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[release-branch.go1.9] bytes, strings: fix comparison of long byte slices on s390x

The existing implementation of bytes.Compare on s390x doesn't work properly for slices longer
than 256 elements. This change fixes that. Added tests for long strings and slices of bytes.

Fixes #26118

Change-Id: If6d8b68ee6dbcf99a24f867a1d3438b1f208954f
Reviewed-on: https://go-review.googlesource.com/121495
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-on: https://go-review.googlesource.com/124137
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
bill_ofarrell 2018-06-28 18:39:37 -04:00 committed by Ian Lance Taylor
parent 1746cff738
commit f865b5fefe
3 changed files with 28 additions and 4 deletions

View File

@ -6,6 +6,7 @@ package bytes_test
import (
. "bytes"
"internal/testenv"
"testing"
)
@ -58,10 +59,20 @@ func TestCompareIdenticalSlice(t *testing.T) {
}
func TestCompareBytes(t *testing.T) {
n := 128
lengths := make([]int, 0) // lengths to test in ascending order
for i := 0; i <= 128; i++ {
lengths = append(lengths, i)
}
lengths = append(lengths, 256, 512, 1024, 1333, 4095, 4096, 4097)
if !testing.Short() || testenv.Builder() != "" {
lengths = append(lengths, 65535, 65536, 65537, 99999)
}
n := lengths[len(lengths)-1]
a := make([]byte, n+1)
b := make([]byte, n+1)
for len := 0; len < 128; len++ {
for _, len := range lengths {
// randomish but deterministic data. No 0 or 255.
for i := 0; i < len; i++ {
a[i] = byte(1 + 31*i%254)

View File

@ -1004,6 +1004,8 @@ loop:
BGT gt
BLT lt
SUB $256, R8
MOVD $256(R3), R3
MOVD $256(R5), R5
CMP R8, $256
BGT loop
tail:

View File

@ -8,6 +8,7 @@ package strings_test
// Benchmarks omitted since the underlying implementation is identical.
import (
"internal/testenv"
. "strings"
"testing"
)
@ -52,10 +53,20 @@ func TestCompareIdenticalString(t *testing.T) {
}
func TestCompareStrings(t *testing.T) {
n := 128
lengths := make([]int, 0) // lengths to test in ascending order
for i := 0; i <= 128; i++ {
lengths = append(lengths, i)
}
lengths = append(lengths, 256, 512, 1024, 1333, 4095, 4096, 4097)
if !testing.Short() || testenv.Builder() != "" {
lengths = append(lengths, 65535, 65536, 65537, 99999)
}
n := lengths[len(lengths)-1]
a := make([]byte, n+1)
b := make([]byte, n+1)
for len := 0; len < 128; len++ {
for _, len := range lengths {
// randomish but deterministic data. No 0 or 255.
for i := 0; i < len; i++ {
a[i] = byte(1 + 31*i%254)