mirror of
https://github.com/golang/go
synced 2024-11-24 18:30:16 -07:00
379567aad1
Add rewrite rules that canonicalize the location of constants in expressions, and fold conststants that appear in operations that can be trivially reassociated. After this change, the compiler constant-folds expressions like "4 + x - 1" and "4 & x & 1" Benchmarks affected on darwin/amd64: name old time/op new time/op delta FmtFprintfInt-8 82.1ns ± 1% 81.7ns ± 1% -0.46% (p=0.023 n=8+9) FmtFprintfIntInt-8 122ns ± 2% 120ns ± 2% -1.48% (p=0.047 n=10+10) FmtManyArgs-8 493ns ± 0% 486ns ± 1% -1.37% (p=0.000 n=8+10) Gzip-8 230ms ± 0% 229ms ± 1% -0.46% (p=0.001 n=10+9) HTTPClientServer-8 74.5µs ± 1% 73.7µs ± 1% -1.11% (p=0.000 n=10+10) JSONDecode-8 51.7ms ± 0% 51.9ms ± 1% +0.42% (p=0.017 n=10+9) RegexpMatchEasy0_32-8 82.6ns ± 1% 81.7ns ± 0% -1.02% (p=0.000 n=9+8) RegexpMatchMedium_32-8 121ns ± 1% 120ns ± 1% -1.48% (p=0.001 n=10+10) Revcomp-8 426ms ± 1% 400ms ± 1% -6.16% (p=0.000 n=10+10) TimeFormat-8 330ns ± 1% 327ns ± 0% -0.82% (p=0.000 n=10+10) name old speed new speed delta Gzip-8 84.4MB/s ± 0% 84.8MB/s ± 1% +0.47% (p=0.001 n=10+9) JSONDecode-8 37.6MB/s ± 0% 37.4MB/s ± 1% -0.42% (p=0.016 n=10+9) RegexpMatchEasy0_32-8 387MB/s ± 1% 392MB/s ± 0% +1.06% (p=0.000 n=9+8) RegexpMatchMedium_32-8 8.21MB/s ± 1% 8.34MB/s ± 1% +1.58% (p=0.000 n=10+9) Revcomp-8 597MB/s ± 1% 636MB/s ± 1% +6.57% (p=0.000 n=10+10) Change-Id: Ie37ff91605b76a984a8400dfd1e34f50bf61c864 Reviewed-on: https://go-review.googlesource.com/37290 Reviewed-by: Keith Randall <khr@golang.org> Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
254 lines
7.1 KiB
Go
254 lines
7.1 KiB
Go
// +build amd64
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// errorcheck -0 -d=ssa/loopbce/debug=3
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package main
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func f0a(a []int) int {
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x := 0
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for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
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x += a[i] // ERROR "Found redundant IsInBounds$"
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}
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return x
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}
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func f0b(a []int) int {
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x := 0
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for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
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b := a[i:] // ERROR "Found redundant IsSliceInBounds$"
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x += b[0]
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}
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return x
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}
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func f0c(a []int) int {
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x := 0
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for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
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b := a[:i+1] // ERROR "Found redundant IsSliceInBounds \(len promoted to cap\)$"
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x += b[0]
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}
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return x
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}
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func f1(a []int) int {
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x := 0
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for _, i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
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x += i
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}
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return x
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}
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func f2(a []int) int {
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x := 0
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for i := 1; i < len(a); i++ { // ERROR "Induction variable with minimum 1 and increment 1$"
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x += a[i] // ERROR "Found redundant IsInBounds$"
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}
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return x
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}
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func f4(a [10]int) int {
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x := 0
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for i := 0; i < len(a); i += 2 { // ERROR "Induction variable with minimum 0 and increment 2$"
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x += a[i] // ERROR "Found redundant IsInBounds$"
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}
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return x
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}
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func f5(a [10]int) int {
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x := 0
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for i := -10; i < len(a); i += 2 { // ERROR "Induction variable with minimum -10 and increment 2$"
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x += a[i]
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}
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return x
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}
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func f6(a []int) {
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for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
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b := a[0:i] // ERROR "Found redundant IsSliceInBounds \(len promoted to cap\)$"
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f6(b)
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}
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}
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func g0a(a string) int {
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x := 0
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for i := 0; i < len(a); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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x += int(a[i]) // ERROR "Found redundant IsInBounds$"
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}
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return x
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}
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func g0b(a string) int {
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x := 0
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for i := 0; len(a) > i; i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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x += int(a[i]) // ERROR "Found redundant IsInBounds$"
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}
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return x
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}
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func g1() int {
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a := "evenlength"
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x := 0
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for i := 0; i < len(a); i += 2 { // ERROR "Induction variable with minimum 0 and increment 2$"
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x += int(a[i]) // ERROR "Found redundant IsInBounds$"
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}
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return x
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}
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func g2() int {
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a := "evenlength"
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x := 0
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for i := 0; i < len(a); i += 2 { // ERROR "Induction variable with minimum 0 and increment 2$"
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j := i
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if a[i] == 'e' { // ERROR "Found redundant IsInBounds$"
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j = j + 1
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}
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x += int(a[j])
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}
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return x
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}
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func g3a() {
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a := "this string has length 25"
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for i := 0; i < len(a); i += 5 { // ERROR "Induction variable with minimum 0 and increment 5$"
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useString(a[i:]) // ERROR "Found redundant IsSliceInBounds$"
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useString(a[:i+3])
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}
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}
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func g3b(a string) {
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for i := 0; i < len(a); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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useString(a[i+1:]) // ERROR "Found redundant IsSliceInBounds$"
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}
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}
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func g3c(a string) {
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for i := 0; i < len(a); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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useString(a[:i+1]) // ERROR "Found redundant IsSliceInBounds$"
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}
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}
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func h1(a []byte) {
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c := a[:128]
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for i := range c { // ERROR "Induction variable with minimum 0 and increment 1$"
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c[i] = byte(i) // ERROR "Found redundant IsInBounds$"
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}
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}
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func h2(a []byte) {
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for i := range a[:128] { // ERROR "Induction variable with minimum 0 and increment 1$"
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a[i] = byte(i)
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}
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}
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func k0(a [100]int) [100]int {
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for i := 10; i < 90; i++ { // ERROR "Induction variable with minimum 10 and increment 1$"
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a[i-11] = i
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a[i-10] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 80$"
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a[i-5] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 85$"
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a[i] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 90$"
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a[i+5] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 95$"
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a[i+10] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 100$"
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a[i+11] = i
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}
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return a
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}
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func k1(a [100]int) [100]int {
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for i := 10; i < 90; i++ { // ERROR "Induction variable with minimum 10 and increment 1$"
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useSlice(a[:i-11])
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useSlice(a[:i-10]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 80$"
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useSlice(a[:i-5]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 85$"
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useSlice(a[:i]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 90$"
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useSlice(a[:i+5]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 95$"
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useSlice(a[:i+10]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 100$"
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useSlice(a[:i+11]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 101$"
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}
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return a
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}
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func k2(a [100]int) [100]int {
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for i := 10; i < 90; i++ { // ERROR "Induction variable with minimum 10 and increment 1$"
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useSlice(a[i-11:])
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useSlice(a[i-10:]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 80$"
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useSlice(a[i-5:]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 85$"
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useSlice(a[i:]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 90$"
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useSlice(a[i+5:]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 95$"
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useSlice(a[i+10:]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 100$"
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useSlice(a[i+11:]) // ERROR "Found redundant \(IsSliceInBounds ind 100\), ind < 101$"
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}
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return a
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}
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func k3(a [100]int) [100]int {
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for i := -10; i < 90; i++ { // ERROR "Induction variable with minimum -10 and increment 1$"
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a[i+10] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 100$"
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}
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return a
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}
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func k4(a [100]int) [100]int {
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min := (-1) << 63
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for i := min; i < min+50; i++ { // ERROR "Induction variable with minimum -9223372036854775808 and increment 1$"
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a[i-min] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 50$"
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}
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return a
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}
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func k5(a [100]int) [100]int {
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max := (1 << 63) - 1
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for i := max - 50; i < max; i++ { // ERROR "Induction variable with minimum 9223372036854775757 and increment 1$"
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a[i-max+50] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 50$"
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a[i-(max-70)] = i // ERROR "Found redundant \(IsInBounds ind 100\), ind < 70$"
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}
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return a
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}
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func nobce1() {
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// tests overflow of max-min
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a := int64(9223372036854774057)
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b := int64(-1547)
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z := int64(1337)
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if a%z == b%z {
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panic("invalid test: modulos should differ")
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}
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for i := b; i < a; i += z {
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// No induction variable is possible because i will overflow a first iteration.
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useString("foobar")
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}
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}
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func nobce2(a string) {
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for i := int64(0); i < int64(len(a)); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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useString(a[i:]) // ERROR "Found redundant IsSliceInBounds$"
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}
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for i := int64(0); i < int64(len(a))-31337; i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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useString(a[i:]) // ERROR "Found redundant IsSliceInBounds$"
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}
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for i := int64(0); i < int64(len(a))+int64(-1<<63); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
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// tests an overflow of StringLen-MinInt64
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useString(a[i:])
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}
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}
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func nobce3(a [100]int64) [100]int64 {
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min := int64((-1) << 63)
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max := int64((1 << 63) - 1)
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for i := min; i < max; i++ { // ERROR "Induction variable with minimum -9223372036854775808 and increment 1$"
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a[i] = i
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}
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return a
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}
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//go:noinline
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func useString(a string) {
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}
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//go:noinline
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func useSlice(a []int) {
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}
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func main() {
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}
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