1 //===-- HexagonPeephole.cpp - Hexagon Peephole Optimiztions ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 // This peephole pass optimizes in the following cases.
9 // 1. Optimizes redundant sign extends for the following case
10 // Transform the following pattern
11 // %vreg170<def> = SXTW %vreg166
13 // %vreg176<def> = COPY %vreg170:subreg_loreg
16 // %vreg176<def> = COPY vreg166
18 // 2. Optimizes redundant negation of predicates.
19 // %vreg15<def> = CMPGTrr %vreg6, %vreg2
21 // %vreg16<def> = NOT_p %vreg15<kill>
23 // JMP_c %vreg16<kill>, <BB#1>, %PC<imp-def,dead>
26 // %vreg15<def> = CMPGTrr %vreg6, %vreg2;
28 // JMP_cNot %vreg15<kill>, <BB#1>, %PC<imp-def,dead>;
30 // Note: The peephole pass makes the instrucstions like
31 // %vreg170<def> = SXTW %vreg166 or %vreg16<def> = NOT_p %vreg15<kill>
32 // redundant and relies on some form of dead removal instrucions, like
33 // DCE or DIE to actually eliminate them.
36 //===----------------------------------------------------------------------===//
38 #define DEBUG_TYPE "hexagon-peephole"
40 #include "HexagonTargetMachine.h"
41 #include "llvm/ADT/DenseMap.h"
42 #include "llvm/ADT/Statistic.h"
43 #include "llvm/CodeGen/MachineFunction.h"
44 #include "llvm/CodeGen/MachineFunctionPass.h"
45 #include "llvm/CodeGen/MachineInstrBuilder.h"
46 #include "llvm/CodeGen/MachineRegisterInfo.h"
47 #include "llvm/CodeGen/Passes.h"
48 #include "llvm/IR/Constants.h"
49 #include "llvm/PassSupport.h"
50 #include "llvm/Support/CommandLine.h"
51 #include "llvm/Support/Debug.h"
52 #include "llvm/Support/raw_ostream.h"
53 #include "llvm/Target/TargetInstrInfo.h"
54 #include "llvm/Target/TargetMachine.h"
55 #include "llvm/Target/TargetRegisterInfo.h"
60 static cl::opt<bool> DisableHexagonPeephole("disable-hexagon-peephole",
61 cl::Hidden, cl::ZeroOrMore, cl::init(false),
62 cl::desc("Disable Peephole Optimization"));
65 DbgPNPCount("pnp-count", cl::init(-1), cl::Hidden,
66 cl::desc("Maximum number of P=NOT(P) to be optimized"));
68 static cl::opt<bool> DisablePNotP("disable-hexagon-pnotp",
69 cl::Hidden, cl::ZeroOrMore, cl::init(false),
70 cl::desc("Disable Optimization of PNotP"));
72 static cl::opt<bool> DisableOptSZExt("disable-hexagon-optszext",
73 cl::Hidden, cl::ZeroOrMore, cl::init(false),
74 cl::desc("Disable Optimization of Sign/Zero Extends"));
76 static cl::opt<bool> DisableOptExtTo64("disable-hexagon-opt-ext-to-64",
77 cl::Hidden, cl::ZeroOrMore, cl::init(false),
78 cl::desc("Disable Optimization of extensions to i64."));
81 struct HexagonPeephole : public MachineFunctionPass {
82 const HexagonInstrInfo *QII;
83 const HexagonRegisterInfo *QRI;
84 const MachineRegisterInfo *MRI;
88 HexagonPeephole() : MachineFunctionPass(ID) { }
90 bool runOnMachineFunction(MachineFunction &MF);
92 const char *getPassName() const {
93 return "Hexagon optimize redundant zero and size extends";
96 void getAnalysisUsage(AnalysisUsage &AU) const {
97 MachineFunctionPass::getAnalysisUsage(AU);
101 void ChangeOpInto(MachineOperand &Dst, MachineOperand &Src);
105 char HexagonPeephole::ID = 0;
107 bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
109 QII = static_cast<const HexagonInstrInfo *>(MF.getTarget().
111 QRI = static_cast<const HexagonRegisterInfo *>(MF.getTarget().
113 MRI = &MF.getRegInfo();
115 DenseMap<unsigned, unsigned> PeepholeMap;
116 DenseMap<unsigned, std::pair<unsigned, unsigned> > PeepholeDoubleRegsMap;
118 if (DisableHexagonPeephole) return false;
120 // Loop over all of the basic blocks.
121 for (MachineFunction::iterator MBBb = MF.begin(), MBBe = MF.end();
122 MBBb != MBBe; ++MBBb) {
123 MachineBasicBlock* MBB = MBBb;
125 PeepholeDoubleRegsMap.clear();
127 // Traverse the basic block.
128 for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
130 MachineInstr *MI = MII;
131 // Look for sign extends:
132 // %vreg170<def> = SXTW %vreg166
133 if (!DisableOptSZExt && MI->getOpcode() == Hexagon::SXTW) {
134 assert (MI->getNumOperands() == 2);
135 MachineOperand &Dst = MI->getOperand(0);
136 MachineOperand &Src = MI->getOperand(1);
137 unsigned DstReg = Dst.getReg();
138 unsigned SrcReg = Src.getReg();
139 // Just handle virtual registers.
140 if (TargetRegisterInfo::isVirtualRegister(DstReg) &&
141 TargetRegisterInfo::isVirtualRegister(SrcReg)) {
142 // Map the following:
143 // %vreg170<def> = SXTW %vreg166
144 // PeepholeMap[170] = vreg166
145 PeepholeMap[DstReg] = SrcReg;
149 // Look for %vreg170<def> = COMBINE_ir_V4 (0, %vreg169)
150 // %vreg170:DoublRegs, %vreg169:IntRegs
151 if (!DisableOptExtTo64 &&
152 MI->getOpcode () == Hexagon::COMBINE_Ir_V4) {
153 assert (MI->getNumOperands() == 3);
154 MachineOperand &Dst = MI->getOperand(0);
155 MachineOperand &Src1 = MI->getOperand(1);
156 MachineOperand &Src2 = MI->getOperand(2);
157 if (Src1.getImm() != 0)
159 unsigned DstReg = Dst.getReg();
160 unsigned SrcReg = Src2.getReg();
161 PeepholeMap[DstReg] = SrcReg;
164 // Look for this sequence below
165 // %vregDoubleReg1 = LSRd_ri %vregDoubleReg0, 32
166 // %vregIntReg = COPY %vregDoubleReg1:subreg_loreg.
168 // %vregIntReg = COPY %vregDoubleReg0:subreg_hireg.
169 if (MI->getOpcode() == Hexagon::LSRd_ri) {
170 assert(MI->getNumOperands() == 3);
171 MachineOperand &Dst = MI->getOperand(0);
172 MachineOperand &Src1 = MI->getOperand(1);
173 MachineOperand &Src2 = MI->getOperand(2);
174 if (Src2.getImm() != 32)
176 unsigned DstReg = Dst.getReg();
177 unsigned SrcReg = Src1.getReg();
178 PeepholeDoubleRegsMap[DstReg] =
179 std::make_pair(*&SrcReg, 1/*Hexagon::subreg_hireg*/);
182 // Look for P=NOT(P).
184 (MI->getOpcode() == Hexagon::NOT_p)) {
185 assert (MI->getNumOperands() == 2);
186 MachineOperand &Dst = MI->getOperand(0);
187 MachineOperand &Src = MI->getOperand(1);
188 unsigned DstReg = Dst.getReg();
189 unsigned SrcReg = Src.getReg();
190 // Just handle virtual registers.
191 if (TargetRegisterInfo::isVirtualRegister(DstReg) &&
192 TargetRegisterInfo::isVirtualRegister(SrcReg)) {
193 // Map the following:
194 // %vreg170<def> = NOT_xx %vreg166
195 // PeepholeMap[170] = vreg166
196 PeepholeMap[DstReg] = SrcReg;
201 // %vreg176<def> = COPY %vreg170:subreg_loreg
202 if (!DisableOptSZExt && MI->isCopy()) {
203 assert (MI->getNumOperands() == 2);
204 MachineOperand &Dst = MI->getOperand(0);
205 MachineOperand &Src = MI->getOperand(1);
207 // Make sure we are copying the lower 32 bits.
208 if (Src.getSubReg() != Hexagon::subreg_loreg)
211 unsigned DstReg = Dst.getReg();
212 unsigned SrcReg = Src.getReg();
213 if (TargetRegisterInfo::isVirtualRegister(DstReg) &&
214 TargetRegisterInfo::isVirtualRegister(SrcReg)) {
215 // Try to find in the map.
216 if (unsigned PeepholeSrc = PeepholeMap.lookup(SrcReg)) {
217 // Change the 1st operand.
218 MI->RemoveOperand(1);
219 MI->addOperand(MachineOperand::CreateReg(PeepholeSrc, false));
221 DenseMap<unsigned, std::pair<unsigned, unsigned> >::iterator DI =
222 PeepholeDoubleRegsMap.find(SrcReg);
223 if (DI != PeepholeDoubleRegsMap.end()) {
224 std::pair<unsigned,unsigned> PeepholeSrc = DI->second;
225 MI->RemoveOperand(1);
226 MI->addOperand(MachineOperand::CreateReg(PeepholeSrc.first,
232 false /*isEarlyClobber*/,
233 PeepholeSrc.second));
239 // Look for Predicated instructions.
242 if (QII->isPredicated(MI)) {
243 MachineOperand &Op0 = MI->getOperand(0);
244 unsigned Reg0 = Op0.getReg();
245 const TargetRegisterClass *RC0 = MRI->getRegClass(Reg0);
246 if (RC0->getID() == Hexagon::PredRegsRegClassID) {
247 // Handle instructions that have a prediate register in op0
248 // (most cases of predicable instructions).
249 if (TargetRegisterInfo::isVirtualRegister(Reg0)) {
250 // Try to find in the map.
251 if (unsigned PeepholeSrc = PeepholeMap.lookup(Reg0)) {
252 // Change the 1st operand and, flip the opcode.
253 MI->getOperand(0).setReg(PeepholeSrc);
254 int NewOp = QII->getInvertedPredicatedOpcode(MI->getOpcode());
255 MI->setDesc(QII->get(NewOp));
263 // Handle special instructions.
264 unsigned Op = MI->getOpcode();
266 unsigned PR = 1, S1 = 2, S2 = 3; // Operand indices.
269 case Hexagon::TFR_condset_rr:
270 case Hexagon::TFR_condset_ii:
271 case Hexagon::MUX_ii:
272 case Hexagon::MUX_rr:
275 case Hexagon::TFR_condset_ri:
276 NewOp = Hexagon::TFR_condset_ir;
278 case Hexagon::TFR_condset_ir:
279 NewOp = Hexagon::TFR_condset_ri;
281 case Hexagon::MUX_ri:
282 NewOp = Hexagon::MUX_ir;
284 case Hexagon::MUX_ir:
285 NewOp = Hexagon::MUX_ri;
289 unsigned PSrc = MI->getOperand(PR).getReg();
290 if (unsigned POrig = PeepholeMap.lookup(PSrc)) {
291 MI->getOperand(PR).setReg(POrig);
292 MI->setDesc(QII->get(NewOp));
293 // Swap operands S1 and S2.
294 MachineOperand Op1 = MI->getOperand(S1);
295 MachineOperand Op2 = MI->getOperand(S2);
296 ChangeOpInto(MI->getOperand(S1), Op2);
297 ChangeOpInto(MI->getOperand(S2), Op1);
302 } // if (!DisablePNotP)
309 void HexagonPeephole::ChangeOpInto(MachineOperand &Dst, MachineOperand &Src) {
310 assert (&Dst != &Src && "Cannot duplicate into itself");
311 switch (Dst.getType()) {
312 case MachineOperand::MO_Register:
314 Dst.setReg(Src.getReg());
315 } else if (Src.isImm()) {
316 Dst.ChangeToImmediate(Src.getImm());
318 llvm_unreachable("Unexpected src operand type");
322 case MachineOperand::MO_Immediate:
324 Dst.setImm(Src.getImm());
325 } else if (Src.isReg()) {
326 Dst.ChangeToRegister(Src.getReg(), Src.isDef(), Src.isImplicit(),
327 Src.isKill(), Src.isDead(), Src.isUndef(),
330 llvm_unreachable("Unexpected src operand type");
335 llvm_unreachable("Unexpected dst operand type");
340 FunctionPass *llvm::createHexagonPeephole() {
341 return new HexagonPeephole();