// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package arm64

import (
	"math"

	"cmd/compile/internal/base"
	"cmd/compile/internal/ir"
	"cmd/compile/internal/logopt"
	"cmd/compile/internal/ssa"
	"cmd/compile/internal/ssagen"
	"cmd/compile/internal/types"
	"cmd/internal/obj"
	"cmd/internal/obj/arm64"
)

// loadByType returns the load instruction of the given type.
func loadByType(t *types.Type) obj.As {
	if t.IsFloat() {
		switch t.Size() {
		case 4:
			return arm64.AFMOVS
		case 8:
			return arm64.AFMOVD
		}
	} else {
		switch t.Size() {
		case 1:
			if t.IsSigned() {
				return arm64.AMOVB
			} else {
				return arm64.AMOVBU
			}
		case 2:
			if t.IsSigned() {
				return arm64.AMOVH
			} else {
				return arm64.AMOVHU
			}
		case 4:
			if t.IsSigned() {
				return arm64.AMOVW
			} else {
				return arm64.AMOVWU
			}
		case 8:
			return arm64.AMOVD
		}
	}
	panic("bad load type")
}

// storeByType returns the store instruction of the given type.
func storeByType(t *types.Type) obj.As {
	if t.IsFloat() {
		switch t.Size() {
		case 4:
			return arm64.AFMOVS
		case 8:
			return arm64.AFMOVD
		}
	} else {
		switch t.Size() {
		case 1:
			return arm64.AMOVB
		case 2:
			return arm64.AMOVH
		case 4:
			return arm64.AMOVW
		case 8:
			return arm64.AMOVD
		}
	}
	panic("bad store type")
}

// makeshift encodes a register shifted by a constant, used as an Offset in Prog
func makeshift(reg int16, typ int64, s int64) int64 {
	return int64(reg&31)<<16 | typ | (s&63)<<10
}

// genshift generates a Prog for r = r0 op (r1 shifted by n)
func genshift(s *ssagen.State, as obj.As, r0, r1, r int16, typ int64, n int64) *obj.Prog {
	p := s.Prog(as)
	p.From.Type = obj.TYPE_SHIFT
	p.From.Offset = makeshift(r1, typ, n)
	p.Reg = r0
	if r != 0 {
		p.To.Type = obj.TYPE_REG
		p.To.Reg = r
	}
	return p
}

// generate the memory operand for the indexed load/store instructions
func genIndexedOperand(v *ssa.Value) obj.Addr {
	// Reg: base register, Index: (shifted) index register
	mop := obj.Addr{Type: obj.TYPE_MEM, Reg: v.Args[0].Reg()}
	switch v.Op {
	case ssa.OpARM64MOVDloadidx8, ssa.OpARM64MOVDstoreidx8, ssa.OpARM64MOVDstorezeroidx8:
		mop.Index = arm64.REG_LSL | 3<<5 | v.Args[1].Reg()&31
	case ssa.OpARM64MOVWloadidx4, ssa.OpARM64MOVWUloadidx4, ssa.OpARM64MOVWstoreidx4, ssa.OpARM64MOVWstorezeroidx4:
		mop.Index = arm64.REG_LSL | 2<<5 | v.Args[1].Reg()&31
	case ssa.OpARM64MOVHloadidx2, ssa.OpARM64MOVHUloadidx2, ssa.OpARM64MOVHstoreidx2, ssa.OpARM64MOVHstorezeroidx2:
		mop.Index = arm64.REG_LSL | 1<<5 | v.Args[1].Reg()&31
	default: // not shifted
		mop.Index = v.Args[1].Reg()
	}
	return mop
}

func ssaGenValue(s *ssagen.State, v *ssa.Value) {
	switch v.Op {
	case ssa.OpCopy, ssa.OpARM64MOVDreg:
		if v.Type.IsMemory() {
			return
		}
		x := v.Args[0].Reg()
		y := v.Reg()
		if x == y {
			return
		}
		as := arm64.AMOVD
		if v.Type.IsFloat() {
			switch v.Type.Size() {
			case 4:
				as = arm64.AFMOVS
			case 8:
				as = arm64.AFMOVD
			default:
				panic("bad float size")
			}
		}
		p := s.Prog(as)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = x
		p.To.Type = obj.TYPE_REG
		p.To.Reg = y
	case ssa.OpARM64MOVDnop:
		if v.Reg() != v.Args[0].Reg() {
			v.Fatalf("input[0] and output not in same register %s", v.LongString())
		}
		// nothing to do
	case ssa.OpLoadReg:
		if v.Type.IsFlags() {
			v.Fatalf("load flags not implemented: %v", v.LongString())
			return
		}
		p := s.Prog(loadByType(v.Type))
		ssagen.AddrAuto(&p.From, v.Args[0])
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpStoreReg:
		if v.Type.IsFlags() {
			v.Fatalf("store flags not implemented: %v", v.LongString())
			return
		}
		p := s.Prog(storeByType(v.Type))
		p.From.Type = obj.TYPE_REG
		p.From.Reg = v.Args[0].Reg()
		ssagen.AddrAuto(&p.To, v)
	case ssa.OpARM64ADD,
		ssa.OpARM64SUB,
		ssa.OpARM64AND,
		ssa.OpARM64OR,
		ssa.OpARM64XOR,
		ssa.OpARM64BIC,
		ssa.OpARM64EON,
		ssa.OpARM64ORN,
		ssa.OpARM64MUL,
		ssa.OpARM64MULW,
		ssa.OpARM64MNEG,
		ssa.OpARM64MNEGW,
		ssa.OpARM64MULH,
		ssa.OpARM64UMULH,
		ssa.OpARM64MULL,
		ssa.OpARM64UMULL,
		ssa.OpARM64DIV,
		ssa.OpARM64UDIV,
		ssa.OpARM64DIVW,
		ssa.OpARM64UDIVW,
		ssa.OpARM64MOD,
		ssa.OpARM64UMOD,
		ssa.OpARM64MODW,
		ssa.OpARM64UMODW,
		ssa.OpARM64SLL,
		ssa.OpARM64SRL,
		ssa.OpARM64SRA,
		ssa.OpARM64FADDS,
		ssa.OpARM64FADDD,
		ssa.OpARM64FSUBS,
		ssa.OpARM64FSUBD,
		ssa.OpARM64FMULS,
		ssa.OpARM64FMULD,
		ssa.OpARM64FNMULS,
		ssa.OpARM64FNMULD,
		ssa.OpARM64FDIVS,
		ssa.OpARM64FDIVD,
		ssa.OpARM64ROR,
		ssa.OpARM64RORW:
		r := v.Reg()
		r1 := v.Args[0].Reg()
		r2 := v.Args[1].Reg()
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r2
		p.Reg = r1
		p.To.Type = obj.TYPE_REG
		p.To.Reg = r
	case ssa.OpARM64FMADDS,
		ssa.OpARM64FMADDD,
		ssa.OpARM64FNMADDS,
		ssa.OpARM64FNMADDD,
		ssa.OpARM64FMSUBS,
		ssa.OpARM64FMSUBD,
		ssa.OpARM64FNMSUBS,
		ssa.OpARM64FNMSUBD,
		ssa.OpARM64MADD,
		ssa.OpARM64MADDW,
		ssa.OpARM64MSUB,
		ssa.OpARM64MSUBW:
		rt := v.Reg()
		ra := v.Args[0].Reg()
		rm := v.Args[1].Reg()
		rn := v.Args[2].Reg()
		p := s.Prog(v.Op.Asm())
		p.Reg = ra
		p.From.Type = obj.TYPE_REG
		p.From.Reg = rm
		p.SetFrom3(obj.Addr{Type: obj.TYPE_REG, Reg: rn})
		p.To.Type = obj.TYPE_REG
		p.To.Reg = rt
	case ssa.OpARM64ADDconst,
		ssa.OpARM64SUBconst,
		ssa.OpARM64ANDconst,
		ssa.OpARM64ORconst,
		ssa.OpARM64XORconst,
		ssa.OpARM64SLLconst,
		ssa.OpARM64SRLconst,
		ssa.OpARM64SRAconst,
		ssa.OpARM64RORconst,
		ssa.OpARM64RORWconst:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt
		p.Reg = v.Args[0].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64ADDSconstflags:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt
		p.Reg = v.Args[0].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg0()
	case ssa.OpARM64ADCzerocarry:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = arm64.REGZERO
		p.Reg = arm64.REGZERO
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64ADCSflags,
		ssa.OpARM64ADDSflags,
		ssa.OpARM64SBCSflags,
		ssa.OpARM64SUBSflags:
		r := v.Reg0()
		r1 := v.Args[0].Reg()
		r2 := v.Args[1].Reg()
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r2
		p.Reg = r1
		p.To.Type = obj.TYPE_REG
		p.To.Reg = r
	case ssa.OpARM64NEGSflags:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = v.Args[0].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg0()
	case ssa.OpARM64NGCzerocarry:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = arm64.REGZERO
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64EXTRconst,
		ssa.OpARM64EXTRWconst:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt
		p.SetFrom3(obj.Addr{Type: obj.TYPE_REG, Reg: v.Args[0].Reg()})
		p.Reg = v.Args[1].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64MVNshiftLL, ssa.OpARM64NEGshiftLL:
		genshift(s, v.Op.Asm(), 0, v.Args[0].Reg(), v.Reg(), arm64.SHIFT_LL, v.AuxInt)
	case ssa.OpARM64MVNshiftRL, ssa.OpARM64NEGshiftRL:
		genshift(s, v.Op.Asm(), 0, v.Args[0].Reg(), v.Reg(), arm64.SHIFT_LR, v.AuxInt)
	case ssa.OpARM64MVNshiftRA, ssa.OpARM64NEGshiftRA:
		genshift(s, v.Op.Asm(), 0, v.Args[0].Reg(), v.Reg(), arm64.SHIFT_AR, v.AuxInt)
	case ssa.OpARM64ADDshiftLL,
		ssa.OpARM64SUBshiftLL,
		ssa.OpARM64ANDshiftLL,
		ssa.OpARM64ORshiftLL,
		ssa.OpARM64XORshiftLL,
		ssa.OpARM64EONshiftLL,
		ssa.OpARM64ORNshiftLL,
		ssa.OpARM64BICshiftLL:
		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), v.Reg(), arm64.SHIFT_LL, v.AuxInt)
	case ssa.OpARM64ADDshiftRL,
		ssa.OpARM64SUBshiftRL,
		ssa.OpARM64ANDshiftRL,
		ssa.OpARM64ORshiftRL,
		ssa.OpARM64XORshiftRL,
		ssa.OpARM64EONshiftRL,
		ssa.OpARM64ORNshiftRL,
		ssa.OpARM64BICshiftRL:
		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), v.Reg(), arm64.SHIFT_LR, v.AuxInt)
	case ssa.OpARM64ADDshiftRA,
		ssa.OpARM64SUBshiftRA,
		ssa.OpARM64ANDshiftRA,
		ssa.OpARM64ORshiftRA,
		ssa.OpARM64XORshiftRA,
		ssa.OpARM64EONshiftRA,
		ssa.OpARM64ORNshiftRA,
		ssa.OpARM64BICshiftRA:
		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), v.Reg(), arm64.SHIFT_AR, v.AuxInt)
	case ssa.OpARM64MOVDconst:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64FMOVSconst,
		ssa.OpARM64FMOVDconst:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_FCONST
		p.From.Val = math.Float64frombits(uint64(v.AuxInt))
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64FCMPS0,
		ssa.OpARM64FCMPD0:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_FCONST
		p.From.Val = math.Float64frombits(0)
		p.Reg = v.Args[0].Reg()
	case ssa.OpARM64CMP,
		ssa.OpARM64CMPW,
		ssa.OpARM64CMN,
		ssa.OpARM64CMNW,
		ssa.OpARM64TST,
		ssa.OpARM64TSTW,
		ssa.OpARM64FCMPS,
		ssa.OpARM64FCMPD:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = v.Args[1].Reg()
		p.Reg = v.Args[0].Reg()
	case ssa.OpARM64CMPconst,
		ssa.OpARM64CMPWconst,
		ssa.OpARM64CMNconst,
		ssa.OpARM64CMNWconst,
		ssa.OpARM64TSTconst,
		ssa.OpARM64TSTWconst:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt
		p.Reg = v.Args[0].Reg()
	case ssa.OpARM64CMPshiftLL, ssa.OpARM64CMNshiftLL, ssa.OpARM64TSTshiftLL:
		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), 0, arm64.SHIFT_LL, v.AuxInt)
	case ssa.OpARM64CMPshiftRL, ssa.OpARM64CMNshiftRL, ssa.OpARM64TSTshiftRL:
		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), 0, arm64.SHIFT_LR, v.AuxInt)
	case ssa.OpARM64CMPshiftRA, ssa.OpARM64CMNshiftRA, ssa.OpARM64TSTshiftRA:
		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), 0, arm64.SHIFT_AR, v.AuxInt)
	case ssa.OpARM64MOVDaddr:
		p := s.Prog(arm64.AMOVD)
		p.From.Type = obj.TYPE_ADDR
		p.From.Reg = v.Args[0].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()

		var wantreg string
		// MOVD $sym+off(base), R
		// the assembler expands it as the following:
		// - base is SP: add constant offset to SP (R13)
		//               when constant is large, tmp register (R11) may be used
		// - base is SB: load external address from constant pool (use relocation)
		switch v.Aux.(type) {
		default:
			v.Fatalf("aux is of unknown type %T", v.Aux)
		case *obj.LSym:
			wantreg = "SB"
			ssagen.AddAux(&p.From, v)
		case *ir.Name:
			wantreg = "SP"
			ssagen.AddAux(&p.From, v)
		case nil:
			// No sym, just MOVD $off(SP), R
			wantreg = "SP"
			p.From.Offset = v.AuxInt
		}
		if reg := v.Args[0].RegName(); reg != wantreg {
			v.Fatalf("bad reg %s for symbol type %T, want %s", reg, v.Aux, wantreg)
		}
	case ssa.OpARM64MOVBload,
		ssa.OpARM64MOVBUload,
		ssa.OpARM64MOVHload,
		ssa.OpARM64MOVHUload,
		ssa.OpARM64MOVWload,
		ssa.OpARM64MOVWUload,
		ssa.OpARM64MOVDload,
		ssa.OpARM64FMOVSload,
		ssa.OpARM64FMOVDload:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.From, v)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64MOVBloadidx,
		ssa.OpARM64MOVBUloadidx,
		ssa.OpARM64MOVHloadidx,
		ssa.OpARM64MOVHUloadidx,
		ssa.OpARM64MOVWloadidx,
		ssa.OpARM64MOVWUloadidx,
		ssa.OpARM64MOVDloadidx,
		ssa.OpARM64FMOVSloadidx,
		ssa.OpARM64FMOVDloadidx,
		ssa.OpARM64MOVHloadidx2,
		ssa.OpARM64MOVHUloadidx2,
		ssa.OpARM64MOVWloadidx4,
		ssa.OpARM64MOVWUloadidx4,
		ssa.OpARM64MOVDloadidx8:
		p := s.Prog(v.Op.Asm())
		p.From = genIndexedOperand(v)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64LDAR,
		ssa.OpARM64LDARB,
		ssa.OpARM64LDARW:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.From, v)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg0()
	case ssa.OpARM64MOVBstore,
		ssa.OpARM64MOVHstore,
		ssa.OpARM64MOVWstore,
		ssa.OpARM64MOVDstore,
		ssa.OpARM64FMOVSstore,
		ssa.OpARM64FMOVDstore,
		ssa.OpARM64STLRB,
		ssa.OpARM64STLR,
		ssa.OpARM64STLRW:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = v.Args[1].Reg()
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.To, v)
	case ssa.OpARM64MOVBstoreidx,
		ssa.OpARM64MOVHstoreidx,
		ssa.OpARM64MOVWstoreidx,
		ssa.OpARM64MOVDstoreidx,
		ssa.OpARM64FMOVSstoreidx,
		ssa.OpARM64FMOVDstoreidx,
		ssa.OpARM64MOVHstoreidx2,
		ssa.OpARM64MOVWstoreidx4,
		ssa.OpARM64MOVDstoreidx8:
		p := s.Prog(v.Op.Asm())
		p.To = genIndexedOperand(v)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = v.Args[2].Reg()
	case ssa.OpARM64STP:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REGREG
		p.From.Reg = v.Args[1].Reg()
		p.From.Offset = int64(v.Args[2].Reg())
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.To, v)
	case ssa.OpARM64MOVBstorezero,
		ssa.OpARM64MOVHstorezero,
		ssa.OpARM64MOVWstorezero,
		ssa.OpARM64MOVDstorezero:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = arm64.REGZERO
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.To, v)
	case ssa.OpARM64MOVBstorezeroidx,
		ssa.OpARM64MOVHstorezeroidx,
		ssa.OpARM64MOVWstorezeroidx,
		ssa.OpARM64MOVDstorezeroidx,
		ssa.OpARM64MOVHstorezeroidx2,
		ssa.OpARM64MOVWstorezeroidx4,
		ssa.OpARM64MOVDstorezeroidx8:
		p := s.Prog(v.Op.Asm())
		p.To = genIndexedOperand(v)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = arm64.REGZERO
	case ssa.OpARM64MOVQstorezero:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REGREG
		p.From.Reg = arm64.REGZERO
		p.From.Offset = int64(arm64.REGZERO)
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.To, v)
	case ssa.OpARM64BFI,
		ssa.OpARM64BFXIL:
		r := v.Reg()
		if r != v.Args[0].Reg() {
			v.Fatalf("input[0] and output not in same register %s", v.LongString())
		}
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt >> 8
		p.SetFrom3(obj.Addr{Type: obj.TYPE_CONST, Offset: v.AuxInt & 0xff})
		p.Reg = v.Args[1].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = r
	case ssa.OpARM64SBFIZ,
		ssa.OpARM64SBFX,
		ssa.OpARM64UBFIZ,
		ssa.OpARM64UBFX:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = v.AuxInt >> 8
		p.SetFrom3(obj.Addr{Type: obj.TYPE_CONST, Offset: v.AuxInt & 0xff})
		p.Reg = v.Args[0].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64LoweredMuluhilo:
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		p := s.Prog(arm64.AUMULH)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r1
		p.Reg = r0
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg0()
		p1 := s.Prog(arm64.AMUL)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = r1
		p1.Reg = r0
		p1.To.Type = obj.TYPE_REG
		p1.To.Reg = v.Reg1()
	case ssa.OpARM64LoweredAtomicExchange64,
		ssa.OpARM64LoweredAtomicExchange32:
		// LDAXR	(Rarg0), Rout
		// STLXR	Rarg1, (Rarg0), Rtmp
		// CBNZ		Rtmp, -2(PC)
		ld := arm64.ALDAXR
		st := arm64.ASTLXR
		if v.Op == ssa.OpARM64LoweredAtomicExchange32 {
			ld = arm64.ALDAXRW
			st = arm64.ASTLXRW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()
		p := s.Prog(ld)
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = r0
		p.To.Type = obj.TYPE_REG
		p.To.Reg = out
		p1 := s.Prog(st)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = r1
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = r0
		p1.RegTo2 = arm64.REGTMP
		p2 := s.Prog(arm64.ACBNZ)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = arm64.REGTMP
		p2.To.Type = obj.TYPE_BRANCH
		p2.To.SetTarget(p)
	case ssa.OpARM64LoweredAtomicExchange64Variant,
		ssa.OpARM64LoweredAtomicExchange32Variant:
		swap := arm64.ASWPALD
		if v.Op == ssa.OpARM64LoweredAtomicExchange32Variant {
			swap = arm64.ASWPALW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()

		// SWPALD	Rarg1, (Rarg0), Rout
		p := s.Prog(swap)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r1
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = r0
		p.RegTo2 = out

	case ssa.OpARM64LoweredAtomicAdd64,
		ssa.OpARM64LoweredAtomicAdd32:
		// LDAXR	(Rarg0), Rout
		// ADD		Rarg1, Rout
		// STLXR	Rout, (Rarg0), Rtmp
		// CBNZ		Rtmp, -3(PC)
		ld := arm64.ALDAXR
		st := arm64.ASTLXR
		if v.Op == ssa.OpARM64LoweredAtomicAdd32 {
			ld = arm64.ALDAXRW
			st = arm64.ASTLXRW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()
		p := s.Prog(ld)
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = r0
		p.To.Type = obj.TYPE_REG
		p.To.Reg = out
		p1 := s.Prog(arm64.AADD)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = r1
		p1.To.Type = obj.TYPE_REG
		p1.To.Reg = out
		p2 := s.Prog(st)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = out
		p2.To.Type = obj.TYPE_MEM
		p2.To.Reg = r0
		p2.RegTo2 = arm64.REGTMP
		p3 := s.Prog(arm64.ACBNZ)
		p3.From.Type = obj.TYPE_REG
		p3.From.Reg = arm64.REGTMP
		p3.To.Type = obj.TYPE_BRANCH
		p3.To.SetTarget(p)
	case ssa.OpARM64LoweredAtomicAdd64Variant,
		ssa.OpARM64LoweredAtomicAdd32Variant:
		// LDADDAL	Rarg1, (Rarg0), Rout
		// ADD		Rarg1, Rout
		op := arm64.ALDADDALD
		if v.Op == ssa.OpARM64LoweredAtomicAdd32Variant {
			op = arm64.ALDADDALW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()
		p := s.Prog(op)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r1
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = r0
		p.RegTo2 = out
		p1 := s.Prog(arm64.AADD)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = r1
		p1.To.Type = obj.TYPE_REG
		p1.To.Reg = out
	case ssa.OpARM64LoweredAtomicCas64,
		ssa.OpARM64LoweredAtomicCas32:
		// LDAXR	(Rarg0), Rtmp
		// CMP		Rarg1, Rtmp
		// BNE		3(PC)
		// STLXR	Rarg2, (Rarg0), Rtmp
		// CBNZ		Rtmp, -4(PC)
		// CSET		EQ, Rout
		ld := arm64.ALDAXR
		st := arm64.ASTLXR
		cmp := arm64.ACMP
		if v.Op == ssa.OpARM64LoweredAtomicCas32 {
			ld = arm64.ALDAXRW
			st = arm64.ASTLXRW
			cmp = arm64.ACMPW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		r2 := v.Args[2].Reg()
		out := v.Reg0()
		p := s.Prog(ld)
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = r0
		p.To.Type = obj.TYPE_REG
		p.To.Reg = arm64.REGTMP
		p1 := s.Prog(cmp)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = r1
		p1.Reg = arm64.REGTMP
		p2 := s.Prog(arm64.ABNE)
		p2.To.Type = obj.TYPE_BRANCH
		p3 := s.Prog(st)
		p3.From.Type = obj.TYPE_REG
		p3.From.Reg = r2
		p3.To.Type = obj.TYPE_MEM
		p3.To.Reg = r0
		p3.RegTo2 = arm64.REGTMP
		p4 := s.Prog(arm64.ACBNZ)
		p4.From.Type = obj.TYPE_REG
		p4.From.Reg = arm64.REGTMP
		p4.To.Type = obj.TYPE_BRANCH
		p4.To.SetTarget(p)
		p5 := s.Prog(arm64.ACSET)
		p5.From.Type = obj.TYPE_REG // assembler encodes conditional bits in Reg
		p5.From.Reg = arm64.COND_EQ
		p5.To.Type = obj.TYPE_REG
		p5.To.Reg = out
		p2.To.SetTarget(p5)
	case ssa.OpARM64LoweredAtomicCas64Variant,
		ssa.OpARM64LoweredAtomicCas32Variant:
		// Rarg0: ptr
		// Rarg1: old
		// Rarg2: new
		// MOV  	Rarg1, Rtmp
		// CASAL	Rtmp, (Rarg0), Rarg2
		// CMP  	Rarg1, Rtmp
		// CSET 	EQ, Rout
		cas := arm64.ACASALD
		cmp := arm64.ACMP
		mov := arm64.AMOVD
		if v.Op == ssa.OpARM64LoweredAtomicCas32Variant {
			cas = arm64.ACASALW
			cmp = arm64.ACMPW
			mov = arm64.AMOVW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		r2 := v.Args[2].Reg()
		out := v.Reg0()

		// MOV  	Rarg1, Rtmp
		p := s.Prog(mov)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r1
		p.To.Type = obj.TYPE_REG
		p.To.Reg = arm64.REGTMP

		// CASAL	Rtmp, (Rarg0), Rarg2
		p1 := s.Prog(cas)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = arm64.REGTMP
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = r0
		p1.RegTo2 = r2

		// CMP  	Rarg1, Rtmp
		p2 := s.Prog(cmp)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = r1
		p2.Reg = arm64.REGTMP

		// CSET 	EQ, Rout
		p3 := s.Prog(arm64.ACSET)
		p3.From.Type = obj.TYPE_REG
		p3.From.Reg = arm64.COND_EQ
		p3.To.Type = obj.TYPE_REG
		p3.To.Reg = out

	case ssa.OpARM64LoweredAtomicAnd8,
		ssa.OpARM64LoweredAtomicAnd32,
		ssa.OpARM64LoweredAtomicOr8,
		ssa.OpARM64LoweredAtomicOr32:
		// LDAXRB/LDAXRW (Rarg0), Rout
		// AND/OR	Rarg1, Rout
		// STLXRB/STLXRB Rout, (Rarg0), Rtmp
		// CBNZ		Rtmp, -3(PC)
		ld := arm64.ALDAXRB
		st := arm64.ASTLXRB
		if v.Op == ssa.OpARM64LoweredAtomicAnd32 || v.Op == ssa.OpARM64LoweredAtomicOr32 {
			ld = arm64.ALDAXRW
			st = arm64.ASTLXRW
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()
		p := s.Prog(ld)
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = r0
		p.To.Type = obj.TYPE_REG
		p.To.Reg = out
		p1 := s.Prog(v.Op.Asm())
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = r1
		p1.To.Type = obj.TYPE_REG
		p1.To.Reg = out
		p2 := s.Prog(st)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = out
		p2.To.Type = obj.TYPE_MEM
		p2.To.Reg = r0
		p2.RegTo2 = arm64.REGTMP
		p3 := s.Prog(arm64.ACBNZ)
		p3.From.Type = obj.TYPE_REG
		p3.From.Reg = arm64.REGTMP
		p3.To.Type = obj.TYPE_BRANCH
		p3.To.SetTarget(p)
	case ssa.OpARM64LoweredAtomicAnd8Variant,
		ssa.OpARM64LoweredAtomicAnd32Variant:
		atomic_clear := arm64.ALDCLRALW
		if v.Op == ssa.OpARM64LoweredAtomicAnd8Variant {
			atomic_clear = arm64.ALDCLRALB
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()

		// MNV       Rarg1 Rtemp
		p := s.Prog(arm64.AMVN)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r1
		p.To.Type = obj.TYPE_REG
		p.To.Reg = arm64.REGTMP

		// LDCLRALW  Rtemp, (Rarg0), Rout
		p1 := s.Prog(atomic_clear)
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = arm64.REGTMP
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = r0
		p1.RegTo2 = out

		// AND       Rarg1, Rout
		p2 := s.Prog(arm64.AAND)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = r1
		p2.To.Type = obj.TYPE_REG
		p2.To.Reg = out

	case ssa.OpARM64LoweredAtomicOr8Variant,
		ssa.OpARM64LoweredAtomicOr32Variant:
		atomic_or := arm64.ALDORALW
		if v.Op == ssa.OpARM64LoweredAtomicOr8Variant {
			atomic_or = arm64.ALDORALB
		}
		r0 := v.Args[0].Reg()
		r1 := v.Args[1].Reg()
		out := v.Reg0()

		// LDORALW  Rarg1, (Rarg0), Rout
		p := s.Prog(atomic_or)
		p.From.Type = obj.TYPE_REG
		p.From.Reg = r1
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = r0
		p.RegTo2 = out

		// ORR       Rarg1, Rout
		p2 := s.Prog(arm64.AORR)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = r1
		p2.To.Type = obj.TYPE_REG
		p2.To.Reg = out

	case ssa.OpARM64MOVBreg,
		ssa.OpARM64MOVBUreg,
		ssa.OpARM64MOVHreg,
		ssa.OpARM64MOVHUreg,
		ssa.OpARM64MOVWreg,
		ssa.OpARM64MOVWUreg:
		a := v.Args[0]
		for a.Op == ssa.OpCopy || a.Op == ssa.OpARM64MOVDreg {
			a = a.Args[0]
		}
		if a.Op == ssa.OpLoadReg {
			t := a.Type
			switch {
			case v.Op == ssa.OpARM64MOVBreg && t.Size() == 1 && t.IsSigned(),
				v.Op == ssa.OpARM64MOVBUreg && t.Size() == 1 && !t.IsSigned(),
				v.Op == ssa.OpARM64MOVHreg && t.Size() == 2 && t.IsSigned(),
				v.Op == ssa.OpARM64MOVHUreg && t.Size() == 2 && !t.IsSigned(),
				v.Op == ssa.OpARM64MOVWreg && t.Size() == 4 && t.IsSigned(),
				v.Op == ssa.OpARM64MOVWUreg && t.Size() == 4 && !t.IsSigned():
				// arg is a proper-typed load, already zero/sign-extended, don't extend again
				if v.Reg() == v.Args[0].Reg() {
					return
				}
				p := s.Prog(arm64.AMOVD)
				p.From.Type = obj.TYPE_REG
				p.From.Reg = v.Args[0].Reg()
				p.To.Type = obj.TYPE_REG
				p.To.Reg = v.Reg()
				return
			default:
			}
		}
		fallthrough
	case ssa.OpARM64MVN,
		ssa.OpARM64NEG,
		ssa.OpARM64FABSD,
		ssa.OpARM64FMOVDfpgp,
		ssa.OpARM64FMOVDgpfp,
		ssa.OpARM64FMOVSfpgp,
		ssa.OpARM64FMOVSgpfp,
		ssa.OpARM64FNEGS,
		ssa.OpARM64FNEGD,
		ssa.OpARM64FSQRTD,
		ssa.OpARM64FCVTZSSW,
		ssa.OpARM64FCVTZSDW,
		ssa.OpARM64FCVTZUSW,
		ssa.OpARM64FCVTZUDW,
		ssa.OpARM64FCVTZSS,
		ssa.OpARM64FCVTZSD,
		ssa.OpARM64FCVTZUS,
		ssa.OpARM64FCVTZUD,
		ssa.OpARM64SCVTFWS,
		ssa.OpARM64SCVTFWD,
		ssa.OpARM64SCVTFS,
		ssa.OpARM64SCVTFD,
		ssa.OpARM64UCVTFWS,
		ssa.OpARM64UCVTFWD,
		ssa.OpARM64UCVTFS,
		ssa.OpARM64UCVTFD,
		ssa.OpARM64FCVTSD,
		ssa.OpARM64FCVTDS,
		ssa.OpARM64REV,
		ssa.OpARM64REVW,
		ssa.OpARM64REV16W,
		ssa.OpARM64RBIT,
		ssa.OpARM64RBITW,
		ssa.OpARM64CLZ,
		ssa.OpARM64CLZW,
		ssa.OpARM64FRINTAD,
		ssa.OpARM64FRINTMD,
		ssa.OpARM64FRINTND,
		ssa.OpARM64FRINTPD,
		ssa.OpARM64FRINTZD:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = v.Args[0].Reg()
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64LoweredRound32F, ssa.OpARM64LoweredRound64F:
		// input is already rounded
	case ssa.OpARM64VCNT:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = (v.Args[0].Reg()-arm64.REG_F0)&31 + arm64.REG_ARNG + ((arm64.ARNG_8B & 15) << 5)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = (v.Reg()-arm64.REG_F0)&31 + arm64.REG_ARNG + ((arm64.ARNG_8B & 15) << 5)
	case ssa.OpARM64VUADDLV:
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG
		p.From.Reg = (v.Args[0].Reg()-arm64.REG_F0)&31 + arm64.REG_ARNG + ((arm64.ARNG_8B & 15) << 5)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg() - arm64.REG_F0 + arm64.REG_V0
	case ssa.OpARM64CSEL, ssa.OpARM64CSEL0:
		r1 := int16(arm64.REGZERO)
		if v.Op != ssa.OpARM64CSEL0 {
			r1 = v.Args[1].Reg()
		}
		p := s.Prog(v.Op.Asm())
		p.From.Type = obj.TYPE_REG // assembler encodes conditional bits in Reg
		p.From.Reg = condBits[ssa.Op(v.AuxInt)]
		p.Reg = v.Args[0].Reg()
		p.SetFrom3(obj.Addr{Type: obj.TYPE_REG, Reg: r1})
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64DUFFZERO:
		// runtime.duffzero expects start address in R20
		p := s.Prog(obj.ADUFFZERO)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		p.To.Sym = ir.Syms.Duffzero
		p.To.Offset = v.AuxInt
	case ssa.OpARM64LoweredZero:
		// STP.P	(ZR,ZR), 16(R16)
		// CMP	Rarg1, R16
		// BLE	-2(PC)
		// arg1 is the address of the last 16-byte unit to zero
		p := s.Prog(arm64.ASTP)
		p.Scond = arm64.C_XPOST
		p.From.Type = obj.TYPE_REGREG
		p.From.Reg = arm64.REGZERO
		p.From.Offset = int64(arm64.REGZERO)
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = arm64.REG_R16
		p.To.Offset = 16
		p2 := s.Prog(arm64.ACMP)
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = v.Args[1].Reg()
		p2.Reg = arm64.REG_R16
		p3 := s.Prog(arm64.ABLE)
		p3.To.Type = obj.TYPE_BRANCH
		p3.To.SetTarget(p)
	case ssa.OpARM64DUFFCOPY:
		p := s.Prog(obj.ADUFFCOPY)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		p.To.Sym = ir.Syms.Duffcopy
		p.To.Offset = v.AuxInt
	case ssa.OpARM64LoweredMove:
		// MOVD.P	8(R16), Rtmp
		// MOVD.P	Rtmp, 8(R17)
		// CMP	Rarg2, R16
		// BLE	-3(PC)
		// arg2 is the address of the last element of src
		p := s.Prog(arm64.AMOVD)
		p.Scond = arm64.C_XPOST
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = arm64.REG_R16
		p.From.Offset = 8
		p.To.Type = obj.TYPE_REG
		p.To.Reg = arm64.REGTMP
		p2 := s.Prog(arm64.AMOVD)
		p2.Scond = arm64.C_XPOST
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = arm64.REGTMP
		p2.To.Type = obj.TYPE_MEM
		p2.To.Reg = arm64.REG_R17
		p2.To.Offset = 8
		p3 := s.Prog(arm64.ACMP)
		p3.From.Type = obj.TYPE_REG
		p3.From.Reg = v.Args[2].Reg()
		p3.Reg = arm64.REG_R16
		p4 := s.Prog(arm64.ABLE)
		p4.To.Type = obj.TYPE_BRANCH
		p4.To.SetTarget(p)
	case ssa.OpARM64CALLstatic, ssa.OpARM64CALLclosure, ssa.OpARM64CALLinter:
		s.Call(v)
	case ssa.OpARM64LoweredWB:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		p.To.Sym = v.Aux.(*obj.LSym)
	case ssa.OpARM64LoweredPanicBoundsA, ssa.OpARM64LoweredPanicBoundsB, ssa.OpARM64LoweredPanicBoundsC:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		p.To.Sym = ssagen.BoundsCheckFunc[v.AuxInt]
		s.UseArgs(16) // space used in callee args area by assembly stubs
	case ssa.OpARM64LoweredNilCheck:
		// Issue a load which will fault if arg is nil.
		p := s.Prog(arm64.AMOVB)
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = v.Args[0].Reg()
		ssagen.AddAux(&p.From, v)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = arm64.REGTMP
		if logopt.Enabled() {
			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
		}
		if base.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Line==1 in generated wrappers
			base.WarnfAt(v.Pos, "generated nil check")
		}
	case ssa.OpARM64Equal,
		ssa.OpARM64NotEqual,
		ssa.OpARM64LessThan,
		ssa.OpARM64LessEqual,
		ssa.OpARM64GreaterThan,
		ssa.OpARM64GreaterEqual,
		ssa.OpARM64LessThanU,
		ssa.OpARM64LessEqualU,
		ssa.OpARM64GreaterThanU,
		ssa.OpARM64GreaterEqualU,
		ssa.OpARM64LessThanF,
		ssa.OpARM64LessEqualF,
		ssa.OpARM64GreaterThanF,
		ssa.OpARM64GreaterEqualF,
		ssa.OpARM64NotLessThanF,
		ssa.OpARM64NotLessEqualF,
		ssa.OpARM64NotGreaterThanF,
		ssa.OpARM64NotGreaterEqualF:
		// generate boolean values using CSET
		p := s.Prog(arm64.ACSET)
		p.From.Type = obj.TYPE_REG // assembler encodes conditional bits in Reg
		p.From.Reg = condBits[v.Op]
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64LoweredGetClosurePtr:
		// Closure pointer is R26 (arm64.REGCTXT).
		ssagen.CheckLoweredGetClosurePtr(v)
	case ssa.OpARM64LoweredGetCallerSP:
		// caller's SP is FixedFrameSize below the address of the first arg
		p := s.Prog(arm64.AMOVD)
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = -base.Ctxt.FixedFrameSize()
		p.From.Name = obj.NAME_PARAM
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64LoweredGetCallerPC:
		p := s.Prog(obj.AGETCALLERPC)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = v.Reg()
	case ssa.OpARM64FlagConstant:
		v.Fatalf("FlagConstant op should never make it to codegen %v", v.LongString())
	case ssa.OpARM64InvertFlags:
		v.Fatalf("InvertFlags should never make it to codegen %v", v.LongString())
	case ssa.OpClobber:
		// TODO: implement for clobberdead experiment. Nop is ok for now.
	default:
		v.Fatalf("genValue not implemented: %s", v.LongString())
	}
}

var condBits = map[ssa.Op]int16{
	ssa.OpARM64Equal:         arm64.COND_EQ,
	ssa.OpARM64NotEqual:      arm64.COND_NE,
	ssa.OpARM64LessThan:      arm64.COND_LT,
	ssa.OpARM64LessThanU:     arm64.COND_LO,
	ssa.OpARM64LessEqual:     arm64.COND_LE,
	ssa.OpARM64LessEqualU:    arm64.COND_LS,
	ssa.OpARM64GreaterThan:   arm64.COND_GT,
	ssa.OpARM64GreaterThanU:  arm64.COND_HI,
	ssa.OpARM64GreaterEqual:  arm64.COND_GE,
	ssa.OpARM64GreaterEqualU: arm64.COND_HS,
	ssa.OpARM64LessThanF:     arm64.COND_MI, // Less than
	ssa.OpARM64LessEqualF:    arm64.COND_LS, // Less than or equal to
	ssa.OpARM64GreaterThanF:  arm64.COND_GT, // Greater than
	ssa.OpARM64GreaterEqualF: arm64.COND_GE, // Greater than or equal to

	// The following condition codes have unordered to handle comparisons related to NaN.
	ssa.OpARM64NotLessThanF:     arm64.COND_PL, // Greater than, equal to, or unordered
	ssa.OpARM64NotLessEqualF:    arm64.COND_HI, // Greater than or unordered
	ssa.OpARM64NotGreaterThanF:  arm64.COND_LE, // Less than, equal to or unordered
	ssa.OpARM64NotGreaterEqualF: arm64.COND_LT, // Less than or unordered
}

var blockJump = map[ssa.BlockKind]struct {
	asm, invasm obj.As
}{
	ssa.BlockARM64EQ:     {arm64.ABEQ, arm64.ABNE},
	ssa.BlockARM64NE:     {arm64.ABNE, arm64.ABEQ},
	ssa.BlockARM64LT:     {arm64.ABLT, arm64.ABGE},
	ssa.BlockARM64GE:     {arm64.ABGE, arm64.ABLT},
	ssa.BlockARM64LE:     {arm64.ABLE, arm64.ABGT},
	ssa.BlockARM64GT:     {arm64.ABGT, arm64.ABLE},
	ssa.BlockARM64ULT:    {arm64.ABLO, arm64.ABHS},
	ssa.BlockARM64UGE:    {arm64.ABHS, arm64.ABLO},
	ssa.BlockARM64UGT:    {arm64.ABHI, arm64.ABLS},
	ssa.BlockARM64ULE:    {arm64.ABLS, arm64.ABHI},
	ssa.BlockARM64Z:      {arm64.ACBZ, arm64.ACBNZ},
	ssa.BlockARM64NZ:     {arm64.ACBNZ, arm64.ACBZ},
	ssa.BlockARM64ZW:     {arm64.ACBZW, arm64.ACBNZW},
	ssa.BlockARM64NZW:    {arm64.ACBNZW, arm64.ACBZW},
	ssa.BlockARM64TBZ:    {arm64.ATBZ, arm64.ATBNZ},
	ssa.BlockARM64TBNZ:   {arm64.ATBNZ, arm64.ATBZ},
	ssa.BlockARM64FLT:    {arm64.ABMI, arm64.ABPL},
	ssa.BlockARM64FGE:    {arm64.ABGE, arm64.ABLT},
	ssa.BlockARM64FLE:    {arm64.ABLS, arm64.ABHI},
	ssa.BlockARM64FGT:    {arm64.ABGT, arm64.ABLE},
	ssa.BlockARM64LTnoov: {arm64.ABMI, arm64.ABPL},
	ssa.BlockARM64GEnoov: {arm64.ABPL, arm64.ABMI},
}

// To model a 'LEnoov' ('<=' without overflow checking) branching
var leJumps = [2][2]ssagen.IndexJump{
	{{Jump: arm64.ABEQ, Index: 0}, {Jump: arm64.ABPL, Index: 1}}, // next == b.Succs[0]
	{{Jump: arm64.ABMI, Index: 0}, {Jump: arm64.ABEQ, Index: 0}}, // next == b.Succs[1]
}

// To model a 'GTnoov' ('>' without overflow checking) branching
var gtJumps = [2][2]ssagen.IndexJump{
	{{Jump: arm64.ABMI, Index: 1}, {Jump: arm64.ABEQ, Index: 1}}, // next == b.Succs[0]
	{{Jump: arm64.ABEQ, Index: 1}, {Jump: arm64.ABPL, Index: 0}}, // next == b.Succs[1]
}

func ssaGenBlock(s *ssagen.State, b, next *ssa.Block) {
	switch b.Kind {
	case ssa.BlockPlain:
		if b.Succs[0].Block() != next {
			p := s.Prog(obj.AJMP)
			p.To.Type = obj.TYPE_BRANCH
			s.Branches = append(s.Branches, ssagen.Branch{P: p, B: b.Succs[0].Block()})
		}

	case ssa.BlockDefer:
		// defer returns in R0:
		// 0 if we should continue executing
		// 1 if we should jump to deferreturn call
		p := s.Prog(arm64.ACMP)
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = 0
		p.Reg = arm64.REG_R0
		p = s.Prog(arm64.ABNE)
		p.To.Type = obj.TYPE_BRANCH
		s.Branches = append(s.Branches, ssagen.Branch{P: p, B: b.Succs[1].Block()})
		if b.Succs[0].Block() != next {
			p := s.Prog(obj.AJMP)
			p.To.Type = obj.TYPE_BRANCH
			s.Branches = append(s.Branches, ssagen.Branch{P: p, B: b.Succs[0].Block()})
		}

	case ssa.BlockExit:

	case ssa.BlockRet:
		s.Prog(obj.ARET)

	case ssa.BlockRetJmp:
		p := s.Prog(obj.ARET)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		p.To.Sym = b.Aux.(*obj.LSym)

	case ssa.BlockARM64EQ, ssa.BlockARM64NE,
		ssa.BlockARM64LT, ssa.BlockARM64GE,
		ssa.BlockARM64LE, ssa.BlockARM64GT,
		ssa.BlockARM64ULT, ssa.BlockARM64UGT,
		ssa.BlockARM64ULE, ssa.BlockARM64UGE,
		ssa.BlockARM64Z, ssa.BlockARM64NZ,
		ssa.BlockARM64ZW, ssa.BlockARM64NZW,
		ssa.BlockARM64FLT, ssa.BlockARM64FGE,
		ssa.BlockARM64FLE, ssa.BlockARM64FGT,
		ssa.BlockARM64LTnoov, ssa.BlockARM64GEnoov:
		jmp := blockJump[b.Kind]
		var p *obj.Prog
		switch next {
		case b.Succs[0].Block():
			p = s.Br(jmp.invasm, b.Succs[1].Block())
		case b.Succs[1].Block():
			p = s.Br(jmp.asm, b.Succs[0].Block())
		default:
			if b.Likely != ssa.BranchUnlikely {
				p = s.Br(jmp.asm, b.Succs[0].Block())
				s.Br(obj.AJMP, b.Succs[1].Block())
			} else {
				p = s.Br(jmp.invasm, b.Succs[1].Block())
				s.Br(obj.AJMP, b.Succs[0].Block())
			}
		}
		if !b.Controls[0].Type.IsFlags() {
			p.From.Type = obj.TYPE_REG
			p.From.Reg = b.Controls[0].Reg()
		}
	case ssa.BlockARM64TBZ, ssa.BlockARM64TBNZ:
		jmp := blockJump[b.Kind]
		var p *obj.Prog
		switch next {
		case b.Succs[0].Block():
			p = s.Br(jmp.invasm, b.Succs[1].Block())
		case b.Succs[1].Block():
			p = s.Br(jmp.asm, b.Succs[0].Block())
		default:
			if b.Likely != ssa.BranchUnlikely {
				p = s.Br(jmp.asm, b.Succs[0].Block())
				s.Br(obj.AJMP, b.Succs[1].Block())
			} else {
				p = s.Br(jmp.invasm, b.Succs[1].Block())
				s.Br(obj.AJMP, b.Succs[0].Block())
			}
		}
		p.From.Offset = b.AuxInt
		p.From.Type = obj.TYPE_CONST
		p.Reg = b.Controls[0].Reg()

	case ssa.BlockARM64LEnoov:
		s.CombJump(b, next, &leJumps)
	case ssa.BlockARM64GTnoov:
		s.CombJump(b, next, &gtJumps)
	default:
		b.Fatalf("branch not implemented: %s", b.LongString())
	}
}