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/MachineFunctionPass.h"
20 #include "llvm/CodeGen/TargetPassConfig.h"
21 #include "llvm/InitializePasses.h"
22
23 #define DEBUG_TYPE "mips-prelegalizer-combiner"
24
25 using namespace llvm;
26
27 namespace {
28 class MipsPreLegalizerCombinerInfo : public CombinerInfo {
29 public:
MipsPreLegalizerCombinerInfo()30 MipsPreLegalizerCombinerInfo()
31 : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
32 /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
33 /*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
34 bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
35 MachineIRBuilder &B) const override;
36 };
37
combine(GISelChangeObserver & Observer,MachineInstr & MI,MachineIRBuilder & B) const38 bool MipsPreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
39 MachineInstr &MI,
40 MachineIRBuilder &B) const {
41 CombinerHelper Helper(Observer, B, /*IsPreLegalize*/ true);
42
43 switch (MI.getOpcode()) {
44 default:
45 return false;
46 case TargetOpcode::G_MEMCPY_INLINE:
47 return Helper.tryEmitMemcpyInline(MI);
48 case TargetOpcode::G_LOAD:
49 case TargetOpcode::G_SEXTLOAD:
50 case TargetOpcode::G_ZEXTLOAD: {
51 // Don't attempt to combine non power of 2 loads or unaligned loads when
52 // subtarget doesn't support them.
53 auto MMO = *MI.memoperands_begin();
54 const MipsSubtarget &STI = MI.getMF()->getSubtarget<MipsSubtarget>();
55 if (!isPowerOf2_64(MMO->getSize()))
56 return false;
57 bool isUnaligned = MMO->getAlign() < MMO->getSize();
58 if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
59 return false;
60
61 return Helper.tryCombineExtendingLoads(MI);
62 }
63 }
64
65 return false;
66 }
67
68 // Pass boilerplate
69 // ================
70
71 class MipsPreLegalizerCombiner : public MachineFunctionPass {
72 public:
73 static char ID;
74
75 MipsPreLegalizerCombiner();
76
getPassName() const77 StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
78
79 bool runOnMachineFunction(MachineFunction &MF) override;
80
81 void getAnalysisUsage(AnalysisUsage &AU) const override;
82 };
83 } // end anonymous namespace
84
getAnalysisUsage(AnalysisUsage & AU) const85 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
86 AU.addRequired<TargetPassConfig>();
87 AU.setPreservesCFG();
88 getSelectionDAGFallbackAnalysisUsage(AU);
89 MachineFunctionPass::getAnalysisUsage(AU);
90 }
91
MipsPreLegalizerCombiner()92 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
93 initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
94 }
95
runOnMachineFunction(MachineFunction & MF)96 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
97 if (MF.getProperties().hasProperty(
98 MachineFunctionProperties::Property::FailedISel))
99 return false;
100 auto *TPC = &getAnalysis<TargetPassConfig>();
101 MipsPreLegalizerCombinerInfo PCInfo;
102 Combiner C(PCInfo, TPC);
103 return C.combineMachineInstrs(MF, nullptr);
104 }
105
106 char MipsPreLegalizerCombiner::ID = 0;
107 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
108 "Combine Mips machine instrs before legalization", false,
109 false)
110 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
111 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
112 "Combine Mips machine instrs before legalization", false,
113 false)
114
115 namespace llvm {
createMipsPreLegalizeCombiner()116 FunctionPass *createMipsPreLegalizeCombiner() {
117 return new MipsPreLegalizerCombiner();
118 }
119 } // end namespace llvm
120