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:
MipsPreLegalizerCombinerInfo()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
combine(GISelChangeObserver & Observer,MachineInstr & MI,MachineIRBuilder & B) const37 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 // Don't attempt to combine non power of 2 loads or unaligned loads when
49 // subtarget doesn't support them.
50 auto MMO = *MI.memoperands_begin();
51 const MipsSubtarget &STI =
52 static_cast<const MipsSubtarget &>(MI.getMF()->getSubtarget());
53 if (!isPowerOf2_64(MMO->getSize()))
54 return false;
55 bool isUnaligned = MMO->getAlign() < MMO->getSize();
56 if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
57 return false;
58
59 return Helper.tryCombineExtendingLoads(MI);
60 }
61 }
62
63 return false;
64 }
65
66 // Pass boilerplate
67 // ================
68
69 class MipsPreLegalizerCombiner : public MachineFunctionPass {
70 public:
71 static char ID;
72
73 MipsPreLegalizerCombiner();
74
getPassName() const75 StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
76
77 bool runOnMachineFunction(MachineFunction &MF) override;
78
79 void getAnalysisUsage(AnalysisUsage &AU) const override;
80 };
81 } // end anonymous namespace
82
getAnalysisUsage(AnalysisUsage & AU) const83 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
84 AU.addRequired<TargetPassConfig>();
85 AU.setPreservesCFG();
86 getSelectionDAGFallbackAnalysisUsage(AU);
87 MachineFunctionPass::getAnalysisUsage(AU);
88 }
89
MipsPreLegalizerCombiner()90 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
91 initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
92 }
93
runOnMachineFunction(MachineFunction & MF)94 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
95 if (MF.getProperties().hasProperty(
96 MachineFunctionProperties::Property::FailedISel))
97 return false;
98 auto *TPC = &getAnalysis<TargetPassConfig>();
99 MipsPreLegalizerCombinerInfo PCInfo;
100 Combiner C(PCInfo, TPC);
101 return C.combineMachineInstrs(MF, nullptr);
102 }
103
104 char MipsPreLegalizerCombiner::ID = 0;
105 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
106 "Combine Mips machine instrs before legalization", false,
107 false)
108 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
109 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
110 "Combine Mips machine instrs before legalization", false,
111 false)
112
113 namespace llvm {
createMipsPreLegalizeCombiner()114 FunctionPass *createMipsPreLegalizeCombiner() {
115 return new MipsPreLegalizerCombiner();
116 }
117 } // end namespace llvm
118