1 //=== lib/CodeGen/GlobalISel/AArch64O0PreLegalizerCombiner.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 "AArch64GlobalISelUtils.h"
15 #include "AArch64TargetMachine.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/GlobalISel/MachineIRBuilder.h"
22 #include "llvm/CodeGen/MachineDominators.h"
23 #include "llvm/CodeGen/MachineFunction.h"
24 #include "llvm/CodeGen/MachineFunctionPass.h"
25 #include "llvm/CodeGen/MachineRegisterInfo.h"
26 #include "llvm/CodeGen/TargetPassConfig.h"
27 #include "llvm/IR/Instructions.h"
28 #include "llvm/Support/Debug.h"
29 
30 #define DEBUG_TYPE "aarch64-O0-prelegalizer-combiner"
31 
32 using namespace llvm;
33 using namespace MIPatternMatch;
34 
35 class AArch64O0PreLegalizerCombinerHelperState {
36 protected:
37   CombinerHelper &Helper;
38 
39 public:
40   AArch64O0PreLegalizerCombinerHelperState(CombinerHelper &Helper)
41       : Helper(Helper) {}
42 };
43 
44 #define AARCH64O0PRELEGALIZERCOMBINERHELPER_GENCOMBINERHELPER_DEPS
45 #include "AArch64GenO0PreLegalizeGICombiner.inc"
46 #undef AARCH64O0PRELEGALIZERCOMBINERHELPER_GENCOMBINERHELPER_DEPS
47 
48 namespace {
49 #define AARCH64O0PRELEGALIZERCOMBINERHELPER_GENCOMBINERHELPER_H
50 #include "AArch64GenO0PreLegalizeGICombiner.inc"
51 #undef AARCH64O0PRELEGALIZERCOMBINERHELPER_GENCOMBINERHELPER_H
52 
53 class AArch64O0PreLegalizerCombinerInfo : public CombinerInfo {
54   GISelKnownBits *KB;
55   MachineDominatorTree *MDT;
56   AArch64GenO0PreLegalizerCombinerHelperRuleConfig GeneratedRuleCfg;
57 
58 public:
59   AArch64O0PreLegalizerCombinerInfo(bool EnableOpt, bool OptSize, bool MinSize,
60                                     GISelKnownBits *KB,
61                                     MachineDominatorTree *MDT)
62       : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
63                      /*LegalizerInfo*/ nullptr, EnableOpt, OptSize, MinSize),
64         KB(KB), MDT(MDT) {
65     if (!GeneratedRuleCfg.parseCommandLineOption())
66       report_fatal_error("Invalid rule identifier");
67   }
68 
69   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
70                        MachineIRBuilder &B) const override;
71 };
72 
73 bool AArch64O0PreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
74                                                 MachineInstr &MI,
75                                                 MachineIRBuilder &B) const {
76   CombinerHelper Helper(Observer, B, KB, MDT);
77   AArch64GenO0PreLegalizerCombinerHelper Generated(GeneratedRuleCfg, Helper);
78 
79   if (Generated.tryCombineAll(Observer, MI, B))
80     return true;
81 
82   unsigned Opc = MI.getOpcode();
83   switch (Opc) {
84   case TargetOpcode::G_CONCAT_VECTORS:
85     return Helper.tryCombineConcatVectors(MI);
86   case TargetOpcode::G_SHUFFLE_VECTOR:
87     return Helper.tryCombineShuffleVector(MI);
88   case TargetOpcode::G_MEMCPY_INLINE:
89     return Helper.tryEmitMemcpyInline(MI);
90   case TargetOpcode::G_MEMCPY:
91   case TargetOpcode::G_MEMMOVE:
92   case TargetOpcode::G_MEMSET: {
93     // At -O0 set a maxlen of 32 to inline;
94     unsigned MaxLen = 32;
95     // Try to inline memcpy type calls if optimizations are enabled.
96     if (Helper.tryCombineMemCpyFamily(MI, MaxLen))
97       return true;
98     if (Opc == TargetOpcode::G_MEMSET)
99       return llvm::AArch64GISelUtils::tryEmitBZero(MI, B, EnableMinSize);
100     return false;
101   }
102   }
103 
104   return false;
105 }
106 
107 #define AARCH64O0PRELEGALIZERCOMBINERHELPER_GENCOMBINERHELPER_CPP
108 #include "AArch64GenO0PreLegalizeGICombiner.inc"
109 #undef AARCH64O0PRELEGALIZERCOMBINERHELPER_GENCOMBINERHELPER_CPP
110 
111 // Pass boilerplate
112 // ================
113 
114 class AArch64O0PreLegalizerCombiner : public MachineFunctionPass {
115 public:
116   static char ID;
117 
118   AArch64O0PreLegalizerCombiner();
119 
120   StringRef getPassName() const override {
121     return "AArch64O0PreLegalizerCombiner";
122   }
123 
124   bool runOnMachineFunction(MachineFunction &MF) override;
125 
126   void getAnalysisUsage(AnalysisUsage &AU) const override;
127 };
128 } // end anonymous namespace
129 
130 void AArch64O0PreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
131   AU.addRequired<TargetPassConfig>();
132   AU.setPreservesCFG();
133   getSelectionDAGFallbackAnalysisUsage(AU);
134   AU.addRequired<GISelKnownBitsAnalysis>();
135   AU.addPreserved<GISelKnownBitsAnalysis>();
136   MachineFunctionPass::getAnalysisUsage(AU);
137 }
138 
139 AArch64O0PreLegalizerCombiner::AArch64O0PreLegalizerCombiner()
140     : MachineFunctionPass(ID) {
141   initializeAArch64O0PreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
142 }
143 
144 bool AArch64O0PreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
145   if (MF.getProperties().hasProperty(
146           MachineFunctionProperties::Property::FailedISel))
147     return false;
148   auto &TPC = getAnalysis<TargetPassConfig>();
149 
150   const Function &F = MF.getFunction();
151   GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
152   AArch64O0PreLegalizerCombinerInfo PCInfo(
153       false, F.hasOptSize(), F.hasMinSize(), KB, nullptr /* MDT */);
154   Combiner C(PCInfo, &TPC);
155   return C.combineMachineInstrs(MF, nullptr /* CSEInfo */);
156 }
157 
158 char AArch64O0PreLegalizerCombiner::ID = 0;
159 INITIALIZE_PASS_BEGIN(AArch64O0PreLegalizerCombiner, DEBUG_TYPE,
160                       "Combine AArch64 machine instrs before legalization",
161                       false, false)
162 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
163 INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
164 INITIALIZE_PASS_DEPENDENCY(GISelCSEAnalysisWrapperPass)
165 INITIALIZE_PASS_END(AArch64O0PreLegalizerCombiner, DEBUG_TYPE,
166                     "Combine AArch64 machine instrs before legalization", false,
167                     false)
168 
169 namespace llvm {
170 FunctionPass *createAArch64O0PreLegalizerCombiner() {
171   return new AArch64O0PreLegalizerCombiner();
172 }
173 } // end namespace llvm
174