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      1 //===-- HexagonExpandPredSpillCode.cpp - Expand Predicate Spill Code ------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 // The Hexagon processor has no instructions that load or store predicate
     10 // registers directly.  So, when these registers must be spilled a general
     11 // purpose register must be found and the value copied to/from it from/to
     12 // the predicate register.  This code currently does not use the register
     13 // scavenger mechanism available in the allocator.  There are two registers
     14 // reserved to allow spilling/restoring predicate registers.  One is used to
     15 // hold the predicate value.  The other is used when stack frame offsets are
     16 // too large.
     17 //
     18 //===----------------------------------------------------------------------===//
     19 
     20 #include "Hexagon.h"
     21 #include "HexagonMachineFunctionInfo.h"
     22 #include "HexagonSubtarget.h"
     23 #include "llvm/ADT/Statistic.h"
     24 #include "llvm/CodeGen/LatencyPriorityQueue.h"
     25 #include "llvm/CodeGen/MachineDominators.h"
     26 #include "llvm/CodeGen/MachineFunctionPass.h"
     27 #include "llvm/CodeGen/MachineInstrBuilder.h"
     28 #include "llvm/CodeGen/MachineLoopInfo.h"
     29 #include "llvm/CodeGen/MachineRegisterInfo.h"
     30 #include "llvm/CodeGen/Passes.h"
     31 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
     32 #include "llvm/CodeGen/SchedulerRegistry.h"
     33 #include "llvm/Support/Compiler.h"
     34 #include "llvm/Support/Debug.h"
     35 #include "llvm/Support/MathExtras.h"
     36 #include "llvm/Target/TargetInstrInfo.h"
     37 #include "llvm/Target/TargetMachine.h"
     38 #include "llvm/Target/TargetRegisterInfo.h"
     39 
     40 using namespace llvm;
     41 
     42 
     43 namespace llvm {
     44   FunctionPass *createHexagonExpandPredSpillCode();
     45   void initializeHexagonExpandPredSpillCodePass(PassRegistry&);
     46 }
     47 
     48 
     49 namespace {
     50 
     51 class HexagonExpandPredSpillCode : public MachineFunctionPass {
     52  public:
     53     static char ID;
     54     HexagonExpandPredSpillCode() : MachineFunctionPass(ID) {
     55       PassRegistry &Registry = *PassRegistry::getPassRegistry();
     56       initializeHexagonExpandPredSpillCodePass(Registry);
     57     }
     58 
     59     const char *getPassName() const override {
     60       return "Hexagon Expand Predicate Spill Code";
     61     }
     62     bool runOnMachineFunction(MachineFunction &Fn) override;
     63 };
     64 
     65 
     66 char HexagonExpandPredSpillCode::ID = 0;
     67 
     68 
     69 bool HexagonExpandPredSpillCode::runOnMachineFunction(MachineFunction &Fn) {
     70 
     71   const HexagonSubtarget &QST = Fn.getSubtarget<HexagonSubtarget>();
     72   const HexagonInstrInfo *TII = QST.getInstrInfo();
     73 
     74   // Loop over all of the basic blocks.
     75   for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
     76        MBBb != MBBe; ++MBBb) {
     77     MachineBasicBlock *MBB = &*MBBb;
     78     // Traverse the basic block.
     79     for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
     80          ++MII) {
     81       MachineInstr *MI = MII;
     82       int Opc = MI->getOpcode();
     83       if (Opc == Hexagon::S2_storerb_pci_pseudo ||
     84           Opc == Hexagon::S2_storerh_pci_pseudo ||
     85           Opc == Hexagon::S2_storeri_pci_pseudo ||
     86           Opc == Hexagon::S2_storerd_pci_pseudo ||
     87           Opc == Hexagon::S2_storerf_pci_pseudo) {
     88         unsigned Opcode;
     89         if (Opc == Hexagon::S2_storerd_pci_pseudo)
     90           Opcode = Hexagon::S2_storerd_pci;
     91         else if (Opc == Hexagon::S2_storeri_pci_pseudo)
     92           Opcode = Hexagon::S2_storeri_pci;
     93         else if (Opc == Hexagon::S2_storerh_pci_pseudo)
     94           Opcode = Hexagon::S2_storerh_pci;
     95         else if (Opc == Hexagon::S2_storerf_pci_pseudo)
     96           Opcode = Hexagon::S2_storerf_pci;
     97         else if (Opc == Hexagon::S2_storerb_pci_pseudo)
     98           Opcode = Hexagon::S2_storerb_pci;
     99         else
    100           llvm_unreachable("wrong Opc");
    101         MachineOperand &Op0 = MI->getOperand(0);
    102         MachineOperand &Op1 = MI->getOperand(1);
    103         MachineOperand &Op2 = MI->getOperand(2);
    104         MachineOperand &Op3 = MI->getOperand(3); // Modifier value.
    105         MachineOperand &Op4 = MI->getOperand(4);
    106         // Emit a "C6 = Rn, C6 is the control register for M0".
    107         BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_tfrrcr),
    108                 Hexagon::C6)->addOperand(Op3);
    109         // Replace the pseude circ_ldd by the real circ_ldd.
    110         MachineInstr *NewMI = BuildMI(*MBB, MII, MI->getDebugLoc(),
    111                                       TII->get(Opcode));
    112         NewMI->addOperand(Op0);
    113         NewMI->addOperand(Op1);
    114         NewMI->addOperand(Op4);
    115         NewMI->addOperand(MachineOperand::CreateReg(Hexagon::M0,
    116                                                     false, /*isDef*/
    117                                                     false, /*isImpl*/
    118                                                     true   /*isKill*/));
    119         NewMI->addOperand(Op2);
    120         MII = MBB->erase(MI);
    121         --MII;
    122       } else if (Opc == Hexagon::L2_loadrd_pci_pseudo ||
    123                  Opc == Hexagon::L2_loadri_pci_pseudo ||
    124                  Opc == Hexagon::L2_loadrh_pci_pseudo ||
    125                  Opc == Hexagon::L2_loadruh_pci_pseudo||
    126                  Opc == Hexagon::L2_loadrb_pci_pseudo ||
    127                  Opc == Hexagon::L2_loadrub_pci_pseudo) {
    128         unsigned Opcode;
    129         if (Opc == Hexagon::L2_loadrd_pci_pseudo)
    130           Opcode = Hexagon::L2_loadrd_pci;
    131         else if (Opc == Hexagon::L2_loadri_pci_pseudo)
    132           Opcode = Hexagon::L2_loadri_pci;
    133         else if (Opc == Hexagon::L2_loadrh_pci_pseudo)
    134           Opcode = Hexagon::L2_loadrh_pci;
    135         else if (Opc == Hexagon::L2_loadruh_pci_pseudo)
    136           Opcode = Hexagon::L2_loadruh_pci;
    137         else if (Opc == Hexagon::L2_loadrb_pci_pseudo)
    138           Opcode = Hexagon::L2_loadrb_pci;
    139         else if (Opc == Hexagon::L2_loadrub_pci_pseudo)
    140           Opcode = Hexagon::L2_loadrub_pci;
    141         else
    142           llvm_unreachable("wrong Opc");
    143 
    144         MachineOperand &Op0 = MI->getOperand(0);
    145         MachineOperand &Op1 = MI->getOperand(1);
    146         MachineOperand &Op2 = MI->getOperand(2);
    147         MachineOperand &Op4 = MI->getOperand(4); // Modifier value.
    148         MachineOperand &Op5 = MI->getOperand(5);
    149         // Emit a "C6 = Rn, C6 is the control register for M0".
    150         BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_tfrrcr),
    151                 Hexagon::C6)->addOperand(Op4);
    152         // Replace the pseude circ_ldd by the real circ_ldd.
    153         MachineInstr *NewMI = BuildMI(*MBB, MII, MI->getDebugLoc(),
    154                                       TII->get(Opcode));
    155         NewMI->addOperand(Op1);
    156         NewMI->addOperand(Op0);
    157         NewMI->addOperand(Op2);
    158         NewMI->addOperand(Op5);
    159         NewMI->addOperand(MachineOperand::CreateReg(Hexagon::M0,
    160                                                     false, /*isDef*/
    161                                                     false, /*isImpl*/
    162                                                     true   /*isKill*/));
    163         MII = MBB->erase(MI);
    164         --MII;
    165       } else if (Opc == Hexagon::L2_loadrd_pbr_pseudo ||
    166                  Opc == Hexagon::L2_loadri_pbr_pseudo ||
    167                  Opc == Hexagon::L2_loadrh_pbr_pseudo ||
    168                  Opc == Hexagon::L2_loadruh_pbr_pseudo||
    169                  Opc == Hexagon::L2_loadrb_pbr_pseudo ||
    170                  Opc == Hexagon::L2_loadrub_pbr_pseudo) {
    171         unsigned Opcode;
    172         if (Opc == Hexagon::L2_loadrd_pbr_pseudo)
    173           Opcode = Hexagon::L2_loadrd_pbr;
    174         else if (Opc == Hexagon::L2_loadri_pbr_pseudo)
    175           Opcode = Hexagon::L2_loadri_pbr;
    176         else if (Opc == Hexagon::L2_loadrh_pbr_pseudo)
    177           Opcode = Hexagon::L2_loadrh_pbr;
    178         else if (Opc == Hexagon::L2_loadruh_pbr_pseudo)
    179           Opcode = Hexagon::L2_loadruh_pbr;
    180         else if (Opc == Hexagon::L2_loadrb_pbr_pseudo)
    181           Opcode = Hexagon::L2_loadrb_pbr;
    182         else if (Opc == Hexagon::L2_loadrub_pbr_pseudo)
    183           Opcode = Hexagon::L2_loadrub_pbr;
    184         else
    185           llvm_unreachable("wrong Opc");
    186         MachineOperand &Op0 = MI->getOperand(0);
    187         MachineOperand &Op1 = MI->getOperand(1);
    188         MachineOperand &Op2 = MI->getOperand(2);
    189         MachineOperand &Op4 = MI->getOperand(4); // Modifier value.
    190         // Emit a "C6 = Rn, C6 is the control register for M0".
    191         BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_tfrrcr),
    192                 Hexagon::C6)->addOperand(Op4);
    193         // Replace the pseudo brev_ldd by the real brev_ldd.
    194         MachineInstr *NewMI = BuildMI(*MBB, MII, MI->getDebugLoc(),
    195                                       TII->get(Opcode));
    196         NewMI->addOperand(Op1);
    197         NewMI->addOperand(Op0);
    198         NewMI->addOperand(Op2);
    199         NewMI->addOperand(MachineOperand::CreateReg(Hexagon::M0,
    200                                                     false, /*isDef*/
    201                                                     false, /*isImpl*/
    202                                                     true   /*isKill*/));
    203         MII = MBB->erase(MI);
    204         --MII;
    205       } else if (Opc == Hexagon::S2_storerd_pbr_pseudo ||
    206                  Opc == Hexagon::S2_storeri_pbr_pseudo ||
    207                  Opc == Hexagon::S2_storerh_pbr_pseudo ||
    208                  Opc == Hexagon::S2_storerb_pbr_pseudo ||
    209                  Opc == Hexagon::S2_storerf_pbr_pseudo) {
    210         unsigned Opcode;
    211         if (Opc == Hexagon::S2_storerd_pbr_pseudo)
    212           Opcode = Hexagon::S2_storerd_pbr;
    213         else if (Opc == Hexagon::S2_storeri_pbr_pseudo)
    214           Opcode = Hexagon::S2_storeri_pbr;
    215         else if (Opc == Hexagon::S2_storerh_pbr_pseudo)
    216           Opcode = Hexagon::S2_storerh_pbr;
    217         else if (Opc == Hexagon::S2_storerf_pbr_pseudo)
    218           Opcode = Hexagon::S2_storerf_pbr;
    219         else if (Opc == Hexagon::S2_storerb_pbr_pseudo)
    220           Opcode = Hexagon::S2_storerb_pbr;
    221         else
    222           llvm_unreachable("wrong Opc");
    223         MachineOperand &Op0 = MI->getOperand(0);
    224         MachineOperand &Op1 = MI->getOperand(1);
    225         MachineOperand &Op2 = MI->getOperand(2);
    226         MachineOperand &Op3 = MI->getOperand(3); // Modifier value.
    227         // Emit a "C6 = Rn, C6 is the control register for M0".
    228         BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_tfrrcr),
    229                 Hexagon::C6)->addOperand(Op3);
    230         // Replace the pseudo brev_ldd by the real brev_ldd.
    231         MachineInstr *NewMI = BuildMI(*MBB, MII, MI->getDebugLoc(),
    232                                       TII->get(Opcode));
    233         NewMI->addOperand(Op0);
    234         NewMI->addOperand(Op1);
    235         NewMI->addOperand(MachineOperand::CreateReg(Hexagon::M0,
    236                                                     false, /*isDef*/
    237                                                     false, /*isImpl*/
    238                                                     true   /*isKill*/));
    239         NewMI->addOperand(Op2);
    240         MII = MBB->erase(MI);
    241         --MII;
    242       } else if (Opc == Hexagon::STriw_pred) {
    243         // STriw_pred [R30], ofst, SrcReg;
    244         unsigned FP = MI->getOperand(0).getReg();
    245         assert(FP == QST.getRegisterInfo()->getFrameRegister() &&
    246                "Not a Frame Pointer, Nor a Spill Slot");
    247         assert(MI->getOperand(1).isImm() && "Not an offset");
    248         int Offset = MI->getOperand(1).getImm();
    249         int SrcReg = MI->getOperand(2).getReg();
    250         assert(Hexagon::PredRegsRegClass.contains(SrcReg) &&
    251                "Not a predicate register");
    252         if (!TII->isValidOffset(Hexagon::S2_storeri_io, Offset)) {
    253           if (!TII->isValidOffset(Hexagon::A2_addi, Offset)) {
    254             BuildMI(*MBB, MII, MI->getDebugLoc(),
    255                     TII->get(Hexagon::CONST32_Int_Real),
    256                       HEXAGON_RESERVED_REG_1).addImm(Offset);
    257             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_add),
    258                     HEXAGON_RESERVED_REG_1)
    259               .addReg(FP).addReg(HEXAGON_RESERVED_REG_1);
    260             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::C2_tfrpr),
    261                       HEXAGON_RESERVED_REG_2).addReg(SrcReg);
    262             BuildMI(*MBB, MII, MI->getDebugLoc(),
    263                     TII->get(Hexagon::S2_storeri_io))
    264               .addReg(HEXAGON_RESERVED_REG_1)
    265               .addImm(0).addReg(HEXAGON_RESERVED_REG_2);
    266           } else {
    267             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_addi),
    268                       HEXAGON_RESERVED_REG_1).addReg(FP).addImm(Offset);
    269             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::C2_tfrpr),
    270                       HEXAGON_RESERVED_REG_2).addReg(SrcReg);
    271             BuildMI(*MBB, MII, MI->getDebugLoc(),
    272                           TII->get(Hexagon::S2_storeri_io))
    273               .addReg(HEXAGON_RESERVED_REG_1)
    274               .addImm(0)
    275               .addReg(HEXAGON_RESERVED_REG_2);
    276           }
    277         } else {
    278           BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::C2_tfrpr),
    279                     HEXAGON_RESERVED_REG_2).addReg(SrcReg);
    280           BuildMI(*MBB, MII, MI->getDebugLoc(),
    281                         TII->get(Hexagon::S2_storeri_io)).
    282                     addReg(FP).addImm(Offset).addReg(HEXAGON_RESERVED_REG_2);
    283         }
    284         MII = MBB->erase(MI);
    285         --MII;
    286       } else if (Opc == Hexagon::LDriw_pred) {
    287         // DstReg = LDriw_pred [R30], ofst.
    288         int DstReg = MI->getOperand(0).getReg();
    289         assert(Hexagon::PredRegsRegClass.contains(DstReg) &&
    290                "Not a predicate register");
    291         unsigned FP = MI->getOperand(1).getReg();
    292         assert(FP == QST.getRegisterInfo()->getFrameRegister() &&
    293                "Not a Frame Pointer, Nor a Spill Slot");
    294         assert(MI->getOperand(2).isImm() && "Not an offset");
    295         int Offset = MI->getOperand(2).getImm();
    296         if (!TII->isValidOffset(Hexagon::L2_loadri_io, Offset)) {
    297           if (!TII->isValidOffset(Hexagon::A2_addi, Offset)) {
    298             BuildMI(*MBB, MII, MI->getDebugLoc(),
    299                     TII->get(Hexagon::CONST32_Int_Real),
    300                       HEXAGON_RESERVED_REG_1).addImm(Offset);
    301             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_add),
    302                     HEXAGON_RESERVED_REG_1)
    303               .addReg(FP)
    304               .addReg(HEXAGON_RESERVED_REG_1);
    305             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::L2_loadri_io),
    306                       HEXAGON_RESERVED_REG_2)
    307               .addReg(HEXAGON_RESERVED_REG_1)
    308               .addImm(0);
    309             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::C2_tfrrp),
    310                       DstReg).addReg(HEXAGON_RESERVED_REG_2);
    311           } else {
    312             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::A2_addi),
    313                       HEXAGON_RESERVED_REG_1).addReg(FP).addImm(Offset);
    314             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::L2_loadri_io),
    315                       HEXAGON_RESERVED_REG_2)
    316               .addReg(HEXAGON_RESERVED_REG_1)
    317               .addImm(0);
    318             BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::C2_tfrrp),
    319                       DstReg).addReg(HEXAGON_RESERVED_REG_2);
    320           }
    321         } else {
    322           BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::L2_loadri_io),
    323                     HEXAGON_RESERVED_REG_2).addReg(FP).addImm(Offset);
    324           BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::C2_tfrrp),
    325                     DstReg).addReg(HEXAGON_RESERVED_REG_2);
    326         }
    327         MII = MBB->erase(MI);
    328         --MII;
    329       }
    330     }
    331   }
    332 
    333   return true;
    334 }
    335 
    336 }
    337 
    338 //===----------------------------------------------------------------------===//
    339 //                         Public Constructor Functions
    340 //===----------------------------------------------------------------------===//
    341 
    342 static void initializePassOnce(PassRegistry &Registry) {
    343   const char *Name = "Hexagon Expand Predicate Spill Code";
    344   PassInfo *PI = new PassInfo(Name, "hexagon-spill-pred",
    345                               &HexagonExpandPredSpillCode::ID,
    346                               nullptr, false, false);
    347   Registry.registerPass(*PI, true);
    348 }
    349 
    350 void llvm::initializeHexagonExpandPredSpillCodePass(PassRegistry &Registry) {
    351   CALL_ONCE_INITIALIZATION(initializePassOnce)
    352 }
    353 
    354 FunctionPass*
    355 llvm::createHexagonExpandPredSpillCode() {
    356   return new HexagonExpandPredSpillCode();
    357 }
    358