Index: llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp =================================================================== --- llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp +++ llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp @@ -52,6 +52,8 @@ /// The register to be used for temporary storage. const unsigned SCRATCH_REGISTER = AVR::R0; + /// The register that will always contain zero. + const unsigned ZERO_REGISTER = AVR::R1; /// The IO address of the status register. const unsigned SREG_ADDR = 0x3f; @@ -1242,6 +1244,93 @@ return true; } +template <> +bool AVRExpandPseudo::expand(Block &MBB, BlockIt MBBI) { + // In AVR, the rotate instructions behave quite unintuitively. They rotate + // bits through the carry bit in SREG, effectively rotating over 9 bits, + // instead of 8. This is useful when we are dealing with numbers over + // multiple registers, but when we actually need to rotate stuff, we have + // to explicitly add the carry bit. + + MachineInstr &MI = *MBBI; + unsigned OpShift, OpCarry; + unsigned DstReg = MI.getOperand(0).getReg(); + bool DstIsDead = MI.getOperand(0).isDead(); + OpShift = AVR::ADDRdRr; + OpCarry = AVR::ADCRdRr; + + // add r16, r16 + // adc r16, r1 + + // Shift part + buildMI(MBB, MBBI, OpShift) + .addReg(DstReg, RegState::Define | getDeadRegState(DstIsDead)) + .addReg(DstReg) + .addReg(DstReg); + + // Add the carry bit + auto MIB = buildMI(MBB, MBBI, OpCarry) + .addReg(DstReg, RegState::Define | getDeadRegState(DstIsDead)) + .addReg(DstReg) + .addReg(ZERO_REGISTER); + + // SREG is always implicitly killed + MIB->getOperand(2).setIsKill(); + + MI.eraseFromParent(); + return true; +} + +template <> +bool AVRExpandPseudo::expand(Block &MBB, BlockIt MBBI) { + // In AVR, the rotate instructions behave quite unintuitively. They rotate + // bits through the carry bit in SREG, effectively rotating over 9 bits, + // instead of 8. This is useful when we are dealing with numbers over + // multiple registers, but when we actually need to rotate stuff, we have + // to explicitly add the carry bit. + + MachineInstr &MI = *MBBI; + unsigned OpShiftOut, OpLoad, OpShiftIn, OpAdd; + unsigned DstReg = MI.getOperand(0).getReg(); + bool DstIsDead = MI.getOperand(0).isDead(); + OpShiftOut = AVR::LSRRd; + OpLoad = AVR::LDIRdK; + OpShiftIn = AVR::RORRd; + OpAdd = AVR::ORRdRr; + + // lsr r16 + // ldi r0, 0 + // ror r0 + // or r16, r17 + + // Shift out + buildMI(MBB, MBBI, OpShiftOut) + .addReg(DstReg, RegState::Define | getDeadRegState(DstIsDead)) + .addReg(DstReg); + + // Put 0 in temporary register + buildMI(MBB, MBBI, OpLoad) + .addReg(SCRATCH_REGISTER, RegState::Define | getDeadRegState(true)) + .addImm(0x00); + + // Shift in + buildMI(MBB, MBBI, OpShiftIn) + .addReg(SCRATCH_REGISTER, RegState::Define | getDeadRegState(true)) + .addReg(SCRATCH_REGISTER); + + // Add the results together using an or-instruction + auto MIB = buildMI(MBB, MBBI, OpAdd) + .addReg(DstReg, RegState::Define | getDeadRegState(DstIsDead)) + .addReg(DstReg) + .addReg(SCRATCH_REGISTER); + + // SREG is always implicitly killed + MIB->getOperand(2).setIsKill(); + + MI.eraseFromParent(); + return true; +} + template <> bool AVRExpandPseudo::expand(Block &MBB, BlockIt MBBI) { MachineInstr &MI = *MBBI; @@ -1562,6 +1651,8 @@ EXPAND(AVR::OUTWARr); EXPAND(AVR::PUSHWRr); EXPAND(AVR::POPWRd); + EXPAND(AVR::ROLBRd); + EXPAND(AVR::RORBRd); EXPAND(AVR::LSLWRd); EXPAND(AVR::LSRWRd); EXPAND(AVR::RORWRd); Index: llvm/lib/Target/AVR/AVRISelLowering.cpp =================================================================== --- llvm/lib/Target/AVR/AVRISelLowering.cpp +++ llvm/lib/Target/AVR/AVRISelLowering.cpp @@ -1472,16 +1472,15 @@ RC = &AVR::DREGSRegClass; break; case AVR::Rol8: - Opc = AVR::ADCRdRr; // ROL is an alias of ADC Rd, Rd + Opc = AVR::ROLBRd; RC = &AVR::GPR8RegClass; - HasRepeatedOperand = true; break; case AVR::Rol16: Opc = AVR::ROLWRd; RC = &AVR::DREGSRegClass; break; case AVR::Ror8: - Opc = AVR::RORRd; + Opc = AVR::RORBRd; RC = &AVR::GPR8RegClass; break; case AVR::Ror16: Index: llvm/lib/Target/AVR/AVRInstrInfo.td =================================================================== --- llvm/lib/Target/AVR/AVRInstrInfo.td +++ llvm/lib/Target/AVR/AVRInstrInfo.td @@ -1676,6 +1676,16 @@ { // 8-bit ROL is an alias of ADC Rd, Rd + def ROLBRd : Pseudo<(outs GPR8:$rd), + (ins GPR8:$src), + "rolb\t$rd", + [(set i8:$rd, (AVRrol i8:$src)), (implicit SREG)]>; + + def RORBRd : Pseudo<(outs GPR8:$rd), + (ins GPR8:$src), + "rorb\t$rd", + [(set i8:$rd, (AVRrol i8:$src)), (implicit SREG)]>; + def ROLWRd : Pseudo<(outs DREGS:$rd), (ins DREGS:$src), "rolw\t$rd", Index: llvm/test/CodeGen/AVR/rot.ll =================================================================== --- llvm/test/CodeGen/AVR/rot.ll +++ llvm/test/CodeGen/AVR/rot.ll @@ -10,7 +10,8 @@ ; CHECK-NEXT: breq LBB0_2 ; CHECK-NEXT: LBB0_1: - ; CHECK-NEXT: rol r24 + ; CHECK-NEXT: lsl r24 + ; CHECK-NEXT: adc r24, r1 ; CHECK-NEXT: subi r22, 1 ; CHECK-NEXT: brne LBB0_1 @@ -36,7 +37,10 @@ ; CHECK-NEXT: breq LBB1_2 ; CHECK-NEXT: LBB1_1: - ; CHECK-NEXT: ror r24 + ; CHECK-NEXT: lsr r24 + ; CHECK-NEXT: ldi r0, 0 + ; CHECK-NEXT: ror r0 + ; CHECK-NEXT: or r24, r0 ; CHECK-NEXT: subi r22, 1 ; CHECK-NEXT: brne LBB1_1