCombinerInfo()
33 : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
34 /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
35 /*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
36 };
37
38 class MipsPreLegalizerCombinerImpl : public Combiner {
39 protected:
40 const MipsSubtarget &STI;
41 // TODO: Make CombinerHelper methods const.
42 mutable CombinerHelper Helper;
43
44 public:
MipsPreLegalizerCombinerImpl(MachineFunction & MF,CombinerInfo & CInfo,const TargetPassConfig * TPC,GISelKnownBits & KB,GISelCSEInfo * CSEInfo,const MipsSubtarget & STI,MachineDominatorTree * MDT,const LegalizerInfo * LI)45 MipsPreLegalizerCombinerImpl(MachineFunction &MF, CombinerInfo &CInfo,
46 const TargetPassConfig *TPC, GISelKnownBits &KB,
47 GISelCSEInfo *CSEInfo, const MipsSubtarget &STI,
48 MachineDominatorTree *MDT,
49 const LegalizerInfo *LI)
50 : Combiner(MF, CInfo, TPC, &KB, CSEInfo), STI(STI),
51 Helper(Observer, B, /*IsPreLegalize*/ true, &KB, MDT, LI) {}
52
getName()53 static const char *getName() { return "MipsPreLegalizerCombiner"; }
54
setupGeneratedPerFunctionState(MachineFunction & MF)55 void setupGeneratedPerFunctionState(MachineFunction &MF) override {
56 // TODO: TableGen-erate this class' impl.
57 }
58
tryCombineAll(MachineInstr & MI) const59 bool tryCombineAll(MachineInstr &MI) const override {
60
61 switch (MI.getOpcode()) {
62 default:
63 return false;
64 case TargetOpcode::G_MEMCPY_INLINE:
65 return Helper.tryEmitMemcpyInline(MI);
66 case TargetOpcode::G_LOAD:
67 case TargetOpcode::G_SEXTLOAD:
68 case TargetOpcode::G_ZEXTLOAD: {
69 // Don't attempt to combine non power of 2 loads or unaligned loads when
70 // subtarget doesn't support them.
71 auto MMO = *MI.memoperands_begin();
72 const MipsSubtarget &STI = MI.getMF()->getSubtarget<MipsSubtarget>();
73 if (!MMO->getSize().hasValue() ||
74 !isPowerOf2_64(MMO->getSize().getValue()))
75 return false;
76 bool isUnaligned = MMO->getAlign() < MMO->getSize().getValue();
77 if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
78 return false;
79
80 return Helper.tryCombineExtendingLoads(MI);
81 }
82 }
83
84 return false;
85 }
86 };
87
88 // Pass boilerplate
89 // ================
90
91 class MipsPreLegalizerCombiner : public MachineFunctionPass {
92 public:
93 static char ID;
94
95 MipsPreLegalizerCombiner();
96
getPassName() const97 StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
98
99 bool runOnMachineFunction(MachineFunction &MF) override;
100
101 void getAnalysisUsage(AnalysisUsage &AU) const override;
102 };
103 } // end anonymous namespace
104
getAnalysisUsage(AnalysisUsage & AU) const105 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
106 AU.addRequired<TargetPassConfig>();
107 AU.addRequired<GISelKnownBitsAnalysis>();
108 AU.addPreserved<GISelKnownBitsAnalysis>();
109 AU.setPreservesCFG();
110 getSelectionDAGFallbackAnalysisUsage(AU);
111 MachineFunctionPass::getAnalysisUsage(AU);
112 }
113
MipsPreLegalizerCombiner()114 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
115 initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
116 }
117
runOnMachineFunction(MachineFunction & MF)118 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
119 if (MF.getProperties().hasProperty(
120 MachineFunctionProperties::Property::FailedISel))
121 return false;
122
123 auto *TPC = &getAnalysis<TargetPassConfig>();
124 const MipsSubtarget &ST = MF.getSubtarget<MipsSubtarget>();
125 const MipsLegalizerInfo *LI =
126 static_cast<const MipsLegalizerInfo *>(ST.getLegalizerInfo());
127
128 GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
129 MipsPreLegalizerCombinerInfo PCInfo;
130 MipsPreLegalizerCombinerImpl Impl(MF, PCInfo, TPC, *KB, /*CSEInfo*/ nullptr,
131 ST, /*MDT*/ nullptr, LI);
132 return Impl.combineMachineInstrs();
133 }
134
135 char MipsPreLegalizerCombiner::ID = 0;
136 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
137 "Combine Mips machine instrs before legalization", false,
138 false)
139 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
140 INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
141 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
142 "Combine Mips machine instrs before legalization", false,
143 false)
144
145 namespace llvm {
createMipsPreLegalizeCombiner()146 FunctionPass *createMipsPreLegalizeCombiner() {
147 return new MipsPreLegalizerCombiner();
148 }
149 } // end namespace llvm
150