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go/test/prove.go
Alexandru Moșoi b91cc53033 cmd/compile/internal/ssa: BCE for induction variables
There are 5293 loop in the main go repository.
A survey of the top most common for loops:

     18 for __k__ := 0; i < len(sa.Addr); i++ {
     19 for __k__ := 0; ; i++ {
     19 for __k__ := 0; i < 16; i++ {
     25 for __k__ := 0; i < length; i++ {
     30 for __k__ := 0; i < 8; i++ {
     49 for __k__ := 0; i < len(s); i++ {
     67 for __k__ := 0; i < n; i++ {
    376 for __k__ := range __slice__ {
    685 for __k__, __v__ := range __slice__ {
   2074 for __, __v__ := range __slice__ {

The algorithm to find induction variables handles all cases
with an upper limit. It currently doesn't find related induction
variables such as c * ind or c + ind.

842 out of 22954 bound checks are removed for src/make.bash.
1957 out of 42952 bounds checks are removed for src/all.bash.

Things to do in follow-up CLs:
* Find the associated pointer for `for _, v := range a {}`
* Drop the NilChecks on the pointer.
* Replace the implicit induction variable by a loop over the pointer

Generated garbage can be reduced if we share the sdom between passes.

% benchstat old.txt new.txt
name       old time/op     new time/op     delta
Template       337ms ± 3%      333ms ± 3%    ~             (p=0.258 n=9+9)
GoTypes        1.11s ± 2%      1.10s ± 2%    ~           (p=0.912 n=10+10)
Compiler       5.25s ± 1%      5.29s ± 2%    ~             (p=0.077 n=9+9)
MakeBash       33.5s ± 1%      34.1s ± 2%  +1.85%          (p=0.011 n=9+9)

name       old alloc/op    new alloc/op    delta
Template      63.6MB ± 0%     63.9MB ± 0%  +0.52%         (p=0.000 n=10+9)
GoTypes        218MB ± 0%      219MB ± 0%  +0.59%         (p=0.000 n=10+9)
Compiler       978MB ± 0%      985MB ± 0%  +0.69%        (p=0.000 n=10+10)

name       old allocs/op   new allocs/op   delta
Template        582k ± 0%       583k ± 0%  +0.10%        (p=0.000 n=10+10)
GoTypes        1.78M ± 0%      1.78M ± 0%  +0.12%        (p=0.000 n=10+10)
Compiler       7.68M ± 0%      7.69M ± 0%  +0.05%        (p=0.000 n=10+10)

name       old text-bytes  new text-bytes  delta
HelloSize       581k ± 0%       581k ± 0%  -0.08%        (p=0.000 n=10+10)
CmdGoSize      6.40M ± 0%      6.39M ± 0%  -0.08%        (p=0.000 n=10+10)

name       old data-bytes  new data-bytes  delta
HelloSize      3.66k ± 0%      3.66k ± 0%    ~     (all samples are equal)
CmdGoSize       134k ± 0%       134k ± 0%    ~     (all samples are equal)

name       old bss-bytes   new bss-bytes   delta
HelloSize       126k ± 0%       126k ± 0%    ~     (all samples are equal)
CmdGoSize       149k ± 0%       149k ± 0%    ~     (all samples are equal)

name       old exe-bytes   new exe-bytes   delta
HelloSize       947k ± 0%       946k ± 0%  -0.01%        (p=0.000 n=10+10)
CmdGoSize      9.92M ± 0%      9.91M ± 0%  -0.06%        (p=0.000 n=10+10)

Change-Id: Ie74bdff46fd602db41bb457333d3a762a0c3dc4d
Reviewed-on: https://go-review.googlesource.com/20517
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
2016-04-01 09:37:58 +00:00

428 lines
6.1 KiB
Go

// +build amd64
// errorcheck -0 -d=ssa/prove/debug=3
package main
import "math"
func f0(a []int) int {
a[0] = 1
a[0] = 1 // ERROR "Proved boolean IsInBounds$"
a[6] = 1
a[6] = 1 // ERROR "Proved boolean IsInBounds$"
a[5] = 1 // ERROR "Proved IsInBounds$"
a[5] = 1 // ERROR "Proved boolean IsInBounds$"
return 13
}
func f1(a []int) int {
if len(a) <= 5 {
return 18
}
a[0] = 1 // ERROR "Proved non-negative bounds IsInBounds$"
a[0] = 1 // ERROR "Proved boolean IsInBounds$"
a[6] = 1
a[6] = 1 // ERROR "Proved boolean IsInBounds$"
a[5] = 1 // ERROR "Proved IsInBounds$"
a[5] = 1 // ERROR "Proved boolean IsInBounds$"
return 26
}
func f1b(a []int, i int, j uint) int {
if i >= 0 && i < len(a) { // TODO: handle this case
return a[i]
}
if j < uint(len(a)) {
return a[j] // ERROR "Proved IsInBounds"
}
return 0
}
func f2(a []int) int {
for i := range a {
a[i+1] = i
a[i+1] = i // ERROR "Proved boolean IsInBounds$"
}
return 34
}
func f3(a []uint) int {
for i := uint(0); i < uint(len(a)); i++ {
a[i] = i // ERROR "Proved IsInBounds$"
}
return 41
}
func f4a(a, b, c int) int {
if a < b {
if a == b { // ERROR "Disproved Eq64$"
return 47
}
if a > b { // ERROR "Disproved Greater64$"
return 50
}
if a < b { // ERROR "Proved boolean Less64$"
return 53
}
if a == b { // ERROR "Disproved boolean Eq64$"
return 56
}
if a > b { // ERROR "Disproved boolean Greater64$"
return 59
}
return 61
}
return 63
}
func f4b(a, b, c int) int {
if a <= b {
if a >= b {
if a == b { // ERROR "Proved Eq64$"
return 70
}
return 75
}
return 77
}
return 79
}
func f4c(a, b, c int) int {
if a <= b {
if a >= b {
if a != b { // ERROR "Disproved Neq64$"
return 73
}
return 75
}
return 77
}
return 79
}
func f4d(a, b, c int) int {
if a < b {
if a < c {
if a < b { // ERROR "Proved boolean Less64$"
if a < c { // ERROR "Proved boolean Less64$"
return 87
}
return 89
}
return 91
}
return 93
}
return 95
}
func f4e(a, b, c int) int {
if a < b {
if b > a { // ERROR "Proved Greater64$"
return 101
}
return 103
}
return 105
}
func f4f(a, b, c int) int {
if a <= b {
if b > a {
if b == a { // ERROR "Disproved Eq64$"
return 112
}
return 114
}
if b >= a { // ERROR "Proved Geq64$"
if b == a { // ERROR "Proved Eq64$"
return 118
}
return 120
}
return 122
}
return 124
}
func f5(a, b uint) int {
if a == b {
if a <= b { // ERROR "Proved Leq64U$"
return 130
}
return 132
}
return 134
}
// These comparisons are compile time constants.
func f6a(a uint8) int {
if a < a { // ERROR "Disproved Less8U$"
return 140
}
return 151
}
func f6b(a uint8) int {
if a < a { // ERROR "Disproved Less8U$"
return 140
}
return 151
}
func f6x(a uint8) int {
if a > a { // ERROR "Disproved Greater8U$"
return 143
}
return 151
}
func f6d(a uint8) int {
if a <= a { // ERROR "Proved Leq8U$"
return 146
}
return 151
}
func f6e(a uint8) int {
if a >= a { // ERROR "Proved Geq8U$"
return 149
}
return 151
}
func f7(a []int, b int) int {
if b < len(a) {
a[b] = 3
if b < len(a) { // ERROR "Proved boolean Less64$"
a[b] = 5 // ERROR "Proved boolean IsInBounds$"
}
}
return 161
}
func f8(a, b uint) int {
if a == b {
return 166
}
if a > b {
return 169
}
if a < b { // ERROR "Proved Less64U$"
return 172
}
return 174
}
func f9(a, b bool) int {
if a {
return 1
}
if a || b { // ERROR "Disproved boolean Arg$"
return 2
}
return 3
}
func f10(a string) int {
n := len(a)
if a[:n>>1] == "aaa" {
return 0
}
return 1
}
func f11a(a []int, i int) {
useInt(a[i])
useInt(a[i]) // ERROR "Proved boolean IsInBounds$"
}
func f11b(a []int, i int) {
useSlice(a[i:])
useSlice(a[i:]) // ERROR "Proved boolean IsSliceInBounds$"
}
func f11c(a []int, i int) {
useSlice(a[:i])
useSlice(a[:i]) // ERROR "Proved boolean IsSliceInBounds$"
}
func f11d(a []int, i int) {
useInt(a[2*i+7])
useInt(a[2*i+7])
}
func f12(a []int, b int) {
useSlice(a[:b])
}
func f13a(a, b, c int, x bool) int {
if a > 12 {
if x {
if a < 12 { // ERROR "Disproved Less64$"
return 1
}
}
if x {
if a <= 12 { // ERROR "Disproved Leq64$"
return 2
}
}
if x {
if a == 12 { // ERROR "Disproved Eq64$"
return 3
}
}
if x {
if a >= 12 { // ERROR "Proved Geq64$"
return 4
}
}
if x {
if a > 12 { // ERROR "Proved boolean Greater64$"
return 5
}
}
return 6
}
return 0
}
func f13b(a int, x bool) int {
if a == -9 {
if x {
if a < -9 { // ERROR "Disproved Less64$"
return 7
}
}
if x {
if a <= -9 { // ERROR "Proved Leq64$"
return 8
}
}
if x {
if a == -9 { // ERROR "Proved boolean Eq64$"
return 9
}
}
if x {
if a >= -9 { // ERROR "Proved Geq64$"
return 10
}
}
if x {
if a > -9 { // ERROR "Disproved Greater64$"
return 11
}
}
return 12
}
return 0
}
func f13c(a int, x bool) int {
if a < 90 {
if x {
if a < 90 { // ERROR "Proved boolean Less64$"
return 13
}
}
if x {
if a <= 90 { // ERROR "Proved Leq64$"
return 14
}
}
if x {
if a == 90 { // ERROR "Disproved Eq64$"
return 15
}
}
if x {
if a >= 90 { // ERROR "Disproved Geq64$"
return 16
}
}
if x {
if a > 90 { // ERROR "Disproved Greater64$"
return 17
}
}
return 18
}
return 0
}
func f13d(a int) int {
if a < 5 {
if a < 9 { // ERROR "Proved Less64$"
return 1
}
}
return 0
}
func f13e(a int) int {
if a > 9 {
if a > 5 { // ERROR "Proved Greater64$"
return 1
}
}
return 0
}
func f13f(a int64) int64 {
if a > math.MaxInt64 {
// Unreachable, but prove doesn't know that.
if a == 0 {
return 1
}
}
return 0
}
func f13g(a int) int {
if a < 3 {
return 5
}
if a > 3 {
return 6
}
if a == 3 { // ERROR "Proved Eq64$"
return 7
}
return 8
}
func f13h(a int) int {
if a < 3 {
if a > 1 {
if a == 2 { // ERROR "Proved Eq64$"
return 5
}
}
}
return 0
}
func f13i(a uint) int {
if a == 0 {
return 1
}
if a > 0 { // ERROR "Proved Greater64U$"
return 2
}
return 3
}
//go:noinline
func useInt(a int) {
}
//go:noinline
func useSlice(a []int) {
}
func main() {
}