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cmd/compile: add rewrite rules for arithmetic operations

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Add the following common local transformations

(t + x) - (t + y) == x - y
(t + x) - (y + t) == x - y
(x + t) - (y + t) == x - y
(x + t) - (t + y) == x - y
(x - t) + (t + y) == x + y
(x - t) + (y + t) == x + y

The compiler itself matches such patterns many times. This also aligns with other popular compilers.

Fixes #59111
This commit is contained in:
Yi Yang 2023-03-18 22:44:03 +08:00 committed by Yi Yang
parent 20e9b7f1b5
commit 1aad82e62e
3 changed files with 254 additions and 0 deletions
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10
src/cmd/compile/internal/ssa/_gen/generic.rules
View File

@ -573,6 +573,16 @@
(Sub(64|32|16|8) (Com(64|32|16|8) x) (Neg(64|32|16|8) x)) => (Const(64|32|16|8) [-1])
(Add(64|32|16|8) (Com(64|32|16|8) x) x) => (Const(64|32|16|8) [-1])
// Simplification when involving common integer
// (t + x) - (t + y) == x - y
// (t + x) - (y + t) == x - y
// (x + t) - (y + t) == x - y
// (x + t) - (t + y) == x - y
// (x - t) + (t + y) == x + y
// (x - t) + (y + t) == x + y
(Sub(64|32|16|8) (Add(64|32|16|8) t x) (Add(64|32|16|8) t y)) => (Sub(64|32|16|8) x y)
(Add(64|32|16|8) (Sub(64|32|16|8) x t) (Add(64|32|16|8) t y)) => (Add(64|32|16|8) x y)
// ^(x-1) == ^x+1 == -x
(Add(64|32|16|8) (Const(64|32|16|8) [1]) (Com(64|32|16|8) x)) => (Neg(64|32|16|8) x)
(Com(64|32|16|8) (Add(64|32|16|8) (Const(64|32|16|8) [-1]) x)) => (Neg(64|32|16|8) x)

228
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -560,6 +560,33 @@ func rewriteValuegeneric_OpAdd16(v *Value) bool {
}
break
}
// match: (Add16 (Sub16 x t) (Add16 t y))
// result: (Add16 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpSub16 {
continue
}
t := v_0.Args[1]
x := v_0.Args[0]
if v_1.Op != OpAdd16 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpAdd16)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Add16 (Const16 [1]) (Com16 x))
// result: (Neg16 x)
for {
@ -1146,6 +1173,33 @@ func rewriteValuegeneric_OpAdd32(v *Value) bool {
}
break
}
// match: (Add32 (Sub32 x t) (Add32 t y))
// result: (Add32 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpSub32 {
continue
}
t := v_0.Args[1]
x := v_0.Args[0]
if v_1.Op != OpAdd32 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpAdd32)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Add32 (Const32 [1]) (Com32 x))
// result: (Neg32 x)
for {
@ -1759,6 +1813,33 @@ func rewriteValuegeneric_OpAdd64(v *Value) bool {
}
break
}
// match: (Add64 (Sub64 x t) (Add64 t y))
// result: (Add64 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpSub64 {
continue
}
t := v_0.Args[1]
x := v_0.Args[0]
if v_1.Op != OpAdd64 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpAdd64)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Add64 (Const64 [1]) (Com64 x))
// result: (Neg64 x)
for {
@ -2372,6 +2453,33 @@ func rewriteValuegeneric_OpAdd8(v *Value) bool {
}
break
}
// match: (Add8 (Sub8 x t) (Add8 t y))
// result: (Add8 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpSub8 {
continue
}
t := v_0.Args[1]
x := v_0.Args[0]
if v_1.Op != OpAdd8 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpAdd8)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Add8 (Const8 [1]) (Com8 x))
// result: (Neg8 x)
for {
@ -28976,6 +29084,36 @@ func rewriteValuegeneric_OpSub16(v *Value) bool {
v.AuxInt = int16ToAuxInt(-1)
return true
}
// match: (Sub16 (Add16 t x) (Add16 t y))
// result: (Sub16 x y)
for {
if v_0.Op != OpAdd16 {
break
}
_ = v_0.Args[1]
v_0_0 := v_0.Args[0]
v_0_1 := v_0.Args[1]
for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
t := v_0_0
x := v_0_1
if v_1.Op != OpAdd16 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpSub16)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Sub16 (Add16 x y) x)
// result: y
for {
@ -29319,6 +29457,36 @@ func rewriteValuegeneric_OpSub32(v *Value) bool {
v.AuxInt = int32ToAuxInt(-1)
return true
}
// match: (Sub32 (Add32 t x) (Add32 t y))
// result: (Sub32 x y)
for {
if v_0.Op != OpAdd32 {
break
}
_ = v_0.Args[1]
v_0_0 := v_0.Args[0]
v_0_1 := v_0.Args[1]
for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
t := v_0_0
x := v_0_1
if v_1.Op != OpAdd32 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpSub32)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Sub32 (Add32 x y) x)
// result: y
for {
@ -29686,6 +29854,36 @@ func rewriteValuegeneric_OpSub64(v *Value) bool {
v.AuxInt = int64ToAuxInt(-1)
return true
}
// match: (Sub64 (Add64 t x) (Add64 t y))
// result: (Sub64 x y)
for {
if v_0.Op != OpAdd64 {
break
}
_ = v_0.Args[1]
v_0_0 := v_0.Args[0]
v_0_1 := v_0.Args[1]
for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
t := v_0_0
x := v_0_1
if v_1.Op != OpAdd64 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpSub64)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Sub64 (Add64 x y) x)
// result: y
for {
@ -30053,6 +30251,36 @@ func rewriteValuegeneric_OpSub8(v *Value) bool {
v.AuxInt = int8ToAuxInt(-1)
return true
}
// match: (Sub8 (Add8 t x) (Add8 t y))
// result: (Sub8 x y)
for {
if v_0.Op != OpAdd8 {
break
}
_ = v_0.Args[1]
v_0_0 := v_0.Args[0]
v_0_1 := v_0.Args[1]
for _i0 := 0; _i0 <= 1; _i0, v_0_0, v_0_1 = _i0+1, v_0_1, v_0_0 {
t := v_0_0
x := v_0_1
if v_1.Op != OpAdd8 {
continue
}
_ = v_1.Args[1]
v_1_0 := v_1.Args[0]
v_1_1 := v_1.Args[1]
for _i1 := 0; _i1 <= 1; _i1, v_1_0, v_1_1 = _i1+1, v_1_1, v_1_0 {
if t != v_1_0 {
continue
}
y := v_1_1
v.reset(OpSub8)
v.AddArg2(x, y)
return true
}
}
break
}
// match: (Sub8 (Add8 x y) x)
// result: y
for {

16
test/codegen/arithmetic.go
View File

@ -92,6 +92,22 @@ func SubAddSimplify(a, b int) int {
return r
}
func SubAddSimplify2(a, b, c int) (int, int, int, int, int, int) {
// amd64:-"ADDQ"
r := (a + b) - (a + c)
// amd64:-"ADDQ"
r1 := (a + b) - (c + a)
// amd64:-"ADDQ"
r2 := (b + a) - (a + c)
// amd64:-"ADDQ"
r3 := (b + a) - (c + a)
// amd64:-"SUBQ"
r4 := (a - c) + (c + b)
// amd64:-"SUBQ"
r5 := (a - c) + (b + c)
return r, r1, r2, r3, r4, r5
}
func SubAddNegSimplify(a, b int) int {
// amd64:"NEGQ",-"ADDQ",-"SUBQ"
// ppc64x:"NEG",-"ADD",-"SUB"