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/GIMatchTableExecutorImpl.h"
20#include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
21#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
22#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
23#include "llvm/CodeGen/MachineDominators.h"
24#include "llvm/CodeGen/MachineFunction.h"
25#include "llvm/CodeGen/MachineFunctionPass.h"
26#include "llvm/CodeGen/MachineRegisterInfo.h"
27#include "llvm/CodeGen/TargetPassConfig.h"
28#include "llvm/IR/Instructions.h"
29#include "llvm/Support/Debug.h"
30
31#define GET_GICOMBINER_DEPS
32#include "AArch64GenO0PreLegalizeGICombiner.inc"
33#undef GET_GICOMBINER_DEPS
34
35#define DEBUG_TYPE "aarch64-O0-prelegalizer-combiner"
36
37using namespace llvm;
38using namespace MIPatternMatch;
39namespace {
40#define GET_GICOMBINER_TYPES
41#include "AArch64GenO0PreLegalizeGICombiner.inc"
42#undef GET_GICOMBINER_TYPES
43
44class AArch64O0PreLegalizerCombinerImpl : public Combiner {
45protected:
46 // TODO: Make CombinerHelper methods const.
47 mutable CombinerHelper Helper;
48 const AArch64O0PreLegalizerCombinerImplRuleConfig &RuleConfig;
49 const AArch64Subtarget &STI;
50
51public:
52 AArch64O0PreLegalizerCombinerImpl(
53 MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
54 GISelKnownBits &KB, GISelCSEInfo *CSEInfo,
55 const AArch64O0PreLegalizerCombinerImplRuleConfig &RuleConfig,
56 const AArch64Subtarget &STI);
57
58 static const char *getName() { return "AArch64O0PreLegalizerCombiner"; }
59
60 bool tryCombineAll(MachineInstr &I) const override;
61
62 bool tryCombineAllImpl(MachineInstr &I) const;
63
64private:
65#define GET_GICOMBINER_CLASS_MEMBERS
66#include "AArch64GenO0PreLegalizeGICombiner.inc"
67#undef GET_GICOMBINER_CLASS_MEMBERS
68};
69
70#define GET_GICOMBINER_IMPL
71#include "AArch64GenO0PreLegalizeGICombiner.inc"
72#undef GET_GICOMBINER_IMPL
73
74AArch64O0PreLegalizerCombinerImpl::AArch64O0PreLegalizerCombinerImpl(
75 MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
76 GISelKnownBits &KB, GISelCSEInfo *CSEInfo,
77 const AArch64O0PreLegalizerCombinerImplRuleConfig &RuleConfig,
78 const AArch64Subtarget &STI)
79 : Combiner(MF, CInfo, TPC, &KB, CSEInfo),
80 Helper(Observer, B, /*IsPreLegalize*/ true, &KB), RuleConfig(RuleConfig),
81 STI(STI),
82#define GET_GICOMBINER_CONSTRUCTOR_INITS
83#include "AArch64GenO0PreLegalizeGICombiner.inc"
84#undef GET_GICOMBINER_CONSTRUCTOR_INITS
85{
86}
87
88bool AArch64O0PreLegalizerCombinerImpl::tryCombineAll(MachineInstr &MI) const {
89 if (tryCombineAllImpl(I&: MI))
90 return true;
91
92 unsigned Opc = MI.getOpcode();
93 switch (Opc) {
94 case TargetOpcode::G_SHUFFLE_VECTOR:
95 return Helper.tryCombineShuffleVector(MI);
96 case TargetOpcode::G_MEMCPY_INLINE:
97 return Helper.tryEmitMemcpyInline(MI);
98 case TargetOpcode::G_MEMCPY:
99 case TargetOpcode::G_MEMMOVE:
100 case TargetOpcode::G_MEMSET: {
101 // At -O0 set a maxlen of 32 to inline;
102 unsigned MaxLen = 32;
103 // Try to inline memcpy type calls if optimizations are enabled.
104 if (Helper.tryCombineMemCpyFamily(MI, MaxLen))
105 return true;
106 if (Opc == TargetOpcode::G_MEMSET)
107 return llvm::AArch64GISelUtils::tryEmitBZero(MI, MIRBuilder&: B, MinSize: CInfo.EnableMinSize);
108 return false;
109 }
110 }
111
112 return false;
113}
114
115// Pass boilerplate
116// ================
117
118class AArch64O0PreLegalizerCombiner : public MachineFunctionPass {
119public:
120 static char ID;
121
122 AArch64O0PreLegalizerCombiner();
123
124 StringRef getPassName() const override {
125 return "AArch64O0PreLegalizerCombiner";
126 }
127
128 bool runOnMachineFunction(MachineFunction &MF) override;
129
130 void getAnalysisUsage(AnalysisUsage &AU) const override;
131
132private:
133 AArch64O0PreLegalizerCombinerImplRuleConfig RuleConfig;
134};
135} // end anonymous namespace
136
137void AArch64O0PreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
138 AU.addRequired<TargetPassConfig>();
139 AU.setPreservesCFG();
140 getSelectionDAGFallbackAnalysisUsage(AU);
141 AU.addRequired<GISelKnownBitsAnalysis>();
142 AU.addPreserved<GISelKnownBitsAnalysis>();
143 MachineFunctionPass::getAnalysisUsage(AU);
144}
145
146AArch64O0PreLegalizerCombiner::AArch64O0PreLegalizerCombiner()
147 : MachineFunctionPass(ID) {
148 initializeAArch64O0PreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
149
150 if (!RuleConfig.parseCommandLineOption())
151 report_fatal_error(reason: "Invalid rule identifier");
152}
153
154bool AArch64O0PreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
155 if (MF.getProperties().hasProperty(
156 P: MachineFunctionProperties::Property::FailedISel))
157 return false;
158 auto &TPC = getAnalysis<TargetPassConfig>();
159
160 const Function &F = MF.getFunction();
161 GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
162
163 const AArch64Subtarget &ST = MF.getSubtarget<AArch64Subtarget>();
164
165 CombinerInfo CInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
166 /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
167 F.hasOptSize(), F.hasMinSize());
168 // Disable fixed-point iteration in the Combiner. This improves compile-time
169 // at the cost of possibly missing optimizations. See PR#94291 for details.
170 CInfo.MaxIterations = 1;
171
172 AArch64O0PreLegalizerCombinerImpl Impl(MF, CInfo, &TPC, *KB,
173 /*CSEInfo*/ nullptr, RuleConfig, ST);
174 return Impl.combineMachineInstrs();
175}
176
177char AArch64O0PreLegalizerCombiner::ID = 0;
178INITIALIZE_PASS_BEGIN(AArch64O0PreLegalizerCombiner, DEBUG_TYPE,
179 "Combine AArch64 machine instrs before legalization",
180 false, false)
181INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
182INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
183INITIALIZE_PASS_DEPENDENCY(GISelCSEAnalysisWrapperPass)
184INITIALIZE_PASS_END(AArch64O0PreLegalizerCombiner, DEBUG_TYPE,
185 "Combine AArch64 machine instrs before legalization", false,
186 false)
187
188namespace llvm {
189FunctionPass *createAArch64O0PreLegalizerCombiner() {
190 return new AArch64O0PreLegalizerCombiner();
191}
192} // end namespace llvm
193