LLVM 20.0.0git
HexagonRDFOpt.cpp
Go to the documentation of this file.
1//===- HexagonRDFOpt.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#include "HexagonInstrInfo.h"
10#include "HexagonSubtarget.h"
12#include "RDFCopy.h"
13#include "RDFDeadCode.h"
14#include "llvm/ADT/DenseMap.h"
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/ADT/SetVector.h"
28#include "llvm/Pass.h"
31#include "llvm/Support/Debug.h"
34#include <cassert>
35#include <limits>
36#include <utility>
37
38using namespace llvm;
39using namespace rdf;
40
41namespace llvm {
42
45
46} // end namespace llvm
47
48static unsigned RDFCount = 0;
49
51 RDFLimit("hexagon-rdf-limit",
52 cl::init(std::numeric_limits<unsigned>::max()));
53
55
56static cl::opt<bool> RDFDump("hexagon-rdf-dump", cl::Hidden);
57static cl::opt<bool> RDFTrackReserved("hexagon-rdf-track-reserved", cl::Hidden);
58
59namespace {
60
61 class HexagonRDFOpt : public MachineFunctionPass {
62 public:
63 HexagonRDFOpt() : MachineFunctionPass(ID) {}
64
65 void getAnalysisUsage(AnalysisUsage &AU) const override {
68 AU.setPreservesAll();
70 }
71
72 StringRef getPassName() const override {
73 return "Hexagon RDF optimizations";
74 }
75
76 bool runOnMachineFunction(MachineFunction &MF) override;
77
80 MachineFunctionProperties::Property::NoVRegs);
81 }
82
83 static char ID;
84
85 private:
88 };
89
90struct HexagonCP : public CopyPropagation {
91 HexagonCP(DataFlowGraph &G) : CopyPropagation(G) {}
92
93 bool interpretAsCopy(const MachineInstr *MI, EqualityMap &EM) override;
94};
95
96struct HexagonDCE : public DeadCodeElimination {
99
101 void removeOperand(NodeAddr<InstrNode*> IA, unsigned OpNum);
102
103 bool run();
104};
105
106} // end anonymous namespace
107
108char HexagonRDFOpt::ID = 0;
109
110INITIALIZE_PASS_BEGIN(HexagonRDFOpt, "hexagon-rdf-opt",
111 "Hexagon RDF optimizations", false, false)
114INITIALIZE_PASS_END(HexagonRDFOpt, "hexagon-rdf-opt",
115 "Hexagon RDF optimizations", false, false)
116
117bool HexagonCP::interpretAsCopy(const MachineInstr *MI, EqualityMap &EM) {
118 auto mapRegs = [&EM] (RegisterRef DstR, RegisterRef SrcR) -> void {
119 EM.insert(std::make_pair(DstR, SrcR));
120 };
121
122 DataFlowGraph &DFG = getDFG();
123 unsigned Opc = MI->getOpcode();
124 switch (Opc) {
125 case Hexagon::A2_combinew: {
126 const MachineOperand &DstOp = MI->getOperand(0);
127 const MachineOperand &HiOp = MI->getOperand(1);
128 const MachineOperand &LoOp = MI->getOperand(2);
129 assert(DstOp.getSubReg() == 0 && "Unexpected subregister");
130 mapRegs(DFG.makeRegRef(DstOp.getReg(), Hexagon::isub_hi),
131 DFG.makeRegRef(HiOp.getReg(), HiOp.getSubReg()));
132 mapRegs(DFG.makeRegRef(DstOp.getReg(), Hexagon::isub_lo),
133 DFG.makeRegRef(LoOp.getReg(), LoOp.getSubReg()));
134 return true;
135 }
136 case Hexagon::A2_addi: {
137 const MachineOperand &A = MI->getOperand(2);
138 if (!A.isImm() || A.getImm() != 0)
139 return false;
140 [[fallthrough]];
141 }
142 case Hexagon::A2_tfr: {
143 const MachineOperand &DstOp = MI->getOperand(0);
144 const MachineOperand &SrcOp = MI->getOperand(1);
145 mapRegs(DFG.makeRegRef(DstOp.getReg(), DstOp.getSubReg()),
146 DFG.makeRegRef(SrcOp.getReg(), SrcOp.getSubReg()));
147 return true;
148 }
149 }
150
151 return CopyPropagation::interpretAsCopy(MI, EM);
152}
153
154bool HexagonDCE::run() {
155 bool Collected = collect();
156 if (!Collected)
157 return false;
158
159 const SetVector<NodeId> &DeadNodes = getDeadNodes();
160 const SetVector<NodeId> &DeadInstrs = getDeadInstrs();
161
162 using RefToInstrMap = DenseMap<NodeId, NodeId>;
163
164 RefToInstrMap R2I;
165 SetVector<NodeId> PartlyDead;
166 DataFlowGraph &DFG = getDFG();
167
168 for (NodeAddr<BlockNode*> BA : DFG.getFunc().Addr->members(DFG)) {
169 for (auto TA : BA.Addr->members_if(DFG.IsCode<NodeAttrs::Stmt>, DFG)) {
171 for (NodeAddr<RefNode*> RA : SA.Addr->members(DFG)) {
172 R2I.insert(std::make_pair(RA.Id, SA.Id));
173 if (DFG.IsDef(RA) && DeadNodes.count(RA.Id))
174 if (!DeadInstrs.count(SA.Id))
175 PartlyDead.insert(SA.Id);
176 }
177 }
178 }
179
180 // Nodes to remove.
181 SetVector<NodeId> Remove = DeadInstrs;
182
183 bool Changed = false;
184 for (NodeId N : PartlyDead) {
185 auto SA = DFG.addr<StmtNode*>(N);
186 if (trace())
187 dbgs() << "Partly dead: " << *SA.Addr->getCode();
188 Changed |= rewrite(SA, Remove);
189 }
190
191 return erase(Remove) || Changed;
192}
193
194void HexagonDCE::removeOperand(NodeAddr<InstrNode*> IA, unsigned OpNum) {
195 MachineInstr *MI = NodeAddr<StmtNode*>(IA).Addr->getCode();
196
197 auto getOpNum = [MI] (MachineOperand &Op) -> unsigned {
198 for (unsigned i = 0, n = MI->getNumOperands(); i != n; ++i)
199 if (&MI->getOperand(i) == &Op)
200 return i;
201 llvm_unreachable("Invalid operand");
202 };
204 DataFlowGraph &DFG = getDFG();
205 NodeList Refs = IA.Addr->members(DFG);
206 for (NodeAddr<RefNode*> RA : Refs)
207 OpMap.insert(std::make_pair(RA.Id, getOpNum(RA.Addr->getOp())));
208
209 MI->removeOperand(OpNum);
210
211 for (NodeAddr<RefNode*> RA : Refs) {
212 unsigned N = OpMap[RA.Id];
213 if (N < OpNum)
214 RA.Addr->setRegRef(&MI->getOperand(N), DFG);
215 else if (N > OpNum)
216 RA.Addr->setRegRef(&MI->getOperand(N-1), DFG);
217 }
218}
219
220bool HexagonDCE::rewrite(NodeAddr<InstrNode*> IA, SetVector<NodeId> &Remove) {
221 if (!getDFG().IsCode<NodeAttrs::Stmt>(IA))
222 return false;
223 DataFlowGraph &DFG = getDFG();
224 MachineInstr &MI = *NodeAddr<StmtNode*>(IA).Addr->getCode();
225 auto &HII = static_cast<const HexagonInstrInfo&>(DFG.getTII());
226 if (HII.getAddrMode(MI) != HexagonII::PostInc)
227 return false;
228 unsigned Opc = MI.getOpcode();
229 unsigned OpNum, NewOpc;
230 switch (Opc) {
231 case Hexagon::L2_loadri_pi:
232 NewOpc = Hexagon::L2_loadri_io;
233 OpNum = 1;
234 break;
235 case Hexagon::L2_loadrd_pi:
236 NewOpc = Hexagon::L2_loadrd_io;
237 OpNum = 1;
238 break;
239 case Hexagon::V6_vL32b_pi:
240 NewOpc = Hexagon::V6_vL32b_ai;
241 OpNum = 1;
242 break;
243 case Hexagon::S2_storeri_pi:
244 NewOpc = Hexagon::S2_storeri_io;
245 OpNum = 0;
246 break;
247 case Hexagon::S2_storerd_pi:
248 NewOpc = Hexagon::S2_storerd_io;
249 OpNum = 0;
250 break;
251 case Hexagon::V6_vS32b_pi:
252 NewOpc = Hexagon::V6_vS32b_ai;
253 OpNum = 0;
254 break;
255 default:
256 return false;
257 }
258 auto IsDead = [this] (NodeAddr<DefNode*> DA) -> bool {
259 return getDeadNodes().count(DA.Id);
260 };
261 NodeList Defs;
262 MachineOperand &Op = MI.getOperand(OpNum);
263 for (NodeAddr<DefNode*> DA : IA.Addr->members_if(DFG.IsDef, DFG)) {
264 if (&DA.Addr->getOp() != &Op)
265 continue;
266 Defs = DFG.getRelatedRefs(IA, DA);
267 if (!llvm::all_of(Defs, IsDead))
268 return false;
269 break;
270 }
271
272 // Mark all nodes in Defs for removal.
273 for (auto D : Defs)
274 Remove.insert(D.Id);
275
276 if (trace())
277 dbgs() << "Rewriting: " << MI;
278 MI.setDesc(HII.get(NewOpc));
279 MI.getOperand(OpNum+2).setImm(0);
280 removeOperand(IA, OpNum);
281 if (trace())
282 dbgs() << " to: " << MI;
283
284 return true;
285}
286
287bool HexagonRDFOpt::runOnMachineFunction(MachineFunction &MF) {
288 if (skipFunction(MF.getFunction()))
289 return false;
290
291 // Perform RDF optimizations only if number of basic blocks in the
292 // function is less than the limit
293 if (MF.size() > RDFFuncBlockLimit) {
294 if (RDFDump)
295 dbgs() << "Skipping " << getPassName() << ": too many basic blocks\n";
296 return false;
297 }
298
299 if (RDFLimit.getPosition()) {
300 if (RDFCount >= RDFLimit)
301 return false;
302 RDFCount++;
303 }
304
305 MDT = &getAnalysis<MachineDominatorTreeWrapperPass>().getDomTree();
306 const auto &MDF = getAnalysis<MachineDominanceFrontier>();
307 const auto &HII = *MF.getSubtarget<HexagonSubtarget>().getInstrInfo();
308 const auto &HRI = *MF.getSubtarget<HexagonSubtarget>().getRegisterInfo();
309 MRI = &MF.getRegInfo();
310 bool Changed;
311
312 if (RDFDump)
313 MF.print(dbgs() << "Before " << getPassName() << "\n", nullptr);
314
315 DataFlowGraph G(MF, HII, HRI, *MDT, MDF);
316 // Dead phi nodes are necessary for copy propagation: we can add a use
317 // of a register in a block where it would need a phi node, but which
318 // was dead (and removed) during the graph build time.
323 G.build(Cfg);
324
325 if (RDFDump)
326 dbgs() << "Starting copy propagation on: " << MF.getName() << '\n'
327 << PrintNode<FuncNode*>(G.getFunc(), G) << '\n';
328 HexagonCP CP(G);
329 CP.trace(RDFDump);
330 Changed = CP.run();
331
332 if (RDFDump)
333 dbgs() << "Starting dead code elimination on: " << MF.getName() << '\n'
334 << PrintNode<FuncNode*>(G.getFunc(), G) << '\n';
335 HexagonDCE DCE(G, *MRI);
336 DCE.trace(RDFDump);
337 Changed |= DCE.run();
338
339 if (Changed) {
340 if (RDFDump) {
341 dbgs() << "Starting liveness recomputation on: " << MF.getName() << '\n'
342 << PrintNode<FuncNode*>(G.getFunc(), G) << '\n';
343 }
344 Liveness LV(*MRI, G);
345 LV.trace(RDFDump);
346 LV.computeLiveIns();
347 LV.resetLiveIns();
348 LV.resetKills();
349 }
350
351 if (RDFDump)
352 MF.print(dbgs() << "After " << getPassName() << "\n", nullptr);
353
354 return false;
355}
356
358 return new HexagonRDFOpt();
359}
unsigned const MachineRegisterInfo * MRI
aarch64 promote const
static GCRegistry::Add< ErlangGC > A("erlang", "erlang-compatible garbage collector")
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
This file defines the DenseMap class.
static cl::opt< bool > RDFTrackReserved("hexagon-rdf-track-reserved", cl::Hidden)
static cl::opt< unsigned > RDFLimit("hexagon-rdf-limit", cl::init(std::numeric_limits< unsigned >::max()))
hexagon rdf Hexagon RDF optimizations
hexagon rdf opt
cl::opt< unsigned > RDFFuncBlockLimit
static unsigned RDFCount
static cl::opt< bool > RDFDump("hexagon-rdf-dump", cl::Hidden)
IRTranslator LLVM IR MI
#define G(x, y, z)
Definition: MD5.cpp:56
#define INITIALIZE_PASS_DEPENDENCY(depName)
Definition: PassSupport.h:55
#define INITIALIZE_PASS_END(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:57
#define INITIALIZE_PASS_BEGIN(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:52
static bool rewrite(Function &F)
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
bool IsDead
SI optimize exec mask operations pre RA
This file contains some templates that are useful if you are working with the STL at all.
This file implements a set that has insertion order iteration characteristics.
Represent the analysis usage information of a pass.
AnalysisUsage & addRequired()
void setPreservesAll()
Set by analyses that do not transform their input at all.
This class represents an Operation in the Expression.
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: DenseMap.h:211
Register getReg() const
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:310
Analysis pass which computes a MachineDominatorTree.
DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to compute a normal dominat...
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
virtual bool runOnMachineFunction(MachineFunction &MF)=0
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
virtual MachineFunctionProperties getRequiredProperties() const
Properties which a MachineFunction may have at a given point in time.
MachineFunctionProperties & set(Property P)
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
StringRef getName() const
getName - Return the name of the corresponding LLVM function.
unsigned size() const
MachineRegisterInfo & getRegInfo()
getRegInfo - Return information about the registers currently in use.
Function & getFunction()
Return the LLVM function that this machine code represents.
void print(raw_ostream &OS, const SlotIndexes *=nullptr) const
print - Print out the MachineFunction in a format suitable for debugging to the specified stream.
Representation of each machine instruction.
Definition: MachineInstr.h:69
MachineOperand class - Representation of each machine instruction operand.
unsigned getSubReg() const
Register getReg() const
getReg - Returns the register number.
MachineRegisterInfo - Keep track of information for virtual and physical registers,...
PassRegistry - This class manages the registration and intitialization of the pass subsystem as appli...
Definition: PassRegistry.h:37
virtual StringRef getPassName() const
getPassName - Return a nice clean name for a pass.
Definition: Pass.cpp:81
A vector that has set insertion semantics.
Definition: SetVector.h:57
size_type count(const key_type &key) const
Count the number of elements of a given key in the SetVector.
Definition: SetVector.h:264
bool insert(const value_type &X)
Insert a new element into the SetVector.
Definition: SetVector.h:162
Register getReg() const
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
unsigned ID
LLVM IR allows to use arbitrary numbers as calling convention identifiers.
Definition: CallingConv.h:24
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:443
PointerTypeMap run(const Module &M)
Compute the PointerTypeMap for the module M.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
bool all_of(R &&range, UnaryPredicate P)
Provide wrappers to std::all_of which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1722
void initializeHexagonRDFOptPass(PassRegistry &)
void erase(Container &C, ValueType V)
Wrapper function to remove a value from a container:
Definition: STLExtras.h:2072
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
DWARFExpression::Operation Op
FunctionPass * createHexagonRDFOpt()
#define N
NodeList members(const DataFlowGraph &G) const
Definition: RDFGraph.cpp:520
RegisterRef makeRegRef(unsigned Reg, unsigned Sub) const
Definition: RDFGraph.cpp:985
static bool IsDef(const Node BA)
Definition: RDFGraph.h:825
Func getFunc() const
Definition: RDFGraph.h:693
NodeList getRelatedRefs(Instr IA, Ref RA) const
Definition: RDFGraph.cpp:1136
const TargetInstrInfo & getTII() const
Definition: RDFGraph.h:695
static bool IsCode(const Node BA)
Definition: RDFGraph.h:821
NodeAddr< T > addr(NodeId N) const
Definition: RDFGraph.h:689