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cmd/compile: more negation related generic SSA rewrite rules

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The x + (-y) => x - y rule is hitted 75 times while building stage 3 and tools
and make the linux-amd64 go binary 0.007% smaller.
It transform:
  NEG AX
  ADD BX, AX
Into:
  SUB BX, AX
Which is 2X faster (assuming this assembly in a vacum).

The x ^ (-1) => ^x rule is not hitted in the toolchain.
It transforms:
  XOR $-1, AX
Into:
  NOT AX
Which is more compact as it doesn't encode the immediate.
Cache usage aside, this does not affect performance
(assuming this assembly in a vacum).
On my ryzen 3600, with some surrouding code, this randomly might be 2X faster,
I guess this has to do with loading the immediate into a temporary register.
Combined to an other rule that already exists it also rewrite manual two's
complement negation from:
  XOR $-1, AX
  INC AX
Into:
  NEG AX
Which is 2X faster.

The other rules just eliminates similar trivial cases and help constants
folding.

This should generalise to other architectures.

Change-Id: Ia1e51b340622e7ed88e5d856f3b1aa424aa039de
GitHub-Last-Rev: ce35ff2efd
GitHub-Pull-Request: golang/go#52395
Reviewed-on: https://go-review.googlesource.com/c/go/+/400714
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
This commit is contained in:
Jorropo 2022-04-18 17:46:43 +00:00 committed by Gopher Robot
parent aa8262d800
commit e858c14f91
2 changed files with 512 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/cmd/compile/internal/ssa/gen/generic.rules
View File

@ -515,15 +515,18 @@
// simplifications
(Or(64|32|16|8) x x) => x
(Or(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
(Or(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
(Or(64|32|16|8) (Const(64|32|16|8) [-1]) _) => (Const(64|32|16|8) [-1])
(Or(64|32|16|8) (Com(64|32|16|8) x) x) => (Const(64|32|16|8) [-1])
(And(64|32|16|8) x x) => x
(And(64|32|16|8) (Const(64|32|16|8) [-1]) x) => x
(And(64|32|16|8) (Const(64|32|16|8) [0]) _) => (Const(64|32|16|8) [0])
(And(64|32|16|8) (Const(64|32|16|8) [0]) _) => (Const(64|32|16|8) [0])
(And(64|32|16|8) (Com(64|32|16|8) x) x) => (Const(64|32|16|8) [0])
(Xor(64|32|16|8) x x) => (Const(64|32|16|8) [0])
(Xor(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
(Xor(64|32|16|8) (Com(64|32|16|8) x) x) => (Const(64|32|16|8) [-1])
(Add(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
(Sub(64|32|16|8) x x) => (Const(64|32|16|8) [0])
@ -533,6 +536,13 @@
(Com(64|32|16|8) (Const(64|32|16|8) [c])) => (Const(64|32|16|8) [^c])
(Neg(64|32|16|8) (Sub(64|32|16|8) x y)) => (Sub(64|32|16|8) y x)
(Add(64|32|16|8) x (Neg(64|32|16|8) y)) => (Sub(64|32|16|8) x y)
(Xor(64|32|16|8) (Const(64|32|16|8) [-1]) x) => (Com(64|32|16|8) x)
(Sub(64|32|16|8) (Neg(64|32|16|8) x) (Com(64|32|16|8) x)) => (Const(64|32|16|8) [1])
(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])
// ^(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)

500
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -519,6 +519,38 @@ func rewriteValuegeneric_OpAdd16(v *Value) bool {
}
break
}
// match: (Add16 x (Neg16 y))
// result: (Sub16 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
x := v_0
if v_1.Op != OpNeg16 {
continue
}
y := v_1.Args[0]
v.reset(OpSub16)
v.AddArg2(x, y)
return true
}
break
}
// match: (Add16 (Com16 x) x)
// result: (Const16 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom16 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst16)
v.AuxInt = int16ToAuxInt(-1)
return true
}
break
}
// match: (Add16 (Const16 [1]) (Com16 x))
// result: (Neg16 x)
for {
@ -764,6 +796,38 @@ func rewriteValuegeneric_OpAdd32(v *Value) bool {
}
break
}
// match: (Add32 x (Neg32 y))
// result: (Sub32 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
x := v_0
if v_1.Op != OpNeg32 {
continue
}
y := v_1.Args[0]
v.reset(OpSub32)
v.AddArg2(x, y)
return true
}
break
}
// match: (Add32 (Com32 x) x)
// result: (Const32 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom32 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(-1)
return true
}
break
}
// match: (Add32 (Const32 [1]) (Com32 x))
// result: (Neg32 x)
for {
@ -1036,6 +1100,38 @@ func rewriteValuegeneric_OpAdd64(v *Value) bool {
}
break
}
// match: (Add64 x (Neg64 y))
// result: (Sub64 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
x := v_0
if v_1.Op != OpNeg64 {
continue
}
y := v_1.Args[0]
v.reset(OpSub64)
v.AddArg2(x, y)
return true
}
break
}
// match: (Add64 (Com64 x) x)
// result: (Const64 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom64 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst64)
v.AuxInt = int64ToAuxInt(-1)
return true
}
break
}
// match: (Add64 (Const64 [1]) (Com64 x))
// result: (Neg64 x)
for {
@ -1308,6 +1404,38 @@ func rewriteValuegeneric_OpAdd8(v *Value) bool {
}
break
}
// match: (Add8 x (Neg8 y))
// result: (Sub8 x y)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
x := v_0
if v_1.Op != OpNeg8 {
continue
}
y := v_1.Args[0]
v.reset(OpSub8)
v.AddArg2(x, y)
return true
}
break
}
// match: (Add8 (Com8 x) x)
// result: (Const8 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom8 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst8)
v.AuxInt = int8ToAuxInt(-1)
return true
}
break
}
// match: (Add8 (Const8 [1]) (Com8 x))
// result: (Neg8 x)
for {
@ -1630,6 +1758,23 @@ func rewriteValuegeneric_OpAnd16(v *Value) bool {
}
break
}
// match: (And16 (Com16 x) x)
// result: (Const16 [0])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom16 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst16)
v.AuxInt = int16ToAuxInt(0)
return true
}
break
}
// match: (And16 x (And16 x y))
// result: (And16 x y)
for {
@ -1828,6 +1973,23 @@ func rewriteValuegeneric_OpAnd32(v *Value) bool {
}
break
}
// match: (And32 (Com32 x) x)
// result: (Const32 [0])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom32 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(0)
return true
}
break
}
// match: (And32 x (And32 x y))
// result: (And32 x y)
for {
@ -2026,6 +2188,23 @@ func rewriteValuegeneric_OpAnd64(v *Value) bool {
}
break
}
// match: (And64 (Com64 x) x)
// result: (Const64 [0])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom64 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst64)
v.AuxInt = int64ToAuxInt(0)
return true
}
break
}
// match: (And64 x (And64 x y))
// result: (And64 x y)
for {
@ -2224,6 +2403,23 @@ func rewriteValuegeneric_OpAnd8(v *Value) bool {
}
break
}
// match: (And8 (Com8 x) x)
// result: (Const8 [0])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom8 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst8)
v.AuxInt = int8ToAuxInt(0)
return true
}
break
}
// match: (And8 x (And8 x y))
// result: (And8 x y)
for {
@ -16964,6 +17160,23 @@ func rewriteValuegeneric_OpOr16(v *Value) bool {
}
break
}
// match: (Or16 (Com16 x) x)
// result: (Const16 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom16 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst16)
v.AuxInt = int16ToAuxInt(-1)
return true
}
break
}
// match: (Or16 x (Or16 x y))
// result: (Or16 x y)
for {
@ -17142,6 +17355,23 @@ func rewriteValuegeneric_OpOr32(v *Value) bool {
}
break
}
// match: (Or32 (Com32 x) x)
// result: (Const32 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom32 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(-1)
return true
}
break
}
// match: (Or32 x (Or32 x y))
// result: (Or32 x y)
for {
@ -17320,6 +17550,23 @@ func rewriteValuegeneric_OpOr64(v *Value) bool {
}
break
}
// match: (Or64 (Com64 x) x)
// result: (Const64 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom64 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst64)
v.AuxInt = int64ToAuxInt(-1)
return true
}
break
}
// match: (Or64 x (Or64 x y))
// result: (Or64 x y)
for {
@ -17498,6 +17745,23 @@ func rewriteValuegeneric_OpOr8(v *Value) bool {
}
break
}
// match: (Or8 (Com8 x) x)
// result: (Const8 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom8 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst8)
v.AuxInt = int8ToAuxInt(-1)
return true
}
break
}
// match: (Or8 x (Or8 x y))
// result: (Or8 x y)
for {
@ -22994,6 +23258,34 @@ func rewriteValuegeneric_OpSub16(v *Value) bool {
v.AuxInt = int16ToAuxInt(0)
return true
}
// match: (Sub16 (Neg16 x) (Com16 x))
// result: (Const16 [1])
for {
if v_0.Op != OpNeg16 {
break
}
x := v_0.Args[0]
if v_1.Op != OpCom16 || x != v_1.Args[0] {
break
}
v.reset(OpConst16)
v.AuxInt = int16ToAuxInt(1)
return true
}
// match: (Sub16 (Com16 x) (Neg16 x))
// result: (Const16 [-1])
for {
if v_0.Op != OpCom16 {
break
}
x := v_0.Args[0]
if v_1.Op != OpNeg16 || x != v_1.Args[0] {
break
}
v.reset(OpConst16)
v.AuxInt = int16ToAuxInt(-1)
return true
}
// match: (Sub16 (Add16 x y) x)
// result: y
for {
@ -23309,6 +23601,34 @@ func rewriteValuegeneric_OpSub32(v *Value) bool {
v.AuxInt = int32ToAuxInt(0)
return true
}
// match: (Sub32 (Neg32 x) (Com32 x))
// result: (Const32 [1])
for {
if v_0.Op != OpNeg32 {
break
}
x := v_0.Args[0]
if v_1.Op != OpCom32 || x != v_1.Args[0] {
break
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(1)
return true
}
// match: (Sub32 (Com32 x) (Neg32 x))
// result: (Const32 [-1])
for {
if v_0.Op != OpCom32 {
break
}
x := v_0.Args[0]
if v_1.Op != OpNeg32 || x != v_1.Args[0] {
break
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(-1)
return true
}
// match: (Sub32 (Add32 x y) x)
// result: y
for {
@ -23648,6 +23968,34 @@ func rewriteValuegeneric_OpSub64(v *Value) bool {
v.AuxInt = int64ToAuxInt(0)
return true
}
// match: (Sub64 (Neg64 x) (Com64 x))
// result: (Const64 [1])
for {
if v_0.Op != OpNeg64 {
break
}
x := v_0.Args[0]
if v_1.Op != OpCom64 || x != v_1.Args[0] {
break
}
v.reset(OpConst64)
v.AuxInt = int64ToAuxInt(1)
return true
}
// match: (Sub64 (Com64 x) (Neg64 x))
// result: (Const64 [-1])
for {
if v_0.Op != OpCom64 {
break
}
x := v_0.Args[0]
if v_1.Op != OpNeg64 || x != v_1.Args[0] {
break
}
v.reset(OpConst64)
v.AuxInt = int64ToAuxInt(-1)
return true
}
// match: (Sub64 (Add64 x y) x)
// result: y
for {
@ -23987,6 +24335,34 @@ func rewriteValuegeneric_OpSub8(v *Value) bool {
v.AuxInt = int8ToAuxInt(0)
return true
}
// match: (Sub8 (Neg8 x) (Com8 x))
// result: (Const8 [1])
for {
if v_0.Op != OpNeg8 {
break
}
x := v_0.Args[0]
if v_1.Op != OpCom8 || x != v_1.Args[0] {
break
}
v.reset(OpConst8)
v.AuxInt = int8ToAuxInt(1)
return true
}
// match: (Sub8 (Com8 x) (Neg8 x))
// result: (Const8 [-1])
for {
if v_0.Op != OpCom8 {
break
}
x := v_0.Args[0]
if v_1.Op != OpNeg8 || x != v_1.Args[0] {
break
}
v.reset(OpConst8)
v.AuxInt = int8ToAuxInt(-1)
return true
}
// match: (Sub8 (Add8 x y) x)
// result: y
for {
@ -24714,6 +25090,37 @@ func rewriteValuegeneric_OpXor16(v *Value) bool {
}
break
}
// match: (Xor16 (Com16 x) x)
// result: (Const16 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom16 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst16)
v.AuxInt = int16ToAuxInt(-1)
return true
}
break
}
// match: (Xor16 (Const16 [-1]) x)
// result: (Com16 x)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpConst16 || auxIntToInt16(v_0.AuxInt) != -1 {
continue
}
x := v_1
v.reset(OpCom16)
v.AddArg(x)
return true
}
break
}
// match: (Xor16 x (Xor16 x y))
// result: y
for {
@ -24845,6 +25252,37 @@ func rewriteValuegeneric_OpXor32(v *Value) bool {
}
break
}
// match: (Xor32 (Com32 x) x)
// result: (Const32 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom32 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst32)
v.AuxInt = int32ToAuxInt(-1)
return true
}
break
}
// match: (Xor32 (Const32 [-1]) x)
// result: (Com32 x)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpConst32 || auxIntToInt32(v_0.AuxInt) != -1 {
continue
}
x := v_1
v.reset(OpCom32)
v.AddArg(x)
return true
}
break
}
// match: (Xor32 x (Xor32 x y))
// result: y
for {
@ -24976,6 +25414,37 @@ func rewriteValuegeneric_OpXor64(v *Value) bool {
}
break
}
// match: (Xor64 (Com64 x) x)
// result: (Const64 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom64 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst64)
v.AuxInt = int64ToAuxInt(-1)
return true
}
break
}
// match: (Xor64 (Const64 [-1]) x)
// result: (Com64 x)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpConst64 || auxIntToInt64(v_0.AuxInt) != -1 {
continue
}
x := v_1
v.reset(OpCom64)
v.AddArg(x)
return true
}
break
}
// match: (Xor64 x (Xor64 x y))
// result: y
for {
@ -25107,6 +25576,37 @@ func rewriteValuegeneric_OpXor8(v *Value) bool {
}
break
}
// match: (Xor8 (Com8 x) x)
// result: (Const8 [-1])
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpCom8 {
continue
}
x := v_0.Args[0]
if x != v_1 {
continue
}
v.reset(OpConst8)
v.AuxInt = int8ToAuxInt(-1)
return true
}
break
}
// match: (Xor8 (Const8 [-1]) x)
// result: (Com8 x)
for {
for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
if v_0.Op != OpConst8 || auxIntToInt8(v_0.AuxInt) != -1 {
continue
}
x := v_1
v.reset(OpCom8)
v.AddArg(x)
return true
}
break
}
// match: (Xor8 x (Xor8 x y))
// result: y
for {