[dev.ssa] cmd/compile: some SSA optimizations
Some optimizations of things I've seen looking at generated code.
(x+y)-x == y
x-0 == x
The ptr portion of the constant string "" can be nil.
Also update TODO with recent changes.
Change-Id: I02c41ca2f9e9e178bf889058d3e083b446672dbe
Reviewed-on: https://go-review.googlesource.com/16771
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index c349603..174967a 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -818,12 +818,60 @@
b := v.Block
_ = b
// match: (ConstString {s})
- // cond: config.PtrSize == 4
+ // cond: config.PtrSize == 4 && s.(string) == ""
+ // result: (StringMake (ConstNil) (Const32 <config.fe.TypeInt()> [0]))
+ {
+ s := v.Aux
+ if !(config.PtrSize == 4 && s.(string) == "") {
+ goto end85d5f388ba947643af63cdc68c1155a5
+ }
+ v.Op = OpStringMake
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v0 := b.NewValue0(v.Line, OpConstNil, TypeInvalid)
+ v0.Type = config.fe.TypeBytePtr()
+ v.AddArg(v0)
+ v1 := b.NewValue0(v.Line, OpConst32, TypeInvalid)
+ v1.Type = config.fe.TypeInt()
+ v1.AuxInt = 0
+ v.AddArg(v1)
+ return true
+ }
+ goto end85d5f388ba947643af63cdc68c1155a5
+end85d5f388ba947643af63cdc68c1155a5:
+ ;
+ // match: (ConstString {s})
+ // cond: config.PtrSize == 8 && s.(string) == ""
+ // result: (StringMake (ConstNil) (Const64 <config.fe.TypeInt()> [0]))
+ {
+ s := v.Aux
+ if !(config.PtrSize == 8 && s.(string) == "") {
+ goto endc807259a5ed2760fbbd3dc7386641343
+ }
+ v.Op = OpStringMake
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v0 := b.NewValue0(v.Line, OpConstNil, TypeInvalid)
+ v0.Type = config.fe.TypeBytePtr()
+ v.AddArg(v0)
+ v1 := b.NewValue0(v.Line, OpConst64, TypeInvalid)
+ v1.Type = config.fe.TypeInt()
+ v1.AuxInt = 0
+ v.AddArg(v1)
+ return true
+ }
+ goto endc807259a5ed2760fbbd3dc7386641343
+endc807259a5ed2760fbbd3dc7386641343:
+ ;
+ // match: (ConstString {s})
+ // cond: config.PtrSize == 4 && s.(string) != ""
// result: (StringMake (Addr <config.fe.TypeBytePtr()> {config.fe.StringData(s.(string))} (SB)) (Const32 <config.fe.TypeInt()> [int64(len(s.(string)))]))
{
s := v.Aux
- if !(config.PtrSize == 4) {
- goto endaa2b20a40588873f370c5a12f084505a
+ if !(config.PtrSize == 4 && s.(string) != "") {
+ goto end107a700a4519d18f418602421444ddb6
}
v.Op = OpStringMake
v.AuxInt = 0
@@ -842,16 +890,16 @@
v.AddArg(v2)
return true
}
- goto endaa2b20a40588873f370c5a12f084505a
-endaa2b20a40588873f370c5a12f084505a:
+ goto end107a700a4519d18f418602421444ddb6
+end107a700a4519d18f418602421444ddb6:
;
// match: (ConstString {s})
- // cond: config.PtrSize == 8
+ // cond: config.PtrSize == 8 && s.(string) != ""
// result: (StringMake (Addr <config.fe.TypeBytePtr()> {config.fe.StringData(s.(string))} (SB)) (Const64 <config.fe.TypeInt()> [int64(len(s.(string)))]))
{
s := v.Aux
- if !(config.PtrSize == 8) {
- goto endab37d89f3959d3cf1e71b57a3c61b8eb
+ if !(config.PtrSize == 8 && s.(string) != "") {
+ goto end7ce9db29d17866f26d21e6e12f442e54
}
v.Op = OpStringMake
v.AuxInt = 0
@@ -870,8 +918,8 @@
v.AddArg(v2)
return true
}
- goto endab37d89f3959d3cf1e71b57a3c61b8eb
-endab37d89f3959d3cf1e71b57a3c61b8eb:
+ goto end7ce9db29d17866f26d21e6e12f442e54
+end7ce9db29d17866f26d21e6e12f442e54:
;
return false
}
@@ -3384,6 +3432,52 @@
goto end83da541391be564f2a08464e674a49e7
end83da541391be564f2a08464e674a49e7:
;
+ // match: (Sub16 (Add16 x y) x)
+ // cond:
+ // result: y
+ {
+ if v.Args[0].Op != OpAdd16 {
+ goto end0dd8f250c457b9c005ecbed59fc2e758
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != x {
+ goto end0dd8f250c457b9c005ecbed59fc2e758
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = y.Type
+ v.AddArg(y)
+ return true
+ }
+ goto end0dd8f250c457b9c005ecbed59fc2e758
+end0dd8f250c457b9c005ecbed59fc2e758:
+ ;
+ // match: (Sub16 (Add16 x y) y)
+ // cond:
+ // result: x
+ {
+ if v.Args[0].Op != OpAdd16 {
+ goto end01c8db2e0bce69e048cf79f3bdc82b9b
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != y {
+ goto end01c8db2e0bce69e048cf79f3bdc82b9b
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = x.Type
+ v.AddArg(x)
+ return true
+ }
+ goto end01c8db2e0bce69e048cf79f3bdc82b9b
+end01c8db2e0bce69e048cf79f3bdc82b9b:
+ ;
return false
}
func rewriteValuegeneric_OpSub32(v *Value, config *Config) bool {
@@ -3429,6 +3523,52 @@
goto enda747581e798f199e07f4ad69747cd069
enda747581e798f199e07f4ad69747cd069:
;
+ // match: (Sub32 (Add32 x y) x)
+ // cond:
+ // result: y
+ {
+ if v.Args[0].Op != OpAdd32 {
+ goto end70c1e60e58a6c106d060f10cd3f179ea
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != x {
+ goto end70c1e60e58a6c106d060f10cd3f179ea
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = y.Type
+ v.AddArg(y)
+ return true
+ }
+ goto end70c1e60e58a6c106d060f10cd3f179ea
+end70c1e60e58a6c106d060f10cd3f179ea:
+ ;
+ // match: (Sub32 (Add32 x y) y)
+ // cond:
+ // result: x
+ {
+ if v.Args[0].Op != OpAdd32 {
+ goto end20e42db178ec4f423cc56a991863a4a2
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != y {
+ goto end20e42db178ec4f423cc56a991863a4a2
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = x.Type
+ v.AddArg(x)
+ return true
+ }
+ goto end20e42db178ec4f423cc56a991863a4a2
+end20e42db178ec4f423cc56a991863a4a2:
+ ;
return false
}
func rewriteValuegeneric_OpSub64(v *Value, config *Config) bool {
@@ -3474,6 +3614,52 @@
goto end0387dc2b7bbe57d4aa54eab5d959da4b
end0387dc2b7bbe57d4aa54eab5d959da4b:
;
+ // match: (Sub64 (Add64 x y) x)
+ // cond:
+ // result: y
+ {
+ if v.Args[0].Op != OpAdd64 {
+ goto end7d177451cf8959cb781f52d5ded46fff
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != x {
+ goto end7d177451cf8959cb781f52d5ded46fff
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = y.Type
+ v.AddArg(y)
+ return true
+ }
+ goto end7d177451cf8959cb781f52d5ded46fff
+end7d177451cf8959cb781f52d5ded46fff:
+ ;
+ // match: (Sub64 (Add64 x y) y)
+ // cond:
+ // result: x
+ {
+ if v.Args[0].Op != OpAdd64 {
+ goto end6ea8172b21100cfe3dc86b7a850fbe97
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != y {
+ goto end6ea8172b21100cfe3dc86b7a850fbe97
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = x.Type
+ v.AddArg(x)
+ return true
+ }
+ goto end6ea8172b21100cfe3dc86b7a850fbe97
+end6ea8172b21100cfe3dc86b7a850fbe97:
+ ;
return false
}
func rewriteValuegeneric_OpSub8(v *Value, config *Config) bool {
@@ -3519,6 +3705,52 @@
goto end4e2ee15ef17611919a1a6b5f80bbfe18
end4e2ee15ef17611919a1a6b5f80bbfe18:
;
+ // match: (Sub8 (Add8 x y) x)
+ // cond:
+ // result: y
+ {
+ if v.Args[0].Op != OpAdd8 {
+ goto endd79d561e14dc3d11da4c3bb20270b541
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != x {
+ goto endd79d561e14dc3d11da4c3bb20270b541
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = y.Type
+ v.AddArg(y)
+ return true
+ }
+ goto endd79d561e14dc3d11da4c3bb20270b541
+endd79d561e14dc3d11da4c3bb20270b541:
+ ;
+ // match: (Sub8 (Add8 x y) y)
+ // cond:
+ // result: x
+ {
+ if v.Args[0].Op != OpAdd8 {
+ goto endcb7111b11d6d068c97026a97ecff8248
+ }
+ x := v.Args[0].Args[0]
+ y := v.Args[0].Args[1]
+ if v.Args[1] != y {
+ goto endcb7111b11d6d068c97026a97ecff8248
+ }
+ v.Op = OpCopy
+ v.AuxInt = 0
+ v.Aux = nil
+ v.resetArgs()
+ v.Type = x.Type
+ v.AddArg(x)
+ return true
+ }
+ goto endcb7111b11d6d068c97026a97ecff8248
+endcb7111b11d6d068c97026a97ecff8248:
+ ;
return false
}
func rewriteValuegeneric_OpXor16(v *Value, config *Config) bool {
