go/src/cmd/compile/internal/test/divconst_test.go

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package test
import (
"testing"
)
cmd/compile: add signed divisibility by power of 2 rules For powers of two (c=1<<k), the divisibility check x%c == 0 can be made just by checking the trailing zeroes via a mask x&(c-1) == 0 even for signed integers. This avoids division fix-ups when just divisibility check is needed. To apply this rule, we match on the fixed-up version of the division. This is neccessary because the mod and division rewrite rules are already applied during the initial opt pass. The speed up on amd64 due to elimination of unneccessary fix-up code is ~55%: name old time/op new time/op delta DivconstI64-4 2.08ns ± 0% 2.09ns ± 1% ~ (p=0.730 n=5+5) DivisiblePow2constI64-4 1.78ns ± 1% 0.81ns ± 1% -54.66% (p=0.008 n=5+5) DivconstU64-4 2.08ns ± 0% 2.08ns ± 0% ~ (p=0.683 n=5+5) DivconstI32-4 1.53ns ± 0% 1.53ns ± 1% ~ (p=0.968 n=4+5) DivisiblePow2constI32-4 1.79ns ± 1% 0.81ns ± 1% -54.97% (p=0.008 n=5+5) DivconstU32-4 1.78ns ± 1% 1.80ns ± 2% ~ (p=0.206 n=5+5) DivconstI16-4 1.54ns ± 2% 1.54ns ± 0% ~ (p=0.238 n=5+4) DivisiblePow2constI16-4 1.78ns ± 0% 0.81ns ± 1% -54.72% (p=0.000 n=4+5) DivconstU16-4 1.00ns ± 5% 1.01ns ± 1% ~ (p=0.119 n=5+5) DivconstI8-4 1.54ns ± 0% 1.54ns ± 2% ~ (p=0.571 n=4+5) DivisiblePow2constI8-4 1.78ns ± 0% 0.82ns ± 8% -53.71% (p=0.008 n=5+5) DivconstU8-4 0.93ns ± 1% 0.93ns ± 1% ~ (p=0.643 n=5+5) A follow-up CL will address the general case of x%c == 0 for signed integers. Updates #15806 Change-Id: Iabadbbe369b6e0998c8ce85d038ebc236142e42a Reviewed-on: https://go-review.googlesource.com/c/go/+/173557 Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-04-23 22:04:38 -06:00
var boolres bool
var i64res int64
func BenchmarkDivconstI64(b *testing.B) {
for i := 0; i < b.N; i++ {
i64res = int64(i) / 7
}
}
cmd/compile: add signed divisibility by power of 2 rules For powers of two (c=1<<k), the divisibility check x%c == 0 can be made just by checking the trailing zeroes via a mask x&(c-1) == 0 even for signed integers. This avoids division fix-ups when just divisibility check is needed. To apply this rule, we match on the fixed-up version of the division. This is neccessary because the mod and division rewrite rules are already applied during the initial opt pass. The speed up on amd64 due to elimination of unneccessary fix-up code is ~55%: name old time/op new time/op delta DivconstI64-4 2.08ns ± 0% 2.09ns ± 1% ~ (p=0.730 n=5+5) DivisiblePow2constI64-4 1.78ns ± 1% 0.81ns ± 1% -54.66% (p=0.008 n=5+5) DivconstU64-4 2.08ns ± 0% 2.08ns ± 0% ~ (p=0.683 n=5+5) DivconstI32-4 1.53ns ± 0% 1.53ns ± 1% ~ (p=0.968 n=4+5) DivisiblePow2constI32-4 1.79ns ± 1% 0.81ns ± 1% -54.97% (p=0.008 n=5+5) DivconstU32-4 1.78ns ± 1% 1.80ns ± 2% ~ (p=0.206 n=5+5) DivconstI16-4 1.54ns ± 2% 1.54ns ± 0% ~ (p=0.238 n=5+4) DivisiblePow2constI16-4 1.78ns ± 0% 0.81ns ± 1% -54.72% (p=0.000 n=4+5) DivconstU16-4 1.00ns ± 5% 1.01ns ± 1% ~ (p=0.119 n=5+5) DivconstI8-4 1.54ns ± 0% 1.54ns ± 2% ~ (p=0.571 n=4+5) DivisiblePow2constI8-4 1.78ns ± 0% 0.82ns ± 8% -53.71% (p=0.008 n=5+5) DivconstU8-4 0.93ns ± 1% 0.93ns ± 1% ~ (p=0.643 n=5+5) A follow-up CL will address the general case of x%c == 0 for signed integers. Updates #15806 Change-Id: Iabadbbe369b6e0998c8ce85d038ebc236142e42a Reviewed-on: https://go-review.googlesource.com/c/go/+/173557 Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-04-23 22:04:38 -06:00
func BenchmarkDivisiblePow2constI64(b *testing.B) {
for i := 0; i < b.N; i++ {
boolres = int64(i)%16 == 0
}
}
var u64res uint64
func BenchmarkDivconstU64(b *testing.B) {
for i := 0; i < b.N; i++ {
u64res = uint64(i) / 7
}
}
var i32res int32
func BenchmarkDivconstI32(b *testing.B) {
for i := 0; i < b.N; i++ {
i32res = int32(i) / 7
}
}
cmd/compile: add signed divisibility by power of 2 rules For powers of two (c=1<<k), the divisibility check x%c == 0 can be made just by checking the trailing zeroes via a mask x&(c-1) == 0 even for signed integers. This avoids division fix-ups when just divisibility check is needed. To apply this rule, we match on the fixed-up version of the division. This is neccessary because the mod and division rewrite rules are already applied during the initial opt pass. The speed up on amd64 due to elimination of unneccessary fix-up code is ~55%: name old time/op new time/op delta DivconstI64-4 2.08ns ± 0% 2.09ns ± 1% ~ (p=0.730 n=5+5) DivisiblePow2constI64-4 1.78ns ± 1% 0.81ns ± 1% -54.66% (p=0.008 n=5+5) DivconstU64-4 2.08ns ± 0% 2.08ns ± 0% ~ (p=0.683 n=5+5) DivconstI32-4 1.53ns ± 0% 1.53ns ± 1% ~ (p=0.968 n=4+5) DivisiblePow2constI32-4 1.79ns ± 1% 0.81ns ± 1% -54.97% (p=0.008 n=5+5) DivconstU32-4 1.78ns ± 1% 1.80ns ± 2% ~ (p=0.206 n=5+5) DivconstI16-4 1.54ns ± 2% 1.54ns ± 0% ~ (p=0.238 n=5+4) DivisiblePow2constI16-4 1.78ns ± 0% 0.81ns ± 1% -54.72% (p=0.000 n=4+5) DivconstU16-4 1.00ns ± 5% 1.01ns ± 1% ~ (p=0.119 n=5+5) DivconstI8-4 1.54ns ± 0% 1.54ns ± 2% ~ (p=0.571 n=4+5) DivisiblePow2constI8-4 1.78ns ± 0% 0.82ns ± 8% -53.71% (p=0.008 n=5+5) DivconstU8-4 0.93ns ± 1% 0.93ns ± 1% ~ (p=0.643 n=5+5) A follow-up CL will address the general case of x%c == 0 for signed integers. Updates #15806 Change-Id: Iabadbbe369b6e0998c8ce85d038ebc236142e42a Reviewed-on: https://go-review.googlesource.com/c/go/+/173557 Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-04-23 22:04:38 -06:00
func BenchmarkDivisiblePow2constI32(b *testing.B) {
for i := 0; i < b.N; i++ {
boolres = int32(i)%16 == 0
}
}
var u32res uint32
func BenchmarkDivconstU32(b *testing.B) {
for i := 0; i < b.N; i++ {
u32res = uint32(i) / 7
}
}
var i16res int16
func BenchmarkDivconstI16(b *testing.B) {
for i := 0; i < b.N; i++ {
i16res = int16(i) / 7
}
}
cmd/compile: add signed divisibility by power of 2 rules For powers of two (c=1<<k), the divisibility check x%c == 0 can be made just by checking the trailing zeroes via a mask x&(c-1) == 0 even for signed integers. This avoids division fix-ups when just divisibility check is needed. To apply this rule, we match on the fixed-up version of the division. This is neccessary because the mod and division rewrite rules are already applied during the initial opt pass. The speed up on amd64 due to elimination of unneccessary fix-up code is ~55%: name old time/op new time/op delta DivconstI64-4 2.08ns ± 0% 2.09ns ± 1% ~ (p=0.730 n=5+5) DivisiblePow2constI64-4 1.78ns ± 1% 0.81ns ± 1% -54.66% (p=0.008 n=5+5) DivconstU64-4 2.08ns ± 0% 2.08ns ± 0% ~ (p=0.683 n=5+5) DivconstI32-4 1.53ns ± 0% 1.53ns ± 1% ~ (p=0.968 n=4+5) DivisiblePow2constI32-4 1.79ns ± 1% 0.81ns ± 1% -54.97% (p=0.008 n=5+5) DivconstU32-4 1.78ns ± 1% 1.80ns ± 2% ~ (p=0.206 n=5+5) DivconstI16-4 1.54ns ± 2% 1.54ns ± 0% ~ (p=0.238 n=5+4) DivisiblePow2constI16-4 1.78ns ± 0% 0.81ns ± 1% -54.72% (p=0.000 n=4+5) DivconstU16-4 1.00ns ± 5% 1.01ns ± 1% ~ (p=0.119 n=5+5) DivconstI8-4 1.54ns ± 0% 1.54ns ± 2% ~ (p=0.571 n=4+5) DivisiblePow2constI8-4 1.78ns ± 0% 0.82ns ± 8% -53.71% (p=0.008 n=5+5) DivconstU8-4 0.93ns ± 1% 0.93ns ± 1% ~ (p=0.643 n=5+5) A follow-up CL will address the general case of x%c == 0 for signed integers. Updates #15806 Change-Id: Iabadbbe369b6e0998c8ce85d038ebc236142e42a Reviewed-on: https://go-review.googlesource.com/c/go/+/173557 Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-04-23 22:04:38 -06:00
func BenchmarkDivisiblePow2constI16(b *testing.B) {
for i := 0; i < b.N; i++ {
boolres = int16(i)%16 == 0
}
}
var u16res uint16
func BenchmarkDivconstU16(b *testing.B) {
for i := 0; i < b.N; i++ {
u16res = uint16(i) / 7
}
}
var i8res int8
func BenchmarkDivconstI8(b *testing.B) {
for i := 0; i < b.N; i++ {
i8res = int8(i) / 7
}
}
cmd/compile: add signed divisibility by power of 2 rules For powers of two (c=1<<k), the divisibility check x%c == 0 can be made just by checking the trailing zeroes via a mask x&(c-1) == 0 even for signed integers. This avoids division fix-ups when just divisibility check is needed. To apply this rule, we match on the fixed-up version of the division. This is neccessary because the mod and division rewrite rules are already applied during the initial opt pass. The speed up on amd64 due to elimination of unneccessary fix-up code is ~55%: name old time/op new time/op delta DivconstI64-4 2.08ns ± 0% 2.09ns ± 1% ~ (p=0.730 n=5+5) DivisiblePow2constI64-4 1.78ns ± 1% 0.81ns ± 1% -54.66% (p=0.008 n=5+5) DivconstU64-4 2.08ns ± 0% 2.08ns ± 0% ~ (p=0.683 n=5+5) DivconstI32-4 1.53ns ± 0% 1.53ns ± 1% ~ (p=0.968 n=4+5) DivisiblePow2constI32-4 1.79ns ± 1% 0.81ns ± 1% -54.97% (p=0.008 n=5+5) DivconstU32-4 1.78ns ± 1% 1.80ns ± 2% ~ (p=0.206 n=5+5) DivconstI16-4 1.54ns ± 2% 1.54ns ± 0% ~ (p=0.238 n=5+4) DivisiblePow2constI16-4 1.78ns ± 0% 0.81ns ± 1% -54.72% (p=0.000 n=4+5) DivconstU16-4 1.00ns ± 5% 1.01ns ± 1% ~ (p=0.119 n=5+5) DivconstI8-4 1.54ns ± 0% 1.54ns ± 2% ~ (p=0.571 n=4+5) DivisiblePow2constI8-4 1.78ns ± 0% 0.82ns ± 8% -53.71% (p=0.008 n=5+5) DivconstU8-4 0.93ns ± 1% 0.93ns ± 1% ~ (p=0.643 n=5+5) A follow-up CL will address the general case of x%c == 0 for signed integers. Updates #15806 Change-Id: Iabadbbe369b6e0998c8ce85d038ebc236142e42a Reviewed-on: https://go-review.googlesource.com/c/go/+/173557 Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-04-23 22:04:38 -06:00
func BenchmarkDivisiblePow2constI8(b *testing.B) {
for i := 0; i < b.N; i++ {
boolres = int8(i)%16 == 0
}
}
var u8res uint8
func BenchmarkDivconstU8(b *testing.B) {
for i := 0; i < b.N; i++ {
u8res = uint8(i) / 7
}
}