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Commit 098208a0 authored by Giovanni Bajo's avatar Giovanni Bajo
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cmd/compile: fold bit masking on bits that have been shifted away 

Spotted while working on #18943, it triggers once during bootstrap.

Change-Id: Ia4330ccc6395627c233a8eb4dcc0e3e2a770bea7
Reviewed-on: https://go-review.googlesource.com/94764Reviewed-by: default avatarKeith Randall <khr@golang.org>
parent ecd9e8a2
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Inline Side-by-side
Showing with 487 additions and 28 deletions
src/cmd/compile/internal/ssa/gen/generic.rules
View file @ 098208a0
......@@ -396,6 +396,18 @@
&& uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
-> (Lsh(64|32|16|8)x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
// (x >> c) & uppermask = 0
(And64 (Const64 [m]) (Rsh64Ux64 _ (Const64 [c]))) && c >= 64-ntz(m) -> (Const64 [0])
(And32 (Const32 [m]) (Rsh32Ux64 _ (Const64 [c]))) && c >= 64-ntz(m) -> (Const32 [0])
(And16 (Const16 [m]) (Rsh16Ux64 _ (Const64 [c]))) && c >= 64-ntz(m) -> (Const16 [0])
(And8 (Const8 [m]) (Rsh8Ux64 _ (Const64 [c]))) && c >= 64-ntz(m) -> (Const8 [0])
// (x << c) & lowermask = 0
(And64 (Const64 [m]) (Lsh64x64 _ (Const64 [c]))) && c >= 64-nlz(m) -> (Const64 [0])
(And32 (Const32 [m]) (Lsh32x64 _ (Const64 [c]))) && c >= 64-nlz(m) -> (Const32 [0])
(And16 (Const16 [m]) (Lsh16x64 _ (Const64 [c]))) && c >= 64-nlz(m) -> (Const16 [0])
(And8 (Const8 [m]) (Lsh8x64 _ (Const64 [c]))) && c >= 64-nlz(m) -> (Const8 [0])
// replace shifts with zero extensions
(Rsh16Ux64 (Lsh16x64 x (Const64 [8])) (Const64 [8])) -> (ZeroExt8to16 (Trunc16to8 <typ.UInt8> x))
(Rsh32Ux64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) -> (ZeroExt8to32 (Trunc32to8 <typ.UInt8> x))
......
src/cmd/compile/internal/ssa/rewritegeneric.go
View file @ 098208a0
......@@ -30,13 +30,13 @@ func rewriteValuegeneric(v *Value) bool {
case OpAddPtr:
return rewriteValuegeneric_OpAddPtr_0(v)
case OpAnd16:
return rewriteValuegeneric_OpAnd16_0(v) || rewriteValuegeneric_OpAnd16_10(v)
return rewriteValuegeneric_OpAnd16_0(v) || rewriteValuegeneric_OpAnd16_10(v) || rewriteValuegeneric_OpAnd16_20(v)
case OpAnd32:
return rewriteValuegeneric_OpAnd32_0(v) || rewriteValuegeneric_OpAnd32_10(v)
return rewriteValuegeneric_OpAnd32_0(v) || rewriteValuegeneric_OpAnd32_10(v) || rewriteValuegeneric_OpAnd32_20(v)
case OpAnd64:
return rewriteValuegeneric_OpAnd64_0(v) || rewriteValuegeneric_OpAnd64_10(v) || rewriteValuegeneric_OpAnd64_20(v)
case OpAnd8:
return rewriteValuegeneric_OpAnd8_0(v) || rewriteValuegeneric_OpAnd8_10(v)
return rewriteValuegeneric_OpAnd8_0(v) || rewriteValuegeneric_OpAnd8_10(v) || rewriteValuegeneric_OpAnd8_20(v)
case OpArg:
return rewriteValuegeneric_OpArg_0(v) || rewriteValuegeneric_OpArg_10(v)
case OpArraySelect:
......@@ -4572,6 +4572,114 @@ func rewriteValuegeneric_OpAnd16_0(v *Value) bool {
v.AuxInt = int64(int16(c & d))
return true
}
// match: (And16 (Const16 [m]) (Rsh16Ux64 _ (Const64 [c])))
// cond: c >= 64-ntz(m)
// result: (Const16 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst16 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpRsh16Ux64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst16)
v.AuxInt = 0
return true
}
// match: (And16 (Rsh16Ux64 _ (Const64 [c])) (Const16 [m]))
// cond: c >= 64-ntz(m)
// result: (Const16 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpRsh16Ux64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst16 {
break
}
m := v_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst16)
v.AuxInt = 0
return true
}
// match: (And16 (Const16 [m]) (Lsh16x64 _ (Const64 [c])))
// cond: c >= 64-nlz(m)
// result: (Const16 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst16 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpLsh16x64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst16)
v.AuxInt = 0
return true
}
// match: (And16 (Lsh16x64 _ (Const64 [c])) (Const16 [m]))
// cond: c >= 64-nlz(m)
// result: (Const16 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpLsh16x64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst16 {
break
}
m := v_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst16)
v.AuxInt = 0
return true
}
// match: (And16 x x)
// cond:
// result: x
......@@ -4638,6 +4746,11 @@ func rewriteValuegeneric_OpAnd16_0(v *Value) bool {
v.AuxInt = 0
return true
}
return false
}
func rewriteValuegeneric_OpAnd16_10(v *Value) bool {
b := v.Block
_ = b
// match: (And16 _ (Const16 [0]))
// cond:
// result: (Const16 [0])
......@@ -4714,11 +4827,6 @@ func rewriteValuegeneric_OpAnd16_0(v *Value) bool {
v.AddArg(y)
return true
}
return false
}
func rewriteValuegeneric_OpAnd16_10(v *Value) bool {
b := v.Block
_ = b
// match: (And16 (And16 y x) x)
// cond:
// result: (And16 x y)
......@@ -4883,6 +4991,11 @@ func rewriteValuegeneric_OpAnd16_10(v *Value) bool {
v.AddArg(x)
return true
}
return false
}
func rewriteValuegeneric_OpAnd16_20(v *Value) bool {
b := v.Block
_ = b
// match: (And16 (Const16 <t> [c]) (And16 x (Const16 <t> [d])))
// cond:
// result: (And16 (Const16 <t> [int64(int16(c&d))]) x)
......@@ -5020,6 +5133,114 @@ func rewriteValuegeneric_OpAnd32_0(v *Value) bool {
v.AuxInt = int64(int32(c & d))
return true
}
// match: (And32 (Const32 [m]) (Rsh32Ux64 _ (Const64 [c])))
// cond: c >= 64-ntz(m)
// result: (Const32 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst32 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpRsh32Ux64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst32)
v.AuxInt = 0
return true
}
// match: (And32 (Rsh32Ux64 _ (Const64 [c])) (Const32 [m]))
// cond: c >= 64-ntz(m)
// result: (Const32 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpRsh32Ux64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst32 {
break
}
m := v_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst32)
v.AuxInt = 0
return true
}
// match: (And32 (Const32 [m]) (Lsh32x64 _ (Const64 [c])))
// cond: c >= 64-nlz(m)
// result: (Const32 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst32 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpLsh32x64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst32)
v.AuxInt = 0
return true
}
// match: (And32 (Lsh32x64 _ (Const64 [c])) (Const32 [m]))
// cond: c >= 64-nlz(m)
// result: (Const32 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpLsh32x64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst32 {
break
}
m := v_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst32)
v.AuxInt = 0
return true
}
// match: (And32 x x)
// cond:
// result: x
......@@ -5086,6 +5307,11 @@ func rewriteValuegeneric_OpAnd32_0(v *Value) bool {
v.AuxInt = 0
return true
}
return false
}
func rewriteValuegeneric_OpAnd32_10(v *Value) bool {
b := v.Block
_ = b
// match: (And32 _ (Const32 [0]))
// cond:
// result: (Const32 [0])
......@@ -5162,11 +5388,6 @@ func rewriteValuegeneric_OpAnd32_0(v *Value) bool {
v.AddArg(y)
return true
}
return false
}
func rewriteValuegeneric_OpAnd32_10(v *Value) bool {
b := v.Block
_ = b
// match: (And32 (And32 y x) x)
// cond:
// result: (And32 x y)
......@@ -5331,6 +5552,11 @@ func rewriteValuegeneric_OpAnd32_10(v *Value) bool {
v.AddArg(x)
return true
}
return false
}
func rewriteValuegeneric_OpAnd32_20(v *Value) bool {
b := v.Block
_ = b
// match: (And32 (Const32 <t> [c]) (And32 x (Const32 <t> [d])))
// cond:
// result: (And32 (Const32 <t> [int64(int32(c&d))]) x)
......@@ -5468,6 +5694,114 @@ func rewriteValuegeneric_OpAnd64_0(v *Value) bool {
v.AuxInt = c & d
return true
}
// match: (And64 (Const64 [m]) (Rsh64Ux64 _ (Const64 [c])))
// cond: c >= 64-ntz(m)
// result: (Const64 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst64 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpRsh64Ux64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst64)
v.AuxInt = 0
return true
}
// match: (And64 (Rsh64Ux64 _ (Const64 [c])) (Const64 [m]))
// cond: c >= 64-ntz(m)
// result: (Const64 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpRsh64Ux64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst64 {
break
}
m := v_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst64)
v.AuxInt = 0
return true
}
// match: (And64 (Const64 [m]) (Lsh64x64 _ (Const64 [c])))
// cond: c >= 64-nlz(m)
// result: (Const64 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst64 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpLsh64x64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst64)
v.AuxInt = 0
return true
}
// match: (And64 (Lsh64x64 _ (Const64 [c])) (Const64 [m]))
// cond: c >= 64-nlz(m)
// result: (Const64 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpLsh64x64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst64 {
break
}
m := v_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst64)
v.AuxInt = 0
return true
}
// match: (And64 x x)
// cond:
// result: x
......@@ -5534,6 +5868,11 @@ func rewriteValuegeneric_OpAnd64_0(v *Value) bool {
v.AuxInt = 0
return true
}
return false
}
func rewriteValuegeneric_OpAnd64_10(v *Value) bool {
b := v.Block
_ = b
// match: (And64 _ (Const64 [0]))
// cond:
// result: (Const64 [0])
......@@ -5610,11 +5949,6 @@ func rewriteValuegeneric_OpAnd64_0(v *Value) bool {
v.AddArg(y)
return true
}
return false
}
func rewriteValuegeneric_OpAnd64_10(v *Value) bool {
b := v.Block
_ = b
// match: (And64 (And64 y x) x)
// cond:
// result: (And64 x y)
......@@ -5771,6 +6105,11 @@ func rewriteValuegeneric_OpAnd64_10(v *Value) bool {
v.AddArg(v0)
return true
}
return false
}
func rewriteValuegeneric_OpAnd64_20(v *Value) bool {
b := v.Block
_ = b
// match: (And64 (And64 z i:(Const64 <t>)) x)
// cond: (z.Op != OpConst64 && x.Op != OpConst64)
// result: (And64 i (And64 <t> z x))
......@@ -5887,11 +6226,6 @@ func rewriteValuegeneric_OpAnd64_10(v *Value) bool {
v.AddArg(x)
return true
}
return false
}
func rewriteValuegeneric_OpAnd64_20(v *Value) bool {
b := v.Block
_ = b
// match: (And64 (Const64 <t> [c]) (And64 x (Const64 <t> [d])))
// cond:
// result: (And64 (Const64 <t> [c&d]) x)
......@@ -6029,6 +6363,114 @@ func rewriteValuegeneric_OpAnd8_0(v *Value) bool {
v.AuxInt = int64(int8(c & d))
return true
}
// match: (And8 (Const8 [m]) (Rsh8Ux64 _ (Const64 [c])))
// cond: c >= 64-ntz(m)
// result: (Const8 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst8 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpRsh8Ux64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst8)
v.AuxInt = 0
return true
}
// match: (And8 (Rsh8Ux64 _ (Const64 [c])) (Const8 [m]))
// cond: c >= 64-ntz(m)
// result: (Const8 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpRsh8Ux64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst8 {
break
}
m := v_1.AuxInt
if !(c >= 64-ntz(m)) {
break
}
v.reset(OpConst8)
v.AuxInt = 0
return true
}
// match: (And8 (Const8 [m]) (Lsh8x64 _ (Const64 [c])))
// cond: c >= 64-nlz(m)
// result: (Const8 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpConst8 {
break
}
m := v_0.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpLsh8x64 {
break
}
_ = v_1.Args[1]
v_1_1 := v_1.Args[1]
if v_1_1.Op != OpConst64 {
break
}
c := v_1_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst8)
v.AuxInt = 0
return true
}
// match: (And8 (Lsh8x64 _ (Const64 [c])) (Const8 [m]))
// cond: c >= 64-nlz(m)
// result: (Const8 [0])
for {
_ = v.Args[1]
v_0 := v.Args[0]
if v_0.Op != OpLsh8x64 {
break
}
_ = v_0.Args[1]
v_0_1 := v_0.Args[1]
if v_0_1.Op != OpConst64 {
break
}
c := v_0_1.AuxInt
v_1 := v.Args[1]
if v_1.Op != OpConst8 {
break
}
m := v_1.AuxInt
if !(c >= 64-nlz(m)) {
break
}
v.reset(OpConst8)
v.AuxInt = 0
return true
}
// match: (And8 x x)
// cond:
// result: x
......@@ -6095,6 +6537,11 @@ func rewriteValuegeneric_OpAnd8_0(v *Value) bool {
v.AuxInt = 0
return true
}
return false
}
func rewriteValuegeneric_OpAnd8_10(v *Value) bool {
b := v.Block
_ = b
// match: (And8 _ (Const8 [0]))
// cond:
// result: (Const8 [0])
......@@ -6171,11 +6618,6 @@ func rewriteValuegeneric_OpAnd8_0(v *Value) bool {
v.AddArg(y)
return true
}
return false
}
func rewriteValuegeneric_OpAnd8_10(v *Value) bool {
b := v.Block
_ = b
// match: (And8 (And8 y x) x)
// cond:
// result: (And8 x y)
......@@ -6340,6 +6782,11 @@ func rewriteValuegeneric_OpAnd8_10(v *Value) bool {
v.AddArg(x)
return true
}
return false
}
func rewriteValuegeneric_OpAnd8_20(v *Value) bool {
b := v.Block
_ = b
// match: (And8 (Const8 <t> [c]) (And8 x (Const8 <t> [d])))
// cond:
// result: (And8 (Const8 <t> [int64(int8(c&d))]) x)
......
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