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cmd/compile: rewrite >>c<<c to &^(1<<c-1) 

Fixes #54496

Change-Id: I3c2ed8cd55836d5b07c8cdec00d3b584885aca79
Reviewed-on: https://go-review.googlesource.com/c/go/+/424856
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Martin Möhrmann <martin@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Martin Möhrmann <martin@golang.org>
This commit is contained in:
Keith Randall 2022-08-17 13:09:12 -07:00
parent 34f0029a85
commit 5b1fbfba1c
3 changed files with 308 additions and 0 deletions
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11
src/cmd/compile/internal/ssa/gen/generic.rules
View File

@ -443,6 +443,17 @@
(Rsh32Ux64 (Rsh32x64 x _) (Const64 <t> [31])) => (Rsh32Ux64 x (Const64 <t> [31]))
(Rsh64Ux64 (Rsh64x64 x _) (Const64 <t> [63])) => (Rsh64Ux64 x (Const64 <t> [63]))
// Convert x>>c<<c to x&^(1<<c-1)
(Lsh64x64 i:(Rsh(64|64U)x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(-1) << c]))
(Lsh32x64 i:(Rsh(32|32U)x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(-1) << c]))
(Lsh16x64 i:(Rsh(16|16U)x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(-1) << c]))
(Lsh8x64 i:(Rsh(8|8U)x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8 && i.Uses == 1 => (And8 x (Const8 <v.Type> [int8(-1) << c]))
// similarly for x<<c>>c
(Rsh64Ux64 i:(Lsh64x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(^uint64(0)>>c)]))
(Rsh32Ux64 i:(Lsh32x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(^uint32(0)>>c)]))
(Rsh16Ux64 i:(Lsh16x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(^uint16(0)>>c)]))
(Rsh8Ux64 i:(Lsh8x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8 && i.Uses == 1 => (And8 x (Const8 <v.Type> [int8 (^uint8 (0)>>c)]))
// ((x >> c1) << c2) >> c3
(Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
&& uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)

288
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -12792,6 +12792,54 @@ func rewriteValuegeneric_OpLsh16x64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Lsh16x64 i:(Rsh16x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 16 && i.Uses == 1
// result: (And16 x (Const16 <v.Type> [int16(-1) << c]))
for {
i := v_0
if i.Op != OpRsh16x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 16 && i.Uses == 1) {
break
}
v.reset(OpAnd16)
v0 := b.NewValue0(v.Pos, OpConst16, v.Type)
v0.AuxInt = int16ToAuxInt(int16(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh16x64 i:(Rsh16Ux64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 16 && i.Uses == 1
// result: (And16 x (Const16 <v.Type> [int16(-1) << c]))
for {
i := v_0
if i.Op != OpRsh16Ux64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 16 && i.Uses == 1) {
break
}
v.reset(OpAnd16)
v0 := b.NewValue0(v.Pos, OpConst16, v.Type)
v0.AuxInt = int16ToAuxInt(int16(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh16x64 (Rsh16Ux64 (Lsh16x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Lsh16x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -13007,6 +13055,54 @@ func rewriteValuegeneric_OpLsh32x64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Lsh32x64 i:(Rsh32x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 32 && i.Uses == 1
// result: (And32 x (Const32 <v.Type> [int32(-1) << c]))
for {
i := v_0
if i.Op != OpRsh32x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 32 && i.Uses == 1) {
break
}
v.reset(OpAnd32)
v0 := b.NewValue0(v.Pos, OpConst32, v.Type)
v0.AuxInt = int32ToAuxInt(int32(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh32x64 i:(Rsh32Ux64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 32 && i.Uses == 1
// result: (And32 x (Const32 <v.Type> [int32(-1) << c]))
for {
i := v_0
if i.Op != OpRsh32Ux64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 32 && i.Uses == 1) {
break
}
v.reset(OpAnd32)
v0 := b.NewValue0(v.Pos, OpConst32, v.Type)
v0.AuxInt = int32ToAuxInt(int32(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh32x64 (Rsh32Ux64 (Lsh32x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Lsh32x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -13222,6 +13318,54 @@ func rewriteValuegeneric_OpLsh64x64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Lsh64x64 i:(Rsh64x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 64 && i.Uses == 1
// result: (And64 x (Const64 <v.Type> [int64(-1) << c]))
for {
i := v_0
if i.Op != OpRsh64x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 64 && i.Uses == 1) {
break
}
v.reset(OpAnd64)
v0 := b.NewValue0(v.Pos, OpConst64, v.Type)
v0.AuxInt = int64ToAuxInt(int64(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh64x64 i:(Rsh64Ux64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 64 && i.Uses == 1
// result: (And64 x (Const64 <v.Type> [int64(-1) << c]))
for {
i := v_0
if i.Op != OpRsh64Ux64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 64 && i.Uses == 1) {
break
}
v.reset(OpAnd64)
v0 := b.NewValue0(v.Pos, OpConst64, v.Type)
v0.AuxInt = int64ToAuxInt(int64(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh64x64 (Rsh64Ux64 (Lsh64x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Lsh64x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -13437,6 +13581,54 @@ func rewriteValuegeneric_OpLsh8x64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Lsh8x64 i:(Rsh8x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 8 && i.Uses == 1
// result: (And8 x (Const8 <v.Type> [int8(-1) << c]))
for {
i := v_0
if i.Op != OpRsh8x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 8 && i.Uses == 1) {
break
}
v.reset(OpAnd8)
v0 := b.NewValue0(v.Pos, OpConst8, v.Type)
v0.AuxInt = int8ToAuxInt(int8(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh8x64 i:(Rsh8Ux64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 8 && i.Uses == 1
// result: (And8 x (Const8 <v.Type> [int8(-1) << c]))
for {
i := v_0
if i.Op != OpRsh8Ux64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 8 && i.Uses == 1) {
break
}
v.reset(OpAnd8)
v0 := b.NewValue0(v.Pos, OpConst8, v.Type)
v0.AuxInt = int8ToAuxInt(int8(-1) << c)
v.AddArg2(x, v0)
return true
}
// match: (Lsh8x64 (Rsh8Ux64 (Lsh8x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Lsh8x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -24225,6 +24417,30 @@ func rewriteValuegeneric_OpRsh16Ux64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Rsh16Ux64 i:(Lsh16x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 16 && i.Uses == 1
// result: (And16 x (Const16 <v.Type> [int16(^uint16(0)>>c)]))
for {
i := v_0
if i.Op != OpLsh16x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 16 && i.Uses == 1) {
break
}
v.reset(OpAnd16)
v0 := b.NewValue0(v.Pos, OpConst16, v.Type)
v0.AuxInt = int16ToAuxInt(int16(^uint16(0) >> c))
v.AddArg2(x, v0)
return true
}
// match: (Rsh16Ux64 (Lsh16x64 (Rsh16Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Rsh16Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -24659,6 +24875,30 @@ func rewriteValuegeneric_OpRsh32Ux64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Rsh32Ux64 i:(Lsh32x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 32 && i.Uses == 1
// result: (And32 x (Const32 <v.Type> [int32(^uint32(0)>>c)]))
for {
i := v_0
if i.Op != OpLsh32x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 32 && i.Uses == 1) {
break
}
v.reset(OpAnd32)
v0 := b.NewValue0(v.Pos, OpConst32, v.Type)
v0.AuxInt = int32ToAuxInt(int32(^uint32(0) >> c))
v.AddArg2(x, v0)
return true
}
// match: (Rsh32Ux64 (Lsh32x64 (Rsh32Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Rsh32Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -25129,6 +25369,30 @@ func rewriteValuegeneric_OpRsh64Ux64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Rsh64Ux64 i:(Lsh64x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 64 && i.Uses == 1
// result: (And64 x (Const64 <v.Type> [int64(^uint64(0)>>c)]))
for {
i := v_0
if i.Op != OpLsh64x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 64 && i.Uses == 1) {
break
}
v.reset(OpAnd64)
v0 := b.NewValue0(v.Pos, OpConst64, v.Type)
v0.AuxInt = int64ToAuxInt(int64(^uint64(0) >> c))
v.AddArg2(x, v0)
return true
}
// match: (Rsh64Ux64 (Lsh64x64 (Rsh64Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Rsh64Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))
@ -25635,6 +25899,30 @@ func rewriteValuegeneric_OpRsh8Ux64(v *Value) bool {
v.AddArg2(x, v0)
return true
}
// match: (Rsh8Ux64 i:(Lsh8x64 x (Const64 [c])) (Const64 [c]))
// cond: c >= 0 && c < 8 && i.Uses == 1
// result: (And8 x (Const8 <v.Type> [int8 (^uint8 (0)>>c)]))
for {
i := v_0
if i.Op != OpLsh8x64 {
break
}
_ = i.Args[1]
x := i.Args[0]
i_1 := i.Args[1]
if i_1.Op != OpConst64 {
break
}
c := auxIntToInt64(i_1.AuxInt)
if v_1.Op != OpConst64 || auxIntToInt64(v_1.AuxInt) != c || !(c >= 0 && c < 8 && i.Uses == 1) {
break
}
v.reset(OpAnd8)
v0 := b.NewValue0(v.Pos, OpConst8, v.Type)
v0.AuxInt = int8ToAuxInt(int8(^uint8(0) >> c))
v.AddArg2(x, v0)
return true
}
// match: (Rsh8Ux64 (Lsh8x64 (Rsh8Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
// cond: uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
// result: (Rsh8Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))

9
test/codegen/shift.go
View File

@ -392,3 +392,12 @@ func check128bitShifts(x, y uint64, bits uint) (uint64, uint64) {
shl := x<<s | y>>ŝ
return shr, shl
}
func checkShiftToMask(u []uint64, s []int64) {
// amd64:-"SHR",-"SHL","ANDQ"
u[0] = u[0] >> 5 << 5
// amd64:-"SAR",-"SHL","ANDQ"
s[0] = s[0] >> 5 << 5
// amd64:-"SHR",-"SHL","ANDQ"
u[1] = u[1] << 5 >> 5
}