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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Tests load/store ordering
package main
import "testing"
// testLoadStoreOrder tests for reordering of stores/loads.
func testLoadStoreOrder(t *testing.T) {
z := uint32(1000)
if testLoadStoreOrder_ssa(&z, 100) == 0 {
t.Errorf("testLoadStoreOrder failed")
}
}
//go:noinline
func testLoadStoreOrder_ssa(z *uint32, prec uint) int {
old := *z // load
*z = uint32(prec) // store
if *z < old { // load
return 1
}
return 0
}
func testStoreSize(t *testing.T) {
a := [4]uint16{11, 22, 33, 44}
testStoreSize_ssa(&a[0], &a[2], 77)
want := [4]uint16{77, 22, 33, 44}
if a != want {
t.Errorf("testStoreSize failed. want = %d, got = %d", want, a)
}
}
//go:noinline
func testStoreSize_ssa(p *uint16, q *uint16, v uint32) {
// Test to make sure that (Store ptr (Trunc32to16 val) mem)
// does not end up as a 32-bit store. It must stay a 16 bit store
// even when Trunc32to16 is rewritten to be a nop.
// To ensure that we get rewrite the Trunc32to16 before
// we rewrite the Store, we force the truncate into an
// earlier basic block by using it on both branches.
w := uint16(v)
if p != nil {
*p = w
} else {
*q = w
}
}
//go:noinline
func testExtStore_ssa(p *byte, b bool) int {
x := *p
*p = 7
if b {
return int(x)
}
return 0
}
func testExtStore(t *testing.T) {
const start = 8
var b byte = start
if got := testExtStore_ssa(&b, true); got != start {
t.Errorf("testExtStore failed. want = %d, got = %d", start, got)
}
}
var b int
// testDeadStorePanic_ssa ensures that we don't optimize away stores
// that could be read by after recover(). Modeled after fixedbugs/issue1304.
//
//go:noinline
func testDeadStorePanic_ssa(a int) (r int) {
defer func() {
recover()
r = a
}()
a = 2 // store
b := a - a // optimized to zero
c := 4
a = c / b // store, but panics
a = 3 // store
r = a
return
}
func testDeadStorePanic(t *testing.T) {
if want, got := 2, testDeadStorePanic_ssa(1); want != got {
t.Errorf("testDeadStorePanic failed. want = %d, got = %d", want, got)
}
}
//go:noinline
func loadHitStore8(x int8, p *int8) int32 {
x *= x // try to trash high bits (arch-dependent)
*p = x // store
return int32(*p) // load and cast
}
//go:noinline
func loadHitStoreU8(x uint8, p *uint8) uint32 {
x *= x // try to trash high bits (arch-dependent)
*p = x // store
return uint32(*p) // load and cast
}
//go:noinline
func loadHitStore16(x int16, p *int16) int32 {
x *= x // try to trash high bits (arch-dependent)
*p = x // store
return int32(*p) // load and cast
}
//go:noinline
func loadHitStoreU16(x uint16, p *uint16) uint32 {
x *= x // try to trash high bits (arch-dependent)
*p = x // store
return uint32(*p) // load and cast
}
//go:noinline
func loadHitStore32(x int32, p *int32) int64 {
x *= x // try to trash high bits (arch-dependent)
*p = x // store
return int64(*p) // load and cast
}
//go:noinline
func loadHitStoreU32(x uint32, p *uint32) uint64 {
x *= x // try to trash high bits (arch-dependent)
*p = x // store
return uint64(*p) // load and cast
}
func testLoadHitStore(t *testing.T) {
// Test that sign/zero extensions are kept when a load-hit-store
// is replaced by a register-register move.
{
var in int8 = (1 << 6) + 1
var p int8
got := loadHitStore8(in, &p)
want := int32(in * in)
if got != want {
t.Errorf("testLoadHitStore (int8) failed. want = %d, got = %d", want, got)
}
}
{
var in uint8 = (1 << 6) + 1
var p uint8
got := loadHitStoreU8(in, &p)
want := uint32(in * in)
if got != want {
t.Errorf("testLoadHitStore (uint8) failed. want = %d, got = %d", want, got)
}
}
{
var in int16 = (1 << 10) + 1
var p int16
got := loadHitStore16(in, &p)
want := int32(in * in)
if got != want {
t.Errorf("testLoadHitStore (int16) failed. want = %d, got = %d", want, got)
}
}
{
var in uint16 = (1 << 10) + 1
var p uint16
got := loadHitStoreU16(in, &p)
want := uint32(in * in)
if got != want {
t.Errorf("testLoadHitStore (uint16) failed. want = %d, got = %d", want, got)
}
}
{
var in int32 = (1 << 30) + 1
var p int32
got := loadHitStore32(in, &p)
want := int64(in * in)
if got != want {
t.Errorf("testLoadHitStore (int32) failed. want = %d, got = %d", want, got)
}
}
{
var in uint32 = (1 << 30) + 1
var p uint32
got := loadHitStoreU32(in, &p)
want := uint64(in * in)
if got != want {
t.Errorf("testLoadHitStore (uint32) failed. want = %d, got = %d", want, got)
}
}
}
func TestLoadStore(t *testing.T) {
testLoadStoreOrder(t)
testStoreSize(t)
testExtStore(t)
testDeadStorePanic(t)
testLoadHitStore(t)
}
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