cmd/compile: arm64 intrinsics for math/bits.OnesCount

This adds math/bits intrinsics for OnesCount on arm64. name old time/op new time/op delta OnesCount 3.81ns ± 0% 1.60ns ± 0% -57.96% (p=0.000 n=7+8) OnesCount8 1.60ns ± 0% 1.60ns ± 0% ~ (all equal) OnesCount16 2.41ns ± 0% 1.60ns ± 0% -33.61% (p=0.000 n=8+8) OnesCount32 4.17ns ± 0% 1.60ns ± 0% -61.58% (p=0.000 n=8+8) OnesCount64 3.80ns ± 0% 1.60ns ± 0% -57.84% (p=0.000 n=8+8) Update #18616 Conflicts: src/cmd/compile/internal/gc/asm_test.go Change-Id: I63ac2f63acafdb1f60656ab8a56be0b326eec5cb Reviewed-on: https://go-review.googlesource.com/90835 Run-TryBot: Cherry Zhang <cherryyz@google.com> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2024-11-23 15:40:06 -07:00 · 2018-01-30 12:16:52 -05:00 · 2018-01-30 12:16:52 -05:00 · fcba05148f
commit fcba05148f
parent c26fac88d4
11 changed files with 277 additions and 14 deletions
--- a/src/cmd/asm/internal/asm/testdata/arm64enc.s
+++ b/src/cmd/asm/internal/asm/testdata/arm64enc.s
@ -388,6 +388,7 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$-8
   UMULL R18, R22, R19                        // d37eb29b
   UXTBW R2, R6                               // 461c0053
   UXTHW R7, R20                              // f43c0053
+   VCNT V0.B8, V0.B8                          // 0058200e
   WFE                                        // 5f2003d5
   WFI                                        // 7f2003d5
   YIELD                                      // 3f2003d5
--- a/src/cmd/compile/internal/arm64/ssa.go
+++ b/src/cmd/compile/internal/arm64/ssa.go
@ -530,6 +530,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		fallthrough
 	case ssa.OpARM64MVN,
 		ssa.OpARM64NEG,
+		ssa.OpARM64FMOVDfpgp,
+		ssa.OpARM64FMOVDgpfp,
 		ssa.OpARM64FNEGS,
 		ssa.OpARM64FNEGD,
 		ssa.OpARM64FSQRTD,
@ -563,6 +565,18 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.From.Reg = v.Args[0].Reg()
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
+	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.OpARM64CSELULT,
 		ssa.OpARM64CSELULT0:
 		r1 := int16(arm64.REGZERO)
--- a/src/cmd/compile/internal/gc/asm_test.go
+++ b/src/cmd/compile/internal/gc/asm_test.go
@ -2751,6 +2751,30 @@ var linuxARM64Tests = []*asmTest{
 		`,
 		pos: []string{"TBZ"},
 	},
+	{
+		fn: `
+		func $(x uint64) int {
+			return bits.OnesCount64(x)
+		}
+		`,
+		pos: []string{"\tVCNT\t", "\tVUADDLV\t"},
+	},
+	{
+		fn: `
+		func $(x uint32) int {
+			return bits.OnesCount32(x)
+		}
+		`,
+		pos: []string{"\tVCNT\t", "\tVUADDLV\t"},
+	},
+	{
+		fn: `
+		func $(x uint16) int {
+			return bits.OnesCount16(x)
+		}
+		`,
+		pos: []string{"\tVCNT\t", "\tVUADDLV\t"},
+	},
 	// Load-combining tests.
 	{
 		fn: `
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@ -3156,7 +3156,7 @@ func init() {
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
 			return s.newValue1(ssa.OpPopCount64, types.Types[TINT], args[0])
 		},
-		sys.PPC64)
+		sys.PPC64, sys.ARM64)
 	addF("math/bits", "OnesCount32",
 		makeOnesCountAMD64(ssa.OpPopCount32, ssa.OpPopCount32),
 		sys.AMD64)
@ -3164,10 +3164,15 @@ func init() {
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
 			return s.newValue1(ssa.OpPopCount32, types.Types[TINT], args[0])
 		},
-		sys.PPC64)
+		sys.PPC64, sys.ARM64)
 	addF("math/bits", "OnesCount16",
 		makeOnesCountAMD64(ssa.OpPopCount16, ssa.OpPopCount16),
 		sys.AMD64)
+	addF("math/bits", "OnesCount16",
+		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
+			return s.newValue1(ssa.OpPopCount16, types.Types[TINT], args[0])
+		},
+		sys.ARM64)
 	// Note: no OnesCount8, the Go implementation is faster - just a table load.
 	addF("math/bits", "OnesCount",
 		makeOnesCountAMD64(ssa.OpPopCount64, ssa.OpPopCount32),
--- a/src/cmd/compile/internal/ssa/gen/ARM64.rules
+++ b/src/cmd/compile/internal/ssa/gen/ARM64.rules
@ -86,6 +86,16 @@
 (Ctz64 <t> x) -> (CLZ (RBIT <t> x))
 (Ctz32 <t> x) -> (CLZW (RBITW <t> x))

+(PopCount64 <t> x) -> (FMOVDfpgp <t> (VUADDLV <typ.Float64> (VCNT <typ.Float64> (FMOVDgpfp <typ.Float64> x))))
+(PopCount32 <t> x) -> (FMOVDfpgp <t> (VUADDLV <typ.Float64> (VCNT <typ.Float64> (FMOVDgpfp <typ.Float64> (ZeroExt32to64 x)))))
+(PopCount16 <t> x) -> (FMOVDfpgp <t> (VUADDLV <typ.Float64> (VCNT <typ.Float64> (FMOVDgpfp <typ.Float64> (ZeroExt16to64 x)))))
+
+// Load args directly into the register class where it will be used.
+(FMOVDgpfp <t> (Arg [off] {sym})) -> @b.Func.Entry (Arg <t> [off] {sym})
+// Similarly for stores, if we see a store after FPR <-> GPR move, then redirect store to use the other register set.
+(MOVDstore ptr (FMOVDfpgp val) mem) -> (FMOVDstore ptr val mem)
+(FMOVDstore ptr (FMOVDgpfp val) mem) -> (MOVDstore ptr val mem)
+
 (BitLen64 x) -> (SUB (MOVDconst [64]) (CLZ <typ.Int> x))

 (Bswap64 x) -> (REV x)
--- a/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
@ -199,18 +199,20 @@ func init() {
 		{name: "BICconst", argLength: 1, reg: gp11, asm: "BIC", aux: "Int64"}, // arg0 &^ auxInt

 		// unary ops
-		{name: "MVN", argLength: 1, reg: gp11, asm: "MVN"},       // ^arg0
-		{name: "NEG", argLength: 1, reg: gp11, asm: "NEG"},       // -arg0
-		{name: "FNEGS", argLength: 1, reg: fp11, asm: "FNEGS"},   // -arg0, float32
-		{name: "FNEGD", argLength: 1, reg: fp11, asm: "FNEGD"},   // -arg0, float64
-		{name: "FSQRTD", argLength: 1, reg: fp11, asm: "FSQRTD"}, // sqrt(arg0), float64
-		{name: "REV", argLength: 1, reg: gp11, asm: "REV"},       // byte reverse, 64-bit
-		{name: "REVW", argLength: 1, reg: gp11, asm: "REVW"},     // byte reverse, 32-bit
-		{name: "REV16W", argLength: 1, reg: gp11, asm: "REV16W"}, // byte reverse in each 16-bit halfword, 32-bit
-		{name: "RBIT", argLength: 1, reg: gp11, asm: "RBIT"},     // bit reverse, 64-bit
-		{name: "RBITW", argLength: 1, reg: gp11, asm: "RBITW"},   // bit reverse, 32-bit
-		{name: "CLZ", argLength: 1, reg: gp11, asm: "CLZ"},       // count leading zero, 64-bit
-		{name: "CLZW", argLength: 1, reg: gp11, asm: "CLZW"},     // count leading zero, 32-bit
+		{name: "MVN", argLength: 1, reg: gp11, asm: "MVN"},         // ^arg0
+		{name: "NEG", argLength: 1, reg: gp11, asm: "NEG"},         // -arg0
+		{name: "FNEGS", argLength: 1, reg: fp11, asm: "FNEGS"},     // -arg0, float32
+		{name: "FNEGD", argLength: 1, reg: fp11, asm: "FNEGD"},     // -arg0, float64
+		{name: "FSQRTD", argLength: 1, reg: fp11, asm: "FSQRTD"},   // sqrt(arg0), float64
+		{name: "REV", argLength: 1, reg: gp11, asm: "REV"},         // byte reverse, 64-bit
+		{name: "REVW", argLength: 1, reg: gp11, asm: "REVW"},       // byte reverse, 32-bit
+		{name: "REV16W", argLength: 1, reg: gp11, asm: "REV16W"},   // byte reverse in each 16-bit halfword, 32-bit
+		{name: "RBIT", argLength: 1, reg: gp11, asm: "RBIT"},       // bit reverse, 64-bit
+		{name: "RBITW", argLength: 1, reg: gp11, asm: "RBITW"},     // bit reverse, 32-bit
+		{name: "CLZ", argLength: 1, reg: gp11, asm: "CLZ"},         // count leading zero, 64-bit
+		{name: "CLZW", argLength: 1, reg: gp11, asm: "CLZW"},       // count leading zero, 32-bit
+		{name: "VCNT", argLength: 1, reg: fp11, asm: "VCNT"},       // count set bits for each 8-bit unit and store the result in each 8-bit unit
+		{name: "VUADDLV", argLength: 1, reg: fp11, asm: "VUADDLV"}, // unsigned sum of eight bytes in a 64-bit value, zero extended to 64-bit.

 		// shifts
 		{name: "SLL", argLength: 2, reg: gp21, asm: "LSL"},                      // arg0 << arg1, shift amount is mod 64
@ -288,6 +290,9 @@ func init() {
 		{name: "MOVDstorezero", argLength: 2, reg: gpstore0, aux: "SymOff", asm: "MOVD", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"}, // store 8 bytes of zero to arg0 + auxInt + aux.  arg1=mem.
 		{name: "MOVQstorezero", argLength: 2, reg: gpstore0, aux: "SymOff", asm: "STP", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"},  // store 16 bytes of zero to arg0 + auxInt + aux.  arg1=mem.

+		{name: "FMOVDgpfp", argLength: 1, reg: gpfp, asm: "FMOVD"}, // move int64 to float64 (no conversion)
+		{name: "FMOVDfpgp", argLength: 1, reg: fpgp, asm: "FMOVD"}, // move float64 to int64 (no conversion)
+
 		// conversions
 		{name: "MOVBreg", argLength: 1, reg: gp11, asm: "MOVB"},   // move from arg0, sign-extended from byte
 		{name: "MOVBUreg", argLength: 1, reg: gp11, asm: "MOVBU"}, // move from arg0, unsign-extended from byte
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@ -999,6 +999,8 @@ const (
 	OpARM64RBITW
 	OpARM64CLZ
 	OpARM64CLZW
+	OpARM64VCNT
+	OpARM64VUADDLV
 	OpARM64SLL
 	OpARM64SLLconst
 	OpARM64SRL
@ -1063,6 +1065,8 @@ const (
 	OpARM64MOVWstorezero
 	OpARM64MOVDstorezero
 	OpARM64MOVQstorezero
+	OpARM64FMOVDgpfp
+	OpARM64FMOVDfpgp
 	OpARM64MOVBreg
 	OpARM64MOVBUreg
 	OpARM64MOVHreg
@ -12689,6 +12693,32 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:   "VCNT",
+		argLen: 1,
+		asm:    arm64.AVCNT,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+		},
+	},
+	{
+		name:   "VUADDLV",
+		argLen: 1,
+		asm:    arm64.AVUADDLV,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+		},
+	},
 	{
 		name:   "SLL",
 		argLen: 2,
@ -13577,6 +13607,32 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:   "FMOVDgpfp",
+		argLen: 1,
+		asm:    arm64.AFMOVD,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 670826495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 R30
+			},
+			outputs: []outputInfo{
+				{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+		},
+	},
+	{
+		name:   "FMOVDfpgp",
+		argLen: 1,
+		asm:    arm64.AFMOVD,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 9223372034707292160}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 670826495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 R30
+			},
+		},
+	},
 	{
 		name:   "MOVBreg",
 		argLen: 1,
--- a/src/cmd/compile/internal/ssa/rewriteARM64.go
+++ b/src/cmd/compile/internal/ssa/rewriteARM64.go
@ -69,6 +69,8 @@ func rewriteValueARM64(v *Value) bool {
 		return rewriteValueARM64_OpARM64DIVW_0(v)
 	case OpARM64Equal:
 		return rewriteValueARM64_OpARM64Equal_0(v)
+	case OpARM64FMOVDgpfp:
+		return rewriteValueARM64_OpARM64FMOVDgpfp_0(v)
 	case OpARM64FMOVDload:
 		return rewriteValueARM64_OpARM64FMOVDload_0(v)
 	case OpARM64FMOVDstore:
@ -599,6 +601,12 @@ func rewriteValueARM64(v *Value) bool {
 		return rewriteValueARM64_OpOr8_0(v)
 	case OpOrB:
 		return rewriteValueARM64_OpOrB_0(v)
+	case OpPopCount16:
+		return rewriteValueARM64_OpPopCount16_0(v)
+	case OpPopCount32:
+		return rewriteValueARM64_OpPopCount32_0(v)
+	case OpPopCount64:
+		return rewriteValueARM64_OpPopCount64_0(v)
 	case OpRound32F:
 		return rewriteValueARM64_OpRound32F_0(v)
 	case OpRound64F:
@ -2871,6 +2879,30 @@ func rewriteValueARM64_OpARM64Equal_0(v *Value) bool {
 	}
 	return false
 }
+func rewriteValueARM64_OpARM64FMOVDgpfp_0(v *Value) bool {
+	b := v.Block
+	_ = b
+	// match: (FMOVDgpfp <t> (Arg [off] {sym}))
+	// cond:
+	// result: @b.Func.Entry (Arg <t> [off] {sym})
+	for {
+		t := v.Type
+		v_0 := v.Args[0]
+		if v_0.Op != OpArg {
+			break
+		}
+		off := v_0.AuxInt
+		sym := v_0.Aux
+		b = b.Func.Entry
+		v0 := b.NewValue0(v.Pos, OpArg, t)
+		v.reset(OpCopy)
+		v.AddArg(v0)
+		v0.AuxInt = off
+		v0.Aux = sym
+		return true
+	}
+	return false
+}
 func rewriteValueARM64_OpARM64FMOVDload_0(v *Value) bool {
 	b := v.Block
 	_ = b
@ -2932,6 +2964,24 @@ func rewriteValueARM64_OpARM64FMOVDstore_0(v *Value) bool {
 	_ = b
 	config := b.Func.Config
 	_ = config
+	// match: (FMOVDstore ptr (FMOVDgpfp val) mem)
+	// cond:
+	// result: (MOVDstore ptr val mem)
+	for {
+		_ = v.Args[2]
+		ptr := v.Args[0]
+		v_1 := v.Args[1]
+		if v_1.Op != OpARM64FMOVDgpfp {
+			break
+		}
+		val := v_1.Args[0]
+		mem := v.Args[2]
+		v.reset(OpARM64MOVDstore)
+		v.AddArg(ptr)
+		v.AddArg(val)
+		v.AddArg(mem)
+		return true
+	}
 	// match: (FMOVDstore [off1] {sym} (ADDconst [off2] ptr) val mem)
 	// cond: is32Bit(off1+off2) 	&& (ptr.Op != OpSB || !config.ctxt.Flag_shared)
 	// result: (FMOVDstore [off1+off2] {sym} ptr val mem)
@ -4600,6 +4650,24 @@ func rewriteValueARM64_OpARM64MOVDstore_0(v *Value) bool {
 	_ = b
 	config := b.Func.Config
 	_ = config
+	// match: (MOVDstore ptr (FMOVDfpgp val) mem)
+	// cond:
+	// result: (FMOVDstore ptr val mem)
+	for {
+		_ = v.Args[2]
+		ptr := v.Args[0]
+		v_1 := v.Args[1]
+		if v_1.Op != OpARM64FMOVDfpgp {
+			break
+		}
+		val := v_1.Args[0]
+		mem := v.Args[2]
+		v.reset(OpARM64FMOVDstore)
+		v.AddArg(ptr)
+		v.AddArg(val)
+		v.AddArg(mem)
+		return true
+	}
 	// match: (MOVDstore [off1] {sym} (ADDconst [off2] ptr) val mem)
 	// cond: is32Bit(off1+off2) 	&& (ptr.Op != OpSB || !config.ctxt.Flag_shared)
 	// result: (MOVDstore [off1+off2] {sym} ptr val mem)
@ -14576,6 +14644,79 @@ func rewriteValueARM64_OpOrB_0(v *Value) bool {
 		return true
 	}
 }
+func rewriteValueARM64_OpPopCount16_0(v *Value) bool {
+	b := v.Block
+	_ = b
+	typ := &b.Func.Config.Types
+	_ = typ
+	// match: (PopCount16 <t> x)
+	// cond:
+	// result: (FMOVDfpgp <t> (VUADDLV <typ.Float64> (VCNT <typ.Float64> (FMOVDgpfp <typ.Float64> (ZeroExt16to64 x)))))
+	for {
+		t := v.Type
+		x := v.Args[0]
+		v.reset(OpARM64FMOVDfpgp)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpARM64VUADDLV, typ.Float64)
+		v1 := b.NewValue0(v.Pos, OpARM64VCNT, typ.Float64)
+		v2 := b.NewValue0(v.Pos, OpARM64FMOVDgpfp, typ.Float64)
+		v3 := b.NewValue0(v.Pos, OpZeroExt16to64, typ.UInt64)
+		v3.AddArg(x)
+		v2.AddArg(v3)
+		v1.AddArg(v2)
+		v0.AddArg(v1)
+		v.AddArg(v0)
+		return true
+	}
+}
+func rewriteValueARM64_OpPopCount32_0(v *Value) bool {
+	b := v.Block
+	_ = b
+	typ := &b.Func.Config.Types
+	_ = typ
+	// match: (PopCount32 <t> x)
+	// cond:
+	// result: (FMOVDfpgp <t> (VUADDLV <typ.Float64> (VCNT <typ.Float64> (FMOVDgpfp <typ.Float64> (ZeroExt32to64 x)))))
+	for {
+		t := v.Type
+		x := v.Args[0]
+		v.reset(OpARM64FMOVDfpgp)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpARM64VUADDLV, typ.Float64)
+		v1 := b.NewValue0(v.Pos, OpARM64VCNT, typ.Float64)
+		v2 := b.NewValue0(v.Pos, OpARM64FMOVDgpfp, typ.Float64)
+		v3 := b.NewValue0(v.Pos, OpZeroExt32to64, typ.UInt64)
+		v3.AddArg(x)
+		v2.AddArg(v3)
+		v1.AddArg(v2)
+		v0.AddArg(v1)
+		v.AddArg(v0)
+		return true
+	}
+}
+func rewriteValueARM64_OpPopCount64_0(v *Value) bool {
+	b := v.Block
+	_ = b
+	typ := &b.Func.Config.Types
+	_ = typ
+	// match: (PopCount64 <t> x)
+	// cond:
+	// result: (FMOVDfpgp <t> (VUADDLV <typ.Float64> (VCNT <typ.Float64> (FMOVDgpfp <typ.Float64> x))))
+	for {
+		t := v.Type
+		x := v.Args[0]
+		v.reset(OpARM64FMOVDfpgp)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpARM64VUADDLV, typ.Float64)
+		v1 := b.NewValue0(v.Pos, OpARM64VCNT, typ.Float64)
+		v2 := b.NewValue0(v.Pos, OpARM64FMOVDgpfp, typ.Float64)
+		v2.AddArg(x)
+		v1.AddArg(v2)
+		v0.AddArg(v1)
+		v.AddArg(v0)
+		return true
+	}
+}
 func rewriteValueARM64_OpRound32F_0(v *Value) bool {
 	// match: (Round32F x)
 	// cond:
--- a/src/cmd/internal/obj/arm64/a.out.go
+++ b/src/cmd/internal/obj/arm64/a.out.go
@ -753,6 +753,7 @@ const (
 	AVADDP
 	AVAND
 	AVCMEQ
+	AVCNT
 	AVEOR
 	AVMOV
 	AVLD1
--- a/src/cmd/internal/obj/arm64/anames.go
+++ b/src/cmd/internal/obj/arm64/anames.go
@ -370,6 +370,7 @@ var Anames = []string{
 	"VADDP",
 	"VAND",
 	"VCMEQ",
+	"VCNT",
 	"VEOR",
 	"VMOV",
 	"VLD1",
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@ -598,6 +598,7 @@ var optab = []Optab{
 	{AVST1, C_LIST, C_NONE, C_ROFF, 84, 4, 0, 0, C_XPOST},
 	{AVDUP, C_ELEM, C_NONE, C_ARNG, 79, 4, 0, 0, 0},
 	{AVADDV, C_ARNG, C_NONE, C_VREG, 85, 4, 0, 0, 0},
+	{AVCNT, C_ARNG, C_NONE, C_ARNG, 29, 4, 0, 0, 0},
 	{AVMOVI, C_ADDCON, C_NONE, C_ARNG, 86, 4, 0, 0, 0},

 	{obj.AUNDEF, C_NONE, C_NONE, C_NONE, 90, 4, 0, 0, 0},
@ -2126,6 +2127,7 @@ func buildop(ctxt *obj.Link) {
 			oprangeset(AVUADDLV, t)

 		case ASHA1H,
+			AVCNT,
 			AVMOV,
 			AVLD1,
 			AVREV32,
@ -4323,6 +4325,9 @@ func (c *ctxt7) oprrr(p *obj.Prog, a obj.As) uint32 {
 	case AVCMEQ:
 		return 1<<29 | 0x71<<21 | 0x23<<10

+	case AVCNT:
+		return 0<<31 | 0<<29 | 0xE<<24 | 0x10<<17 | 5<<12 | 2<<10
+
 	case AVEOR:
 		return 1<<29 | 0x71<<21 | 7<<10