diff options
Diffstat (limited to 'llvm/lib/Target')
| -rw-r--r-- | llvm/lib/Target/X86/X86InstructionSelector.cpp | 220 | ||||
| -rw-r--r-- | llvm/lib/Target/X86/X86LegalizerInfo.cpp | 10 |
2 files changed, 178 insertions, 52 deletions
diff --git a/llvm/lib/Target/X86/X86InstructionSelector.cpp b/llvm/lib/Target/X86/X86InstructionSelector.cpp index b2bcfa074f9..e592330ce16 100644 --- a/llvm/lib/Target/X86/X86InstructionSelector.cpp +++ b/llvm/lib/Target/X86/X86InstructionSelector.cpp @@ -116,8 +116,8 @@ private: bool selectImplicitDefOrPHI(MachineInstr &I, MachineRegisterInfo &MRI) const; bool selectShift(MachineInstr &I, MachineRegisterInfo &MRI, MachineFunction &MF) const; - bool selectSDiv(MachineInstr &I, MachineRegisterInfo &MRI, - MachineFunction &MF) const; + bool selectDivRem(MachineInstr &I, MachineRegisterInfo &MRI, + MachineFunction &MF) const; bool selectIntrinsicWSideEffects(MachineInstr &I, MachineRegisterInfo &MRI, MachineFunction &MF) const; @@ -388,7 +388,10 @@ bool X86InstructionSelector::select(MachineInstr &I, case TargetOpcode::G_LSHR: return selectShift(I, MRI, MF); case TargetOpcode::G_SDIV: - return selectSDiv(I, MRI, MF); + case TargetOpcode::G_UDIV: + case TargetOpcode::G_SREM: + case TargetOpcode::G_UREM: + return selectDivRem(I, MRI, MF); case TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS: return selectIntrinsicWSideEffects(I, MRI, MF); } @@ -1585,23 +1588,33 @@ bool X86InstructionSelector::selectShift(MachineInstr &I, return true; } -bool X86InstructionSelector::selectSDiv(MachineInstr &I, - MachineRegisterInfo &MRI, - MachineFunction &MF) const { - - assert(I.getOpcode() == TargetOpcode::G_SDIV && "unexpected instruction"); +bool X86InstructionSelector::selectDivRem(MachineInstr &I, + MachineRegisterInfo &MRI, + MachineFunction &MF) const { + // The implementation of this function is taken from X86FastISel. + assert((I.getOpcode() == TargetOpcode::G_SDIV || + I.getOpcode() == TargetOpcode::G_SREM || + I.getOpcode() == TargetOpcode::G_UDIV || + I.getOpcode() == TargetOpcode::G_UREM) && + "unexpected instruction"); const unsigned DstReg = I.getOperand(0).getReg(); - const unsigned DividentReg = I.getOperand(1).getReg(); - const unsigned DiviserReg = I.getOperand(2).getReg(); + const unsigned Op1Reg = I.getOperand(1).getReg(); + const unsigned Op2Reg = I.getOperand(2).getReg(); const LLT RegTy = MRI.getType(DstReg); - assert(RegTy == MRI.getType(DividentReg) && - RegTy == MRI.getType(DiviserReg) && + assert(RegTy == MRI.getType(Op1Reg) && RegTy == MRI.getType(Op2Reg) && "Arguments and return value types must match"); const RegisterBank &RegRB = *RBI.getRegBank(DstReg, MRI, TRI); + if (RegRB.getID() != X86::GPRRegBankID) + return false; + const static unsigned NumTypes = 4; // i8, i16, i32, i64 + const static unsigned NumOps = 4; // SDiv, SRem, UDiv, URem + const static bool S = true; // IsSigned + const static bool U = false; // !IsSigned + const static unsigned Copy = TargetOpcode::COPY; // For the X86 IDIV instruction, in most cases the dividend // (numerator) must be in a specific register pair highreg:lowreg, // producing the quotient in lowreg and the remainder in highreg. @@ -1610,57 +1623,168 @@ bool X86InstructionSelector::selectSDiv(MachineInstr &I, // exception is i8, where the dividend is defined as a single register rather // than a register pair, and we therefore directly sign-extend the dividend // into lowreg, instead of copying, and ignore the highreg. - const static struct SDivEntry { + const static struct DivRemEntry { + // The following portion depends only on the data type. unsigned SizeInBits; - unsigned QuotientReg; - unsigned DividentRegUpper; - unsigned DividentRegLower; - unsigned OpSignExtend; - unsigned OpCopy; - unsigned OpDiv; - } OpTable[] = { - {8, X86::AL, X86::NoRegister, X86::AX, 0, X86::MOVSX16rr8, - X86::IDIV8r}, // i8 - {16, X86::AX, X86::DX, X86::AX, X86::CWD, TargetOpcode::COPY, - X86::IDIV16r}, // i16 - {32, X86::EAX, X86::EDX, X86::EAX, X86::CDQ, TargetOpcode::COPY, - X86::IDIV32r}, // i32 - {64, X86::RAX, X86::RDX, X86::RAX, X86::CQO, TargetOpcode::COPY, - X86::IDIV64r} // i64 + unsigned LowInReg; // low part of the register pair + unsigned HighInReg; // high part of the register pair + // The following portion depends on both the data type and the operation. + struct DivRemResult { + unsigned OpDivRem; // The specific DIV/IDIV opcode to use. + unsigned OpSignExtend; // Opcode for sign-extending lowreg into + // highreg, or copying a zero into highreg. + unsigned OpCopy; // Opcode for copying dividend into lowreg, or + // zero/sign-extending into lowreg for i8. + unsigned DivRemResultReg; // Register containing the desired result. + bool IsOpSigned; // Whether to use signed or unsigned form. + } ResultTable[NumOps]; + } OpTable[NumTypes] = { + {8, + X86::AX, + 0, + { + {X86::IDIV8r, 0, X86::MOVSX16rr8, X86::AL, S}, // SDiv + {X86::IDIV8r, 0, X86::MOVSX16rr8, X86::AH, S}, // SRem + {X86::DIV8r, 0, X86::MOVZX16rr8, X86::AL, U}, // UDiv + {X86::DIV8r, 0, X86::MOVZX16rr8, X86::AH, U}, // URem + }}, // i8 + {16, + X86::AX, + X86::DX, + { + {X86::IDIV16r, X86::CWD, Copy, X86::AX, S}, // SDiv + {X86::IDIV16r, X86::CWD, Copy, X86::DX, S}, // SRem + {X86::DIV16r, X86::MOV32r0, Copy, X86::AX, U}, // UDiv + {X86::DIV16r, X86::MOV32r0, Copy, X86::DX, U}, // URem + }}, // i16 + {32, + X86::EAX, + X86::EDX, + { + {X86::IDIV32r, X86::CDQ, Copy, X86::EAX, S}, // SDiv + {X86::IDIV32r, X86::CDQ, Copy, X86::EDX, S}, // SRem + {X86::DIV32r, X86::MOV32r0, Copy, X86::EAX, U}, // UDiv + {X86::DIV32r, X86::MOV32r0, Copy, X86::EDX, U}, // URem + }}, // i32 + {64, + X86::RAX, + X86::RDX, + { + {X86::IDIV64r, X86::CQO, Copy, X86::RAX, S}, // SDiv + {X86::IDIV64r, X86::CQO, Copy, X86::RDX, S}, // SRem + {X86::DIV64r, X86::MOV32r0, Copy, X86::RAX, U}, // UDiv + {X86::DIV64r, X86::MOV32r0, Copy, X86::RDX, U}, // URem + }}, // i64 }; - if (RegRB.getID() != X86::GPRRegBankID) + auto OpEntryIt = std::find_if(std::begin(OpTable), std::end(OpTable), + [RegTy](const DivRemEntry &El) { + return El.SizeInBits == RegTy.getSizeInBits(); + }); + if (OpEntryIt == std::end(OpTable)) return false; - auto SDivEntryIt = std::find_if( - std::begin(OpTable), std::end(OpTable), [RegTy](const SDivEntry &El) { - return El.SizeInBits == RegTy.getSizeInBits(); - }); + unsigned OpIndex; + switch (I.getOpcode()) { + default: + llvm_unreachable("Unexpected div/rem opcode"); + case TargetOpcode::G_SDIV: + OpIndex = 0; + break; + case TargetOpcode::G_SREM: + OpIndex = 1; + break; + case TargetOpcode::G_UDIV: + OpIndex = 2; + break; + case TargetOpcode::G_UREM: + OpIndex = 3; + break; + } - if (SDivEntryIt == std::end(OpTable)) - return false; + const DivRemEntry &TypeEntry = *OpEntryIt; + const DivRemEntry::DivRemResult &OpEntry = TypeEntry.ResultTable[OpIndex]; const TargetRegisterClass *RegRC = getRegClass(RegTy, RegRB); - if (!RBI.constrainGenericRegister(DividentReg, *RegRC, MRI) || - !RBI.constrainGenericRegister(DiviserReg, *RegRC, MRI) || + if (!RBI.constrainGenericRegister(Op1Reg, *RegRC, MRI) || + !RBI.constrainGenericRegister(Op2Reg, *RegRC, MRI) || !RBI.constrainGenericRegister(DstReg, *RegRC, MRI)) { LLVM_DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode()) << " operand\n"); return false; } - BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(SDivEntryIt->OpCopy), - SDivEntryIt->DividentRegLower) - .addReg(DividentReg); - if (SDivEntryIt->DividentRegUpper != X86::NoRegister) + // Move op1 into low-order input register. + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(OpEntry.OpCopy), + TypeEntry.LowInReg) + .addReg(Op1Reg); + // Zero-extend or sign-extend into high-order input register. + if (OpEntry.OpSignExtend) { + if (OpEntry.IsOpSigned) + BuildMI(*I.getParent(), I, I.getDebugLoc(), + TII.get(OpEntry.OpSignExtend)); + else { + unsigned Zero32 = MRI.createVirtualRegister(&X86::GR32RegClass); + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::MOV32r0), + Zero32); + + // Copy the zero into the appropriate sub/super/identical physical + // register. Unfortunately the operations needed are not uniform enough + // to fit neatly into the table above. + if (RegTy.getSizeInBits() == 16) { + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Copy), + TypeEntry.HighInReg) + .addReg(Zero32, 0, X86::sub_16bit); + } else if (RegTy.getSizeInBits() == 32) { + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Copy), + TypeEntry.HighInReg) + .addReg(Zero32); + } else if (RegTy.getSizeInBits() == 64) { + BuildMI(*I.getParent(), I, I.getDebugLoc(), + TII.get(TargetOpcode::SUBREG_TO_REG), TypeEntry.HighInReg) + .addImm(0) + .addReg(Zero32) + .addImm(X86::sub_32bit); + } + } + } + // Generate the DIV/IDIV instruction. + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(OpEntry.OpDivRem)) + .addReg(Op2Reg); + // For i8 remainder, we can't reference ah directly, as we'll end + // up with bogus copies like %r9b = COPY %ah. Reference ax + // instead to prevent ah references in a rex instruction. + // + // The current assumption of the fast register allocator is that isel + // won't generate explicit references to the GR8_NOREX registers. If + // the allocator and/or the backend get enhanced to be more robust in + // that regard, this can be, and should be, removed. + if ((I.getOpcode() == Instruction::SRem || + I.getOpcode() == Instruction::URem) && + OpEntry.DivRemResultReg == X86::AH && STI.is64Bit()) { + unsigned SourceSuperReg = MRI.createVirtualRegister(&X86::GR16RegClass); + unsigned ResultSuperReg = MRI.createVirtualRegister(&X86::GR16RegClass); + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Copy), SourceSuperReg) + .addReg(X86::AX); + + // Shift AX right by 8 bits instead of using AH. + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::SHR16ri), + ResultSuperReg) + .addReg(SourceSuperReg) + .addImm(8); + + // Now reference the 8-bit subreg of the result. BuildMI(*I.getParent(), I, I.getDebugLoc(), - TII.get(SDivEntryIt->OpSignExtend)); - BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(SDivEntryIt->OpDiv)) - .addReg(DiviserReg); - BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(TargetOpcode::COPY), - DstReg) - .addReg(SDivEntryIt->QuotientReg); - + TII.get(TargetOpcode::SUBREG_TO_REG)) + .addDef(DstReg) + .addImm(0) + .addReg(ResultSuperReg) + .addImm(X86::sub_8bit); + } else { + BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(TargetOpcode::COPY), + DstReg) + .addReg(OpEntry.DivRemResultReg); + } I.eraseFromParent(); return true; } diff --git a/llvm/lib/Target/X86/X86LegalizerInfo.cpp b/llvm/lib/Target/X86/X86LegalizerInfo.cpp index 4e64e8ea980..4f59e0f79a7 100644 --- a/llvm/lib/Target/X86/X86LegalizerInfo.cpp +++ b/llvm/lib/Target/X86/X86LegalizerInfo.cpp @@ -133,7 +133,8 @@ void X86LegalizerInfo::setLegalizerInfo32bit() { getActionDefinitionsBuilder(G_INTTOPTR).legalFor({{p0, s32}}); // Shifts and SDIV - getActionDefinitionsBuilder({G_SHL, G_LSHR, G_ASHR, G_SDIV}) + getActionDefinitionsBuilder( + {G_SHL, G_LSHR, G_ASHR, G_SDIV, G_SREM, G_UDIV, G_UREM}) .legalFor({s8, s16, s32}) .clampScalar(0, s8, s32); } @@ -236,9 +237,10 @@ void X86LegalizerInfo::setLegalizerInfo64bit() { .widenScalarToNextPow2(1); // Shifts and SDIV - getActionDefinitionsBuilder({G_SHL, G_LSHR, G_ASHR, G_SDIV}) - .legalFor({s8, s16, s32, s64}) - .clampScalar(0, s8, s64); + getActionDefinitionsBuilder( + {G_SHL, G_LSHR, G_ASHR, G_SDIV, G_SREM, G_UDIV, G_UREM}) + .legalFor({s8, s16, s32, s64}) + .clampScalar(0, s8, s64); // Merge/Unmerge setAction({G_MERGE_VALUES, s128}, Legal); |
