go/test/loopbce.go
Giovanni Bajo 7ec25d0acf cmd/compile: implement loop BCE in prove
Reuse findIndVar to discover induction variables, and then
register the facts we know about them into the facts table
when entering the loop block.

Moreover, handle "x+delta > w" while updating the facts table,
to be able to prove accesses to slices with constant offsets
such as slice[i-10].

Change-Id: I2a63d050ed58258136d54712ac7015b25c893d71
Reviewed-on: https://go-review.googlesource.com/104038
Run-TryBot: Giovanni Bajo <rasky@develer.com>
Reviewed-by: David Chase <drchase@google.com>
2018-04-29 09:37:35 +00:00

258 lines
6.4 KiB
Go

// +build amd64
// errorcheck -0 -d=ssa/prove/debug=1
package main
func f0a(a []int) int {
x := 0
for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
x += a[i] // ERROR "Proved IsInBounds$"
}
return x
}
func f0b(a []int) int {
x := 0
for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
b := a[i:] // ERROR "Proved IsSliceInBounds$"
x += b[0]
}
return x
}
func f0c(a []int) int {
x := 0
for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
b := a[:i+1] // ERROR "Proved IsSliceInBounds$"
x += b[0]
}
return x
}
func f1(a []int) int {
x := 0
for _, i := range a { // ERROR "Induction variable with minimum 0 and increment 1"
x += i
}
return x
}
func f2(a []int) int {
x := 0
for i := 1; i < len(a); i++ { // ERROR "Induction variable with minimum 1 and increment 1$"
x += a[i] // ERROR "Proved IsInBounds$"
}
return x
}
func f4(a [10]int) int {
x := 0
for i := 0; i < len(a); i += 2 { // ERROR "Induction variable with minimum 0 and increment 2$"
x += a[i] // ERROR "Proved IsInBounds$"
}
return x
}
func f5(a [10]int) int {
x := 0
for i := -10; i < len(a); i += 2 { // ERROR "Induction variable with minimum -10 and increment 2$"
x += a[i]
}
return x
}
func f6(a []int) {
for i := range a { // ERROR "Induction variable with minimum 0 and increment 1$"
b := a[0:i] // ERROR "Proved IsSliceInBounds$"
f6(b)
}
}
func g0a(a string) int {
x := 0
for i := 0; i < len(a); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
x += int(a[i]) // ERROR "Proved IsInBounds$"
}
return x
}
func g0b(a string) int {
x := 0
for i := 0; len(a) > i; i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
x += int(a[i]) // ERROR "Proved IsInBounds$"
}
return x
}
func g1() int {
a := "evenlength"
x := 0
for i := 0; i < len(a); i += 2 { // ERROR "Induction variable with minimum 0 and increment 2$"
x += int(a[i]) // ERROR "Proved IsInBounds$"
}
return x
}
func g2() int {
a := "evenlength"
x := 0
for i := 0; i < len(a); i += 2 { // ERROR "Induction variable with minimum 0 and increment 2$"
j := i
if a[i] == 'e' { // ERROR "Proved IsInBounds$"
j = j + 1
}
x += int(a[j])
}
return x
}
func g3a() {
a := "this string has length 25"
for i := 0; i < len(a); i += 5 { // ERROR "Induction variable with minimum 0 and increment 5$"
useString(a[i:]) // ERROR "Proved IsSliceInBounds$"
useString(a[:i+3])
}
}
func g3b(a string) {
for i := 0; i < len(a); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
useString(a[i+1:]) // ERROR "Proved IsSliceInBounds$"
}
}
func g3c(a string) {
for i := 0; i < len(a); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
useString(a[:i+1]) // ERROR "Proved IsSliceInBounds$"
}
}
func h1(a []byte) {
c := a[:128]
for i := range c { // ERROR "Induction variable with minimum 0 and increment 1$"
c[i] = byte(i) // ERROR "Proved IsInBounds$"
}
}
func h2(a []byte) {
for i := range a[:128] { // ERROR "Induction variable with minimum 0 and increment 1$"
a[i] = byte(i)
}
}
func k0(a [100]int) [100]int {
for i := 10; i < 90; i++ { // ERROR "Induction variable with minimum 10 and increment 1$"
a[i-11] = i
a[i-10] = i // ERROR "Proved IsInBounds$"
a[i-5] = i // ERROR "Proved IsInBounds$"
a[i] = i // ERROR "Proved IsInBounds$"
a[i+5] = i // ERROR "Proved IsInBounds$"
a[i+10] = i // ERROR "Proved IsInBounds$"
a[i+11] = i
}
return a
}
func k1(a [100]int) [100]int {
for i := 10; i < 90; i++ { // ERROR "Induction variable with minimum 10 and increment 1$"
useSlice(a[:i-11])
useSlice(a[:i-10]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[:i-5]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[:i]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[:i+5]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[:i+10]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[:i+11]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[:i+12])
}
return a
}
func k2(a [100]int) [100]int {
for i := 10; i < 90; i++ { // ERROR "Induction variable with minimum 10 and increment 1$"
useSlice(a[i-11:])
useSlice(a[i-10:]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[i-5:]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[i:]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[i+5:]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[i+10:]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[i+11:]) // ERROR "Proved IsSliceInBounds$"
useSlice(a[i+12:])
}
return a
}
func k3(a [100]int) [100]int {
for i := -10; i < 90; i++ { // ERROR "Induction variable with minimum -10 and increment 1$"
a[i+9] = i
a[i+10] = i // ERROR "Proved IsInBounds$"
a[i+11] = i
}
return a
}
func k4(a [100]int) [100]int {
min := (-1) << 63
for i := min; i < min+50; i++ { // ERROR "Induction variable with minimum -9223372036854775808 and increment 1$"
a[i-min] = i // ERROR "Proved IsInBounds$"
}
return a
}
func k5(a [100]int) [100]int {
max := (1 << 63) - 1
for i := max - 50; i < max; i++ { // ERROR "Induction variable with minimum 9223372036854775757 and increment 1$"
a[i-max+50] = i // ERROR "Proved IsInBounds$"
a[i-(max-70)] = i // ERROR "Proved IsInBounds$"
}
return a
}
func nobce1() {
// tests overflow of max-min
a := int64(9223372036854774057)
b := int64(-1547)
z := int64(1337)
if a%z == b%z {
panic("invalid test: modulos should differ")
}
for i := b; i < a; i += z {
// No induction variable is possible because i will overflow a first iteration.
useString("foobar")
}
}
func nobce2(a string) {
for i := int64(0); i < int64(len(a)); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
useString(a[i:]) // ERROR "Proved IsSliceInBounds$"
}
for i := int64(0); i < int64(len(a))-31337; i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
useString(a[i:]) // ERROR "Proved IsSliceInBounds$"
}
for i := int64(0); i < int64(len(a))+int64(-1<<63); i++ { // ERROR "Induction variable with minimum 0 and increment 1$"
// tests an overflow of StringLen-MinInt64
useString(a[i:])
}
}
func nobce3(a [100]int64) [100]int64 {
min := int64((-1) << 63)
max := int64((1 << 63) - 1)
for i := min; i < max; i++ { // ERROR "Induction variable with minimum -9223372036854775808 and increment 1$"
a[i] = i
}
return a
}
//go:noinline
func useString(a string) {
}
//go:noinline
func useSlice(a []int) {
}
func main() {
}