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cmd/compile: const folding for float32/64

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Split the auxFloat type into 32/64 bit versions and perform checking for
exactly representable float32 values.  Perform const folding on
float32/64.  Comment out some const negation rules that the frontend
already performs.

Change-Id: Ib3f8d59fa8b30e50fe0267786cfb3c50a06169d2
Reviewed-on: https://go-review.googlesource.com/20568
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Todd Neal 2016-03-11 19:36:54 -06:00
parent cd798dcb88
commit f6ceed2cab
10 changed files with 232 additions and 69 deletions
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12
src/cmd/compile/internal/ssa/check.go
View File

@ -171,8 +171,13 @@ func checkFunc(f *Func) {
canHaveAuxInt := false
switch opcodeTable[v.Op].auxType {
case auxNone:
case auxBool, auxInt8, auxInt16, auxInt32, auxInt64, auxFloat:
case auxBool, auxInt8, auxInt16, auxInt32, auxInt64, auxFloat64:
canHaveAuxInt = true
case auxFloat32:
canHaveAuxInt = true
if !isExactFloat32(v) {
f.Fatalf("value %v has an AuxInt value that is not an exact float32", v)
}
case auxString, auxSym:
canHaveAux = true
case auxSymOff, auxSymValAndOff:
@ -299,3 +304,8 @@ func domCheck(f *Func, sdom sparseTree, x, y *Block) bool {
}
return sdom.isAncestorEq(x, y)
}
// isExactFloat32 reoprts whether v has an AuxInt that can be exactly represented as a float32.
func isExactFloat32(v *Value) bool {
return v.AuxFloat() == float64(float32(v.AuxFloat()))
}

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

@ -341,7 +341,7 @@ func (f *Func) ConstInt64(line int32, t Type, c int64) *Value {
return f.constVal(line, OpConst64, t, c, true)
}
func (f *Func) ConstFloat32(line int32, t Type, c float64) *Value {
return f.constVal(line, OpConst32F, t, int64(math.Float64bits(c)), true)
return f.constVal(line, OpConst32F, t, int64(math.Float64bits(float64(float32(c)))), true)
}
func (f *Func) ConstFloat64(line int32, t Type, c float64) *Value {
return f.constVal(line, OpConst64F, t, int64(math.Float64bits(c)), true)

12
src/cmd/compile/internal/ssa/gen/AMD64Ops.go
View File

@ -153,12 +153,12 @@ func init() {
{name: "DIVSS", argLength: 2, reg: fp21x15, asm: "DIVSS", resultInArg0: true}, // fp32 div
{name: "DIVSD", argLength: 2, reg: fp21x15, asm: "DIVSD", resultInArg0: true}, // fp64 div
{name: "MOVSSload", argLength: 2, reg: fpload, asm: "MOVSS", aux: "SymOff"}, // fp32 load
{name: "MOVSDload", argLength: 2, reg: fpload, asm: "MOVSD", aux: "SymOff"}, // fp64 load
{name: "MOVSSconst", reg: fp01, asm: "MOVSS", aux: "Float", rematerializeable: true}, // fp32 constant
{name: "MOVSDconst", reg: fp01, asm: "MOVSD", aux: "Float", rematerializeable: true}, // fp64 constant
{name: "MOVSSloadidx4", argLength: 3, reg: fploadidx, asm: "MOVSS", aux: "SymOff"}, // fp32 load
{name: "MOVSDloadidx8", argLength: 3, reg: fploadidx, asm: "MOVSD", aux: "SymOff"}, // fp64 load
{name: "MOVSSload", argLength: 2, reg: fpload, asm: "MOVSS", aux: "SymOff"}, // fp32 load
{name: "MOVSDload", argLength: 2, reg: fpload, asm: "MOVSD", aux: "SymOff"}, // fp64 load
{name: "MOVSSconst", reg: fp01, asm: "MOVSS", aux: "Float32", rematerializeable: true}, // fp32 constant
{name: "MOVSDconst", reg: fp01, asm: "MOVSD", aux: "Float64", rematerializeable: true}, // fp64 constant
{name: "MOVSSloadidx4", argLength: 3, reg: fploadidx, asm: "MOVSS", aux: "SymOff"}, // fp32 load
{name: "MOVSDloadidx8", argLength: 3, reg: fploadidx, asm: "MOVSD", aux: "SymOff"}, // fp64 load
{name: "MOVSSstore", argLength: 3, reg: fpstore, asm: "MOVSS", aux: "SymOff"}, // fp32 store
{name: "MOVSDstore", argLength: 3, reg: fpstore, asm: "MOVSD", aux: "SymOff"}, // fp64 store

22
src/cmd/compile/internal/ssa/gen/generic.rules
View File

@ -30,26 +30,40 @@
(Trunc64to8 (Const64 [c])) -> (Const8 [int64(int8(c))])
(Trunc64to16 (Const64 [c])) -> (Const16 [int64(int16(c))])
(Trunc64to32 (Const64 [c])) -> (Const32 [int64(int32(c))])
(Cvt64Fto32F (Const64F [c])) -> (Const32F [f2i(float64(i2f32(c)))])
(Cvt32Fto64F (Const32F [c])) -> (Const64F [c]) // c is already a 64 bit float
(Neg8 (Const8 [c])) -> (Const8 [-c])
(Neg16 (Const16 [c])) -> (Const16 [-c])
(Neg32 (Const32 [c])) -> (Const32 [-c])
(Neg64 (Const64 [c])) -> (Const64 [-c])
// const negation is currently handled by frontend
//(Neg8 (Const8 [c])) -> (Const8 [-c])
//(Neg16 (Const16 [c])) -> (Const16 [-c])
//(Neg32 (Const32 [c])) -> (Const32 [-c])
//(Neg64 (Const64 [c])) -> (Const64 [-c])
//(Neg32F (Const32F [c])) -> (Const32F [f2i(-i2f(c))])
//(Neg64F (Const64F [c])) -> (Const64F [f2i(-i2f(c))])
(Add8 (Const8 [c]) (Const8 [d])) -> (Const8 [c+d])
(Add16 (Const16 [c]) (Const16 [d])) -> (Const16 [c+d])
(Add32 (Const32 [c]) (Const32 [d])) -> (Const32 [c+d])
(Add64 (Const64 [c]) (Const64 [d])) -> (Const64 [c+d])
(Add32F (Const32F [c]) (Const32F [d])) ->
(Const32F [f2i(float64(i2f32(c) + i2f32(d)))]) // ensure we combine the operands with 32 bit precision
(Add64F (Const64F [c]) (Const64F [d])) -> (Const64F [f2i(i2f(c) + i2f(d))])
(Sub8 (Const8 [c]) (Const8 [d])) -> (Const8 [c-d])
(Sub16 (Const16 [c]) (Const16 [d])) -> (Const16 [c-d])
(Sub32 (Const32 [c]) (Const32 [d])) -> (Const32 [c-d])
(Sub64 (Const64 [c]) (Const64 [d])) -> (Const64 [c-d])
(Sub32F (Const32F [c]) (Const32F [d])) ->
(Const32F [f2i(float64(i2f32(c) - i2f32(d)))])
(Sub64F (Const64F [c]) (Const64F [d])) -> (Const64F [f2i(i2f(c) - i2f(d))])
(Mul8 (Const8 [c]) (Const8 [d])) -> (Const8 [c*d])
(Mul16 (Const16 [c]) (Const16 [d])) -> (Const16 [c*d])
(Mul32 (Const32 [c]) (Const32 [d])) -> (Const32 [c*d])
(Mul64 (Const64 [c]) (Const64 [d])) -> (Const64 [c*d])
(Mul32F (Const32F [c]) (Const32F [d])) ->
(Const32F [f2i(float64(i2f32(c) * i2f32(d)))])
(Mul64F (Const64F [c]) (Const64F [d])) -> (Const64F [f2i(i2f(c) * i2f(d))])
(Lsh64x64 (Const64 [c]) (Const64 [d])) -> (Const64 [c << uint64(d)])
(Rsh64x64 (Const64 [c]) (Const64 [d])) -> (Const64 [c >> uint64(d)])

4
src/cmd/compile/internal/ssa/gen/genericOps.go
View File

@ -259,8 +259,8 @@ var genericOps = []opData{
{name: "Const16", aux: "Int16"}, // value is low 16 bits of auxint
{name: "Const32", aux: "Int32"}, // value is low 32 bits of auxint
{name: "Const64", aux: "Int64"}, // value is auxint
{name: "Const32F", aux: "Float"}, // value is math.Float64frombits(uint64(auxint))
{name: "Const64F", aux: "Float"}, // value is math.Float64frombits(uint64(auxint))
{name: "Const32F", aux: "Float32"}, // value is math.Float64frombits(uint64(auxint)) and is exactly prepresentable as float 32
{name: "Const64F", aux: "Float64"}, // value is math.Float64frombits(uint64(auxint))
{name: "ConstInterface"}, // nil interface
{name: "ConstSlice"}, // nil slice

3
src/cmd/compile/internal/ssa/op.go
View File

@ -49,7 +49,8 @@ const (
auxInt16 // auxInt is a 16-bit integer
auxInt32 // auxInt is a 32-bit integer
auxInt64 // auxInt is a 64-bit integer
auxFloat // auxInt is a float64 (encoded with math.Float64bits)
auxFloat32 // auxInt is a float32 (encoded with math.Float64bits)
auxFloat64 // auxInt is a float64 (encoded with math.Float64bits)
auxString // auxInt is a string
auxSym // aux is a symbol
auxSymOff // aux is a symbol, auxInt is an offset

8
src/cmd/compile/internal/ssa/opGen.go
View File

@ -748,7 +748,7 @@ var opcodeTable = [...]opInfo{
},
{
name: "MOVSSconst",
auxType: auxFloat,
auxType: auxFloat32,
argLen: 0,
rematerializeable: true,
asm: x86.AMOVSS,
@ -760,7 +760,7 @@ var opcodeTable = [...]opInfo{
},
{
name: "MOVSDconst",
auxType: auxFloat,
auxType: auxFloat64,
argLen: 0,
rematerializeable: true,
asm: x86.AMOVSD,
@ -4957,13 +4957,13 @@ var opcodeTable = [...]opInfo{
},
{
name: "Const32F",
auxType: auxFloat,
auxType: auxFloat32,
argLen: 0,
generic: true,
},
{
name: "Const64F",
auxType: auxFloat,
auxType: auxFloat64,
argLen: 0,
generic: true,
},

10
src/cmd/compile/internal/ssa/rewrite.go
View File

@ -192,6 +192,16 @@ func b2i(b bool) int64 {
return 0
}
// i2f is used in rules for converting from an AuxInt to a float.
func i2f(i int64) float64 {
return math.Float64frombits(uint64(i))
}
// i2f32 is used in rules for converting from an AuxInt to a float32.
func i2f32(i int64) float32 {
return float32(math.Float64frombits(uint64(i)))
}
// f2i is used in the rules for storing a float in AuxInt.
func f2i(f float64) int64 {
return int64(math.Float64bits(f))

224
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -12,8 +12,12 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
return rewriteValuegeneric_OpAdd16(v, config)
case OpAdd32:
return rewriteValuegeneric_OpAdd32(v, config)
case OpAdd32F:
return rewriteValuegeneric_OpAdd32F(v, config)
case OpAdd64:
return rewriteValuegeneric_OpAdd64(v, config)
case OpAdd64F:
return rewriteValuegeneric_OpAdd64F(v, config)
case OpAdd8:
return rewriteValuegeneric_OpAdd8(v, config)
case OpAnd16:
@ -48,6 +52,10 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
return rewriteValuegeneric_OpConstString(v, config)
case OpConvert:
return rewriteValuegeneric_OpConvert(v, config)
case OpCvt32Fto64F:
return rewriteValuegeneric_OpCvt32Fto64F(v, config)
case OpCvt64Fto32F:
return rewriteValuegeneric_OpCvt64Fto32F(v, config)
case OpDiv64:
return rewriteValuegeneric_OpDiv64(v, config)
case OpDiv64u:
@ -180,8 +188,12 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
return rewriteValuegeneric_OpMul16(v, config)
case OpMul32:
return rewriteValuegeneric_OpMul32(v, config)
case OpMul32F:
return rewriteValuegeneric_OpMul32F(v, config)
case OpMul64:
return rewriteValuegeneric_OpMul64(v, config)
case OpMul64F:
return rewriteValuegeneric_OpMul64F(v, config)
case OpMul8:
return rewriteValuegeneric_OpMul8(v, config)
case OpNeg16:
@ -304,8 +316,12 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
return rewriteValuegeneric_OpSub16(v, config)
case OpSub32:
return rewriteValuegeneric_OpSub32(v, config)
case OpSub32F:
return rewriteValuegeneric_OpSub32F(v, config)
case OpSub64:
return rewriteValuegeneric_OpSub64(v, config)
case OpSub64F:
return rewriteValuegeneric_OpSub64F(v, config)
case OpSub8:
return rewriteValuegeneric_OpSub8(v, config)
case OpTrunc16to8:
@ -445,6 +461,27 @@ func rewriteValuegeneric_OpAdd32(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpAdd32F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Add32F (Const32F [c]) (Const32F [d]))
// cond:
// result: (Const32F [f2i(float64(i2f32(c) + i2f32(d)))])
for {
if v.Args[0].Op != OpConst32F {
break
}
c := v.Args[0].AuxInt
if v.Args[1].Op != OpConst32F {
break
}
d := v.Args[1].AuxInt
v.reset(OpConst32F)
v.AuxInt = f2i(float64(i2f32(c) + i2f32(d)))
return true
}
return false
}
func rewriteValuegeneric_OpAdd64(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -502,6 +539,27 @@ func rewriteValuegeneric_OpAdd64(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpAdd64F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Add64F (Const64F [c]) (Const64F [d]))
// cond:
// result: (Const64F [f2i(i2f(c) + i2f(d))])
for {
if v.Args[0].Op != OpConst64F {
break
}
c := v.Args[0].AuxInt
if v.Args[1].Op != OpConst64F {
break
}
d := v.Args[1].AuxInt
v.reset(OpConst64F)
v.AuxInt = f2i(i2f(c) + i2f(d))
return true
}
return false
}
func rewriteValuegeneric_OpAdd8(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -1423,6 +1481,40 @@ func rewriteValuegeneric_OpConvert(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpCvt32Fto64F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Cvt32Fto64F (Const32F [c]))
// cond:
// result: (Const64F [c])
for {
if v.Args[0].Op != OpConst32F {
break
}
c := v.Args[0].AuxInt
v.reset(OpConst64F)
v.AuxInt = c
return true
}
return false
}
func rewriteValuegeneric_OpCvt64Fto32F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Cvt64Fto32F (Const64F [c]))
// cond:
// result: (Const32F [f2i(float64(i2f32(c)))])
for {
if v.Args[0].Op != OpConst64F {
break
}
c := v.Args[0].AuxInt
v.reset(OpConst32F)
v.AuxInt = f2i(float64(i2f32(c)))
return true
}
return false
}
func rewriteValuegeneric_OpDiv64(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -4248,6 +4340,27 @@ func rewriteValuegeneric_OpMul32(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpMul32F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Mul32F (Const32F [c]) (Const32F [d]))
// cond:
// result: (Const32F [f2i(float64(i2f32(c) * i2f32(d)))])
for {
if v.Args[0].Op != OpConst32F {
break
}
c := v.Args[0].AuxInt
if v.Args[1].Op != OpConst32F {
break
}
d := v.Args[1].AuxInt
v.reset(OpConst32F)
v.AuxInt = f2i(float64(i2f32(c) * i2f32(d)))
return true
}
return false
}
func rewriteValuegeneric_OpMul64(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -4338,6 +4451,27 @@ func rewriteValuegeneric_OpMul64(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpMul64F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Mul64F (Const64F [c]) (Const64F [d]))
// cond:
// result: (Const64F [f2i(i2f(c) * i2f(d))])
for {
if v.Args[0].Op != OpConst64F {
break
}
c := v.Args[0].AuxInt
if v.Args[1].Op != OpConst64F {
break
}
d := v.Args[1].AuxInt
v.reset(OpConst64F)
v.AuxInt = f2i(i2f(c) * i2f(d))
return true
}
return false
}
func rewriteValuegeneric_OpMul8(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -4396,18 +4530,6 @@ func rewriteValuegeneric_OpMul8(v *Value, config *Config) bool {
func rewriteValuegeneric_OpNeg16(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Neg16 (Const16 [c]))
// cond:
// result: (Const16 [-c])
for {
if v.Args[0].Op != OpConst16 {
break
}
c := v.Args[0].AuxInt
v.reset(OpConst16)
v.AuxInt = -c
return true
}
// match: (Neg16 (Sub16 x y))
// cond:
// result: (Sub16 y x)
@ -4427,18 +4549,6 @@ func rewriteValuegeneric_OpNeg16(v *Value, config *Config) bool {
func rewriteValuegeneric_OpNeg32(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Neg32 (Const32 [c]))
// cond:
// result: (Const32 [-c])
for {
if v.Args[0].Op != OpConst32 {
break
}
c := v.Args[0].AuxInt
v.reset(OpConst32)
v.AuxInt = -c
return true
}
// match: (Neg32 (Sub32 x y))
// cond:
// result: (Sub32 y x)
@ -4458,18 +4568,6 @@ func rewriteValuegeneric_OpNeg32(v *Value, config *Config) bool {
func rewriteValuegeneric_OpNeg64(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Neg64 (Const64 [c]))
// cond:
// result: (Const64 [-c])
for {
if v.Args[0].Op != OpConst64 {
break
}
c := v.Args[0].AuxInt
v.reset(OpConst64)
v.AuxInt = -c
return true
}
// match: (Neg64 (Sub64 x y))
// cond:
// result: (Sub64 y x)
@ -4489,18 +4587,6 @@ func rewriteValuegeneric_OpNeg64(v *Value, config *Config) bool {
func rewriteValuegeneric_OpNeg8(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Neg8 (Const8 [c]))
// cond:
// result: (Const8 [-c])
for {
if v.Args[0].Op != OpConst8 {
break
}
c := v.Args[0].AuxInt
v.reset(OpConst8)
v.AuxInt = -c
return true
}
// match: (Neg8 (Sub8 x y))
// cond:
// result: (Sub8 y x)
@ -7632,6 +7718,27 @@ func rewriteValuegeneric_OpSub32(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpSub32F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Sub32F (Const32F [c]) (Const32F [d]))
// cond:
// result: (Const32F [f2i(float64(i2f32(c) - i2f32(d)))])
for {
if v.Args[0].Op != OpConst32F {
break
}
c := v.Args[0].AuxInt
if v.Args[1].Op != OpConst32F {
break
}
d := v.Args[1].AuxInt
v.reset(OpConst32F)
v.AuxInt = f2i(float64(i2f32(c) - i2f32(d)))
return true
}
return false
}
func rewriteValuegeneric_OpSub64(v *Value, config *Config) bool {
b := v.Block
_ = b
@ -7719,6 +7826,27 @@ func rewriteValuegeneric_OpSub64(v *Value, config *Config) bool {
}
return false
}
func rewriteValuegeneric_OpSub64F(v *Value, config *Config) bool {
b := v.Block
_ = b
// match: (Sub64F (Const64F [c]) (Const64F [d]))
// cond:
// result: (Const64F [f2i(i2f(c) - i2f(d))])
for {
if v.Args[0].Op != OpConst64F {
break
}
c := v.Args[0].AuxInt
if v.Args[1].Op != OpConst64F {
break
}
d := v.Args[1].AuxInt
v.reset(OpConst64F)
v.AuxInt = f2i(i2f(c) - i2f(d))
return true
}
return false
}
func rewriteValuegeneric_OpSub8(v *Value, config *Config) bool {
b := v.Block
_ = b

4
src/cmd/compile/internal/ssa/value.go
View File

@ -97,7 +97,7 @@ func (v *Value) AuxInt2Int64() int64 {
}
func (v *Value) AuxFloat() float64 {
if opcodeTable[v.Op].auxType != auxFloat {
if opcodeTable[v.Op].auxType != auxFloat32 && opcodeTable[v.Op].auxType != auxFloat64 {
v.Fatalf("op %s doesn't have a float aux field", v.Op)
}
return math.Float64frombits(uint64(v.AuxInt))
@ -128,7 +128,7 @@ func (v *Value) LongString() string {
s += fmt.Sprintf(" [%d]", v.AuxInt32())
case auxInt64:
s += fmt.Sprintf(" [%d]", v.AuxInt)
case auxFloat:
case auxFloat32, auxFloat64:
s += fmt.Sprintf(" [%g]", v.AuxFloat())
case auxString:
s += fmt.Sprintf(" {%s}", v.Aux)