mirror of
https://github.com/golang/go
synced 2024-11-24 17:10:03 -07:00
1658263bbf
prove wasn't able to detect induction variables that was bound by another inducation variable. This happened because an indvar is a Phi, and thus in case of a dependency, the loop bounding condition looked as Phi < Phi. This triggered an existing codepath that checked whether the upper bound was a Phi to detect loop conditions written in reversed order respect to the idiomatic way (eg: for i:=0; len(n)>i; i++). To fix this, we call the indvar pattern matching on both operands of the loop condition, so that the first operand that matches will be treated as the indvar. Updates #24660 (removes a boundcheck from Fannkuch) Change-Id: Iade83d8deb54f14277ed3f2e37b190e1ed173d11 Reviewed-on: https://go-review.googlesource.com/c/go/+/195220 Reviewed-by: David Chase <drchase@google.com>
358 lines
9.8 KiB
Go
358 lines
9.8 KiB
Go
// +build amd64
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// errorcheck -0 -d=ssa/prove/debug=1
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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: limits \[0,\?\), increment 1$"
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x += a[i] // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,\?\), increment 1$"
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b := a[i:] // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,\?\), increment 1$"
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b := a[:i+1] // ERROR "(\([0-9]+\) )?Proved 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 f1(a []int) int {
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x := 0
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for _, i := range a { // ERROR "Induction variable: limits \[0,\?\), 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: limits \[1,\?\), increment 1$"
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x += a[i] // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,10\), increment 2$"
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x += a[i] // ERROR "(\([0-9]+\) )?Proved 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: limits \[-10,10\), 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: limits \[0,\?\), increment 1$"
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b := a[0:i] // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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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: limits \[0,\?\), increment 1$"
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x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,\?\), increment 1$"
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x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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}
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return x
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}
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func g0c(a string) int {
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x := 0
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for i := len(a); i > 0; i-- { // ERROR "Induction variable: limits \(0,\?\], increment 1$"
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x += int(a[i-1]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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}
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return x
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}
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func g0d(a string) int {
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x := 0
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for i := len(a); 0 < i; i-- { // ERROR "Induction variable: limits \(0,\?\], increment 1$"
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x += int(a[i-1]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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}
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return x
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}
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func g0e(a string) int {
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x := 0
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for i := len(a) - 1; i >= 0; i-- { // ERROR "Induction variable: limits \[0,\?\], increment 1$"
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x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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}
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return x
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}
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func g0f(a string) int {
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x := 0
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for i := len(a) - 1; 0 <= i; i-- { // ERROR "Induction variable: limits \[0,\?\], increment 1$"
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x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,10\), increment 2$"
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x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,10\), increment 2$"
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j := i
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if a[i] == 'e' { // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,25\), increment 5$"
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useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,\?\), increment 1$"
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useString(a[i+1:]) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,\?\), increment 1$"
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useString(a[:i+1]) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,128\), increment 1$"
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c[i] = byte(i) // ERROR "(\([0-9]+\) )?Proved 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: limits \[0,128\), 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: limits \[10,90\), increment 1$"
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a[i-11] = i
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a[i-10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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a[i-5] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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a[i] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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a[i+5] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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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: limits \[10,90\), increment 1$"
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useSlice(a[:i-11])
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useSlice(a[:i-10]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[:i-5]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[:i]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[:i+5]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[:i+10]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[:i+11]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[:i+12])
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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: limits \[10,90\), increment 1$"
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useSlice(a[i-11:])
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useSlice(a[i-10:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[i-5:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[i+5:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[i+10:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[i+11:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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useSlice(a[i+12:])
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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: limits \[-10,90\), increment 1$"
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a[i+9] = i
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a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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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 k3neg(a [100]int) [100]int {
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for i := 89; i > -11; i-- { // ERROR "Induction variable: limits \(-11,89\], increment 1$"
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a[i+9] = i
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a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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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 k3neg2(a [100]int) [100]int {
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for i := 89; i >= -10; i-- { // ERROR "Induction variable: limits \[-10,89\], increment 1$"
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a[i+9] = i
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a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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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 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: limits \[-9223372036854775808,-9223372036854775758\), increment 1$"
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a[i-min] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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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: limits \[9223372036854775757,9223372036854775807\), increment 1$"
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a[i-max+50] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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a[i-(max-70)] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$"
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}
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return a
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}
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func d1(a [100]int) [100]int {
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for i := 0; i < 100; i++ { // ERROR "Induction variable: limits \[0,100\), increment 1$"
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for j := 0; j < i; j++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
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a[j] = 0 // ERROR "Proved IsInBounds$"
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a[j+1] = 0 // FIXME: this boundcheck should be eliminated
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a[j+2] = 0
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}
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}
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return a
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}
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func d2(a [100]int) [100]int {
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for i := 0; i < 100; i++ { // ERROR "Induction variable: limits \[0,100\), increment 1$"
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for j := 0; i > j; j++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
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a[j] = 0 // ERROR "Proved IsInBounds$"
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a[j+1] = 0 // FIXME: this boundcheck should be eliminated
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a[j+2] = 0
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}
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}
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return a
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}
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func d3(a [100]int) [100]int {
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for i := 0; i <= 99; i++ { // ERROR "Induction variable: limits \[0,99\], increment 1$"
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for j := 0; j <= i-1; j++ { // ERROR "Induction variable: limits \[0,\?\], increment 1$"
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a[j] = 0 // ERROR "Proved IsInBounds$"
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a[j+1] = 0 // ERROR "Proved IsInBounds$"
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a[j+2] = 0
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}
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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: limits \[0,\?\), increment 1$"
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useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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}
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for i := int64(0); i < int64(len(a))-31337; i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
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useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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}
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for i := int64(0); i < int64(len(a))+int64(-1<<63); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
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useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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}
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j := int64(len(a)) - 123
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for i := int64(0); i < j+123+int64(-1<<63); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
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useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$"
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}
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for i := int64(0); i < j+122+int64(-1<<63); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
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// len(a)-123+122+MinInt overflows when len(a) == 0, so a bound check is needed here
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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: limits \[-9223372036854775808,9223372036854775807\), 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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func issue26116a(a []int) {
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// There is no induction variable here. The comparison is in the wrong direction.
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for i := 3; i > 6; i++ {
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a[i] = 0
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}
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for i := 7; i < 3; i-- {
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a[i] = 1
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}
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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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