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cmd/compile: lowered MulUintptr on riscv64

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According to RISCV instruction set manual v2.2 Sec 6.1
MULHU followed by MUL will be fused into one multiply by microarchitecture

name              old time/op  new time/op  delta
MulUintptr/small  11.2ns ±24%   9.2ns ± 0%  -17.54%  (p=0.000 n=10+9)
MulUintptr/large  15.9ns ± 0%  10.9ns ± 0%  -31.55%  (p=0.000 n=8+8)

Change-Id: I3d152218f83948cbc5c576bda29dc86e9b4206ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/338753
Trust: Meng Zhuo <mzh@golangcn.org>
Reviewed-by: Joel Sing <joel@sing.id.au>
This commit is contained in:
Meng Zhuo 2021-07-31 10:20:10 +00:00
parent 2a19333716
commit 1951afc919
6 changed files with 43 additions and 1 deletions
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21
src/cmd/compile/internal/riscv64/ssa.go
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@ -297,6 +297,27 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
p1.Reg = r0
p1.To.Type = obj.TYPE_REG
p1.To.Reg = v.Reg1()
case ssa.OpRISCV64LoweredMuluover:
r0 := v.Args[0].Reg()
r1 := v.Args[1].Reg()
p := s.Prog(riscv.AMULHU)
p.From.Type = obj.TYPE_REG
p.From.Reg = r1
p.Reg = r0
p.To.Type = obj.TYPE_REG
p.To.Reg = v.Reg1()
p1 := s.Prog(riscv.AMUL)
p1.From.Type = obj.TYPE_REG
p1.From.Reg = r1
p1.Reg = r0
p1.To.Type = obj.TYPE_REG
p1.To.Reg = v.Reg0()
p2 := s.Prog(riscv.ASNEZ)
p2.From.Type = obj.TYPE_REG
p2.From.Reg = v.Reg1()
p2.To.Type = obj.TYPE_REG
p2.To.Reg = v.Reg1()
case ssa.OpRISCV64FSQRTS, ssa.OpRISCV64FNEGS, ssa.OpRISCV64FSQRTD, ssa.OpRISCV64FNEGD,
ssa.OpRISCV64FMVSX, ssa.OpRISCV64FMVDX,
ssa.OpRISCV64FCVTSW, ssa.OpRISCV64FCVTSL, ssa.OpRISCV64FCVTWS, ssa.OpRISCV64FCVTLS,

1
src/cmd/compile/internal/ssa/gen/RISCV64.rules
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@ -30,6 +30,7 @@
(Mul64 ...) => (MUL ...)
(Mul64uhilo ...) => (LoweredMuluhilo ...)
(Mul64uover ...) => (LoweredMuluover ...)
(Mul32 ...) => (MULW ...)
(Mul16 x y) => (MULW (SignExt16to32 x) (SignExt16to32 y))
(Mul8 x y) => (MULW (SignExt8to32 x) (SignExt8to32 y))

1
src/cmd/compile/internal/ssa/gen/RISCV64Ops.go
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@ -159,6 +159,7 @@ func init() {
{name: "MULH", argLength: 2, reg: gp21, asm: "MULH", commutative: true, typ: "Int64"},
{name: "MULHU", argLength: 2, reg: gp21, asm: "MULHU", commutative: true, typ: "UInt64"},
{name: "LoweredMuluhilo", argLength: 2, reg: gp22, resultNotInArgs: true}, // arg0 * arg1, return (hi, lo)
{name: "LoweredMuluover", argLength: 2, reg: gp22, resultNotInArgs: true}, // arg0 * arg1, return (64 bits of arg0*arg1, overflow)
{name: "DIV", argLength: 2, reg: gp21, asm: "DIV", typ: "Int64"}, // arg0 / arg1
{name: "DIVU", argLength: 2, reg: gp21, asm: "DIVU", typ: "UInt64"},

16
src/cmd/compile/internal/ssa/opGen.go
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@ -2070,6 +2070,7 @@ const (
OpRISCV64MULH
OpRISCV64MULHU
OpRISCV64LoweredMuluhilo
OpRISCV64LoweredMuluover
OpRISCV64DIV
OpRISCV64DIVU
OpRISCV64DIVW
@ -27619,6 +27620,21 @@ var opcodeTable = [...]opInfo{
},
},
},
{
name: "LoweredMuluover",
argLen: 2,
resultNotInArgs: true,
reg: regInfo{
inputs: []inputInfo{
{0, 1006632948}, // X3 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X28 X29 X30
{1, 1006632948}, // X3 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X28 X29 X30
},
outputs: []outputInfo{
{0, 1006632948}, // X3 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X28 X29 X30
{1, 1006632948}, // X3 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X28 X29 X30
},
},
},
{
name: "DIV",
argLen: 2,

3
src/cmd/compile/internal/ssa/rewriteRISCV64.go
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@ -359,6 +359,9 @@ func rewriteValueRISCV64(v *Value) bool {
case OpMul64uhilo:
v.Op = OpRISCV64LoweredMuluhilo
return true
case OpMul64uover:
v.Op = OpRISCV64LoweredMuluover
return true
case OpMul8:
return rewriteValueRISCV64_OpMul8(v)
case OpNeg16:

2
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -3779,7 +3779,7 @@ func InitTables() {
}
return s.newValue2(ssa.OpMul64uover, types.NewTuple(types.Types[types.TUINT], types.Types[types.TUINT]), args[0], args[1])
},
sys.AMD64, sys.I386, sys.MIPS64)
sys.AMD64, sys.I386, sys.MIPS64, sys.RISCV64)
add("runtime", "KeepAlive",
func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
data := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, args[0])