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[dev.ssa] cmd/compile: fix constant subtraction rules

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(SUBQconst [x] y) computes y-x, not x-y.

Fixes #12137

Change-Id: Idbd0554eee051102f562240d1756647843666ee6
Reviewed-on: https://go-review.googlesource.com/13631
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This commit is contained in:
Keith Randall 2015-08-13 12:47:50 -07:00
parent f85faefa67
commit 3b705824ce
3 changed files with 79 additions and 48 deletions
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31
src/cmd/compile/internal/gc/testdata/arith_ssa.go vendored
View File

@ -222,6 +222,36 @@ func testLrot() {
}
func sub1_ssa() uint64 {
switch {
} // prevent inlining
v1 := uint64(3) // uint64
return v1*v1 - (v1&v1)&v1
}
func sub2_ssa() uint8 {
switch {
}
v1 := uint8(0)
v3 := v1 + v1 + v1 ^ v1 | 3 + v1 ^ v1 | v1 ^ v1
v1-- // dev.ssa doesn't see this one
return v1 ^ v1*v1 - v3
}
func testSubConst() {
x1 := sub1_ssa()
want1 := uint64(6)
if x1 != want1 {
println("sub1_ssa()=", want1, ", got", x1)
failed = true
}
x2 := sub2_ssa()
want2 := uint8(251)
if x2 != want2 {
println("sub2_ssa()=", want2, ", got", x2)
failed = true
}
}
var failed = false
func main() {
@ -233,6 +263,7 @@ func main() {
testBitwiseLogic()
testOcom()
testLrot()
testSubConst()
if failed {
panic("failed")

16
src/cmd/compile/internal/ssa/gen/AMD64.rules
View File

@ -483,14 +483,14 @@
(ADDLconst [c] (ADDLconst [d] x)) -> (ADDLconst [c+d] x)
(ADDWconst [c] (ADDWconst [d] x)) -> (ADDWconst [c+d] x)
(ADDBconst [c] (ADDBconst [d] x)) -> (ADDBconst [c+d] x)
(SUBQconst [c] (MOVQconst [d])) -> (MOVQconst [c-d])
(SUBLconst [c] (MOVLconst [d])) -> (MOVLconst [c-d])
(SUBWconst [c] (MOVWconst [d])) -> (MOVWconst [c-d])
(SUBBconst [c] (MOVBconst [d])) -> (MOVBconst [c-d])
(SUBQconst [c] (SUBQconst [d] x)) -> (ADDQconst [c-d] x)
(SUBLconst [c] (SUBLconst [d] x)) -> (ADDLconst [c-d] x)
(SUBWconst [c] (SUBWconst [d] x)) -> (ADDWconst [c-d] x)
(SUBBconst [c] (SUBBconst [d] x)) -> (ADDBconst [c-d] x)
(SUBQconst [c] (MOVQconst [d])) -> (MOVQconst [d-c])
(SUBLconst [c] (MOVLconst [d])) -> (MOVLconst [d-c])
(SUBWconst [c] (MOVWconst [d])) -> (MOVWconst [d-c])
(SUBBconst [c] (MOVBconst [d])) -> (MOVBconst [d-c])
(SUBQconst [c] (SUBQconst [d] x)) -> (ADDQconst [-c-d] x)
(SUBLconst [c] (SUBLconst [d] x)) -> (ADDLconst [-c-d] x)
(SUBWconst [c] (SUBWconst [d] x)) -> (ADDWconst [-c-d] x)
(SUBBconst [c] (SUBBconst [d] x)) -> (ADDBconst [-c-d] x)
(NEGQ (MOVQconst [c])) -> (MOVQconst [-c])
(NEGL (MOVLconst [c])) -> (MOVLconst [-c])
(NEGW (MOVWconst [c])) -> (MOVWconst [-c])

80
src/cmd/compile/internal/ssa/rewriteAMD64.go
View File

@ -6801,30 +6801,30 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
case OpAMD64SUBBconst:
// match: (SUBBconst [c] (MOVBconst [d]))
// cond:
// result: (MOVBconst [c-d])
// result: (MOVBconst [d-c])
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64MOVBconst {
goto end0e2d5c3e3c02001a20d5433daa9e8317
goto enddc5383558e2f3eae507afcb94eada964
}
d := v.Args[0].AuxInt
v.Op = OpAMD64MOVBconst
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = d - c
return true
}
goto end0e2d5c3e3c02001a20d5433daa9e8317
end0e2d5c3e3c02001a20d5433daa9e8317:
goto enddc5383558e2f3eae507afcb94eada964
enddc5383558e2f3eae507afcb94eada964:
;
// match: (SUBBconst [c] (SUBBconst [d] x))
// cond:
// result: (ADDBconst [c-d] x)
// result: (ADDBconst [-c-d] x)
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64SUBBconst {
goto end48eccb421dfe0c678ea9c47113521d5a
goto end035c57413a46eb347ecb3736d1510915
}
d := v.Args[0].AuxInt
x := v.Args[0].Args[0]
@ -6832,12 +6832,12 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = -c - d
v.AddArg(x)
return true
}
goto end48eccb421dfe0c678ea9c47113521d5a
end48eccb421dfe0c678ea9c47113521d5a:
goto end035c57413a46eb347ecb3736d1510915
end035c57413a46eb347ecb3736d1510915:
;
case OpAMD64SUBL:
// match: (SUBL x (MOVLconst [c]))
@ -6904,30 +6904,30 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
case OpAMD64SUBLconst:
// match: (SUBLconst [c] (MOVLconst [d]))
// cond:
// result: (MOVLconst [c-d])
// result: (MOVLconst [d-c])
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64MOVLconst {
goto endbe7466f3c09d9645544bdfc44c37c922
goto end6c5c6d58d4bdd0a5c2f7bf10b343b41e
}
d := v.Args[0].AuxInt
v.Op = OpAMD64MOVLconst
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = d - c
return true
}
goto endbe7466f3c09d9645544bdfc44c37c922
endbe7466f3c09d9645544bdfc44c37c922:
goto end6c5c6d58d4bdd0a5c2f7bf10b343b41e
end6c5c6d58d4bdd0a5c2f7bf10b343b41e:
;
// match: (SUBLconst [c] (SUBLconst [d] x))
// cond:
// result: (ADDLconst [c-d] x)
// result: (ADDLconst [-c-d] x)
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64SUBLconst {
goto endb5106962a865bc4654b170c2e29a72c4
goto end0c9ffb11e8a56ced1b14dbf6bf9a6737
}
d := v.Args[0].AuxInt
x := v.Args[0].Args[0]
@ -6935,12 +6935,12 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = -c - d
v.AddArg(x)
return true
}
goto endb5106962a865bc4654b170c2e29a72c4
endb5106962a865bc4654b170c2e29a72c4:
goto end0c9ffb11e8a56ced1b14dbf6bf9a6737
end0c9ffb11e8a56ced1b14dbf6bf9a6737:
;
case OpAMD64SUBQ:
// match: (SUBQ x (MOVQconst [c]))
@ -7013,30 +7013,30 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
case OpAMD64SUBQconst:
// match: (SUBQconst [c] (MOVQconst [d]))
// cond:
// result: (MOVQconst [c-d])
// result: (MOVQconst [d-c])
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64MOVQconst {
goto end96c09479fb3c043e875d89d3eb92f1d8
goto endb0daebe6831cf381377c3e4248070f25
}
d := v.Args[0].AuxInt
v.Op = OpAMD64MOVQconst
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = d - c
return true
}
goto end96c09479fb3c043e875d89d3eb92f1d8
end96c09479fb3c043e875d89d3eb92f1d8:
goto endb0daebe6831cf381377c3e4248070f25
endb0daebe6831cf381377c3e4248070f25:
;
// match: (SUBQconst [c] (SUBQconst [d] x))
// cond:
// result: (ADDQconst [c-d] x)
// result: (ADDQconst [-c-d] x)
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64SUBQconst {
goto enddd9d61b404480adb40cfd7fedd7e5ec4
goto end2d40ddb5ae9e90679456254c61858d9d
}
d := v.Args[0].AuxInt
x := v.Args[0].Args[0]
@ -7044,12 +7044,12 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = -c - d
v.AddArg(x)
return true
}
goto enddd9d61b404480adb40cfd7fedd7e5ec4
enddd9d61b404480adb40cfd7fedd7e5ec4:
goto end2d40ddb5ae9e90679456254c61858d9d
end2d40ddb5ae9e90679456254c61858d9d:
;
case OpAMD64SUBW:
// match: (SUBW x (MOVWconst [c]))
@ -7116,30 +7116,30 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
case OpAMD64SUBWconst:
// match: (SUBWconst [c] (MOVWconst [d]))
// cond:
// result: (MOVWconst [c-d])
// result: (MOVWconst [d-c])
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64MOVWconst {
goto end0e5079577fcf00f5925291dbd68306aa
goto endae629a229c399eaed7dbb95b1b0e6f8a
}
d := v.Args[0].AuxInt
v.Op = OpAMD64MOVWconst
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = d - c
return true
}
goto end0e5079577fcf00f5925291dbd68306aa
end0e5079577fcf00f5925291dbd68306aa:
goto endae629a229c399eaed7dbb95b1b0e6f8a
endae629a229c399eaed7dbb95b1b0e6f8a:
;
// match: (SUBWconst [c] (SUBWconst [d] x))
// cond:
// result: (ADDWconst [c-d] x)
// result: (ADDWconst [-c-d] x)
{
c := v.AuxInt
if v.Args[0].Op != OpAMD64SUBWconst {
goto endb628696cf5b329d03782b8093093269b
goto enda59f08d12aa08717b0443b7bb1b71374
}
d := v.Args[0].AuxInt
x := v.Args[0].Args[0]
@ -7147,12 +7147,12 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
v.AuxInt = 0
v.Aux = nil
v.resetArgs()
v.AuxInt = c - d
v.AuxInt = -c - d
v.AddArg(x)
return true
}
goto endb628696cf5b329d03782b8093093269b
endb628696cf5b329d03782b8093093269b:
goto enda59f08d12aa08717b0443b7bb1b71374
enda59f08d12aa08717b0443b7bb1b71374:
;
case OpSignExt16to32:
// match: (SignExt16to32 x)