Revert "r214669 - MachineCombiner Pass for selecting faster instruction"

This commit broke "make check" for several hours, so get it reverted.

llvm-svn: 214697

1 files changed, 10 insertions, 466 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index c804b24ddb4..1273606699c 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -14,7 +14,6 @@
 #include "AArch64InstrInfo.h"
 #include "AArch64Subtarget.h"
 #include "MCTargetDesc/AArch64AddressingModes.h"
-#include "AArch64MachineCombinerPattern.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
@@ -698,12 +697,17 @@ static bool UpdateOperandRegClass(MachineInstr *Instr) {
   return true;
 }
 
-/// convertFlagSettingOpcode - return opcode that does not
-/// set flags when possible. The caller is responsible to do
-/// the actual substitution and legality checking.
-static unsigned convertFlagSettingOpcode(MachineInstr *MI) {
+/// optimizeCompareInstr - Convert the instruction supplying the argument to the
+/// comparison into one that sets the zero bit in the flags register.
+bool AArch64InstrInfo::optimizeCompareInstr(
+    MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2, int CmpMask,
+    int CmpValue, const MachineRegisterInfo *MRI) const {
+
+  // Replace SUBSWrr with SUBWrr if NZCV is not used.
+  int Cmp_NZCV = CmpInstr->findRegisterDefOperandIdx(AArch64::NZCV, true);
+  if (Cmp_NZCV != -1) {
     unsigned NewOpc;
-    switch (MI->getOpcode()) {
+    switch (CmpInstr->getOpcode()) {
     default:
       return false;
     case AArch64::ADDSWrr:      NewOpc = AArch64::ADDWrr; break;
@@ -723,22 +727,7 @@ static unsigned convertFlagSettingOpcode(MachineInstr *MI) {
     case AArch64::SUBSXrs:      NewOpc = AArch64::SUBXrs; break;
     case AArch64::SUBSXrx:      NewOpc = AArch64::SUBXrx; break;
     }
-    return NewOpc;
-}
 
-/// optimizeCompareInstr - Convert the instruction supplying the argument to the
-/// comparison into one that sets the zero bit in the flags register.
-bool AArch64InstrInfo::optimizeCompareInstr(
-    MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2, int CmpMask,
-    int CmpValue, const MachineRegisterInfo *MRI) const {
-
-  // Replace SUBSWrr with SUBWrr if NZCV is not used.
-  int Cmp_NZCV = CmpInstr->findRegisterDefOperandIdx(AArch64::NZCV, true);
-  if (Cmp_NZCV != -1) {
-    unsigned Opc = CmpInstr->getOpcode();
-    unsigned NewOpc = convertFlagSettingOpcode(CmpInstr);
-    if (NewOpc == Opc)
-      return false;
     const MCInstrDesc &MCID = get(NewOpc);
     CmpInstr->setDesc(MCID);
     CmpInstr->RemoveOperand(Cmp_NZCV);
@@ -2196,448 +2185,3 @@ void AArch64InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   NopInst.setOpcode(AArch64::HINT);
   NopInst.addOperand(MCOperand::CreateImm(0));
 }
-/// useMachineCombiner - return true when a target supports MachineCombiner
-bool AArch64InstrInfo::useMachineCombiner(void) const {
-  // AArch64 supports the combiner
-  return true;
-}
-//
-// True when Opc sets flag
-static bool isCombineInstrSettingFlag(unsigned Opc) {
-  switch (Opc) {
-  case AArch64::ADDSWrr:
-  case AArch64::ADDSWri:
-  case AArch64::ADDSXrr:
-  case AArch64::ADDSXri:
-  case AArch64::SUBSWrr:
-  case AArch64::SUBSXrr:
-  // Note: MSUB Wd,Wn,Wm,Wi -> Wd = Wi - WnxWm, not Wd=WnxWm - Wi.
-  case AArch64::SUBSWri:
-  case AArch64::SUBSXri:
-    return true;
-  default:
-    break;
-  }
-  return false;
-}
-//
-// 32b Opcodes that can be combined with a MUL
-static bool isCombineInstrCandidate32(unsigned Opc) {
-  switch (Opc) {
-  case AArch64::ADDWrr:
-  case AArch64::ADDWri:
-  case AArch64::SUBWrr:
-  case AArch64::ADDSWrr:
-  case AArch64::ADDSWri:
-  case AArch64::SUBSWrr:
-  // Note: MSUB Wd,Wn,Wm,Wi -> Wd = Wi - WnxWm, not Wd=WnxWm - Wi.
-  case AArch64::SUBWri:
-  case AArch64::SUBSWri:
-    return true;
-  default:
-    break;
-  }
-  return false;
-}
-//
-// 64b Opcodes that can be combined with a MUL
-static bool isCombineInstrCandidate64(unsigned Opc) {
-  switch (Opc) {
-  case AArch64::ADDXrr:
-  case AArch64::ADDXri:
-  case AArch64::SUBXrr:
-  case AArch64::ADDSXrr:
-  case AArch64::ADDSXri:
-  case AArch64::SUBSXrr:
-  // Note: MSUB Wd,Wn,Wm,Wi -> Wd = Wi - WnxWm, not Wd=WnxWm - Wi.
-  case AArch64::SUBXri:
-  case AArch64::SUBSXri:
-    return true;
-  default:
-    break;
-  }
-  return false;
-}
-//
-// Opcodes that can be combined with a MUL
-static bool isCombineInstrCandidate(unsigned Opc) {
-  return (isCombineInstrCandidate32(Opc) || isCombineInstrCandidate64(Opc));
-}
-
-static bool canCombineWithMUL(MachineBasicBlock &MBB, MachineOperand &MO,
-                              unsigned MulOpc, unsigned ZeroReg) {
-  MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
-  MachineInstr *MI = nullptr;
-  // We need a virtual register definition.
-  if (MO.isReg() && TargetRegisterInfo::isVirtualRegister(MO.getReg()))
-    MI = MRI.getUniqueVRegDef(MO.getReg());
-  // And it needs to be in the trace (otherwise, it won't have a depth).
-  if (!MI || MI->getParent() != &MBB || (unsigned)MI->getOpcode() != MulOpc)
-    return false;
-
-  assert(MI->getNumOperands() >= 4 && MI->getOperand(0).isReg() &&
-         MI->getOperand(1).isReg() && MI->getOperand(2).isReg() &&
-         MI->getOperand(3).isReg() && "MAdd/MSub must have a least 4 regs");
-
-  // The third input reg must be zero.
-  if (MI->getOperand(3).getReg() != ZeroReg)
-    return false;
-
-  // Must only used by the user we combine with.
-  if (!MRI.hasOneNonDBGUse(MI->getOperand(0).getReg()))
-    return false;
-
-  return true;
-}
-
-/// hasPattern - return true when there is potentially a faster code sequence
-/// for an instruction chain ending in \p Root. All potential patterns are
-/// listed
-/// in the \p Pattern vector. Pattern should be sorted in priority order since
-/// the pattern evaluator stops checking as soon as it finds a faster sequence.
-
-bool AArch64InstrInfo::hasPattern(
-    MachineInstr &Root,
-    SmallVectorImpl<MachineCombinerPattern::MC_PATTERN> &Pattern) const {
-  unsigned Opc = Root.getOpcode();
-  MachineBasicBlock &MBB = *Root.getParent();
-  bool Found = false;
-
-  if (!isCombineInstrCandidate(Opc))
-    return 0;
-  if (isCombineInstrSettingFlag(Opc)) {
-    int Cmp_NZCV = Root.findRegisterDefOperandIdx(AArch64::NZCV, true);
-    // When NZCV is live bail out.
-    if (Cmp_NZCV == -1)
-      return 0;
-    unsigned NewOpc = convertFlagSettingOpcode(&Root);
-    // When opcode can't change bail out.
-    // CHECKME: do we miss any cases for opcode conversion?
-    if (NewOpc == Opc)
-      return 0;
-    Opc = NewOpc;
-  }
-
-  switch (Opc) {
-  default:
-    break;
-  case AArch64::ADDWrr:
-    assert(Root.getOperand(1).isReg() && Root.getOperand(2).isReg() &&
-           "ADDWrr does not have register operands");
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
-                          AArch64::WZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULADDW_OP1);
-      Found = true;
-    }
-    if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDWrrr,
-                          AArch64::WZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULADDW_OP2);
-      Found = true;
-    }
-    break;
-  case AArch64::ADDXrr:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
-                          AArch64::XZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULADDX_OP1);
-      Found = true;
-    }
-    if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDXrrr,
-                          AArch64::XZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULADDX_OP2);
-      Found = true;
-    }
-    break;
-  case AArch64::SUBWrr:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
-                          AArch64::WZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULSUBW_OP1);
-      Found = true;
-    }
-    if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDWrrr,
-                          AArch64::WZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULSUBW_OP2);
-      Found = true;
-    }
-    break;
-  case AArch64::SUBXrr:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
-                          AArch64::XZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULSUBX_OP1);
-      Found = true;
-    }
-    if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDXrrr,
-                          AArch64::XZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULSUBX_OP2);
-      Found = true;
-    }
-    break;
-  case AArch64::ADDWri:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
-                          AArch64::WZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULADDWI_OP1);
-      Found = true;
-    }
-    break;
-  case AArch64::ADDXri:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
-                          AArch64::XZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULADDXI_OP1);
-      Found = true;
-    }
-    break;
-  case AArch64::SUBWri:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
-                          AArch64::WZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULSUBWI_OP1);
-      Found = true;
-    }
-    break;
-  case AArch64::SUBXri:
-    if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
-                          AArch64::XZR)) {
-      Pattern.push_back(MachineCombinerPattern::MC_MULSUBXI_OP1);
-      Found = true;
-    }
-    break;
-  }
-  return Found;
-}
-
-/// genMadd - Generate madd instruction and combine mul and add.
-/// Example:
-///  MUL I=A,B,0
-///  ADD R,I,C
-///  ==> MADD R,A,B,C
-/// \param Root is the ADD instruction
-/// \param [out] InsInstr is a vector of machine instructions and will
-/// contain the generated madd instruction
-/// \param IdxMulOpd is index of operand in Root that is the result of
-/// the MUL. In the example above IdxMulOpd is 1.
-/// \param MaddOpc the opcode fo the madd instruction
-static MachineInstr *genMadd(MachineFunction &MF, MachineRegisterInfo &MRI,
-                             const TargetInstrInfo *TII, MachineInstr &Root,
-                             SmallVectorImpl<MachineInstr *> &InsInstrs,
-                             unsigned IdxMulOpd, unsigned MaddOpc) {
-  assert(IdxMulOpd == 1 || IdxMulOpd == 2);
-
-  unsigned IdxOtherOpd = IdxMulOpd == 1 ? 2 : 1;
-  MachineInstr *MUL = MRI.getUniqueVRegDef(Root.getOperand(IdxMulOpd).getReg());
-  MachineOperand R = Root.getOperand(0);
-  MachineOperand A = MUL->getOperand(1);
-  MachineOperand B = MUL->getOperand(2);
-  MachineOperand C = Root.getOperand(IdxOtherOpd);
-  MachineInstrBuilder MIB = BuildMI(MF, Root.getDebugLoc(), TII->get(MaddOpc))
-                                .addOperand(R)
-                                .addOperand(A)
-                                .addOperand(B)
-                                .addOperand(C);
-  // Insert the MADD
-  InsInstrs.push_back(MIB);
-  return MUL;
-}
-
-/// genMaddR - Generate madd instruction and combine mul and add using
-/// an extra virtual register
-/// Example - an ADD intermediate needs to be stored in a register:
-///   MUL I=A,B,0
-///   ADD R,I,Imm
-///   ==> ORR  V, ZR, Imm
-///   ==> MADD R,A,B,V
-/// \param Root is the ADD instruction
-/// \param [out] InsInstr is a vector of machine instructions and will
-/// contain the generated madd instruction
-/// \param IdxMulOpd is index of operand in Root that is the result of
-/// the MUL. In the example above IdxMulOpd is 1.
-/// \param MaddOpc the opcode fo the madd instruction
-/// \param VR is a virtual register that holds the value of an ADD operand
-/// (V in the example above).
-static MachineInstr *genMaddR(MachineFunction &MF, MachineRegisterInfo &MRI,
-                              const TargetInstrInfo *TII, MachineInstr &Root,
-                              SmallVectorImpl<MachineInstr *> &InsInstrs,
-                              unsigned IdxMulOpd, unsigned MaddOpc,
-                              unsigned VR) {
-  assert(IdxMulOpd == 1 || IdxMulOpd == 2);
-
-  MachineInstr *MUL = MRI.getUniqueVRegDef(Root.getOperand(IdxMulOpd).getReg());
-  MachineOperand R = Root.getOperand(0);
-  MachineOperand A = MUL->getOperand(1);
-  MachineOperand B = MUL->getOperand(2);
-  MachineInstrBuilder MIB = BuildMI(MF, Root.getDebugLoc(), TII->get(MaddOpc))
-                                .addOperand(R)
-                                .addOperand(A)
-                                .addOperand(B)
-                                .addReg(VR);
-  // Insert the MADD
-  InsInstrs.push_back(MIB);
-  return MUL;
-}
-/// genAlternativeCodeSequence - when hasPattern() finds a pattern
-/// this function generates the instructions that could replace the
-/// original code sequence
-void AArch64InstrInfo::genAlternativeCodeSequence(
-    MachineInstr &Root, MachineCombinerPattern::MC_PATTERN Pattern,
-    SmallVectorImpl<MachineInstr *> &InsInstrs,
-    SmallVectorImpl<MachineInstr *> &DelInstrs,
-    DenseMap<unsigned, unsigned> &InstrIdxForVirtReg) const {
-  MachineBasicBlock &MBB = *Root.getParent();
-  MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
-  MachineFunction &MF = *MBB.getParent();
-  const TargetInstrInfo *TII = MF.getTarget().getInstrInfo();
-
-  MachineInstr *MUL;
-  unsigned Opc;
-  switch (Pattern) {
-  default:
-    // signal error.
-    break;
-  case MachineCombinerPattern::MC_MULADDW_OP1:
-  case MachineCombinerPattern::MC_MULADDX_OP1:
-    // MUL I=A,B,0
-    // ADD R,I,C
-    // ==> MADD R,A,B,C
-    // --- Create(MADD);
-    Opc = Pattern == MachineCombinerPattern::MC_MULADDW_OP1 ? AArch64::MADDWrrr
-                                                            : AArch64::MADDXrrr;
-    MUL = genMadd(MF, MRI, TII, Root, InsInstrs, 1, Opc);
-    break;
-  case MachineCombinerPattern::MC_MULADDW_OP2:
-  case MachineCombinerPattern::MC_MULADDX_OP2:
-    // MUL I=A,B,0
-    // ADD R,C,I
-    // ==> MADD R,A,B,C
-    // --- Create(MADD);
-    Opc = Pattern == MachineCombinerPattern::MC_MULADDW_OP2 ? AArch64::MADDWrrr
-                                                            : AArch64::MADDXrrr;
-    MUL = genMadd(MF, MRI, TII, Root, InsInstrs, 2, Opc);
-    break;
-  case MachineCombinerPattern::MC_MULADDWI_OP1:
-  case MachineCombinerPattern::MC_MULADDXI_OP1:
-    // MUL I=A,B,0
-    // ADD R,I,Imm
-    // ==> ORR  V, ZR, Imm
-    // ==> MADD R,A,B,V
-    // --- Create(MADD);
-    {
-      const TargetRegisterClass *RC =
-          MRI.getRegClass(Root.getOperand(1).getReg());
-      unsigned NewVR = MRI.createVirtualRegister(RC);
-      unsigned BitSize, OrrOpc, ZeroReg;
-      if (Pattern == MachineCombinerPattern::MC_MULADDWI_OP1) {
-        BitSize = 32;
-        OrrOpc = AArch64::ORRWri;
-        ZeroReg = AArch64::WZR;
-        Opc = AArch64::MADDWrrr;
-      } else {
-        OrrOpc = AArch64::ORRXri;
-        BitSize = 64;
-        ZeroReg = AArch64::XZR;
-        Opc = AArch64::MADDXrrr;
-      }
-      uint64_t Imm = Root.getOperand(2).getImm();
-
-      if (Root.getOperand(3).isImm()) {
-        unsigned val = Root.getOperand(3).getImm();
-        Imm = Imm << val;
-      }
-      uint64_t UImm = Imm << (64 - BitSize) >> (64 - BitSize);
-      uint64_t Encoding;
-
-      if (AArch64_AM::processLogicalImmediate(UImm, BitSize, Encoding)) {
-        MachineInstrBuilder MIB1 =
-            BuildMI(MF, Root.getDebugLoc(), TII->get(OrrOpc))
-                .addOperand(MachineOperand::CreateReg(NewVR, RegState::Define))
-                .addReg(ZeroReg)
-                .addImm(Encoding);
-        InsInstrs.push_back(MIB1);
-        InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
-        MUL = genMaddR(MF, MRI, TII, Root, InsInstrs, 1, Opc, NewVR);
-      }
-    }
-    break;
-  case MachineCombinerPattern::MC_MULSUBW_OP1:
-  case MachineCombinerPattern::MC_MULSUBX_OP1: {
-    // MUL I=A,B,0
-    // SUB R,I, C
-    // ==> SUB  V, 0, C
-    // ==> MADD R,A,B,V // = -C + A*B
-    // --- Create(MADD);
-    const TargetRegisterClass *RC =
-        MRI.getRegClass(Root.getOperand(1).getReg());
-    unsigned NewVR = MRI.createVirtualRegister(RC);
-    unsigned SubOpc, ZeroReg;
-    if (Pattern == MachineCombinerPattern::MC_MULSUBW_OP1) {
-      SubOpc = AArch64::SUBWrr;
-      ZeroReg = AArch64::WZR;
-      Opc = AArch64::MADDWrrr;
-    } else {
-      SubOpc = AArch64::SUBXrr;
-      ZeroReg = AArch64::XZR;
-      Opc = AArch64::MADDXrrr;
-    }
-    // SUB NewVR, 0, C
-    MachineInstrBuilder MIB1 =
-        BuildMI(MF, Root.getDebugLoc(), TII->get(SubOpc))
-            .addOperand(MachineOperand::CreateReg(NewVR, RegState::Define))
-            .addReg(ZeroReg)
-            .addOperand(Root.getOperand(2));
-    InsInstrs.push_back(MIB1);
-    InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
-    MUL = genMaddR(MF, MRI, TII, Root, InsInstrs, 1, Opc, NewVR);
-  } break;
-  case MachineCombinerPattern::MC_MULSUBW_OP2:
-  case MachineCombinerPattern::MC_MULSUBX_OP2:
-    // MUL I=A,B,0
-    // SUB R,C,I
-    // ==> MSUB R,A,B,C (computes C - A*B)
-    // --- Create(MSUB);
-    Opc = Pattern == MachineCombinerPattern::MC_MULSUBW_OP2 ? AArch64::MSUBWrrr
-                                                            : AArch64::MSUBXrrr;
-    MUL = genMadd(MF, MRI, TII, Root, InsInstrs, 2, Opc);
-    break;
-  case MachineCombinerPattern::MC_MULSUBWI_OP1:
-  case MachineCombinerPattern::MC_MULSUBXI_OP1: {
-    // MUL I=A,B,0
-    // SUB R,I, Imm
-    // ==> ORR  V, ZR, -Imm
-    // ==> MADD R,A,B,V // = -Imm + A*B
-    // --- Create(MADD);
-    const TargetRegisterClass *RC =
-        MRI.getRegClass(Root.getOperand(1).getReg());
-    unsigned NewVR = MRI.createVirtualRegister(RC);
-    unsigned BitSize, OrrOpc, ZeroReg;
-    if (Pattern == MachineCombinerPattern::MC_MULSUBWI_OP1) {
-      BitSize = 32;
-      OrrOpc = AArch64::ORRWri;
-      ZeroReg = AArch64::WZR;
-      Opc = AArch64::MADDWrrr;
-    } else {
-      OrrOpc = AArch64::ORRXri;
-      BitSize = 64;
-      ZeroReg = AArch64::XZR;
-      Opc = AArch64::MADDXrrr;
-    }
-    int Imm = Root.getOperand(2).getImm();
-    if (Root.getOperand(3).isImm()) {
-      unsigned val = Root.getOperand(3).getImm();
-      Imm = Imm << val;
-    }
-    uint64_t UImm = -Imm << (64 - BitSize) >> (64 - BitSize);
-    uint64_t Encoding;
-    if (AArch64_AM::processLogicalImmediate(UImm, BitSize, Encoding)) {
-      MachineInstrBuilder MIB1 =
-          BuildMI(MF, Root.getDebugLoc(), TII->get(OrrOpc))
-              .addOperand(MachineOperand::CreateReg(NewVR, RegState::Define))
-              .addReg(ZeroReg)
-              .addImm(Encoding);
-      InsInstrs.push_back(MIB1);
-      InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
-      MUL = genMaddR(MF, MRI, TII, Root, InsInstrs, 1, Opc, NewVR);
-    }
-  } break;
-  }
-  // Record MUL and ADD/SUB for deletion
-  DelInstrs.push_back(MUL);
-  DelInstrs.push_back(&Root);
-
-  return;
-}