1//===- HexagonBitSimplify.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 "BitTracker.h" 10#include "HexagonBitTracker.h" 11#include "HexagonInstrInfo.h" 12#include "HexagonRegisterInfo.h" 13#include "HexagonSubtarget.h" 14#include "llvm/ADT/BitVector.h" 15#include "llvm/ADT/DenseMap.h" 16#include "llvm/ADT/GraphTraits.h" 17#include "llvm/ADT/STLExtras.h" 18#include "llvm/ADT/SmallVector.h" 19#include "llvm/ADT/StringRef.h" 20#include "llvm/CodeGen/MachineBasicBlock.h" 21#include "llvm/CodeGen/MachineDominators.h" 22#include "llvm/CodeGen/MachineFunction.h" 23#include "llvm/CodeGen/MachineFunctionPass.h" 24#include "llvm/CodeGen/MachineInstr.h" 25#include "llvm/CodeGen/MachineInstrBuilder.h" 26#include "llvm/CodeGen/MachineOperand.h" 27#include "llvm/CodeGen/MachineRegisterInfo.h" 28#include "llvm/CodeGen/TargetRegisterInfo.h" 29#include "llvm/IR/DebugLoc.h" 30#include "llvm/InitializePasses.h" 31#include "llvm/MC/MCInstrDesc.h" 32#include "llvm/Pass.h" 33#include "llvm/Support/CommandLine.h" 34#include "llvm/Support/Compiler.h" 35#include "llvm/Support/Debug.h" 36#include "llvm/Support/ErrorHandling.h" 37#include "llvm/Support/MathExtras.h" 38#include "llvm/Support/raw_ostream.h" 39#include <algorithm> 40#include <cassert> 41#include <cstdint> 42#include <deque> 43#include <iterator> 44#include <limits> 45#include <utility> 46#include <vector> 47 48#define DEBUG_TYPE "hexbit" 49 50using namespace llvm; 51 52static cl::opt<bool> PreserveTiedOps("hexbit-keep-tied", cl::Hidden, 53 cl::init(true), cl::desc("Preserve subregisters in tied operands")); 54static cl::opt<bool> GenExtract("hexbit-extract", cl::Hidden, 55 cl::init(true), cl::desc("Generate extract instructions")); 56static cl::opt<bool> GenBitSplit("hexbit-bitsplit", cl::Hidden, 57 cl::init(true), cl::desc("Generate bitsplit instructions")); 58 59static cl::opt<unsigned> MaxExtract("hexbit-max-extract", cl::Hidden, 60 cl::init(std::numeric_limits<unsigned>::max())); 61static unsigned CountExtract = 0; 62static cl::opt<unsigned> MaxBitSplit("hexbit-max-bitsplit", cl::Hidden, 63 cl::init(std::numeric_limits<unsigned>::max())); 64static unsigned CountBitSplit = 0; 65 66static cl::opt<unsigned> RegisterSetLimit("hexbit-registerset-limit", 67 cl::Hidden, cl::init(1000)); 68 69namespace llvm { 70 71 void initializeHexagonBitSimplifyPass(PassRegistry& Registry); 72 FunctionPass *createHexagonBitSimplify(); 73 74} // end namespace llvm 75 76namespace { 77 78 // Set of virtual registers, based on BitVector. 79 struct RegisterSet { 80 RegisterSet() = default; 81 explicit RegisterSet(unsigned s, bool t = false) : Bits(s, t) {} 82 RegisterSet(const RegisterSet &RS) = default; 83 84 void clear() { 85 Bits.clear(); 86 LRU.clear(); 87 } 88 89 unsigned count() const { 90 return Bits.count(); 91 } 92 93 unsigned find_first() const { 94 int First = Bits.find_first(); 95 if (First < 0) 96 return 0; 97 return x2v(First); 98 } 99 100 unsigned find_next(unsigned Prev) const { 101 int Next = Bits.find_next(v2x(Prev)); 102 if (Next < 0) 103 return 0; 104 return x2v(Next); 105 } 106 107 RegisterSet &insert(unsigned R) { 108 unsigned Idx = v2x(R); 109 ensure(Idx); 110 bool Exists = Bits.test(Idx); 111 Bits.set(Idx); 112 if (!Exists) { 113 LRU.push_back(Idx); 114 if (LRU.size() > RegisterSetLimit) { 115 unsigned T = LRU.front(); 116 Bits.reset(T); 117 LRU.pop_front(); 118 } 119 } 120 return *this; 121 } 122 RegisterSet &remove(unsigned R) { 123 unsigned Idx = v2x(R); 124 if (Idx < Bits.size()) { 125 bool Exists = Bits.test(Idx); 126 Bits.reset(Idx); 127 if (Exists) { 128 auto F = llvm::find(LRU, Idx); 129 assert(F != LRU.end()); 130 LRU.erase(F); 131 } 132 } 133 return *this; 134 } 135 136 RegisterSet &insert(const RegisterSet &Rs) { 137 for (unsigned R = Rs.find_first(); R; R = Rs.find_next(R)) 138 insert(R); 139 return *this; 140 } 141 RegisterSet &remove(const RegisterSet &Rs) { 142 for (unsigned R = Rs.find_first(); R; R = Rs.find_next(R)) 143 remove(R); 144 return *this; 145 } 146 147 bool operator[](unsigned R) const { 148 unsigned Idx = v2x(R); 149 return Idx < Bits.size() ? Bits[Idx] : false; 150 } 151 bool has(unsigned R) const { 152 unsigned Idx = v2x(R); 153 if (Idx >= Bits.size()) 154 return false; 155 return Bits.test(Idx); 156 } 157 158 bool empty() const { 159 return !Bits.any(); 160 } 161 bool includes(const RegisterSet &Rs) const { 162 // A.test(B) <=> A-B != {} 163 return !Rs.Bits.test(Bits); 164 } 165 bool intersects(const RegisterSet &Rs) const { 166 return Bits.anyCommon(Rs.Bits); 167 } 168 169 private: 170 BitVector Bits; 171 std::deque<unsigned> LRU; 172 173 void ensure(unsigned Idx) { 174 if (Bits.size() <= Idx) 175 Bits.resize(std::max(Idx+1, 32U)); 176 } 177 178 static inline unsigned v2x(unsigned v) { 179 return Register::virtReg2Index(v); 180 } 181 182 static inline unsigned x2v(unsigned x) { 183 return Register::index2VirtReg(x); 184 } 185 }; 186 187 struct PrintRegSet { 188 PrintRegSet(const RegisterSet &S, const TargetRegisterInfo *RI) 189 : RS(S), TRI(RI) {} 190 191 friend raw_ostream &operator<< (raw_ostream &OS, 192 const PrintRegSet &P); 193 194 private: 195 const RegisterSet &RS; 196 const TargetRegisterInfo *TRI; 197 }; 198 199 raw_ostream &operator<< (raw_ostream &OS, const PrintRegSet &P) 200 LLVM_ATTRIBUTE_UNUSED; 201 raw_ostream &operator<< (raw_ostream &OS, const PrintRegSet &P) { 202 OS << '{'; 203 for (unsigned R = P.RS.find_first(); R; R = P.RS.find_next(R)) 204 OS << ' ' << printReg(R, P.TRI); 205 OS << " }"; 206 return OS; 207 } 208 209 class Transformation; 210 211 class HexagonBitSimplify : public MachineFunctionPass { 212 public: 213 static char ID; 214 215 HexagonBitSimplify() : MachineFunctionPass(ID) {} 216 217 StringRef getPassName() const override { 218 return "Hexagon bit simplification"; 219 } 220 221 void getAnalysisUsage(AnalysisUsage &AU) const override { 222 AU.addRequired<MachineDominatorTree>(); 223 AU.addPreserved<MachineDominatorTree>(); 224 MachineFunctionPass::getAnalysisUsage(AU); 225 } 226 227 bool runOnMachineFunction(MachineFunction &MF) override; 228 229 static void getInstrDefs(const MachineInstr &MI, RegisterSet &Defs); 230 static void getInstrUses(const MachineInstr &MI, RegisterSet &Uses); 231 static bool isEqual(const BitTracker::RegisterCell &RC1, uint16_t B1, 232 const BitTracker::RegisterCell &RC2, uint16_t B2, uint16_t W); 233 static bool isZero(const BitTracker::RegisterCell &RC, uint16_t B, 234 uint16_t W); 235 static bool getConst(const BitTracker::RegisterCell &RC, uint16_t B, 236 uint16_t W, uint64_t &U); 237 static bool replaceReg(Register OldR, Register NewR, 238 MachineRegisterInfo &MRI); 239 static bool getSubregMask(const BitTracker::RegisterRef &RR, 240 unsigned &Begin, unsigned &Width, MachineRegisterInfo &MRI); 241 static bool replaceRegWithSub(Register OldR, Register NewR, unsigned NewSR, 242 MachineRegisterInfo &MRI); 243 static bool replaceSubWithSub(Register OldR, unsigned OldSR, Register NewR, 244 unsigned NewSR, MachineRegisterInfo &MRI); 245 static bool parseRegSequence(const MachineInstr &I, 246 BitTracker::RegisterRef &SL, BitTracker::RegisterRef &SH, 247 const MachineRegisterInfo &MRI); 248 249 static bool getUsedBitsInStore(unsigned Opc, BitVector &Bits, 250 uint16_t Begin); 251 static bool getUsedBits(unsigned Opc, unsigned OpN, BitVector &Bits, 252 uint16_t Begin, const HexagonInstrInfo &HII); 253 254 static const TargetRegisterClass *getFinalVRegClass( 255 const BitTracker::RegisterRef &RR, MachineRegisterInfo &MRI); 256 static bool isTransparentCopy(const BitTracker::RegisterRef &RD, 257 const BitTracker::RegisterRef &RS, MachineRegisterInfo &MRI); 258 259 private: 260 MachineDominatorTree *MDT = nullptr; 261 262 bool visitBlock(MachineBasicBlock &B, Transformation &T, RegisterSet &AVs); 263 static bool hasTiedUse(unsigned Reg, MachineRegisterInfo &MRI, 264 unsigned NewSub = Hexagon::NoSubRegister); 265 }; 266 267 using HBS = HexagonBitSimplify; 268 269 // The purpose of this class is to provide a common facility to traverse 270 // the function top-down or bottom-up via the dominator tree, and keep 271 // track of the available registers. 272 class Transformation { 273 public: 274 bool TopDown; 275 276 Transformation(bool TD) : TopDown(TD) {} 277 virtual ~Transformation() = default; 278 279 virtual bool processBlock(MachineBasicBlock &B, const RegisterSet &AVs) = 0; 280 }; 281 282} // end anonymous namespace 283 284char HexagonBitSimplify::ID = 0; 285 286INITIALIZE_PASS_BEGIN(HexagonBitSimplify, "hexagon-bit-simplify", 287 "Hexagon bit simplification", false, false) 288INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree) 289INITIALIZE_PASS_END(HexagonBitSimplify, "hexagon-bit-simplify", 290 "Hexagon bit simplification", false, false) 291 292bool HexagonBitSimplify::visitBlock(MachineBasicBlock &B, Transformation &T, 293 RegisterSet &AVs) { 294 bool Changed = false; 295 296 if (T.TopDown) 297 Changed = T.processBlock(B, AVs); 298 299 RegisterSet Defs; 300 for (auto &I : B) 301 getInstrDefs(I, Defs); 302 RegisterSet NewAVs = AVs; 303 NewAVs.insert(Defs); 304 305 for (auto *DTN : children<MachineDomTreeNode*>(MDT->getNode(&B))) 306 Changed |= visitBlock(*(DTN->getBlock()), T, NewAVs); 307 308 if (!T.TopDown) 309 Changed |= T.processBlock(B, AVs); 310 311 return Changed; 312} 313 314// 315// Utility functions: 316// 317void HexagonBitSimplify::getInstrDefs(const MachineInstr &MI, 318 RegisterSet &Defs) { 319 for (auto &Op : MI.operands()) { 320 if (!Op.isReg() || !Op.isDef()) 321 continue; 322 Register R = Op.getReg(); 323 if (!R.isVirtual()) 324 continue; 325 Defs.insert(R); 326 } 327} 328 329void HexagonBitSimplify::getInstrUses(const MachineInstr &MI, 330 RegisterSet &Uses) { 331 for (auto &Op : MI.operands()) { 332 if (!Op.isReg() || !Op.isUse()) 333 continue; 334 Register R = Op.getReg(); 335 if (!R.isVirtual()) 336 continue; 337 Uses.insert(R); 338 } 339} 340 341// Check if all the bits in range [B, E) in both cells are equal. 342bool HexagonBitSimplify::isEqual(const BitTracker::RegisterCell &RC1, 343 uint16_t B1, const BitTracker::RegisterCell &RC2, uint16_t B2, 344 uint16_t W) { 345 for (uint16_t i = 0; i < W; ++i) { 346 // If RC1[i] is "bottom", it cannot be proven equal to RC2[i]. 347 if (RC1[B1+i].Type == BitTracker::BitValue::Ref && RC1[B1+i].RefI.Reg == 0) 348 return false; 349 // Same for RC2[i]. 350 if (RC2[B2+i].Type == BitTracker::BitValue::Ref && RC2[B2+i].RefI.Reg == 0) 351 return false; 352 if (RC1[B1+i] != RC2[B2+i]) 353 return false; 354 } 355 return true; 356} 357 358bool HexagonBitSimplify::isZero(const BitTracker::RegisterCell &RC, 359 uint16_t B, uint16_t W) { 360 assert(B < RC.width() && B+W <= RC.width()); 361 for (uint16_t i = B; i < B+W; ++i) 362 if (!RC[i].is(0)) 363 return false; 364 return true; 365} 366 367bool HexagonBitSimplify::getConst(const BitTracker::RegisterCell &RC, 368 uint16_t B, uint16_t W, uint64_t &U) { 369 assert(B < RC.width() && B+W <= RC.width()); 370 int64_t T = 0; 371 for (uint16_t i = B+W; i > B; --i) { 372 const BitTracker::BitValue &BV = RC[i-1]; 373 T <<= 1; 374 if (BV.is(1)) 375 T |= 1; 376 else if (!BV.is(0)) 377 return false; 378 } 379 U = T; 380 return true; 381} 382 383bool HexagonBitSimplify::replaceReg(Register OldR, Register NewR, 384 MachineRegisterInfo &MRI) { 385 if (!OldR.isVirtual() || !NewR.isVirtual()) 386 return false; 387 auto Begin = MRI.use_begin(OldR), End = MRI.use_end(); 388 decltype(End) NextI; 389 for (auto I = Begin; I != End; I = NextI) { 390 NextI = std::next(I); 391 I->setReg(NewR); 392 } 393 return Begin != End; 394} 395 396bool HexagonBitSimplify::replaceRegWithSub(Register OldR, Register NewR, 397 unsigned NewSR, 398 MachineRegisterInfo &MRI) { 399 if (!OldR.isVirtual() || !NewR.isVirtual()) 400 return false; 401 if (hasTiedUse(OldR, MRI, NewSR)) 402 return false; 403 auto Begin = MRI.use_begin(OldR), End = MRI.use_end(); 404 decltype(End) NextI; 405 for (auto I = Begin; I != End; I = NextI) { 406 NextI = std::next(I); 407 I->setReg(NewR); 408 I->setSubReg(NewSR); 409 } 410 return Begin != End; 411} 412 413bool HexagonBitSimplify::replaceSubWithSub(Register OldR, unsigned OldSR, 414 Register NewR, unsigned NewSR, 415 MachineRegisterInfo &MRI) { 416 if (!OldR.isVirtual() || !NewR.isVirtual()) 417 return false; 418 if (OldSR != NewSR && hasTiedUse(OldR, MRI, NewSR)) 419 return false; 420 auto Begin = MRI.use_begin(OldR), End = MRI.use_end(); 421 decltype(End) NextI; 422 for (auto I = Begin; I != End; I = NextI) { 423 NextI = std::next(I); 424 if (I->getSubReg() != OldSR) 425 continue; 426 I->setReg(NewR); 427 I->setSubReg(NewSR); 428 } 429 return Begin != End; 430} 431 432// For a register ref (pair Reg:Sub), set Begin to the position of the LSB 433// of Sub in Reg, and set Width to the size of Sub in bits. Return true, 434// if this succeeded, otherwise return false. 435bool HexagonBitSimplify::getSubregMask(const BitTracker::RegisterRef &RR, 436 unsigned &Begin, unsigned &Width, MachineRegisterInfo &MRI) { 437 const TargetRegisterClass *RC = MRI.getRegClass(RR.Reg); 438 if (RR.Sub == 0) { 439 Begin = 0; 440 Width = MRI.getTargetRegisterInfo()->getRegSizeInBits(*RC); 441 return true; 442 } 443 444 Begin = 0; 445 446 switch (RC->getID()) { 447 case Hexagon::DoubleRegsRegClassID: 448 case Hexagon::HvxWRRegClassID: 449 Width = MRI.getTargetRegisterInfo()->getRegSizeInBits(*RC) / 2; 450 if (RR.Sub == Hexagon::isub_hi || RR.Sub == Hexagon::vsub_hi) 451 Begin = Width; 452 break; 453 default: 454 return false; 455 } 456 return true; 457} 458 459 460// For a REG_SEQUENCE, set SL to the low subregister and SH to the high 461// subregister. 462bool HexagonBitSimplify::parseRegSequence(const MachineInstr &I, 463 BitTracker::RegisterRef &SL, BitTracker::RegisterRef &SH, 464 const MachineRegisterInfo &MRI) { 465 assert(I.getOpcode() == TargetOpcode::REG_SEQUENCE); 466 unsigned Sub1 = I.getOperand(2).getImm(), Sub2 = I.getOperand(4).getImm(); 467 auto &DstRC = *MRI.getRegClass(I.getOperand(0).getReg()); 468 auto &HRI = static_cast<const HexagonRegisterInfo&>( 469 *MRI.getTargetRegisterInfo()); 470 unsigned SubLo = HRI.getHexagonSubRegIndex(DstRC, Hexagon::ps_sub_lo); 471 unsigned SubHi = HRI.getHexagonSubRegIndex(DstRC, Hexagon::ps_sub_hi); 472 assert((Sub1 == SubLo && Sub2 == SubHi) || (Sub1 == SubHi && Sub2 == SubLo)); 473 if (Sub1 == SubLo && Sub2 == SubHi) { 474 SL = I.getOperand(1); 475 SH = I.getOperand(3); 476 return true; 477 } 478 if (Sub1 == SubHi && Sub2 == SubLo) { 479 SH = I.getOperand(1); 480 SL = I.getOperand(3); 481 return true; 482 } 483 return false; 484} 485 486// All stores (except 64-bit stores) take a 32-bit register as the source 487// of the value to be stored. If the instruction stores into a location 488// that is shorter than 32 bits, some bits of the source register are not 489// used. For each store instruction, calculate the set of used bits in 490// the source register, and set appropriate bits in Bits. Return true if 491// the bits are calculated, false otherwise. 492bool HexagonBitSimplify::getUsedBitsInStore(unsigned Opc, BitVector &Bits, 493 uint16_t Begin) { 494 using namespace Hexagon; 495 496 switch (Opc) { 497 // Store byte 498 case S2_storerb_io: // memb(Rs32+#s11:0)=Rt32 499 case S2_storerbnew_io: // memb(Rs32+#s11:0)=Nt8.new 500 case S2_pstorerbt_io: // if (Pv4) memb(Rs32+#u6:0)=Rt32 501 case S2_pstorerbf_io: // if (!Pv4) memb(Rs32+#u6:0)=Rt32 502 case S4_pstorerbtnew_io: // if (Pv4.new) memb(Rs32+#u6:0)=Rt32 503 case S4_pstorerbfnew_io: // if (!Pv4.new) memb(Rs32+#u6:0)=Rt32 504 case S2_pstorerbnewt_io: // if (Pv4) memb(Rs32+#u6:0)=Nt8.new 505 case S2_pstorerbnewf_io: // if (!Pv4) memb(Rs32+#u6:0)=Nt8.new 506 case S4_pstorerbnewtnew_io: // if (Pv4.new) memb(Rs32+#u6:0)=Nt8.new 507 case S4_pstorerbnewfnew_io: // if (!Pv4.new) memb(Rs32+#u6:0)=Nt8.new 508 case S2_storerb_pi: // memb(Rx32++#s4:0)=Rt32 509 case S2_storerbnew_pi: // memb(Rx32++#s4:0)=Nt8.new 510 case S2_pstorerbt_pi: // if (Pv4) memb(Rx32++#s4:0)=Rt32 511 case S2_pstorerbf_pi: // if (!Pv4) memb(Rx32++#s4:0)=Rt32 512 case S2_pstorerbtnew_pi: // if (Pv4.new) memb(Rx32++#s4:0)=Rt32 513 case S2_pstorerbfnew_pi: // if (!Pv4.new) memb(Rx32++#s4:0)=Rt32 514 case S2_pstorerbnewt_pi: // if (Pv4) memb(Rx32++#s4:0)=Nt8.new 515 case S2_pstorerbnewf_pi: // if (!Pv4) memb(Rx32++#s4:0)=Nt8.new 516 case S2_pstorerbnewtnew_pi: // if (Pv4.new) memb(Rx32++#s4:0)=Nt8.new 517 case S2_pstorerbnewfnew_pi: // if (!Pv4.new) memb(Rx32++#s4:0)=Nt8.new 518 case S4_storerb_ap: // memb(Re32=#U6)=Rt32 519 case S4_storerbnew_ap: // memb(Re32=#U6)=Nt8.new 520 case S2_storerb_pr: // memb(Rx32++Mu2)=Rt32 521 case S2_storerbnew_pr: // memb(Rx32++Mu2)=Nt8.new 522 case S4_storerb_ur: // memb(Ru32<<#u2+#U6)=Rt32 523 case S4_storerbnew_ur: // memb(Ru32<<#u2+#U6)=Nt8.new 524 case S2_storerb_pbr: // memb(Rx32++Mu2:brev)=Rt32 525 case S2_storerbnew_pbr: // memb(Rx32++Mu2:brev)=Nt8.new 526 case S2_storerb_pci: // memb(Rx32++#s4:0:circ(Mu2))=Rt32 527 case S2_storerbnew_pci: // memb(Rx32++#s4:0:circ(Mu2))=Nt8.new 528 case S2_storerb_pcr: // memb(Rx32++I:circ(Mu2))=Rt32 529 case S2_storerbnew_pcr: // memb(Rx32++I:circ(Mu2))=Nt8.new 530 case S4_storerb_rr: // memb(Rs32+Ru32<<#u2)=Rt32 531 case S4_storerbnew_rr: // memb(Rs32+Ru32<<#u2)=Nt8.new 532 case S4_pstorerbt_rr: // if (Pv4) memb(Rs32+Ru32<<#u2)=Rt32 533 case S4_pstorerbf_rr: // if (!Pv4) memb(Rs32+Ru32<<#u2)=Rt32 534 case S4_pstorerbtnew_rr: // if (Pv4.new) memb(Rs32+Ru32<<#u2)=Rt32 535 case S4_pstorerbfnew_rr: // if (!Pv4.new) memb(Rs32+Ru32<<#u2)=Rt32 536 case S4_pstorerbnewt_rr: // if (Pv4) memb(Rs32+Ru32<<#u2)=Nt8.new 537 case S4_pstorerbnewf_rr: // if (!Pv4) memb(Rs32+Ru32<<#u2)=Nt8.new 538 case S4_pstorerbnewtnew_rr: // if (Pv4.new) memb(Rs32+Ru32<<#u2)=Nt8.new 539 case S4_pstorerbnewfnew_rr: // if (!Pv4.new) memb(Rs32+Ru32<<#u2)=Nt8.new 540 case S2_storerbgp: // memb(gp+#u16:0)=Rt32 541 case S2_storerbnewgp: // memb(gp+#u16:0)=Nt8.new 542 case S4_pstorerbt_abs: // if (Pv4) memb(#u6)=Rt32 543 case S4_pstorerbf_abs: // if (!Pv4) memb(#u6)=Rt32 544 case S4_pstorerbtnew_abs: // if (Pv4.new) memb(#u6)=Rt32 545 case S4_pstorerbfnew_abs: // if (!Pv4.new) memb(#u6)=Rt32 546 case S4_pstorerbnewt_abs: // if (Pv4) memb(#u6)=Nt8.new 547 case S4_pstorerbnewf_abs: // if (!Pv4) memb(#u6)=Nt8.new 548 case S4_pstorerbnewtnew_abs: // if (Pv4.new) memb(#u6)=Nt8.new 549 case S4_pstorerbnewfnew_abs: // if (!Pv4.new) memb(#u6)=Nt8.new 550 Bits.set(Begin, Begin+8); 551 return true; 552 553 // Store low half 554 case S2_storerh_io: // memh(Rs32+#s11:1)=Rt32 555 case S2_storerhnew_io: // memh(Rs32+#s11:1)=Nt8.new 556 case S2_pstorerht_io: // if (Pv4) memh(Rs32+#u6:1)=Rt32 557 case S2_pstorerhf_io: // if (!Pv4) memh(Rs32+#u6:1)=Rt32 558 case S4_pstorerhtnew_io: // if (Pv4.new) memh(Rs32+#u6:1)=Rt32 559 case S4_pstorerhfnew_io: // if (!Pv4.new) memh(Rs32+#u6:1)=Rt32 560 case S2_pstorerhnewt_io: // if (Pv4) memh(Rs32+#u6:1)=Nt8.new 561 case S2_pstorerhnewf_io: // if (!Pv4) memh(Rs32+#u6:1)=Nt8.new 562 case S4_pstorerhnewtnew_io: // if (Pv4.new) memh(Rs32+#u6:1)=Nt8.new 563 case S4_pstorerhnewfnew_io: // if (!Pv4.new) memh(Rs32+#u6:1)=Nt8.new 564 case S2_storerh_pi: // memh(Rx32++#s4:1)=Rt32 565 case S2_storerhnew_pi: // memh(Rx32++#s4:1)=Nt8.new 566 case S2_pstorerht_pi: // if (Pv4) memh(Rx32++#s4:1)=Rt32 567 case S2_pstorerhf_pi: // if (!Pv4) memh(Rx32++#s4:1)=Rt32 568 case S2_pstorerhtnew_pi: // if (Pv4.new) memh(Rx32++#s4:1)=Rt32 569 case S2_pstorerhfnew_pi: // if (!Pv4.new) memh(Rx32++#s4:1)=Rt32 570 case S2_pstorerhnewt_pi: // if (Pv4) memh(Rx32++#s4:1)=Nt8.new 571 case S2_pstorerhnewf_pi: // if (!Pv4) memh(Rx32++#s4:1)=Nt8.new 572 case S2_pstorerhnewtnew_pi: // if (Pv4.new) memh(Rx32++#s4:1)=Nt8.new 573 case S2_pstorerhnewfnew_pi: // if (!Pv4.new) memh(Rx32++#s4:1)=Nt8.new 574 case S4_storerh_ap: // memh(Re32=#U6)=Rt32 575 case S4_storerhnew_ap: // memh(Re32=#U6)=Nt8.new 576 case S2_storerh_pr: // memh(Rx32++Mu2)=Rt32 577 case S2_storerhnew_pr: // memh(Rx32++Mu2)=Nt8.new 578 case S4_storerh_ur: // memh(Ru32<<#u2+#U6)=Rt32 579 case S4_storerhnew_ur: // memh(Ru32<<#u2+#U6)=Nt8.new 580 case S2_storerh_pbr: // memh(Rx32++Mu2:brev)=Rt32 581 case S2_storerhnew_pbr: // memh(Rx32++Mu2:brev)=Nt8.new 582 case S2_storerh_pci: // memh(Rx32++#s4:1:circ(Mu2))=Rt32 583 case S2_storerhnew_pci: // memh(Rx32++#s4:1:circ(Mu2))=Nt8.new 584 case S2_storerh_pcr: // memh(Rx32++I:circ(Mu2))=Rt32 585 case S2_storerhnew_pcr: // memh(Rx32++I:circ(Mu2))=Nt8.new 586 case S4_storerh_rr: // memh(Rs32+Ru32<<#u2)=Rt32 587 case S4_pstorerht_rr: // if (Pv4) memh(Rs32+Ru32<<#u2)=Rt32 588 case S4_pstorerhf_rr: // if (!Pv4) memh(Rs32+Ru32<<#u2)=Rt32 589 case S4_pstorerhtnew_rr: // if (Pv4.new) memh(Rs32+Ru32<<#u2)=Rt32 590 case S4_pstorerhfnew_rr: // if (!Pv4.new) memh(Rs32+Ru32<<#u2)=Rt32 591 case S4_storerhnew_rr: // memh(Rs32+Ru32<<#u2)=Nt8.new 592 case S4_pstorerhnewt_rr: // if (Pv4) memh(Rs32+Ru32<<#u2)=Nt8.new 593 case S4_pstorerhnewf_rr: // if (!Pv4) memh(Rs32+Ru32<<#u2)=Nt8.new 594 case S4_pstorerhnewtnew_rr: // if (Pv4.new) memh(Rs32+Ru32<<#u2)=Nt8.new 595 case S4_pstorerhnewfnew_rr: // if (!Pv4.new) memh(Rs32+Ru32<<#u2)=Nt8.new 596 case S2_storerhgp: // memh(gp+#u16:1)=Rt32 597 case S2_storerhnewgp: // memh(gp+#u16:1)=Nt8.new 598 case S4_pstorerht_abs: // if (Pv4) memh(#u6)=Rt32 599 case S4_pstorerhf_abs: // if (!Pv4) memh(#u6)=Rt32 600 case S4_pstorerhtnew_abs: // if (Pv4.new) memh(#u6)=Rt32 601 case S4_pstorerhfnew_abs: // if (!Pv4.new) memh(#u6)=Rt32 602 case S4_pstorerhnewt_abs: // if (Pv4) memh(#u6)=Nt8.new 603 case S4_pstorerhnewf_abs: // if (!Pv4) memh(#u6)=Nt8.new 604 case S4_pstorerhnewtnew_abs: // if (Pv4.new) memh(#u6)=Nt8.new 605 case S4_pstorerhnewfnew_abs: // if (!Pv4.new) memh(#u6)=Nt8.new 606 Bits.set(Begin, Begin+16); 607 return true; 608 609 // Store high half 610 case S2_storerf_io: // memh(Rs32+#s11:1)=Rt.H32 611 case S2_pstorerft_io: // if (Pv4) memh(Rs32+#u6:1)=Rt.H32 612 case S2_pstorerff_io: // if (!Pv4) memh(Rs32+#u6:1)=Rt.H32 613 case S4_pstorerftnew_io: // if (Pv4.new) memh(Rs32+#u6:1)=Rt.H32 614 case S4_pstorerffnew_io: // if (!Pv4.new) memh(Rs32+#u6:1)=Rt.H32 615 case S2_storerf_pi: // memh(Rx32++#s4:1)=Rt.H32 616 case S2_pstorerft_pi: // if (Pv4) memh(Rx32++#s4:1)=Rt.H32 617 case S2_pstorerff_pi: // if (!Pv4) memh(Rx32++#s4:1)=Rt.H32 618 case S2_pstorerftnew_pi: // if (Pv4.new) memh(Rx32++#s4:1)=Rt.H32 619 case S2_pstorerffnew_pi: // if (!Pv4.new) memh(Rx32++#s4:1)=Rt.H32 620 case S4_storerf_ap: // memh(Re32=#U6)=Rt.H32 621 case S2_storerf_pr: // memh(Rx32++Mu2)=Rt.H32 622 case S4_storerf_ur: // memh(Ru32<<#u2+#U6)=Rt.H32 623 case S2_storerf_pbr: // memh(Rx32++Mu2:brev)=Rt.H32 624 case S2_storerf_pci: // memh(Rx32++#s4:1:circ(Mu2))=Rt.H32 625 case S2_storerf_pcr: // memh(Rx32++I:circ(Mu2))=Rt.H32 626 case S4_storerf_rr: // memh(Rs32+Ru32<<#u2)=Rt.H32 627 case S4_pstorerft_rr: // if (Pv4) memh(Rs32+Ru32<<#u2)=Rt.H32 628 case S4_pstorerff_rr: // if (!Pv4) memh(Rs32+Ru32<<#u2)=Rt.H32 629 case S4_pstorerftnew_rr: // if (Pv4.new) memh(Rs32+Ru32<<#u2)=Rt.H32 630 case S4_pstorerffnew_rr: // if (!Pv4.new) memh(Rs32+Ru32<<#u2)=Rt.H32 631 case S2_storerfgp: // memh(gp+#u16:1)=Rt.H32 632 case S4_pstorerft_abs: // if (Pv4) memh(#u6)=Rt.H32 633 case S4_pstorerff_abs: // if (!Pv4) memh(#u6)=Rt.H32 634 case S4_pstorerftnew_abs: // if (Pv4.new) memh(#u6)=Rt.H32 635 case S4_pstorerffnew_abs: // if (!Pv4.new) memh(#u6)=Rt.H32 636 Bits.set(Begin+16, Begin+32); 637 return true; 638 } 639 640 return false; 641} 642 643// For an instruction with opcode Opc, calculate the set of bits that it 644// uses in a register in operand OpN. This only calculates the set of used 645// bits for cases where it does not depend on any operands (as is the case 646// in shifts, for example). For concrete instructions from a program, the 647// operand may be a subregister of a larger register, while Bits would 648// correspond to the larger register in its entirety. Because of that, 649// the parameter Begin can be used to indicate which bit of Bits should be 650// considered the LSB of the operand. 651bool HexagonBitSimplify::getUsedBits(unsigned Opc, unsigned OpN, 652 BitVector &Bits, uint16_t Begin, const HexagonInstrInfo &HII) { 653 using namespace Hexagon; 654 655 const MCInstrDesc &D = HII.get(Opc); 656 if (D.mayStore()) { 657 if (OpN == D.getNumOperands()-1) 658 return getUsedBitsInStore(Opc, Bits, Begin); 659 return false; 660 } 661 662 switch (Opc) { 663 // One register source. Used bits: R1[0-7]. 664 case A2_sxtb: 665 case A2_zxtb: 666 case A4_cmpbeqi: 667 case A4_cmpbgti: 668 case A4_cmpbgtui: 669 if (OpN == 1) { 670 Bits.set(Begin, Begin+8); 671 return true; 672 } 673 break; 674 675 // One register source. Used bits: R1[0-15]. 676 case A2_aslh: 677 case A2_sxth: 678 case A2_zxth: 679 case A4_cmpheqi: 680 case A4_cmphgti: 681 case A4_cmphgtui: 682 if (OpN == 1) { 683 Bits.set(Begin, Begin+16); 684 return true; 685 } 686 break; 687 688 // One register source. Used bits: R1[16-31]. 689 case A2_asrh: 690 if (OpN == 1) { 691 Bits.set(Begin+16, Begin+32); 692 return true; 693 } 694 break; 695 696 // Two register sources. Used bits: R1[0-7], R2[0-7]. 697 case A4_cmpbeq: 698 case A4_cmpbgt: 699 case A4_cmpbgtu: 700 if (OpN == 1) { 701 Bits.set(Begin, Begin+8); 702 return true; 703 } 704 break; 705 706 // Two register sources. Used bits: R1[0-15], R2[0-15]. 707 case A4_cmpheq: 708 case A4_cmphgt: 709 case A4_cmphgtu: 710 case A2_addh_h16_ll: 711 case A2_addh_h16_sat_ll: 712 case A2_addh_l16_ll: 713 case A2_addh_l16_sat_ll: 714 case A2_combine_ll: 715 case A2_subh_h16_ll: 716 case A2_subh_h16_sat_ll: 717 case A2_subh_l16_ll: 718 case A2_subh_l16_sat_ll: 719 case M2_mpy_acc_ll_s0: 720 case M2_mpy_acc_ll_s1: 721 case M2_mpy_acc_sat_ll_s0: 722 case M2_mpy_acc_sat_ll_s1: 723 case M2_mpy_ll_s0: 724 case M2_mpy_ll_s1: 725 case M2_mpy_nac_ll_s0: 726 case M2_mpy_nac_ll_s1: 727 case M2_mpy_nac_sat_ll_s0: 728 case M2_mpy_nac_sat_ll_s1: 729 case M2_mpy_rnd_ll_s0: 730 case M2_mpy_rnd_ll_s1: 731 case M2_mpy_sat_ll_s0: 732 case M2_mpy_sat_ll_s1: 733 case M2_mpy_sat_rnd_ll_s0: 734 case M2_mpy_sat_rnd_ll_s1: 735 case M2_mpyd_acc_ll_s0: 736 case M2_mpyd_acc_ll_s1: 737 case M2_mpyd_ll_s0: 738 case M2_mpyd_ll_s1: 739 case M2_mpyd_nac_ll_s0: 740 case M2_mpyd_nac_ll_s1: 741 case M2_mpyd_rnd_ll_s0: 742 case M2_mpyd_rnd_ll_s1: 743 case M2_mpyu_acc_ll_s0: 744 case M2_mpyu_acc_ll_s1: 745 case M2_mpyu_ll_s0: 746 case M2_mpyu_ll_s1: 747 case M2_mpyu_nac_ll_s0: 748 case M2_mpyu_nac_ll_s1: 749 case M2_mpyud_acc_ll_s0: 750 case M2_mpyud_acc_ll_s1: 751 case M2_mpyud_ll_s0: 752 case M2_mpyud_ll_s1: 753 case M2_mpyud_nac_ll_s0: 754 case M2_mpyud_nac_ll_s1: 755 if (OpN == 1 || OpN == 2) { 756 Bits.set(Begin, Begin+16); 757 return true; 758 } 759 break; 760 761 // Two register sources. Used bits: R1[0-15], R2[16-31]. 762 case A2_addh_h16_lh: 763 case A2_addh_h16_sat_lh: 764 case A2_combine_lh: 765 case A2_subh_h16_lh: 766 case A2_subh_h16_sat_lh: 767 case M2_mpy_acc_lh_s0: 768 case M2_mpy_acc_lh_s1: 769 case M2_mpy_acc_sat_lh_s0: 770 case M2_mpy_acc_sat_lh_s1: 771 case M2_mpy_lh_s0: 772 case M2_mpy_lh_s1: 773 case M2_mpy_nac_lh_s0: 774 case M2_mpy_nac_lh_s1: 775 case M2_mpy_nac_sat_lh_s0: 776 case M2_mpy_nac_sat_lh_s1: 777 case M2_mpy_rnd_lh_s0: 778 case M2_mpy_rnd_lh_s1: 779 case M2_mpy_sat_lh_s0: 780 case M2_mpy_sat_lh_s1: 781 case M2_mpy_sat_rnd_lh_s0: 782 case M2_mpy_sat_rnd_lh_s1: 783 case M2_mpyd_acc_lh_s0: 784 case M2_mpyd_acc_lh_s1: 785 case M2_mpyd_lh_s0: 786 case M2_mpyd_lh_s1: 787 case M2_mpyd_nac_lh_s0: 788 case M2_mpyd_nac_lh_s1: 789 case M2_mpyd_rnd_lh_s0: 790 case M2_mpyd_rnd_lh_s1: 791 case M2_mpyu_acc_lh_s0: 792 case M2_mpyu_acc_lh_s1: 793 case M2_mpyu_lh_s0: 794 case M2_mpyu_lh_s1: 795 case M2_mpyu_nac_lh_s0: 796 case M2_mpyu_nac_lh_s1: 797 case M2_mpyud_acc_lh_s0: 798 case M2_mpyud_acc_lh_s1: 799 case M2_mpyud_lh_s0: 800 case M2_mpyud_lh_s1: 801 case M2_mpyud_nac_lh_s0: 802 case M2_mpyud_nac_lh_s1: 803 // These four are actually LH. 804 case A2_addh_l16_hl: 805 case A2_addh_l16_sat_hl: 806 case A2_subh_l16_hl: 807 case A2_subh_l16_sat_hl: 808 if (OpN == 1) { 809 Bits.set(Begin, Begin+16); 810 return true; 811 } 812 if (OpN == 2) { 813 Bits.set(Begin+16, Begin+32); 814 return true; 815 } 816 break; 817 818 // Two register sources, used bits: R1[16-31], R2[0-15]. 819 case A2_addh_h16_hl: 820 case A2_addh_h16_sat_hl: 821 case A2_combine_hl: 822 case A2_subh_h16_hl: 823 case A2_subh_h16_sat_hl: 824 case M2_mpy_acc_hl_s0: 825 case M2_mpy_acc_hl_s1: 826 case M2_mpy_acc_sat_hl_s0: 827 case M2_mpy_acc_sat_hl_s1: 828 case M2_mpy_hl_s0: 829 case M2_mpy_hl_s1: 830 case M2_mpy_nac_hl_s0: 831 case M2_mpy_nac_hl_s1: 832 case M2_mpy_nac_sat_hl_s0: 833 case M2_mpy_nac_sat_hl_s1: 834 case M2_mpy_rnd_hl_s0: 835 case M2_mpy_rnd_hl_s1: 836 case M2_mpy_sat_hl_s0: 837 case M2_mpy_sat_hl_s1: 838 case M2_mpy_sat_rnd_hl_s0: 839 case M2_mpy_sat_rnd_hl_s1: 840 case M2_mpyd_acc_hl_s0: 841 case M2_mpyd_acc_hl_s1: 842 case M2_mpyd_hl_s0: 843 case M2_mpyd_hl_s1: 844 case M2_mpyd_nac_hl_s0: 845 case M2_mpyd_nac_hl_s1: 846 case M2_mpyd_rnd_hl_s0: 847 case M2_mpyd_rnd_hl_s1: 848 case M2_mpyu_acc_hl_s0: 849 case M2_mpyu_acc_hl_s1: 850 case M2_mpyu_hl_s0: 851 case M2_mpyu_hl_s1: 852 case M2_mpyu_nac_hl_s0: 853 case M2_mpyu_nac_hl_s1: 854 case M2_mpyud_acc_hl_s0: 855 case M2_mpyud_acc_hl_s1: 856 case M2_mpyud_hl_s0: 857 case M2_mpyud_hl_s1: 858 case M2_mpyud_nac_hl_s0: 859 case M2_mpyud_nac_hl_s1: 860 if (OpN == 1) { 861 Bits.set(Begin+16, Begin+32); 862 return true; 863 } 864 if (OpN == 2) { 865 Bits.set(Begin, Begin+16); 866 return true; 867 } 868 break; 869 870 // Two register sources, used bits: R1[16-31], R2[16-31]. 871 case A2_addh_h16_hh: 872 case A2_addh_h16_sat_hh: 873 case A2_combine_hh: 874 case A2_subh_h16_hh: 875 case A2_subh_h16_sat_hh: 876 case M2_mpy_acc_hh_s0: 877 case M2_mpy_acc_hh_s1: 878 case M2_mpy_acc_sat_hh_s0: 879 case M2_mpy_acc_sat_hh_s1: 880 case M2_mpy_hh_s0: 881 case M2_mpy_hh_s1: 882 case M2_mpy_nac_hh_s0: 883 case M2_mpy_nac_hh_s1: 884 case M2_mpy_nac_sat_hh_s0: 885 case M2_mpy_nac_sat_hh_s1: 886 case M2_mpy_rnd_hh_s0: 887 case M2_mpy_rnd_hh_s1: 888 case M2_mpy_sat_hh_s0: 889 case M2_mpy_sat_hh_s1: 890 case M2_mpy_sat_rnd_hh_s0: 891 case M2_mpy_sat_rnd_hh_s1: 892 case M2_mpyd_acc_hh_s0: 893 case M2_mpyd_acc_hh_s1: 894 case M2_mpyd_hh_s0: 895 case M2_mpyd_hh_s1: 896 case M2_mpyd_nac_hh_s0: 897 case M2_mpyd_nac_hh_s1: 898 case M2_mpyd_rnd_hh_s0: 899 case M2_mpyd_rnd_hh_s1: 900 case M2_mpyu_acc_hh_s0: 901 case M2_mpyu_acc_hh_s1: 902 case M2_mpyu_hh_s0: 903 case M2_mpyu_hh_s1: 904 case M2_mpyu_nac_hh_s0: 905 case M2_mpyu_nac_hh_s1: 906 case M2_mpyud_acc_hh_s0: 907 case M2_mpyud_acc_hh_s1: 908 case M2_mpyud_hh_s0: 909 case M2_mpyud_hh_s1: 910 case M2_mpyud_nac_hh_s0: 911 case M2_mpyud_nac_hh_s1: 912 if (OpN == 1 || OpN == 2) { 913 Bits.set(Begin+16, Begin+32); 914 return true; 915 } 916 break; 917 } 918 919 return false; 920} 921 922// Calculate the register class that matches Reg:Sub. For example, if 923// %1 is a double register, then %1:isub_hi would match the "int" 924// register class. 925const TargetRegisterClass *HexagonBitSimplify::getFinalVRegClass( 926 const BitTracker::RegisterRef &RR, MachineRegisterInfo &MRI) { 927 if (!RR.Reg.isVirtual()) 928 return nullptr; 929 auto *RC = MRI.getRegClass(RR.Reg); 930 if (RR.Sub == 0) 931 return RC; 932 auto &HRI = static_cast<const HexagonRegisterInfo&>( 933 *MRI.getTargetRegisterInfo()); 934 935 auto VerifySR = [&HRI] (const TargetRegisterClass *RC, unsigned Sub) -> void { 936 (void)HRI; 937 assert(Sub == HRI.getHexagonSubRegIndex(*RC, Hexagon::ps_sub_lo) || 938 Sub == HRI.getHexagonSubRegIndex(*RC, Hexagon::ps_sub_hi)); 939 }; 940 941 switch (RC->getID()) { 942 case Hexagon::DoubleRegsRegClassID: 943 VerifySR(RC, RR.Sub); 944 return &Hexagon::IntRegsRegClass; 945 case Hexagon::HvxWRRegClassID: 946 VerifySR(RC, RR.Sub); 947 return &Hexagon::HvxVRRegClass; 948 } 949 return nullptr; 950} 951 952// Check if RD could be replaced with RS at any possible use of RD. 953// For example a predicate register cannot be replaced with a integer 954// register, but a 64-bit register with a subregister can be replaced 955// with a 32-bit register. 956bool HexagonBitSimplify::isTransparentCopy(const BitTracker::RegisterRef &RD, 957 const BitTracker::RegisterRef &RS, MachineRegisterInfo &MRI) { 958 if (!RD.Reg.isVirtual() || !RS.Reg.isVirtual()) 959 return false; 960 // Return false if one (or both) classes are nullptr. 961 auto *DRC = getFinalVRegClass(RD, MRI); 962 if (!DRC) 963 return false; 964 965 return DRC == getFinalVRegClass(RS, MRI); 966} 967 968bool HexagonBitSimplify::hasTiedUse(unsigned Reg, MachineRegisterInfo &MRI, 969 unsigned NewSub) { 970 if (!PreserveTiedOps) 971 return false; 972 return llvm::any_of(MRI.use_operands(Reg), 973 [NewSub] (const MachineOperand &Op) -> bool { 974 return Op.getSubReg() != NewSub && Op.isTied(); 975 }); 976} 977 978namespace { 979 980 class DeadCodeElimination { 981 public: 982 DeadCodeElimination(MachineFunction &mf, MachineDominatorTree &mdt) 983 : MF(mf), HII(*MF.getSubtarget<HexagonSubtarget>().getInstrInfo()), 984 MDT(mdt), MRI(mf.getRegInfo()) {} 985 986 bool run() { 987 return runOnNode(MDT.getRootNode()); 988 } 989 990 private: 991 bool isDead(unsigned R) const; 992 bool runOnNode(MachineDomTreeNode *N); 993 994 MachineFunction &MF; 995 const HexagonInstrInfo &HII; 996 MachineDominatorTree &MDT; 997 MachineRegisterInfo &MRI; 998 }; 999 1000} // end anonymous namespace 1001 1002bool DeadCodeElimination::isDead(unsigned R) const { 1003 for (const MachineOperand &MO : MRI.use_operands(R)) { 1004 const MachineInstr *UseI = MO.getParent(); 1005 if (UseI->isDebugValue()) 1006 continue; 1007 if (UseI->isPHI()) { 1008 assert(!UseI->getOperand(0).getSubReg()); 1009 Register DR = UseI->getOperand(0).getReg(); 1010 if (DR == R) 1011 continue; 1012 } 1013 return false; 1014 } 1015 return true; 1016} 1017 1018bool DeadCodeElimination::runOnNode(MachineDomTreeNode *N) { 1019 bool Changed = false; 1020 1021 for (auto *DTN : children<MachineDomTreeNode*>(N)) 1022 Changed |= runOnNode(DTN); 1023 1024 MachineBasicBlock *B = N->getBlock(); 1025 std::vector<MachineInstr*> Instrs; 1026 for (MachineInstr &MI : llvm::reverse(*B)) 1027 Instrs.push_back(&MI); 1028 1029 for (auto *MI : Instrs) { 1030 unsigned Opc = MI->getOpcode(); 1031 // Do not touch lifetime markers. This is why the target-independent DCE 1032 // cannot be used. 1033 if (Opc == TargetOpcode::LIFETIME_START || 1034 Opc == TargetOpcode::LIFETIME_END) 1035 continue; 1036 bool Store = false; 1037 if (MI->isInlineAsm()) 1038 continue; 1039 // Delete PHIs if possible. 1040 if (!MI->isPHI() && !MI->isSafeToMove(nullptr, Store)) 1041 continue; 1042 1043 bool AllDead = true; 1044 SmallVector<unsigned,2> Regs; 1045 for (auto &Op : MI->operands()) { 1046 if (!Op.isReg() || !Op.isDef()) 1047 continue; 1048 Register R = Op.getReg(); 1049 if (!R.isVirtual() || !isDead(R)) { 1050 AllDead = false; 1051 break; 1052 } 1053 Regs.push_back(R); 1054 } 1055 if (!AllDead) 1056 continue; 1057 1058 B->erase(MI); 1059 for (unsigned i = 0, n = Regs.size(); i != n; ++i) 1060 MRI.markUsesInDebugValueAsUndef(Regs[i]); 1061 Changed = true; 1062 } 1063 1064 return Changed; 1065} 1066 1067namespace { 1068 1069// Eliminate redundant instructions 1070// 1071// This transformation will identify instructions where the output register 1072// is the same as one of its input registers. This only works on instructions 1073// that define a single register (unlike post-increment loads, for example). 1074// The equality check is actually more detailed: the code calculates which 1075// bits of the output are used, and only compares these bits with the input 1076// registers. 1077// If the output matches an input, the instruction is replaced with COPY. 1078// The copies will be removed by another transformation. 1079 class RedundantInstrElimination : public Transformation { 1080 public: 1081 RedundantInstrElimination(BitTracker &bt, const HexagonInstrInfo &hii, 1082 const HexagonRegisterInfo &hri, MachineRegisterInfo &mri) 1083 : Transformation(true), HII(hii), HRI(hri), MRI(mri), BT(bt) {} 1084 1085 bool processBlock(MachineBasicBlock &B, const RegisterSet &AVs) override; 1086 1087 private: 1088 bool isLossyShiftLeft(const MachineInstr &MI, unsigned OpN, 1089 unsigned &LostB, unsigned &LostE); 1090 bool isLossyShiftRight(const MachineInstr &MI, unsigned OpN, 1091 unsigned &LostB, unsigned &LostE); 1092 bool computeUsedBits(unsigned Reg, BitVector &Bits); 1093 bool computeUsedBits(const MachineInstr &MI, unsigned OpN, BitVector &Bits, 1094 uint16_t Begin); 1095 bool usedBitsEqual(BitTracker::RegisterRef RD, BitTracker::RegisterRef RS); 1096 1097 const HexagonInstrInfo &HII; 1098 const HexagonRegisterInfo &HRI; 1099 MachineRegisterInfo &MRI; 1100 BitTracker &BT; 1101 }; 1102 1103} // end anonymous namespace 1104 1105// Check if the instruction is a lossy shift left, where the input being 1106// shifted is the operand OpN of MI. If true, [LostB, LostE) is the range 1107// of bit indices that are lost. 1108bool RedundantInstrElimination::isLossyShiftLeft(const MachineInstr &MI, 1109 unsigned OpN, unsigned &LostB, unsigned &LostE) { 1110 using namespace Hexagon; 1111 1112 unsigned Opc = MI.getOpcode(); 1113 unsigned ImN, RegN, Width; 1114 switch (Opc) { 1115 case S2_asl_i_p: 1116 ImN = 2; 1117 RegN = 1; 1118 Width = 64; 1119 break; 1120 case S2_asl_i_p_acc: 1121 case S2_asl_i_p_and: 1122 case S2_asl_i_p_nac: 1123 case S2_asl_i_p_or: 1124 case S2_asl_i_p_xacc: 1125 ImN = 3; 1126 RegN = 2; 1127 Width = 64; 1128 break; 1129 case S2_asl_i_r: 1130 ImN = 2; 1131 RegN = 1; 1132 Width = 32; 1133 break; 1134 case S2_addasl_rrri: 1135 case S4_andi_asl_ri: 1136 case S4_ori_asl_ri: 1137 case S4_addi_asl_ri: 1138 case S4_subi_asl_ri: 1139 case S2_asl_i_r_acc: 1140 case S2_asl_i_r_and: 1141 case S2_asl_i_r_nac: 1142 case S2_asl_i_r_or: 1143 case S2_asl_i_r_sat: 1144 case S2_asl_i_r_xacc: 1145 ImN = 3; 1146 RegN = 2; 1147 Width = 32; 1148 break; 1149 default: 1150 return false; 1151 } 1152 1153 if (RegN != OpN) 1154 return false; 1155 1156 assert(MI.getOperand(ImN).isImm()); 1157 unsigned S = MI.getOperand(ImN).getImm(); 1158 if (S == 0) 1159 return false; 1160 LostB = Width-S; 1161 LostE = Width; 1162 return true; 1163} 1164 1165// Check if the instruction is a lossy shift right, where the input being 1166// shifted is the operand OpN of MI. If true, [LostB, LostE) is the range 1167// of bit indices that are lost. 1168bool RedundantInstrElimination::isLossyShiftRight(const MachineInstr &MI, 1169 unsigned OpN, unsigned &LostB, unsigned &LostE) { 1170 using namespace Hexagon; 1171 1172 unsigned Opc = MI.getOpcode(); 1173 unsigned ImN, RegN; 1174 switch (Opc) { 1175 case S2_asr_i_p: 1176 case S2_lsr_i_p: 1177 ImN = 2; 1178 RegN = 1; 1179 break; 1180 case S2_asr_i_p_acc: 1181 case S2_asr_i_p_and: 1182 case S2_asr_i_p_nac: 1183 case S2_asr_i_p_or: 1184 case S2_lsr_i_p_acc: 1185 case S2_lsr_i_p_and: 1186 case S2_lsr_i_p_nac: 1187 case S2_lsr_i_p_or: 1188 case S2_lsr_i_p_xacc: 1189 ImN = 3; 1190 RegN = 2; 1191 break; 1192 case S2_asr_i_r: 1193 case S2_lsr_i_r: 1194 ImN = 2; 1195 RegN = 1; 1196 break; 1197 case S4_andi_lsr_ri: 1198 case S4_ori_lsr_ri: 1199 case S4_addi_lsr_ri: 1200 case S4_subi_lsr_ri: 1201 case S2_asr_i_r_acc: 1202 case S2_asr_i_r_and: 1203 case S2_asr_i_r_nac: 1204 case S2_asr_i_r_or: 1205 case S2_lsr_i_r_acc: 1206 case S2_lsr_i_r_and: 1207 case S2_lsr_i_r_nac: 1208 case S2_lsr_i_r_or: 1209 case S2_lsr_i_r_xacc: 1210 ImN = 3; 1211 RegN = 2; 1212 break; 1213 1214 default: 1215 return false; 1216 } 1217 1218 if (RegN != OpN) 1219 return false; 1220 1221 assert(MI.getOperand(ImN).isImm()); 1222 unsigned S = MI.getOperand(ImN).getImm(); 1223 LostB = 0; 1224 LostE = S; 1225 return true; 1226} 1227 1228// Calculate the bit vector that corresponds to the used bits of register Reg. 1229// The vector Bits has the same size, as the size of Reg in bits. If the cal- 1230// culation fails (i.e. the used bits are unknown), it returns false. Other- 1231// wise, it returns true and sets the corresponding bits in Bits. 1232bool RedundantInstrElimination::computeUsedBits(unsigned Reg, BitVector &Bits) { 1233 BitVector Used(Bits.size()); 1234 RegisterSet Visited; 1235 std::vector<unsigned> Pending; 1236 Pending.push_back(Reg); 1237 1238 for (unsigned i = 0; i < Pending.size(); ++i) { 1239 unsigned R = Pending[i]; 1240 if (Visited.has(R)) 1241 continue; 1242 Visited.insert(R); 1243 for (auto I = MRI.use_begin(R), E = MRI.use_end(); I != E; ++I) { 1244 BitTracker::RegisterRef UR = *I; 1245 unsigned B, W; 1246 if (!HBS::getSubregMask(UR, B, W, MRI)) 1247 return false; 1248 MachineInstr &UseI = *I->getParent(); 1249 if (UseI.isPHI() || UseI.isCopy()) { 1250 Register DefR = UseI.getOperand(0).getReg(); 1251 if (!DefR.isVirtual()) 1252 return false; 1253 Pending.push_back(DefR); 1254 } else { 1255 if (!computeUsedBits(UseI, I.getOperandNo(), Used, B)) 1256 return false; 1257 } 1258 } 1259 } 1260 Bits |= Used; 1261 return true; 1262} 1263 1264// Calculate the bits used by instruction MI in a register in operand OpN. 1265// Return true/false if the calculation succeeds/fails. If is succeeds, set 1266// used bits in Bits. This function does not reset any bits in Bits, so 1267// subsequent calls over different instructions will result in the union 1268// of the used bits in all these instructions. 1269// The register in question may be used with a sub-register, whereas Bits 1270// holds the bits for the entire register. To keep track of that, the 1271// argument Begin indicates where in Bits is the lowest-significant bit 1272// of the register used in operand OpN. For example, in instruction: 1273// %1 = S2_lsr_i_r %2:isub_hi, 10 1274// the operand 1 is a 32-bit register, which happens to be a subregister 1275// of the 64-bit register %2, and that subregister starts at position 32. 1276// In this case Begin=32, since Bits[32] would be the lowest-significant bit 1277// of %2:isub_hi. 1278bool RedundantInstrElimination::computeUsedBits(const MachineInstr &MI, 1279 unsigned OpN, BitVector &Bits, uint16_t Begin) { 1280 unsigned Opc = MI.getOpcode(); 1281 BitVector T(Bits.size()); 1282 bool GotBits = HBS::getUsedBits(Opc, OpN, T, Begin, HII); 1283 // Even if we don't have bits yet, we could still provide some information 1284 // if the instruction is a lossy shift: the lost bits will be marked as 1285 // not used. 1286 unsigned LB, LE; 1287 if (isLossyShiftLeft(MI, OpN, LB, LE) || isLossyShiftRight(MI, OpN, LB, LE)) { 1288 assert(MI.getOperand(OpN).isReg()); 1289 BitTracker::RegisterRef RR = MI.getOperand(OpN); 1290 const TargetRegisterClass *RC = HBS::getFinalVRegClass(RR, MRI); 1291 uint16_t Width = HRI.getRegSizeInBits(*RC); 1292 1293 if (!GotBits) 1294 T.set(Begin, Begin+Width); 1295 assert(LB <= LE && LB < Width && LE <= Width); 1296 T.reset(Begin+LB, Begin+LE); 1297 GotBits = true; 1298 } 1299 if (GotBits) 1300 Bits |= T; 1301 return GotBits; 1302} 1303 1304// Calculates the used bits in RD ("defined register"), and checks if these 1305// bits in RS ("used register") and RD are identical. 1306bool RedundantInstrElimination::usedBitsEqual(BitTracker::RegisterRef RD, 1307 BitTracker::RegisterRef RS) { 1308 const BitTracker::RegisterCell &DC = BT.lookup(RD.Reg); 1309 const BitTracker::RegisterCell &SC = BT.lookup(RS.Reg); 1310 1311 unsigned DB, DW; 1312 if (!HBS::getSubregMask(RD, DB, DW, MRI)) 1313 return false; 1314 unsigned SB, SW; 1315 if (!HBS::getSubregMask(RS, SB, SW, MRI)) 1316 return false; 1317 if (SW != DW) 1318 return false; 1319 1320 BitVector Used(DC.width()); 1321 if (!computeUsedBits(RD.Reg, Used)) 1322 return false; 1323 1324 for (unsigned i = 0; i != DW; ++i) 1325 if (Used[i+DB] && DC[DB+i] != SC[SB+i]) 1326 return false; 1327 return true; 1328} 1329 1330bool RedundantInstrElimination::processBlock(MachineBasicBlock &B, 1331 const RegisterSet&) { 1332 if (!BT.reached(&B)) 1333 return false; 1334 bool Changed = false; 1335 1336 for (auto I = B.begin(), E = B.end(); I != E; ++I) { 1337 MachineInstr *MI = &*I; 1338 1339 if (MI->getOpcode() == TargetOpcode::COPY) 1340 continue; 1341 if (MI->isPHI() || MI->hasUnmodeledSideEffects() || MI->isInlineAsm()) 1342 continue; 1343 unsigned NumD = MI->getDesc().getNumDefs(); 1344 if (NumD != 1) 1345 continue; 1346 1347 BitTracker::RegisterRef RD = MI->getOperand(0); 1348 if (!BT.has(RD.Reg)) 1349 continue; 1350 const BitTracker::RegisterCell &DC = BT.lookup(RD.Reg); 1351 auto At = MachineBasicBlock::iterator(MI); 1352 1353 // Find a source operand that is equal to the result. 1354 for (auto &Op : MI->uses()) { 1355 if (!Op.isReg()) 1356 continue; 1357 BitTracker::RegisterRef RS = Op; 1358 if (!BT.has(RS.Reg)) 1359 continue; 1360 if (!HBS::isTransparentCopy(RD, RS, MRI)) 1361 continue; 1362 1363 unsigned BN, BW; 1364 if (!HBS::getSubregMask(RS, BN, BW, MRI)) 1365 continue; 1366 1367 const BitTracker::RegisterCell &SC = BT.lookup(RS.Reg); 1368 if (!usedBitsEqual(RD, RS) && !HBS::isEqual(DC, 0, SC, BN, BW)) 1369 continue; 1370 1371 // If found, replace the instruction with a COPY. 1372 const DebugLoc &DL = MI->getDebugLoc(); 1373 const TargetRegisterClass *FRC = HBS::getFinalVRegClass(RD, MRI); 1374 Register NewR = MRI.createVirtualRegister(FRC); 1375 MachineInstr *CopyI = 1376 BuildMI(B, At, DL, HII.get(TargetOpcode::COPY), NewR) 1377 .addReg(RS.Reg, 0, RS.Sub); 1378 HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI); 1379 // This pass can create copies between registers that don't have the 1380 // exact same values. Updating the tracker has to involve updating 1381 // all dependent cells. Example: 1382 // %1 = inst %2 ; %1 != %2, but used bits are equal 1383 // 1384 // %3 = copy %2 ; <- inserted 1385 // ... = %3 ; <- replaced from %2 1386 // Indirectly, we can create a "copy" between %1 and %2 even 1387 // though their exact values do not match. 1388 BT.visit(*CopyI); 1389 Changed = true; 1390 break; 1391 } 1392 } 1393 1394 return Changed; 1395} 1396 1397namespace { 1398 1399// Recognize instructions that produce constant values known at compile-time. 1400// Replace them with register definitions that load these constants directly. 1401 class ConstGeneration : public Transformation { 1402 public: 1403 ConstGeneration(BitTracker &bt, const HexagonInstrInfo &hii, 1404 MachineRegisterInfo &mri) 1405 : Transformation(true), HII(hii), MRI(mri), BT(bt) {} 1406 1407 bool processBlock(MachineBasicBlock &B, const RegisterSet &AVs) override; 1408 static bool isTfrConst(const MachineInstr &MI); 1409 1410 private: 1411 Register genTfrConst(const TargetRegisterClass *RC, int64_t C, 1412 MachineBasicBlock &B, MachineBasicBlock::iterator At, 1413 DebugLoc &DL); 1414 1415 const HexagonInstrInfo &HII; 1416 MachineRegisterInfo &MRI; 1417 BitTracker &BT; 1418 }; 1419 1420} // end anonymous namespace 1421 1422bool ConstGeneration::isTfrConst(const MachineInstr &MI) { 1423 unsigned Opc = MI.getOpcode(); 1424 switch (Opc) { 1425 case Hexagon::A2_combineii: 1426 case Hexagon::A4_combineii: 1427 case Hexagon::A2_tfrsi: 1428 case Hexagon::A2_tfrpi: 1429 case Hexagon::PS_true: 1430 case Hexagon::PS_false: 1431 case Hexagon::CONST32: 1432 case Hexagon::CONST64: 1433 return true; 1434 } 1435 return false; 1436} 1437 1438// Generate a transfer-immediate instruction that is appropriate for the 1439// register class and the actual value being transferred. 1440Register ConstGeneration::genTfrConst(const TargetRegisterClass *RC, int64_t C, 1441 MachineBasicBlock &B, 1442 MachineBasicBlock::iterator At, 1443 DebugLoc &DL) { 1444 Register Reg = MRI.createVirtualRegister(RC); 1445 if (RC == &Hexagon::IntRegsRegClass) { 1446 BuildMI(B, At, DL, HII.get(Hexagon::A2_tfrsi), Reg) 1447 .addImm(int32_t(C)); 1448 return Reg; 1449 } 1450 1451 if (RC == &Hexagon::DoubleRegsRegClass) { 1452 if (isInt<8>(C)) { 1453 BuildMI(B, At, DL, HII.get(Hexagon::A2_tfrpi), Reg) 1454 .addImm(C); 1455 return Reg; 1456 } 1457 1458 unsigned Lo = Lo_32(C), Hi = Hi_32(C); 1459 if (isInt<8>(Lo) || isInt<8>(Hi)) { 1460 unsigned Opc = isInt<8>(Lo) ? Hexagon::A2_combineii 1461 : Hexagon::A4_combineii; 1462 BuildMI(B, At, DL, HII.get(Opc), Reg) 1463 .addImm(int32_t(Hi)) 1464 .addImm(int32_t(Lo)); 1465 return Reg; 1466 } 1467 MachineFunction *MF = B.getParent(); 1468 auto &HST = MF->getSubtarget<HexagonSubtarget>(); 1469 1470 // Disable CONST64 for tiny core since it takes a LD resource. 1471 if (!HST.isTinyCore() || 1472 MF->getFunction().hasOptSize()) { 1473 BuildMI(B, At, DL, HII.get(Hexagon::CONST64), Reg) 1474 .addImm(C); 1475 return Reg; 1476 } 1477 } 1478 1479 if (RC == &Hexagon::PredRegsRegClass) { 1480 unsigned Opc; 1481 if (C == 0) 1482 Opc = Hexagon::PS_false; 1483 else if ((C & 0xFF) == 0xFF) 1484 Opc = Hexagon::PS_true; 1485 else 1486 return 0; 1487 BuildMI(B, At, DL, HII.get(Opc), Reg); 1488 return Reg; 1489 } 1490 1491 return 0; 1492} 1493 1494bool ConstGeneration::processBlock(MachineBasicBlock &B, const RegisterSet&) { 1495 if (!BT.reached(&B)) 1496 return false; 1497 bool Changed = false; 1498 RegisterSet Defs; 1499 1500 for (auto I = B.begin(), E = B.end(); I != E; ++I) { 1501 if (isTfrConst(*I)) 1502 continue; 1503 Defs.clear(); 1504 HBS::getInstrDefs(*I, Defs); 1505 if (Defs.count() != 1) 1506 continue; 1507 Register DR = Defs.find_first(); 1508 if (!DR.isVirtual()) 1509 continue; 1510 uint64_t U; 1511 const BitTracker::RegisterCell &DRC = BT.lookup(DR); 1512 if (HBS::getConst(DRC, 0, DRC.width(), U)) { 1513 int64_t C = U; 1514 DebugLoc DL = I->getDebugLoc(); 1515 auto At = I->isPHI() ? B.getFirstNonPHI() : I; 1516 Register ImmReg = genTfrConst(MRI.getRegClass(DR), C, B, At, DL); 1517 if (ImmReg) { 1518 HBS::replaceReg(DR, ImmReg, MRI); 1519 BT.put(ImmReg, DRC); 1520 Changed = true; 1521 } 1522 } 1523 } 1524 return Changed; 1525} 1526 1527namespace { 1528 1529// Identify pairs of available registers which hold identical values. 1530// In such cases, only one of them needs to be calculated, the other one 1531// will be defined as a copy of the first. 1532 class CopyGeneration : public Transformation { 1533 public: 1534 CopyGeneration(BitTracker &bt, const HexagonInstrInfo &hii, 1535 const HexagonRegisterInfo &hri, MachineRegisterInfo &mri) 1536 : Transformation(true), HII(hii), HRI(hri), MRI(mri), BT(bt) {} 1537 1538 bool processBlock(MachineBasicBlock &B, const RegisterSet &AVs) override; 1539 1540 private: 1541 bool findMatch(const BitTracker::RegisterRef &Inp, 1542 BitTracker::RegisterRef &Out, const RegisterSet &AVs); 1543 1544 const HexagonInstrInfo &HII; 1545 const HexagonRegisterInfo &HRI; 1546 MachineRegisterInfo &MRI; 1547 BitTracker &BT; 1548 RegisterSet Forbidden; 1549 }; 1550 1551// Eliminate register copies RD = RS, by replacing the uses of RD with 1552// with uses of RS. 1553 class CopyPropagation : public Transformation { 1554 public: 1555 CopyPropagation(const HexagonRegisterInfo &hri, MachineRegisterInfo &mri) 1556 : Transformation(false), HRI(hri), MRI(mri) {} 1557 1558 bool processBlock(MachineBasicBlock &B, const RegisterSet &AVs) override; 1559 1560 static bool isCopyReg(unsigned Opc, bool NoConv); 1561 1562 private: 1563 bool propagateRegCopy(MachineInstr &MI); 1564 1565 const HexagonRegisterInfo &HRI; 1566 MachineRegisterInfo &MRI; 1567 }; 1568 1569} // end anonymous namespace 1570 1571/// Check if there is a register in AVs that is identical to Inp. If so, 1572/// set Out to the found register. The output may be a pair Reg:Sub. 1573bool CopyGeneration::findMatch(const BitTracker::RegisterRef &Inp, 1574 BitTracker::RegisterRef &Out, const RegisterSet &AVs) { 1575 if (!BT.has(Inp.Reg)) 1576 return false; 1577 const BitTracker::RegisterCell &InpRC = BT.lookup(Inp.Reg); 1578 auto *FRC = HBS::getFinalVRegClass(Inp, MRI); 1579 unsigned B, W; 1580 if (!HBS::getSubregMask(Inp, B, W, MRI)) 1581 return false; 1582 1583 for (Register R = AVs.find_first(); R; R = AVs.find_next(R)) { 1584 if (!BT.has(R) || Forbidden[R]) 1585 continue; 1586 const BitTracker::RegisterCell &RC = BT.lookup(R); 1587 unsigned RW = RC.width(); 1588 if (W == RW) { 1589 if (FRC != MRI.getRegClass(R)) 1590 continue; 1591 if (!HBS::isTransparentCopy(R, Inp, MRI)) 1592 continue; 1593 if (!HBS::isEqual(InpRC, B, RC, 0, W)) 1594 continue; 1595 Out.Reg = R; 1596 Out.Sub = 0; 1597 return true; 1598 } 1599 // Check if there is a super-register, whose part (with a subregister) 1600 // is equal to the input. 1601 // Only do double registers for now. 1602 if (W*2 != RW) 1603 continue; 1604 if (MRI.getRegClass(R) != &Hexagon::DoubleRegsRegClass) 1605 continue; 1606 1607 if (HBS::isEqual(InpRC, B, RC, 0, W)) 1608 Out.Sub = Hexagon::isub_lo; 1609 else if (HBS::isEqual(InpRC, B, RC, W, W)) 1610 Out.Sub = Hexagon::isub_hi; 1611 else 1612 continue; 1613 Out.Reg = R; 1614 if (HBS::isTransparentCopy(Out, Inp, MRI)) 1615 return true; 1616 } 1617 return false; 1618} 1619 1620bool CopyGeneration::processBlock(MachineBasicBlock &B, 1621 const RegisterSet &AVs) { 1622 if (!BT.reached(&B)) 1623 return false; 1624 RegisterSet AVB(AVs); 1625 bool Changed = false; 1626 RegisterSet Defs; 1627 1628 for (auto I = B.begin(), E = B.end(); I != E; ++I, AVB.insert(Defs)) { 1629 Defs.clear(); 1630 HBS::getInstrDefs(*I, Defs); 1631 1632 unsigned Opc = I->getOpcode(); 1633 if (CopyPropagation::isCopyReg(Opc, false) || 1634 ConstGeneration::isTfrConst(*I)) 1635 continue; 1636 1637 DebugLoc DL = I->getDebugLoc(); 1638 auto At = I->isPHI() ? B.getFirstNonPHI() : I; 1639 1640 for (Register R = Defs.find_first(); R; R = Defs.find_next(R)) { 1641 BitTracker::RegisterRef MR; 1642 auto *FRC = HBS::getFinalVRegClass(R, MRI); 1643 1644 if (findMatch(R, MR, AVB)) { 1645 Register NewR = MRI.createVirtualRegister(FRC); 1646 BuildMI(B, At, DL, HII.get(TargetOpcode::COPY), NewR) 1647 .addReg(MR.Reg, 0, MR.Sub); 1648 BT.put(BitTracker::RegisterRef(NewR), BT.get(MR)); 1649 HBS::replaceReg(R, NewR, MRI); 1650 Forbidden.insert(R); 1651 continue; 1652 } 1653 1654 if (FRC == &Hexagon::DoubleRegsRegClass || 1655 FRC == &Hexagon::HvxWRRegClass) { 1656 // Try to generate REG_SEQUENCE. 1657 unsigned SubLo = HRI.getHexagonSubRegIndex(*FRC, Hexagon::ps_sub_lo); 1658 unsigned SubHi = HRI.getHexagonSubRegIndex(*FRC, Hexagon::ps_sub_hi); 1659 BitTracker::RegisterRef TL = { R, SubLo }; 1660 BitTracker::RegisterRef TH = { R, SubHi }; 1661 BitTracker::RegisterRef ML, MH; 1662 if (findMatch(TL, ML, AVB) && findMatch(TH, MH, AVB)) { 1663 auto *FRC = HBS::getFinalVRegClass(R, MRI); 1664 Register NewR = MRI.createVirtualRegister(FRC); 1665 BuildMI(B, At, DL, HII.get(TargetOpcode::REG_SEQUENCE), NewR) 1666 .addReg(ML.Reg, 0, ML.Sub) 1667 .addImm(SubLo) 1668 .addReg(MH.Reg, 0, MH.Sub) 1669 .addImm(SubHi); 1670 BT.put(BitTracker::RegisterRef(NewR), BT.get(R)); 1671 HBS::replaceReg(R, NewR, MRI); 1672 Forbidden.insert(R); 1673 } 1674 } 1675 } 1676 } 1677 1678 return Changed; 1679} 1680 1681bool CopyPropagation::isCopyReg(unsigned Opc, bool NoConv) { 1682 switch (Opc) { 1683 case TargetOpcode::COPY: 1684 case TargetOpcode::REG_SEQUENCE: 1685 case Hexagon::A4_combineir: 1686 case Hexagon::A4_combineri: 1687 return true; 1688 case Hexagon::A2_tfr: 1689 case Hexagon::A2_tfrp: 1690 case Hexagon::A2_combinew: 1691 case Hexagon::V6_vcombine: 1692 return NoConv; 1693 default: 1694 break; 1695 } 1696 return false; 1697} 1698 1699bool CopyPropagation::propagateRegCopy(MachineInstr &MI) { 1700 bool Changed = false; 1701 unsigned Opc = MI.getOpcode(); 1702 BitTracker::RegisterRef RD = MI.getOperand(0); 1703 assert(MI.getOperand(0).getSubReg() == 0); 1704 1705 switch (Opc) { 1706 case TargetOpcode::COPY: 1707 case Hexagon::A2_tfr: 1708 case Hexagon::A2_tfrp: { 1709 BitTracker::RegisterRef RS = MI.getOperand(1); 1710 if (!HBS::isTransparentCopy(RD, RS, MRI)) 1711 break; 1712 if (RS.Sub != 0) 1713 Changed = HBS::replaceRegWithSub(RD.Reg, RS.Reg, RS.Sub, MRI); 1714 else 1715 Changed = HBS::replaceReg(RD.Reg, RS.Reg, MRI); 1716 break; 1717 } 1718 case TargetOpcode::REG_SEQUENCE: { 1719 BitTracker::RegisterRef SL, SH; 1720 if (HBS::parseRegSequence(MI, SL, SH, MRI)) { 1721 const TargetRegisterClass &RC = *MRI.getRegClass(RD.Reg); 1722 unsigned SubLo = HRI.getHexagonSubRegIndex(RC, Hexagon::ps_sub_lo); 1723 unsigned SubHi = HRI.getHexagonSubRegIndex(RC, Hexagon::ps_sub_hi); 1724 Changed = HBS::replaceSubWithSub(RD.Reg, SubLo, SL.Reg, SL.Sub, MRI); 1725 Changed |= HBS::replaceSubWithSub(RD.Reg, SubHi, SH.Reg, SH.Sub, MRI); 1726 } 1727 break; 1728 } 1729 case Hexagon::A2_combinew: 1730 case Hexagon::V6_vcombine: { 1731 const TargetRegisterClass &RC = *MRI.getRegClass(RD.Reg); 1732 unsigned SubLo = HRI.getHexagonSubRegIndex(RC, Hexagon::ps_sub_lo); 1733 unsigned SubHi = HRI.getHexagonSubRegIndex(RC, Hexagon::ps_sub_hi); 1734 BitTracker::RegisterRef RH = MI.getOperand(1), RL = MI.getOperand(2); 1735 Changed = HBS::replaceSubWithSub(RD.Reg, SubLo, RL.Reg, RL.Sub, MRI); 1736 Changed |= HBS::replaceSubWithSub(RD.Reg, SubHi, RH.Reg, RH.Sub, MRI); 1737 break; 1738 } 1739 case Hexagon::A4_combineir: 1740 case Hexagon::A4_combineri: { 1741 unsigned SrcX = (Opc == Hexagon::A4_combineir) ? 2 : 1; 1742 unsigned Sub = (Opc == Hexagon::A4_combineir) ? Hexagon::isub_lo 1743 : Hexagon::isub_hi; 1744 BitTracker::RegisterRef RS = MI.getOperand(SrcX); 1745 Changed = HBS::replaceSubWithSub(RD.Reg, Sub, RS.Reg, RS.Sub, MRI); 1746 break; 1747 } 1748 } 1749 return Changed; 1750} 1751 1752bool CopyPropagation::processBlock(MachineBasicBlock &B, const RegisterSet&) { 1753 std::vector<MachineInstr*> Instrs; 1754 for (MachineInstr &MI : llvm::reverse(B)) 1755 Instrs.push_back(&MI); 1756 1757 bool Changed = false; 1758 for (auto *I : Instrs) { 1759 unsigned Opc = I->getOpcode(); 1760 if (!CopyPropagation::isCopyReg(Opc, true)) 1761 continue; 1762 Changed |= propagateRegCopy(*I); 1763 } 1764 1765 return Changed; 1766} 1767 1768namespace { 1769 1770// Recognize patterns that can be simplified and replace them with the 1771// simpler forms. 1772// This is by no means complete 1773 class BitSimplification : public Transformation { 1774 public: 1775 BitSimplification(BitTracker &bt, const MachineDominatorTree &mdt, 1776 const HexagonInstrInfo &hii, const HexagonRegisterInfo &hri, 1777 MachineRegisterInfo &mri, MachineFunction &mf) 1778 : Transformation(true), MDT(mdt), HII(hii), HRI(hri), MRI(mri), 1779 MF(mf), BT(bt) {} 1780 1781 bool processBlock(MachineBasicBlock &B, const RegisterSet &AVs) override; 1782 1783 private: 1784 struct RegHalf : public BitTracker::RegisterRef { 1785 bool Low; // Low/High halfword. 1786 }; 1787 1788 bool matchHalf(unsigned SelfR, const BitTracker::RegisterCell &RC, 1789 unsigned B, RegHalf &RH); 1790 bool validateReg(BitTracker::RegisterRef R, unsigned Opc, unsigned OpNum); 1791 1792 bool matchPackhl(unsigned SelfR, const BitTracker::RegisterCell &RC, 1793 BitTracker::RegisterRef &Rs, BitTracker::RegisterRef &Rt); 1794 unsigned getCombineOpcode(bool HLow, bool LLow); 1795 1796 bool genStoreUpperHalf(MachineInstr *MI); 1797 bool genStoreImmediate(MachineInstr *MI); 1798 bool genPackhl(MachineInstr *MI, BitTracker::RegisterRef RD, 1799 const BitTracker::RegisterCell &RC); 1800 bool genExtractHalf(MachineInstr *MI, BitTracker::RegisterRef RD, 1801 const BitTracker::RegisterCell &RC); 1802 bool genCombineHalf(MachineInstr *MI, BitTracker::RegisterRef RD, 1803 const BitTracker::RegisterCell &RC); 1804 bool genExtractLow(MachineInstr *MI, BitTracker::RegisterRef RD, 1805 const BitTracker::RegisterCell &RC); 1806 bool genBitSplit(MachineInstr *MI, BitTracker::RegisterRef RD, 1807 const BitTracker::RegisterCell &RC, const RegisterSet &AVs); 1808 bool simplifyTstbit(MachineInstr *MI, BitTracker::RegisterRef RD, 1809 const BitTracker::RegisterCell &RC); 1810 bool simplifyExtractLow(MachineInstr *MI, BitTracker::RegisterRef RD, 1811 const BitTracker::RegisterCell &RC, const RegisterSet &AVs); 1812 bool simplifyRCmp0(MachineInstr *MI, BitTracker::RegisterRef RD); 1813 1814 // Cache of created instructions to avoid creating duplicates. 1815 // XXX Currently only used by genBitSplit. 1816 std::vector<MachineInstr*> NewMIs; 1817 1818 const MachineDominatorTree &MDT; 1819 const HexagonInstrInfo &HII; 1820 const HexagonRegisterInfo &HRI; 1821 MachineRegisterInfo &MRI; 1822 MachineFunction &MF; 1823 BitTracker &BT; 1824 }; 1825 1826} // end anonymous namespace 1827 1828// Check if the bits [B..B+16) in register cell RC form a valid halfword, 1829// i.e. [0..16), [16..32), etc. of some register. If so, return true and 1830// set the information about the found register in RH. 1831bool BitSimplification::matchHalf(unsigned SelfR, 1832 const BitTracker::RegisterCell &RC, unsigned B, RegHalf &RH) { 1833 // XXX This could be searching in the set of available registers, in case 1834 // the match is not exact. 1835 1836 // Match 16-bit chunks, where the RC[B..B+15] references exactly one 1837 // register and all the bits B..B+15 match between RC and the register. 1838 // This is meant to match "v1[0-15]", where v1 = { [0]:0 [1-15]:v1... }, 1839 // and RC = { [0]:0 [1-15]:v1[1-15]... }. 1840 bool Low = false; 1841 unsigned I = B; 1842 while (I < B+16 && RC[I].num()) 1843 I++; 1844 if (I == B+16) 1845 return false; 1846 1847 Register Reg = RC[I].RefI.Reg; 1848 unsigned P = RC[I].RefI.Pos; // The RefI.Pos will be advanced by I-B. 1849 if (P < I-B) 1850 return false; 1851 unsigned Pos = P - (I-B); 1852 1853 if (Reg == 0 || Reg == SelfR) // Don't match "self". 1854 return false; 1855 if (!Reg.isVirtual()) 1856 return false; 1857 if (!BT.has(Reg)) 1858 return false; 1859 1860 const BitTracker::RegisterCell &SC = BT.lookup(Reg); 1861 if (Pos+16 > SC.width()) 1862 return false; 1863 1864 for (unsigned i = 0; i < 16; ++i) { 1865 const BitTracker::BitValue &RV = RC[i+B]; 1866 if (RV.Type == BitTracker::BitValue::Ref) { 1867 if (RV.RefI.Reg != Reg) 1868 return false; 1869 if (RV.RefI.Pos != i+Pos) 1870 return false; 1871 continue; 1872 } 1873 if (RC[i+B] != SC[i+Pos]) 1874 return false; 1875 } 1876 1877 unsigned Sub = 0; 1878 switch (Pos) { 1879 case 0: 1880 Sub = Hexagon::isub_lo; 1881 Low = true; 1882 break; 1883 case 16: 1884 Sub = Hexagon::isub_lo; 1885 Low = false; 1886 break; 1887 case 32: 1888 Sub = Hexagon::isub_hi; 1889 Low = true; 1890 break; 1891 case 48: 1892 Sub = Hexagon::isub_hi; 1893 Low = false; 1894 break; 1895 default: 1896 return false; 1897 } 1898 1899 RH.Reg = Reg; 1900 RH.Sub = Sub; 1901 RH.Low = Low; 1902 // If the subregister is not valid with the register, set it to 0. 1903 if (!HBS::getFinalVRegClass(RH, MRI)) 1904 RH.Sub = 0; 1905 1906 return true; 1907} 1908 1909bool BitSimplification::validateReg(BitTracker::RegisterRef R, unsigned Opc, 1910 unsigned OpNum) { 1911 auto *OpRC = HII.getRegClass(HII.get(Opc), OpNum, &HRI, MF); 1912 auto *RRC = HBS::getFinalVRegClass(R, MRI); 1913 return OpRC->hasSubClassEq(RRC); 1914} 1915 1916// Check if RC matches the pattern of a S2_packhl. If so, return true and 1917// set the inputs Rs and Rt. 1918bool BitSimplification::matchPackhl(unsigned SelfR, 1919 const BitTracker::RegisterCell &RC, BitTracker::RegisterRef &Rs, 1920 BitTracker::RegisterRef &Rt) { 1921 RegHalf L1, H1, L2, H2; 1922 1923 if (!matchHalf(SelfR, RC, 0, L2) || !matchHalf(SelfR, RC, 16, L1)) 1924 return false; 1925 if (!matchHalf(SelfR, RC, 32, H2) || !matchHalf(SelfR, RC, 48, H1)) 1926 return false; 1927 1928 // Rs = H1.L1, Rt = H2.L2 1929 if (H1.Reg != L1.Reg || H1.Sub != L1.Sub || H1.Low || !L1.Low) 1930 return false; 1931 if (H2.Reg != L2.Reg || H2.Sub != L2.Sub || H2.Low || !L2.Low) 1932 return false; 1933 1934 Rs = H1; 1935 Rt = H2; 1936 return true; 1937} 1938 1939unsigned BitSimplification::getCombineOpcode(bool HLow, bool LLow) { 1940 return HLow ? LLow ? Hexagon::A2_combine_ll 1941 : Hexagon::A2_combine_lh 1942 : LLow ? Hexagon::A2_combine_hl 1943 : Hexagon::A2_combine_hh; 1944} 1945 1946// If MI stores the upper halfword of a register (potentially obtained via 1947// shifts or extracts), replace it with a storerf instruction. This could 1948// cause the "extraction" code to become dead. 1949bool BitSimplification::genStoreUpperHalf(MachineInstr *MI) { 1950 unsigned Opc = MI->getOpcode(); 1951 if (Opc != Hexagon::S2_storerh_io) 1952 return false; 1953 1954 MachineOperand &ValOp = MI->getOperand(2); 1955 BitTracker::RegisterRef RS = ValOp; 1956 if (!BT.has(RS.Reg)) 1957 return false; 1958 const BitTracker::RegisterCell &RC = BT.lookup(RS.Reg); 1959 RegHalf H; 1960 if (!matchHalf(0, RC, 0, H)) 1961 return false; 1962 if (H.Low) 1963 return false; 1964 MI->setDesc(HII.get(Hexagon::S2_storerf_io)); 1965 ValOp.setReg(H.Reg); 1966 ValOp.setSubReg(H.Sub); 1967 return true; 1968} 1969 1970// If MI stores a value known at compile-time, and the value is within a range 1971// that avoids using constant-extenders, replace it with a store-immediate. 1972bool BitSimplification::genStoreImmediate(MachineInstr *MI) { 1973 unsigned Opc = MI->getOpcode(); 1974 unsigned Align = 0; 1975 switch (Opc) { 1976 case Hexagon::S2_storeri_io: 1977 Align++; 1978 [[fallthrough]]; 1979 case Hexagon::S2_storerh_io: 1980 Align++; 1981 [[fallthrough]]; 1982 case Hexagon::S2_storerb_io: 1983 break; 1984 default: 1985 return false; 1986 } 1987 1988 // Avoid stores to frame-indices (due to an unknown offset). 1989 if (!MI->getOperand(0).isReg()) 1990 return false; 1991 MachineOperand &OffOp = MI->getOperand(1); 1992 if (!OffOp.isImm()) 1993 return false; 1994 1995 int64_t Off = OffOp.getImm(); 1996 // Offset is u6:a. Sadly, there is no isShiftedUInt(n,x). 1997 if (!isUIntN(6+Align, Off) || (Off & ((1<<Align)-1))) 1998 return false; 1999 // Source register: 2000 BitTracker::RegisterRef RS = MI->getOperand(2); 2001 if (!BT.has(RS.Reg)) 2002 return false; 2003 const BitTracker::RegisterCell &RC = BT.lookup(RS.Reg); 2004 uint64_t U; 2005 if (!HBS::getConst(RC, 0, RC.width(), U)) 2006 return false; 2007 2008 // Only consider 8-bit values to avoid constant-extenders. 2009 int V; 2010 switch (Opc) { 2011 case Hexagon::S2_storerb_io: 2012 V = int8_t(U); 2013 break; 2014 case Hexagon::S2_storerh_io: 2015 V = int16_t(U); 2016 break; 2017 case Hexagon::S2_storeri_io: 2018 V = int32_t(U); 2019 break; 2020 default: 2021 // Opc is already checked above to be one of the three store instructions. 2022 // This silences a -Wuninitialized false positive on GCC 5.4. 2023 llvm_unreachable("Unexpected store opcode"); 2024 } 2025 if (!isInt<8>(V)) 2026 return false; 2027 2028 MI->removeOperand(2); 2029 switch (Opc) { 2030 case Hexagon::S2_storerb_io: 2031 MI->setDesc(HII.get(Hexagon::S4_storeirb_io)); 2032 break; 2033 case Hexagon::S2_storerh_io: 2034 MI->setDesc(HII.get(Hexagon::S4_storeirh_io)); 2035 break; 2036 case Hexagon::S2_storeri_io: 2037 MI->setDesc(HII.get(Hexagon::S4_storeiri_io)); 2038 break; 2039 } 2040 MI->addOperand(MachineOperand::CreateImm(V)); 2041 return true; 2042} 2043 2044// If MI is equivalent o S2_packhl, generate the S2_packhl. MI could be the 2045// last instruction in a sequence that results in something equivalent to 2046// the pack-halfwords. The intent is to cause the entire sequence to become 2047// dead. 2048bool BitSimplification::genPackhl(MachineInstr *MI, 2049 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC) { 2050 unsigned Opc = MI->getOpcode(); 2051 if (Opc == Hexagon::S2_packhl) 2052 return false; 2053 BitTracker::RegisterRef Rs, Rt; 2054 if (!matchPackhl(RD.Reg, RC, Rs, Rt)) 2055 return false; 2056 if (!validateReg(Rs, Hexagon::S2_packhl, 1) || 2057 !validateReg(Rt, Hexagon::S2_packhl, 2)) 2058 return false; 2059 2060 MachineBasicBlock &B = *MI->getParent(); 2061 Register NewR = MRI.createVirtualRegister(&Hexagon::DoubleRegsRegClass); 2062 DebugLoc DL = MI->getDebugLoc(); 2063 auto At = MI->isPHI() ? B.getFirstNonPHI() 2064 : MachineBasicBlock::iterator(MI); 2065 BuildMI(B, At, DL, HII.get(Hexagon::S2_packhl), NewR) 2066 .addReg(Rs.Reg, 0, Rs.Sub) 2067 .addReg(Rt.Reg, 0, Rt.Sub); 2068 HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI); 2069 BT.put(BitTracker::RegisterRef(NewR), RC); 2070 return true; 2071} 2072 2073// If MI produces halfword of the input in the low half of the output, 2074// replace it with zero-extend or extractu. 2075bool BitSimplification::genExtractHalf(MachineInstr *MI, 2076 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC) { 2077 RegHalf L; 2078 // Check for halfword in low 16 bits, zeros elsewhere. 2079 if (!matchHalf(RD.Reg, RC, 0, L) || !HBS::isZero(RC, 16, 16)) 2080 return false; 2081 2082 unsigned Opc = MI->getOpcode(); 2083 MachineBasicBlock &B = *MI->getParent(); 2084 DebugLoc DL = MI->getDebugLoc(); 2085 2086 // Prefer zxth, since zxth can go in any slot, while extractu only in 2087 // slots 2 and 3. 2088 unsigned NewR = 0; 2089 auto At = MI->isPHI() ? B.getFirstNonPHI() 2090 : MachineBasicBlock::iterator(MI); 2091 if (L.Low && Opc != Hexagon::A2_zxth) { 2092 if (validateReg(L, Hexagon::A2_zxth, 1)) { 2093 NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass); 2094 BuildMI(B, At, DL, HII.get(Hexagon::A2_zxth), NewR) 2095 .addReg(L.Reg, 0, L.Sub); 2096 } 2097 } else if (!L.Low && Opc != Hexagon::S2_lsr_i_r) { 2098 if (validateReg(L, Hexagon::S2_lsr_i_r, 1)) { 2099 NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass); 2100 BuildMI(B, MI, DL, HII.get(Hexagon::S2_lsr_i_r), NewR) 2101 .addReg(L.Reg, 0, L.Sub) 2102 .addImm(16); 2103 } 2104 } 2105 if (NewR == 0) 2106 return false; 2107 HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI); 2108 BT.put(BitTracker::RegisterRef(NewR), RC); 2109 return true; 2110} 2111 2112// If MI is equivalent to a combine(.L/.H, .L/.H) replace with with the 2113// combine. 2114bool BitSimplification::genCombineHalf(MachineInstr *MI, 2115 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC) { 2116 RegHalf L, H; 2117 // Check for combine h/l 2118 if (!matchHalf(RD.Reg, RC, 0, L) || !matchHalf(RD.Reg, RC, 16, H)) 2119 return false; 2120 // Do nothing if this is just a reg copy. 2121 if (L.Reg == H.Reg && L.Sub == H.Sub && !H.Low && L.Low) 2122 return false; 2123 2124 unsigned Opc = MI->getOpcode(); 2125 unsigned COpc = getCombineOpcode(H.Low, L.Low); 2126 if (COpc == Opc) 2127 return false; 2128 if (!validateReg(H, COpc, 1) || !validateReg(L, COpc, 2)) 2129 return false; 2130 2131 MachineBasicBlock &B = *MI->getParent(); 2132 DebugLoc DL = MI->getDebugLoc(); 2133 Register NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass); 2134 auto At = MI->isPHI() ? B.getFirstNonPHI() 2135 : MachineBasicBlock::iterator(MI); 2136 BuildMI(B, At, DL, HII.get(COpc), NewR) 2137 .addReg(H.Reg, 0, H.Sub) 2138 .addReg(L.Reg, 0, L.Sub); 2139 HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI); 2140 BT.put(BitTracker::RegisterRef(NewR), RC); 2141 return true; 2142} 2143 2144// If MI resets high bits of a register and keeps the lower ones, replace it 2145// with zero-extend byte/half, and-immediate, or extractu, as appropriate. 2146bool BitSimplification::genExtractLow(MachineInstr *MI, 2147 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC) { 2148 unsigned Opc = MI->getOpcode(); 2149 switch (Opc) { 2150 case Hexagon::A2_zxtb: 2151 case Hexagon::A2_zxth: 2152 case Hexagon::S2_extractu: 2153 return false; 2154 } 2155 if (Opc == Hexagon::A2_andir && MI->getOperand(2).isImm()) { 2156 int32_t Imm = MI->getOperand(2).getImm(); 2157 if (isInt<10>(Imm)) 2158 return false; 2159 } 2160 2161 if (MI->hasUnmodeledSideEffects() || MI->isInlineAsm()) 2162 return false; 2163 unsigned W = RC.width(); 2164 while (W > 0 && RC[W-1].is(0)) 2165 W--; 2166 if (W == 0 || W == RC.width()) 2167 return false; 2168 unsigned NewOpc = (W == 8) ? Hexagon::A2_zxtb 2169 : (W == 16) ? Hexagon::A2_zxth 2170 : (W < 10) ? Hexagon::A2_andir 2171 : Hexagon::S2_extractu; 2172 MachineBasicBlock &B = *MI->getParent(); 2173 DebugLoc DL = MI->getDebugLoc(); 2174 2175 for (auto &Op : MI->uses()) { 2176 if (!Op.isReg()) 2177 continue; 2178 BitTracker::RegisterRef RS = Op; 2179 if (!BT.has(RS.Reg)) 2180 continue; 2181 const BitTracker::RegisterCell &SC = BT.lookup(RS.Reg); 2182 unsigned BN, BW; 2183 if (!HBS::getSubregMask(RS, BN, BW, MRI)) 2184 continue; 2185 if (BW < W || !HBS::isEqual(RC, 0, SC, BN, W)) 2186 continue; 2187 if (!validateReg(RS, NewOpc, 1)) 2188 continue; 2189 2190 Register NewR = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass); 2191 auto At = MI->isPHI() ? B.getFirstNonPHI() 2192 : MachineBasicBlock::iterator(MI); 2193 auto MIB = BuildMI(B, At, DL, HII.get(NewOpc), NewR) 2194 .addReg(RS.Reg, 0, RS.Sub); 2195 if (NewOpc == Hexagon::A2_andir) 2196 MIB.addImm((1 << W) - 1); 2197 else if (NewOpc == Hexagon::S2_extractu) 2198 MIB.addImm(W).addImm(0); 2199 HBS::replaceSubWithSub(RD.Reg, RD.Sub, NewR, 0, MRI); 2200 BT.put(BitTracker::RegisterRef(NewR), RC); 2201 return true; 2202 } 2203 return false; 2204} 2205 2206bool BitSimplification::genBitSplit(MachineInstr *MI, 2207 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC, 2208 const RegisterSet &AVs) { 2209 if (!GenBitSplit) 2210 return false; 2211 if (MaxBitSplit.getNumOccurrences()) { 2212 if (CountBitSplit >= MaxBitSplit) 2213 return false; 2214 } 2215 2216 unsigned Opc = MI->getOpcode(); 2217 switch (Opc) { 2218 case Hexagon::A4_bitsplit: 2219 case Hexagon::A4_bitspliti: 2220 return false; 2221 } 2222 2223 unsigned W = RC.width(); 2224 if (W != 32) 2225 return false; 2226 2227 auto ctlz = [] (const BitTracker::RegisterCell &C) -> unsigned { 2228 unsigned Z = C.width(); 2229 while (Z > 0 && C[Z-1].is(0)) 2230 --Z; 2231 return C.width() - Z; 2232 }; 2233 2234 // Count the number of leading zeros in the target RC. 2235 unsigned Z = ctlz(RC); 2236 if (Z == 0 || Z == W) 2237 return false; 2238 2239 // A simplistic analysis: assume the source register (the one being split) 2240 // is fully unknown, and that all its bits are self-references. 2241 const BitTracker::BitValue &B0 = RC[0]; 2242 if (B0.Type != BitTracker::BitValue::Ref) 2243 return false; 2244 2245 unsigned SrcR = B0.RefI.Reg; 2246 unsigned SrcSR = 0; 2247 unsigned Pos = B0.RefI.Pos; 2248 2249 // All the non-zero bits should be consecutive bits from the same register. 2250 for (unsigned i = 1; i < W-Z; ++i) { 2251 const BitTracker::BitValue &V = RC[i]; 2252 if (V.Type != BitTracker::BitValue::Ref) 2253 return false; 2254 if (V.RefI.Reg != SrcR || V.RefI.Pos != Pos+i) 2255 return false; 2256 } 2257 2258 // Now, find the other bitfield among AVs. 2259 for (unsigned S = AVs.find_first(); S; S = AVs.find_next(S)) { 2260 // The number of leading zeros here should be the number of trailing 2261 // non-zeros in RC. 2262 unsigned SRC = MRI.getRegClass(S)->getID(); 2263 if (SRC != Hexagon::IntRegsRegClassID && 2264 SRC != Hexagon::DoubleRegsRegClassID) 2265 continue; 2266 if (!BT.has(S)) 2267 continue; 2268 const BitTracker::RegisterCell &SC = BT.lookup(S); 2269 if (SC.width() != W || ctlz(SC) != W-Z) 2270 continue; 2271 // The Z lower bits should now match SrcR. 2272 const BitTracker::BitValue &S0 = SC[0]; 2273 if (S0.Type != BitTracker::BitValue::Ref || S0.RefI.Reg != SrcR) 2274 continue; 2275 unsigned P = S0.RefI.Pos; 2276 2277 if (Pos <= P && (Pos + W-Z) != P) 2278 continue; 2279 if (P < Pos && (P + Z) != Pos) 2280 continue; 2281 // The starting bitfield position must be at a subregister boundary. 2282 if (std::min(P, Pos) != 0 && std::min(P, Pos) != 32) 2283 continue; 2284 2285 unsigned I; 2286 for (I = 1; I < Z; ++I) { 2287 const BitTracker::BitValue &V = SC[I]; 2288 if (V.Type != BitTracker::BitValue::Ref) 2289 break; 2290 if (V.RefI.Reg != SrcR || V.RefI.Pos != P+I) 2291 break; 2292 } 2293 if (I != Z) 2294 continue; 2295 2296 // Generate bitsplit where S is defined. 2297 if (MaxBitSplit.getNumOccurrences()) 2298 CountBitSplit++; 2299 MachineInstr *DefS = MRI.getVRegDef(S); 2300 assert(DefS != nullptr); 2301 DebugLoc DL = DefS->getDebugLoc(); 2302 MachineBasicBlock &B = *DefS->getParent(); 2303 auto At = DefS->isPHI() ? B.getFirstNonPHI() 2304 : MachineBasicBlock::iterator(DefS); 2305 if (MRI.getRegClass(SrcR)->getID() == Hexagon::DoubleRegsRegClassID) 2306 SrcSR = (std::min(Pos, P) == 32) ? Hexagon::isub_hi : Hexagon::isub_lo; 2307 if (!validateReg({SrcR,SrcSR}, Hexagon::A4_bitspliti, 1)) 2308 continue; 2309 unsigned ImmOp = Pos <= P ? W-Z : Z; 2310 2311 // Find an existing bitsplit instruction if one already exists. 2312 unsigned NewR = 0; 2313 for (MachineInstr *In : NewMIs) { 2314 if (In->getOpcode() != Hexagon::A4_bitspliti) 2315 continue; 2316 MachineOperand &Op1 = In->getOperand(1); 2317 if (Op1.getReg() != SrcR || Op1.getSubReg() != SrcSR) 2318 continue; 2319 if (In->getOperand(2).getImm() != ImmOp) 2320 continue; 2321 // Check if the target register is available here. 2322 MachineOperand &Op0 = In->getOperand(0); 2323 MachineInstr *DefI = MRI.getVRegDef(Op0.getReg()); 2324 assert(DefI != nullptr); 2325 if (!MDT.dominates(DefI, &*At)) 2326 continue; 2327 2328 // Found one that can be reused. 2329 assert(Op0.getSubReg() == 0); 2330 NewR = Op0.getReg(); 2331 break; 2332 } 2333 if (!NewR) { 2334 NewR = MRI.createVirtualRegister(&Hexagon::DoubleRegsRegClass); 2335 auto NewBS = BuildMI(B, At, DL, HII.get(Hexagon::A4_bitspliti), NewR) 2336 .addReg(SrcR, 0, SrcSR) 2337 .addImm(ImmOp); 2338 NewMIs.push_back(NewBS); 2339 } 2340 if (Pos <= P) { 2341 HBS::replaceRegWithSub(RD.Reg, NewR, Hexagon::isub_lo, MRI); 2342 HBS::replaceRegWithSub(S, NewR, Hexagon::isub_hi, MRI); 2343 } else { 2344 HBS::replaceRegWithSub(S, NewR, Hexagon::isub_lo, MRI); 2345 HBS::replaceRegWithSub(RD.Reg, NewR, Hexagon::isub_hi, MRI); 2346 } 2347 return true; 2348 } 2349 2350 return false; 2351} 2352 2353// Check for tstbit simplification opportunity, where the bit being checked 2354// can be tracked back to another register. For example: 2355// %2 = S2_lsr_i_r %1, 5 2356// %3 = S2_tstbit_i %2, 0 2357// => 2358// %3 = S2_tstbit_i %1, 5 2359bool BitSimplification::simplifyTstbit(MachineInstr *MI, 2360 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC) { 2361 unsigned Opc = MI->getOpcode(); 2362 if (Opc != Hexagon::S2_tstbit_i) 2363 return false; 2364 2365 unsigned BN = MI->getOperand(2).getImm(); 2366 BitTracker::RegisterRef RS = MI->getOperand(1); 2367 unsigned F, W; 2368 DebugLoc DL = MI->getDebugLoc(); 2369 if (!BT.has(RS.Reg) || !HBS::getSubregMask(RS, F, W, MRI)) 2370 return false; 2371 MachineBasicBlock &B = *MI->getParent(); 2372 auto At = MI->isPHI() ? B.getFirstNonPHI() 2373 : MachineBasicBlock::iterator(MI); 2374 2375 const BitTracker::RegisterCell &SC = BT.lookup(RS.Reg); 2376 const BitTracker::BitValue &V = SC[F+BN]; 2377 if (V.Type == BitTracker::BitValue::Ref && V.RefI.Reg != RS.Reg) { 2378 const TargetRegisterClass *TC = MRI.getRegClass(V.RefI.Reg); 2379 // Need to map V.RefI.Reg to a 32-bit register, i.e. if it is 2380 // a double register, need to use a subregister and adjust bit 2381 // number. 2382 unsigned P = std::numeric_limits<unsigned>::max(); 2383 BitTracker::RegisterRef RR(V.RefI.Reg, 0); 2384 if (TC == &Hexagon::DoubleRegsRegClass) { 2385 P = V.RefI.Pos; 2386 RR.Sub = Hexagon::isub_lo; 2387 if (P >= 32) { 2388 P -= 32; 2389 RR.Sub = Hexagon::isub_hi; 2390 } 2391 } else if (TC == &Hexagon::IntRegsRegClass) { 2392 P = V.RefI.Pos; 2393 } 2394 if (P != std::numeric_limits<unsigned>::max()) { 2395 Register NewR = MRI.createVirtualRegister(&Hexagon::PredRegsRegClass); 2396 BuildMI(B, At, DL, HII.get(Hexagon::S2_tstbit_i), NewR) 2397 .addReg(RR.Reg, 0, RR.Sub) 2398 .addImm(P); 2399 HBS::replaceReg(RD.Reg, NewR, MRI); 2400 BT.put(NewR, RC); 2401 return true; 2402 } 2403 } else if (V.is(0) || V.is(1)) { 2404 Register NewR = MRI.createVirtualRegister(&Hexagon::PredRegsRegClass); 2405 unsigned NewOpc = V.is(0) ? Hexagon::PS_false : Hexagon::PS_true; 2406 BuildMI(B, At, DL, HII.get(NewOpc), NewR); 2407 HBS::replaceReg(RD.Reg, NewR, MRI); 2408 return true; 2409 } 2410 2411 return false; 2412} 2413 2414// Detect whether RD is a bitfield extract (sign- or zero-extended) of 2415// some register from the AVs set. Create a new corresponding instruction 2416// at the location of MI. The intent is to recognize situations where 2417// a sequence of instructions performs an operation that is equivalent to 2418// an extract operation, such as a shift left followed by a shift right. 2419bool BitSimplification::simplifyExtractLow(MachineInstr *MI, 2420 BitTracker::RegisterRef RD, const BitTracker::RegisterCell &RC, 2421 const RegisterSet &AVs) { 2422 if (!GenExtract) 2423 return false; 2424 if (MaxExtract.getNumOccurrences()) { 2425 if (CountExtract >= MaxExtract) 2426 return false; 2427 CountExtract++; 2428 } 2429 2430 unsigned W = RC.width(); 2431 unsigned RW = W; 2432 unsigned Len; 2433 bool Signed; 2434 2435 // The code is mostly class-independent, except for the part that generates 2436 // the extract instruction, and establishes the source register (in case it 2437 // needs to use a subregister). 2438 const TargetRegisterClass *FRC = HBS::getFinalVRegClass(RD, MRI); 2439 if (FRC != &Hexagon::IntRegsRegClass && FRC != &Hexagon::DoubleRegsRegClass) 2440 return false; 2441 assert(RD.Sub == 0); 2442 2443 // Observation: 2444 // If the cell has a form of 00..0xx..x with k zeros and n remaining 2445 // bits, this could be an extractu of the n bits, but it could also be 2446 // an extractu of a longer field which happens to have 0s in the top 2447 // bit positions. 2448 // The same logic applies to sign-extended fields. 2449 // 2450 // Do not check for the extended extracts, since it would expand the 2451 // search space quite a bit. The search may be expensive as it is. 2452 2453 const BitTracker::BitValue &TopV = RC[W-1]; 2454 2455 // Eliminate candidates that have self-referential bits, since they 2456 // cannot be extracts from other registers. Also, skip registers that 2457 // have compile-time constant values. 2458 bool IsConst = true; 2459 for (unsigned I = 0; I != W; ++I) { 2460 const BitTracker::BitValue &V = RC[I]; 2461 if (V.Type == BitTracker::BitValue::Ref && V.RefI.Reg == RD.Reg) 2462 return false; 2463 IsConst = IsConst && (V.is(0) || V.is(1)); 2464 } 2465 if (IsConst) 2466 return false; 2467 2468 if (TopV.is(0) || TopV.is(1)) { 2469 bool S = TopV.is(1); 2470 for (--W; W > 0 && RC[W-1].is(S); --W) 2471 ; 2472 Len = W; 2473 Signed = S; 2474 // The sign bit must be a part of the field being extended. 2475 if (Signed) 2476 ++Len; 2477 } else { 2478 // This could still be a sign-extended extract. 2479 assert(TopV.Type == BitTracker::BitValue::Ref); 2480 if (TopV.RefI.Reg == RD.Reg || TopV.RefI.Pos == W-1) 2481 return false; 2482 for (--W; W > 0 && RC[W-1] == TopV; --W) 2483 ; 2484 // The top bits of RC are copies of TopV. One occurrence of TopV will 2485 // be a part of the field. 2486 Len = W + 1; 2487 Signed = true; 2488 } 2489 2490 // This would be just a copy. It should be handled elsewhere. 2491 if (Len == RW) 2492 return false; 2493 2494 LLVM_DEBUG({ 2495 dbgs() << __func__ << " on reg: " << printReg(RD.Reg, &HRI, RD.Sub) 2496 << ", MI: " << *MI; 2497 dbgs() << "Cell: " << RC << '\n'; 2498 dbgs() << "Expected bitfield size: " << Len << " bits, " 2499 << (Signed ? "sign" : "zero") << "-extended\n"; 2500 }); 2501 2502 bool Changed = false; 2503 2504 for (unsigned R = AVs.find_first(); R != 0; R = AVs.find_next(R)) { 2505 if (!BT.has(R)) 2506 continue; 2507 const BitTracker::RegisterCell &SC = BT.lookup(R); 2508 unsigned SW = SC.width(); 2509 2510 // The source can be longer than the destination, as long as its size is 2511 // a multiple of the size of the destination. Also, we would need to be 2512 // able to refer to the subregister in the source that would be of the 2513 // same size as the destination, but only check the sizes here. 2514 if (SW < RW || (SW % RW) != 0) 2515 continue; 2516 2517 // The field can start at any offset in SC as long as it contains Len 2518 // bits and does not cross subregister boundary (if the source register 2519 // is longer than the destination). 2520 unsigned Off = 0; 2521 while (Off <= SW-Len) { 2522 unsigned OE = (Off+Len)/RW; 2523 if (OE != Off/RW) { 2524 // The assumption here is that if the source (R) is longer than the 2525 // destination, then the destination is a sequence of words of 2526 // size RW, and each such word in R can be accessed via a subregister. 2527 // 2528 // If the beginning and the end of the field cross the subregister 2529 // boundary, advance to the next subregister. 2530 Off = OE*RW; 2531 continue; 2532 } 2533 if (HBS::isEqual(RC, 0, SC, Off, Len)) 2534 break; 2535 ++Off; 2536 } 2537 2538 if (Off > SW-Len) 2539 continue; 2540 2541 // Found match. 2542 unsigned ExtOpc = 0; 2543 if (Off == 0) { 2544 if (Len == 8) 2545 ExtOpc = Signed ? Hexagon::A2_sxtb : Hexagon::A2_zxtb; 2546 else if (Len == 16) 2547 ExtOpc = Signed ? Hexagon::A2_sxth : Hexagon::A2_zxth; 2548 else if (Len < 10 && !Signed) 2549 ExtOpc = Hexagon::A2_andir; 2550 } 2551 if (ExtOpc == 0) { 2552 ExtOpc = 2553 Signed ? (RW == 32 ? Hexagon::S4_extract : Hexagon::S4_extractp) 2554 : (RW == 32 ? Hexagon::S2_extractu : Hexagon::S2_extractup); 2555 } 2556 unsigned SR = 0; 2557 // This only recognizes isub_lo and isub_hi. 2558 if (RW != SW && RW*2 != SW) 2559 continue; 2560 if (RW != SW) 2561 SR = (Off/RW == 0) ? Hexagon::isub_lo : Hexagon::isub_hi; 2562 Off = Off % RW; 2563 2564 if (!validateReg({R,SR}, ExtOpc, 1)) 2565 continue; 2566 2567 // Don't generate the same instruction as the one being optimized. 2568 if (MI->getOpcode() == ExtOpc) { 2569 // All possible ExtOpc's have the source in operand(1). 2570 const MachineOperand &SrcOp = MI->getOperand(1); 2571 if (SrcOp.getReg() == R) 2572 continue; 2573 } 2574 2575 DebugLoc DL = MI->getDebugLoc(); 2576 MachineBasicBlock &B = *MI->getParent(); 2577 Register NewR = MRI.createVirtualRegister(FRC); 2578 auto At = MI->isPHI() ? B.getFirstNonPHI() 2579 : MachineBasicBlock::iterator(MI); 2580 auto MIB = BuildMI(B, At, DL, HII.get(ExtOpc), NewR) 2581 .addReg(R, 0, SR); 2582 switch (ExtOpc) { 2583 case Hexagon::A2_sxtb: 2584 case Hexagon::A2_zxtb: 2585 case Hexagon::A2_sxth: 2586 case Hexagon::A2_zxth: 2587 break; 2588 case Hexagon::A2_andir: 2589 MIB.addImm((1u << Len) - 1); 2590 break; 2591 case Hexagon::S4_extract: 2592 case Hexagon::S2_extractu: 2593 case Hexagon::S4_extractp: 2594 case Hexagon::S2_extractup: 2595 MIB.addImm(Len) 2596 .addImm(Off); 2597 break; 2598 default: 2599 llvm_unreachable("Unexpected opcode"); 2600 } 2601 2602 HBS::replaceReg(RD.Reg, NewR, MRI); 2603 BT.put(BitTracker::RegisterRef(NewR), RC); 2604 Changed = true; 2605 break; 2606 } 2607 2608 return Changed; 2609} 2610 2611bool BitSimplification::simplifyRCmp0(MachineInstr *MI, 2612 BitTracker::RegisterRef RD) { 2613 unsigned Opc = MI->getOpcode(); 2614 if (Opc != Hexagon::A4_rcmpeqi && Opc != Hexagon::A4_rcmpneqi) 2615 return false; 2616 MachineOperand &CmpOp = MI->getOperand(2); 2617 if (!CmpOp.isImm() || CmpOp.getImm() != 0) 2618 return false; 2619 2620 const TargetRegisterClass *FRC = HBS::getFinalVRegClass(RD, MRI); 2621 if (FRC != &Hexagon::IntRegsRegClass && FRC != &Hexagon::DoubleRegsRegClass) 2622 return false; 2623 assert(RD.Sub == 0); 2624 2625 MachineBasicBlock &B = *MI->getParent(); 2626 const DebugLoc &DL = MI->getDebugLoc(); 2627 auto At = MI->isPHI() ? B.getFirstNonPHI() 2628 : MachineBasicBlock::iterator(MI); 2629 bool KnownZ = true; 2630 bool KnownNZ = false; 2631 2632 BitTracker::RegisterRef SR = MI->getOperand(1); 2633 if (!BT.has(SR.Reg)) 2634 return false; 2635 const BitTracker::RegisterCell &SC = BT.lookup(SR.Reg); 2636 unsigned F, W; 2637 if (!HBS::getSubregMask(SR, F, W, MRI)) 2638 return false; 2639 2640 for (uint16_t I = F; I != F+W; ++I) { 2641 const BitTracker::BitValue &V = SC[I]; 2642 if (!V.is(0)) 2643 KnownZ = false; 2644 if (V.is(1)) 2645 KnownNZ = true; 2646 } 2647 2648 auto ReplaceWithConst = [&](int C) { 2649 Register NewR = MRI.createVirtualRegister(FRC); 2650 BuildMI(B, At, DL, HII.get(Hexagon::A2_tfrsi), NewR) 2651 .addImm(C); 2652 HBS::replaceReg(RD.Reg, NewR, MRI); 2653 BitTracker::RegisterCell NewRC(W); 2654 for (uint16_t I = 0; I != W; ++I) { 2655 NewRC[I] = BitTracker::BitValue(C & 1); 2656 C = unsigned(C) >> 1; 2657 } 2658 BT.put(BitTracker::RegisterRef(NewR), NewRC); 2659 return true; 2660 }; 2661 2662 auto IsNonZero = [] (const MachineOperand &Op) { 2663 if (Op.isGlobal() || Op.isBlockAddress()) 2664 return true; 2665 if (Op.isImm()) 2666 return Op.getImm() != 0; 2667 if (Op.isCImm()) 2668 return !Op.getCImm()->isZero(); 2669 if (Op.isFPImm()) 2670 return !Op.getFPImm()->isZero(); 2671 return false; 2672 }; 2673 2674 auto IsZero = [] (const MachineOperand &Op) { 2675 if (Op.isGlobal() || Op.isBlockAddress()) 2676 return false; 2677 if (Op.isImm()) 2678 return Op.getImm() == 0; 2679 if (Op.isCImm()) 2680 return Op.getCImm()->isZero(); 2681 if (Op.isFPImm()) 2682 return Op.getFPImm()->isZero(); 2683 return false; 2684 }; 2685 2686 // If the source register is known to be 0 or non-0, the comparison can 2687 // be folded to a load of a constant. 2688 if (KnownZ || KnownNZ) { 2689 assert(KnownZ != KnownNZ && "Register cannot be both 0 and non-0"); 2690 return ReplaceWithConst(KnownZ == (Opc == Hexagon::A4_rcmpeqi)); 2691 } 2692 2693 // Special case: if the compare comes from a C2_muxii, then we know the 2694 // two possible constants that can be the source value. 2695 MachineInstr *InpDef = MRI.getVRegDef(SR.Reg); 2696 if (!InpDef) 2697 return false; 2698 if (SR.Sub == 0 && InpDef->getOpcode() == Hexagon::C2_muxii) { 2699 MachineOperand &Src1 = InpDef->getOperand(2); 2700 MachineOperand &Src2 = InpDef->getOperand(3); 2701 // Check if both are non-zero. 2702 bool KnownNZ1 = IsNonZero(Src1), KnownNZ2 = IsNonZero(Src2); 2703 if (KnownNZ1 && KnownNZ2) 2704 return ReplaceWithConst(Opc == Hexagon::A4_rcmpneqi); 2705 // Check if both are zero. 2706 bool KnownZ1 = IsZero(Src1), KnownZ2 = IsZero(Src2); 2707 if (KnownZ1 && KnownZ2) 2708 return ReplaceWithConst(Opc == Hexagon::A4_rcmpeqi); 2709 2710 // If for both operands we know that they are either 0 or non-0, 2711 // replace the comparison with a C2_muxii, using the same predicate 2712 // register, but with operands substituted with 0/1 accordingly. 2713 if ((KnownZ1 || KnownNZ1) && (KnownZ2 || KnownNZ2)) { 2714 Register NewR = MRI.createVirtualRegister(FRC); 2715 BuildMI(B, At, DL, HII.get(Hexagon::C2_muxii), NewR) 2716 .addReg(InpDef->getOperand(1).getReg()) 2717 .addImm(KnownZ1 == (Opc == Hexagon::A4_rcmpeqi)) 2718 .addImm(KnownZ2 == (Opc == Hexagon::A4_rcmpeqi)); 2719 HBS::replaceReg(RD.Reg, NewR, MRI); 2720 // Create a new cell with only the least significant bit unknown. 2721 BitTracker::RegisterCell NewRC(W); 2722 NewRC[0] = BitTracker::BitValue::self(); 2723 NewRC.fill(1, W, BitTracker::BitValue::Zero); 2724 BT.put(BitTracker::RegisterRef(NewR), NewRC); 2725 return true; 2726 } 2727 } 2728 2729 return false; 2730} 2731 2732bool BitSimplification::processBlock(MachineBasicBlock &B, 2733 const RegisterSet &AVs) { 2734 if (!BT.reached(&B)) 2735 return false; 2736 bool Changed = false; 2737 RegisterSet AVB = AVs; 2738 RegisterSet Defs; 2739 2740 for (auto I = B.begin(), E = B.end(); I != E; ++I, AVB.insert(Defs)) { 2741 MachineInstr *MI = &*I; 2742 Defs.clear(); 2743 HBS::getInstrDefs(*MI, Defs); 2744 2745 unsigned Opc = MI->getOpcode(); 2746 if (Opc == TargetOpcode::COPY || Opc == TargetOpcode::REG_SEQUENCE) 2747 continue; 2748 2749 if (MI->mayStore()) { 2750 bool T = genStoreUpperHalf(MI); 2751 T = T || genStoreImmediate(MI); 2752 Changed |= T; 2753 continue; 2754 } 2755 2756 if (Defs.count() != 1) 2757 continue; 2758 const MachineOperand &Op0 = MI->getOperand(0); 2759 if (!Op0.isReg() || !Op0.isDef()) 2760 continue; 2761 BitTracker::RegisterRef RD = Op0; 2762 if (!BT.has(RD.Reg)) 2763 continue; 2764 const TargetRegisterClass *FRC = HBS::getFinalVRegClass(RD, MRI); 2765 const BitTracker::RegisterCell &RC = BT.lookup(RD.Reg); 2766 2767 if (FRC->getID() == Hexagon::DoubleRegsRegClassID) { 2768 bool T = genPackhl(MI, RD, RC); 2769 T = T || simplifyExtractLow(MI, RD, RC, AVB); 2770 Changed |= T; 2771 continue; 2772 } 2773 2774 if (FRC->getID() == Hexagon::IntRegsRegClassID) { 2775 bool T = genBitSplit(MI, RD, RC, AVB); 2776 T = T || simplifyExtractLow(MI, RD, RC, AVB); 2777 T = T || genExtractHalf(MI, RD, RC); 2778 T = T || genCombineHalf(MI, RD, RC); 2779 T = T || genExtractLow(MI, RD, RC); 2780 T = T || simplifyRCmp0(MI, RD); 2781 Changed |= T; 2782 continue; 2783 } 2784 2785 if (FRC->getID() == Hexagon::PredRegsRegClassID) { 2786 bool T = simplifyTstbit(MI, RD, RC); 2787 Changed |= T; 2788 continue; 2789 } 2790 } 2791 return Changed; 2792} 2793 2794bool HexagonBitSimplify::runOnMachineFunction(MachineFunction &MF) { 2795 if (skipFunction(MF.getFunction())) 2796 return false; 2797 2798 auto &HST = MF.getSubtarget<HexagonSubtarget>(); 2799 auto &HRI = *HST.getRegisterInfo(); 2800 auto &HII = *HST.getInstrInfo(); 2801 2802 MDT = &getAnalysis<MachineDominatorTree>(); 2803 MachineRegisterInfo &MRI = MF.getRegInfo(); 2804 bool Changed; 2805 2806 Changed = DeadCodeElimination(MF, *MDT).run(); 2807 2808 const HexagonEvaluator HE(HRI, MRI, HII, MF); 2809 BitTracker BT(HE, MF); 2810 LLVM_DEBUG(BT.trace(true)); 2811 BT.run(); 2812 2813 MachineBasicBlock &Entry = MF.front(); 2814 2815 RegisterSet AIG; // Available registers for IG. 2816 ConstGeneration ImmG(BT, HII, MRI); 2817 Changed |= visitBlock(Entry, ImmG, AIG); 2818 2819 RegisterSet ARE; // Available registers for RIE. 2820 RedundantInstrElimination RIE(BT, HII, HRI, MRI); 2821 bool Ried = visitBlock(Entry, RIE, ARE); 2822 if (Ried) { 2823 Changed = true; 2824 BT.run(); 2825 } 2826 2827 RegisterSet ACG; // Available registers for CG. 2828 CopyGeneration CopyG(BT, HII, HRI, MRI); 2829 Changed |= visitBlock(Entry, CopyG, ACG); 2830 2831 RegisterSet ACP; // Available registers for CP. 2832 CopyPropagation CopyP(HRI, MRI); 2833 Changed |= visitBlock(Entry, CopyP, ACP); 2834 2835 Changed = DeadCodeElimination(MF, *MDT).run() || Changed; 2836 2837 BT.run(); 2838 RegisterSet ABS; // Available registers for BS. 2839 BitSimplification BitS(BT, *MDT, HII, HRI, MRI, MF); 2840 Changed |= visitBlock(Entry, BitS, ABS); 2841 2842 Changed = DeadCodeElimination(MF, *MDT).run() || Changed; 2843 2844 if (Changed) { 2845 for (auto &B : MF) 2846 for (auto &I : B) 2847 I.clearKillInfo(); 2848 DeadCodeElimination(MF, *MDT).run(); 2849 } 2850 return Changed; 2851} 2852 2853// Recognize loops where the code at the end of the loop matches the code 2854// before the entry of the loop, and the matching code is such that is can 2855// be simplified. This pass relies on the bit simplification above and only 2856// prepares code in a way that can be handled by the bit simplifcation. 2857// 2858// This is the motivating testcase (and explanation): 2859// 2860// { 2861// loop0(.LBB0_2, r1) // %for.body.preheader 2862// r5:4 = memd(r0++#8) 2863// } 2864// { 2865// r3 = lsr(r4, #16) 2866// r7:6 = combine(r5, r5) 2867// } 2868// { 2869// r3 = insert(r5, #16, #16) 2870// r7:6 = vlsrw(r7:6, #16) 2871// } 2872// .LBB0_2: 2873// { 2874// memh(r2+#4) = r5 2875// memh(r2+#6) = r6 # R6 is really R5.H 2876// } 2877// { 2878// r2 = add(r2, #8) 2879// memh(r2+#0) = r4 2880// memh(r2+#2) = r3 # R3 is really R4.H 2881// } 2882// { 2883// r5:4 = memd(r0++#8) 2884// } 2885// { # "Shuffling" code that sets up R3 and R6 2886// r3 = lsr(r4, #16) # so that their halves can be stored in the 2887// r7:6 = combine(r5, r5) # next iteration. This could be folded into 2888// } # the stores if the code was at the beginning 2889// { # of the loop iteration. Since the same code 2890// r3 = insert(r5, #16, #16) # precedes the loop, it can actually be moved 2891// r7:6 = vlsrw(r7:6, #16) # there. 2892// }:endloop0 2893// 2894// 2895// The outcome: 2896// 2897// { 2898// loop0(.LBB0_2, r1) 2899// r5:4 = memd(r0++#8) 2900// } 2901// .LBB0_2: 2902// { 2903// memh(r2+#4) = r5 2904// memh(r2+#6) = r5.h 2905// } 2906// { 2907// r2 = add(r2, #8) 2908// memh(r2+#0) = r4 2909// memh(r2+#2) = r4.h 2910// } 2911// { 2912// r5:4 = memd(r0++#8) 2913// }:endloop0 2914 2915namespace llvm { 2916 2917 FunctionPass *createHexagonLoopRescheduling(); 2918 void initializeHexagonLoopReschedulingPass(PassRegistry&); 2919 2920} // end namespace llvm 2921 2922namespace { 2923 2924 class HexagonLoopRescheduling : public MachineFunctionPass { 2925 public: 2926 static char ID; 2927 2928 HexagonLoopRescheduling() : MachineFunctionPass(ID) { 2929 initializeHexagonLoopReschedulingPass(*PassRegistry::getPassRegistry()); 2930 } 2931 2932 bool runOnMachineFunction(MachineFunction &MF) override; 2933 2934 private: 2935 const HexagonInstrInfo *HII = nullptr; 2936 const HexagonRegisterInfo *HRI = nullptr; 2937 MachineRegisterInfo *MRI = nullptr; 2938 BitTracker *BTP = nullptr; 2939 2940 struct LoopCand { 2941 LoopCand(MachineBasicBlock *lb, MachineBasicBlock *pb, 2942 MachineBasicBlock *eb) : LB(lb), PB(pb), EB(eb) {} 2943 2944 MachineBasicBlock *LB, *PB, *EB; 2945 }; 2946 using InstrList = std::vector<MachineInstr *>; 2947 struct InstrGroup { 2948 BitTracker::RegisterRef Inp, Out; 2949 InstrList Ins; 2950 }; 2951 struct PhiInfo { 2952 PhiInfo(MachineInstr &P, MachineBasicBlock &B); 2953 2954 unsigned DefR; 2955 BitTracker::RegisterRef LR, PR; // Loop Register, Preheader Register 2956 MachineBasicBlock *LB, *PB; // Loop Block, Preheader Block 2957 }; 2958 2959 static unsigned getDefReg(const MachineInstr *MI); 2960 bool isConst(unsigned Reg) const; 2961 bool isBitShuffle(const MachineInstr *MI, unsigned DefR) const; 2962 bool isStoreInput(const MachineInstr *MI, unsigned DefR) const; 2963 bool isShuffleOf(unsigned OutR, unsigned InpR) const; 2964 bool isSameShuffle(unsigned OutR1, unsigned InpR1, unsigned OutR2, 2965 unsigned &InpR2) const; 2966 void moveGroup(InstrGroup &G, MachineBasicBlock &LB, MachineBasicBlock &PB, 2967 MachineBasicBlock::iterator At, unsigned OldPhiR, unsigned NewPredR); 2968 bool processLoop(LoopCand &C); 2969 }; 2970 2971} // end anonymous namespace 2972 2973char HexagonLoopRescheduling::ID = 0; 2974 2975INITIALIZE_PASS(HexagonLoopRescheduling, "hexagon-loop-resched", 2976 "Hexagon Loop Rescheduling", false, false) 2977 2978HexagonLoopRescheduling::PhiInfo::PhiInfo(MachineInstr &P, 2979 MachineBasicBlock &B) { 2980 DefR = HexagonLoopRescheduling::getDefReg(&P); 2981 LB = &B; 2982 PB = nullptr; 2983 for (unsigned i = 1, n = P.getNumOperands(); i < n; i += 2) { 2984 const MachineOperand &OpB = P.getOperand(i+1); 2985 if (OpB.getMBB() == &B) { 2986 LR = P.getOperand(i); 2987 continue; 2988 } 2989 PB = OpB.getMBB(); 2990 PR = P.getOperand(i); 2991 } 2992} 2993 2994unsigned HexagonLoopRescheduling::getDefReg(const MachineInstr *MI) { 2995 RegisterSet Defs; 2996 HBS::getInstrDefs(*MI, Defs); 2997 if (Defs.count() != 1) 2998 return 0; 2999 return Defs.find_first(); 3000} 3001 3002bool HexagonLoopRescheduling::isConst(unsigned Reg) const { 3003 if (!BTP->has(Reg)) 3004 return false; 3005 const BitTracker::RegisterCell &RC = BTP->lookup(Reg); 3006 for (unsigned i = 0, w = RC.width(); i < w; ++i) { 3007 const BitTracker::BitValue &V = RC[i]; 3008 if (!V.is(0) && !V.is(1)) 3009 return false; 3010 } 3011 return true; 3012} 3013 3014bool HexagonLoopRescheduling::isBitShuffle(const MachineInstr *MI, 3015 unsigned DefR) const { 3016 unsigned Opc = MI->getOpcode(); 3017 switch (Opc) { 3018 case TargetOpcode::COPY: 3019 case Hexagon::S2_lsr_i_r: 3020 case Hexagon::S2_asr_i_r: 3021 case Hexagon::S2_asl_i_r: 3022 case Hexagon::S2_lsr_i_p: 3023 case Hexagon::S2_asr_i_p: 3024 case Hexagon::S2_asl_i_p: 3025 case Hexagon::S2_insert: 3026 case Hexagon::A2_or: 3027 case Hexagon::A2_orp: 3028 case Hexagon::A2_and: 3029 case Hexagon::A2_andp: 3030 case Hexagon::A2_combinew: 3031 case Hexagon::A4_combineri: 3032 case Hexagon::A4_combineir: 3033 case Hexagon::A2_combineii: 3034 case Hexagon::A4_combineii: 3035 case Hexagon::A2_combine_ll: 3036 case Hexagon::A2_combine_lh: 3037 case Hexagon::A2_combine_hl: 3038 case Hexagon::A2_combine_hh: 3039 return true; 3040 } 3041 return false; 3042} 3043 3044bool HexagonLoopRescheduling::isStoreInput(const MachineInstr *MI, 3045 unsigned InpR) const { 3046 for (unsigned i = 0, n = MI->getNumOperands(); i < n; ++i) { 3047 const MachineOperand &Op = MI->getOperand(i); 3048 if (!Op.isReg()) 3049 continue; 3050 if (Op.getReg() == InpR) 3051 return i == n-1; 3052 } 3053 return false; 3054} 3055 3056bool HexagonLoopRescheduling::isShuffleOf(unsigned OutR, unsigned InpR) const { 3057 if (!BTP->has(OutR) || !BTP->has(InpR)) 3058 return false; 3059 const BitTracker::RegisterCell &OutC = BTP->lookup(OutR); 3060 for (unsigned i = 0, w = OutC.width(); i < w; ++i) { 3061 const BitTracker::BitValue &V = OutC[i]; 3062 if (V.Type != BitTracker::BitValue::Ref) 3063 continue; 3064 if (V.RefI.Reg != InpR) 3065 return false; 3066 } 3067 return true; 3068} 3069 3070bool HexagonLoopRescheduling::isSameShuffle(unsigned OutR1, unsigned InpR1, 3071 unsigned OutR2, unsigned &InpR2) const { 3072 if (!BTP->has(OutR1) || !BTP->has(InpR1) || !BTP->has(OutR2)) 3073 return false; 3074 const BitTracker::RegisterCell &OutC1 = BTP->lookup(OutR1); 3075 const BitTracker::RegisterCell &OutC2 = BTP->lookup(OutR2); 3076 unsigned W = OutC1.width(); 3077 unsigned MatchR = 0; 3078 if (W != OutC2.width()) 3079 return false; 3080 for (unsigned i = 0; i < W; ++i) { 3081 const BitTracker::BitValue &V1 = OutC1[i], &V2 = OutC2[i]; 3082 if (V1.Type != V2.Type || V1.Type == BitTracker::BitValue::One) 3083 return false; 3084 if (V1.Type != BitTracker::BitValue::Ref) 3085 continue; 3086 if (V1.RefI.Pos != V2.RefI.Pos) 3087 return false; 3088 if (V1.RefI.Reg != InpR1) 3089 return false; 3090 if (V2.RefI.Reg == 0 || V2.RefI.Reg == OutR2) 3091 return false; 3092 if (!MatchR) 3093 MatchR = V2.RefI.Reg; 3094 else if (V2.RefI.Reg != MatchR) 3095 return false; 3096 } 3097 InpR2 = MatchR; 3098 return true; 3099} 3100 3101void HexagonLoopRescheduling::moveGroup(InstrGroup &G, MachineBasicBlock &LB, 3102 MachineBasicBlock &PB, MachineBasicBlock::iterator At, unsigned OldPhiR, 3103 unsigned NewPredR) { 3104 DenseMap<unsigned,unsigned> RegMap; 3105 3106 const TargetRegisterClass *PhiRC = MRI->getRegClass(NewPredR); 3107 Register PhiR = MRI->createVirtualRegister(PhiRC); 3108 BuildMI(LB, At, At->getDebugLoc(), HII->get(TargetOpcode::PHI), PhiR) 3109 .addReg(NewPredR) 3110 .addMBB(&PB) 3111 .addReg(G.Inp.Reg) 3112 .addMBB(&LB); 3113 RegMap.insert(std::make_pair(G.Inp.Reg, PhiR)); 3114 3115 for (const MachineInstr *SI : llvm::reverse(G.Ins)) { 3116 unsigned DR = getDefReg(SI); 3117 const TargetRegisterClass *RC = MRI->getRegClass(DR); 3118 Register NewDR = MRI->createVirtualRegister(RC); 3119 DebugLoc DL = SI->getDebugLoc(); 3120 3121 auto MIB = BuildMI(LB, At, DL, HII->get(SI->getOpcode()), NewDR); 3122 for (const MachineOperand &Op : SI->operands()) { 3123 if (!Op.isReg()) { 3124 MIB.add(Op); 3125 continue; 3126 } 3127 if (!Op.isUse()) 3128 continue; 3129 unsigned UseR = RegMap[Op.getReg()]; 3130 MIB.addReg(UseR, 0, Op.getSubReg()); 3131 } 3132 RegMap.insert(std::make_pair(DR, NewDR)); 3133 } 3134 3135 HBS::replaceReg(OldPhiR, RegMap[G.Out.Reg], *MRI); 3136} 3137 3138bool HexagonLoopRescheduling::processLoop(LoopCand &C) { 3139 LLVM_DEBUG(dbgs() << "Processing loop in " << printMBBReference(*C.LB) 3140 << "\n"); 3141 std::vector<PhiInfo> Phis; 3142 for (auto &I : *C.LB) { 3143 if (!I.isPHI()) 3144 break; 3145 unsigned PR = getDefReg(&I); 3146 if (isConst(PR)) 3147 continue; 3148 bool BadUse = false, GoodUse = false; 3149 for (const MachineOperand &MO : MRI->use_operands(PR)) { 3150 const MachineInstr *UseI = MO.getParent(); 3151 if (UseI->getParent() != C.LB) { 3152 BadUse = true; 3153 break; 3154 } 3155 if (isBitShuffle(UseI, PR) || isStoreInput(UseI, PR)) 3156 GoodUse = true; 3157 } 3158 if (BadUse || !GoodUse) 3159 continue; 3160 3161 Phis.push_back(PhiInfo(I, *C.LB)); 3162 } 3163 3164 LLVM_DEBUG({ 3165 dbgs() << "Phis: {"; 3166 for (auto &I : Phis) { 3167 dbgs() << ' ' << printReg(I.DefR, HRI) << "=phi(" 3168 << printReg(I.PR.Reg, HRI, I.PR.Sub) << ":b" << I.PB->getNumber() 3169 << ',' << printReg(I.LR.Reg, HRI, I.LR.Sub) << ":b" 3170 << I.LB->getNumber() << ')'; 3171 } 3172 dbgs() << " }\n"; 3173 }); 3174 3175 if (Phis.empty()) 3176 return false; 3177 3178 bool Changed = false; 3179 InstrList ShufIns; 3180 3181 // Go backwards in the block: for each bit shuffling instruction, check 3182 // if that instruction could potentially be moved to the front of the loop: 3183 // the output of the loop cannot be used in a non-shuffling instruction 3184 // in this loop. 3185 for (MachineInstr &MI : llvm::reverse(*C.LB)) { 3186 if (MI.isTerminator()) 3187 continue; 3188 if (MI.isPHI()) 3189 break; 3190 3191 RegisterSet Defs; 3192 HBS::getInstrDefs(MI, Defs); 3193 if (Defs.count() != 1) 3194 continue; 3195 Register DefR = Defs.find_first(); 3196 if (!DefR.isVirtual()) 3197 continue; 3198 if (!isBitShuffle(&MI, DefR)) 3199 continue; 3200 3201 bool BadUse = false; 3202 for (auto UI = MRI->use_begin(DefR), UE = MRI->use_end(); UI != UE; ++UI) { 3203 MachineInstr *UseI = UI->getParent(); 3204 if (UseI->getParent() == C.LB) { 3205 if (UseI->isPHI()) { 3206 // If the use is in a phi node in this loop, then it should be 3207 // the value corresponding to the back edge. 3208 unsigned Idx = UI.getOperandNo(); 3209 if (UseI->getOperand(Idx+1).getMBB() != C.LB) 3210 BadUse = true; 3211 } else { 3212 if (!llvm::is_contained(ShufIns, UseI)) 3213 BadUse = true; 3214 } 3215 } else { 3216 // There is a use outside of the loop, but there is no epilog block 3217 // suitable for a copy-out. 3218 if (C.EB == nullptr) 3219 BadUse = true; 3220 } 3221 if (BadUse) 3222 break; 3223 } 3224 3225 if (BadUse) 3226 continue; 3227 ShufIns.push_back(&MI); 3228 } 3229 3230 // Partition the list of shuffling instructions into instruction groups, 3231 // where each group has to be moved as a whole (i.e. a group is a chain of 3232 // dependent instructions). A group produces a single live output register, 3233 // which is meant to be the input of the loop phi node (although this is 3234 // not checked here yet). It also uses a single register as its input, 3235 // which is some value produced in the loop body. After moving the group 3236 // to the beginning of the loop, that input register would need to be 3237 // the loop-carried register (through a phi node) instead of the (currently 3238 // loop-carried) output register. 3239 using InstrGroupList = std::vector<InstrGroup>; 3240 InstrGroupList Groups; 3241 3242 for (unsigned i = 0, n = ShufIns.size(); i < n; ++i) { 3243 MachineInstr *SI = ShufIns[i]; 3244 if (SI == nullptr) 3245 continue; 3246 3247 InstrGroup G; 3248 G.Ins.push_back(SI); 3249 G.Out.Reg = getDefReg(SI); 3250 RegisterSet Inputs; 3251 HBS::getInstrUses(*SI, Inputs); 3252 3253 for (unsigned j = i+1; j < n; ++j) { 3254 MachineInstr *MI = ShufIns[j]; 3255 if (MI == nullptr) 3256 continue; 3257 RegisterSet Defs; 3258 HBS::getInstrDefs(*MI, Defs); 3259 // If this instruction does not define any pending inputs, skip it. 3260 if (!Defs.intersects(Inputs)) 3261 continue; 3262 // Otherwise, add it to the current group and remove the inputs that 3263 // are defined by MI. 3264 G.Ins.push_back(MI); 3265 Inputs.remove(Defs); 3266 // Then add all registers used by MI. 3267 HBS::getInstrUses(*MI, Inputs); 3268 ShufIns[j] = nullptr; 3269 } 3270 3271 // Only add a group if it requires at most one register. 3272 if (Inputs.count() > 1) 3273 continue; 3274 auto LoopInpEq = [G] (const PhiInfo &P) -> bool { 3275 return G.Out.Reg == P.LR.Reg; 3276 }; 3277 if (llvm::none_of(Phis, LoopInpEq)) 3278 continue; 3279 3280 G.Inp.Reg = Inputs.find_first(); 3281 Groups.push_back(G); 3282 } 3283 3284 LLVM_DEBUG({ 3285 for (unsigned i = 0, n = Groups.size(); i < n; ++i) { 3286 InstrGroup &G = Groups[i]; 3287 dbgs() << "Group[" << i << "] inp: " 3288 << printReg(G.Inp.Reg, HRI, G.Inp.Sub) 3289 << " out: " << printReg(G.Out.Reg, HRI, G.Out.Sub) << "\n"; 3290 for (const MachineInstr *MI : G.Ins) 3291 dbgs() << " " << MI; 3292 } 3293 }); 3294 3295 for (InstrGroup &G : Groups) { 3296 if (!isShuffleOf(G.Out.Reg, G.Inp.Reg)) 3297 continue; 3298 auto LoopInpEq = [G] (const PhiInfo &P) -> bool { 3299 return G.Out.Reg == P.LR.Reg; 3300 }; 3301 auto F = llvm::find_if(Phis, LoopInpEq); 3302 if (F == Phis.end()) 3303 continue; 3304 unsigned PrehR = 0; 3305 if (!isSameShuffle(G.Out.Reg, G.Inp.Reg, F->PR.Reg, PrehR)) { 3306 const MachineInstr *DefPrehR = MRI->getVRegDef(F->PR.Reg); 3307 unsigned Opc = DefPrehR->getOpcode(); 3308 if (Opc != Hexagon::A2_tfrsi && Opc != Hexagon::A2_tfrpi) 3309 continue; 3310 if (!DefPrehR->getOperand(1).isImm()) 3311 continue; 3312 if (DefPrehR->getOperand(1).getImm() != 0) 3313 continue; 3314 const TargetRegisterClass *RC = MRI->getRegClass(G.Inp.Reg); 3315 if (RC != MRI->getRegClass(F->PR.Reg)) { 3316 PrehR = MRI->createVirtualRegister(RC); 3317 unsigned TfrI = (RC == &Hexagon::IntRegsRegClass) ? Hexagon::A2_tfrsi 3318 : Hexagon::A2_tfrpi; 3319 auto T = C.PB->getFirstTerminator(); 3320 DebugLoc DL = (T != C.PB->end()) ? T->getDebugLoc() : DebugLoc(); 3321 BuildMI(*C.PB, T, DL, HII->get(TfrI), PrehR) 3322 .addImm(0); 3323 } else { 3324 PrehR = F->PR.Reg; 3325 } 3326 } 3327 // isSameShuffle could match with PrehR being of a wider class than 3328 // G.Inp.Reg, for example if G shuffles the low 32 bits of its input, 3329 // it would match for the input being a 32-bit register, and PrehR 3330 // being a 64-bit register (where the low 32 bits match). This could 3331 // be handled, but for now skip these cases. 3332 if (MRI->getRegClass(PrehR) != MRI->getRegClass(G.Inp.Reg)) 3333 continue; 3334 moveGroup(G, *F->LB, *F->PB, F->LB->getFirstNonPHI(), F->DefR, PrehR); 3335 Changed = true; 3336 } 3337 3338 return Changed; 3339} 3340 3341bool HexagonLoopRescheduling::runOnMachineFunction(MachineFunction &MF) { 3342 if (skipFunction(MF.getFunction())) 3343 return false; 3344 3345 auto &HST = MF.getSubtarget<HexagonSubtarget>(); 3346 HII = HST.getInstrInfo(); 3347 HRI = HST.getRegisterInfo(); 3348 MRI = &MF.getRegInfo(); 3349 const HexagonEvaluator HE(*HRI, *MRI, *HII, MF); 3350 BitTracker BT(HE, MF); 3351 LLVM_DEBUG(BT.trace(true)); 3352 BT.run(); 3353 BTP = &BT; 3354 3355 std::vector<LoopCand> Cand; 3356 3357 for (auto &B : MF) { 3358 if (B.pred_size() != 2 || B.succ_size() != 2) 3359 continue; 3360 MachineBasicBlock *PB = nullptr; 3361 bool IsLoop = false; 3362 for (MachineBasicBlock *Pred : B.predecessors()) { 3363 if (Pred != &B) 3364 PB = Pred; 3365 else 3366 IsLoop = true; 3367 } 3368 if (!IsLoop) 3369 continue; 3370 3371 MachineBasicBlock *EB = nullptr; 3372 for (MachineBasicBlock *Succ : B.successors()) { 3373 if (Succ == &B) 3374 continue; 3375 // Set EP to the epilog block, if it has only 1 predecessor (i.e. the 3376 // edge from B to EP is non-critical. 3377 if (Succ->pred_size() == 1) 3378 EB = Succ; 3379 break; 3380 } 3381 3382 Cand.push_back(LoopCand(&B, PB, EB)); 3383 } 3384 3385 bool Changed = false; 3386 for (auto &C : Cand) 3387 Changed |= processLoop(C); 3388 3389 return Changed; 3390} 3391 3392//===----------------------------------------------------------------------===// 3393// Public Constructor Functions 3394//===----------------------------------------------------------------------===// 3395 3396FunctionPass *llvm::createHexagonLoopRescheduling() { 3397 return new HexagonLoopRescheduling(); 3398} 3399 3400FunctionPass *llvm::createHexagonBitSimplify() { 3401 return new HexagonBitSimplify(); 3402} 3403