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go/test/reorder.go
Matthew Dempsky 6de9423445 [dev.regabi] cmd/compile: cleanup OAS2FUNC ordering
Currently, to ensure OAS2FUNC results are assigned in the correct
order, they're always assigned to temporary variables. However, these
temporary variables are typed based on the destination type, which may
require an interface conversion. This means walk may have to then
introduce a second set of temporaries to ensure result parameters are
all copied out of the results area, before it emits calls to runtime
conversion functions.

That's just silly. Instead, this CL changes order to allocate the
result temporaries with the same type as the function returns in the
first place, and then assign them one at a time to their destinations,
with conversions as needed.

While here, also fix an order-of-evaluation issue with has-ok
assignments that I almost added to multi-value function call
assignments, and add tests for each.

Change-Id: I9f4e962425fe3c5e3305adbbfeae2c7f253ec365
Reviewed-on: https://go-review.googlesource.com/c/go/+/284220
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2021-01-16 23:19:26 +00:00

168 lines
2.3 KiB
Go

// run
// Copyright 2011 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.
// Test reordering of assignments.
package main
import "fmt"
func main() {
p1()
p2()
p3()
p4()
p5()
p6()
p7()
p8()
p9()
p10()
p11()
}
var gx []int
func f(i int) int {
return gx[i]
}
func check(x []int, x0, x1, x2 int) {
if x[0] != x0 || x[1] != x1 || x[2] != x2 {
fmt.Printf("%v, want %d,%d,%d\n", x, x0, x1, x2)
panic("failed")
}
}
func check3(x, y, z, xx, yy, zz int) {
if x != xx || y != yy || z != zz {
fmt.Printf("%d,%d,%d, want %d,%d,%d\n", x, y, z, xx, yy, zz)
panic("failed")
}
}
func p1() {
x := []int{1, 2, 3}
i := 0
i, x[i] = 1, 100
_ = i
check(x, 100, 2, 3)
}
func p2() {
x := []int{1, 2, 3}
i := 0
x[i], i = 100, 1
_ = i
check(x, 100, 2, 3)
}
func p3() {
x := []int{1, 2, 3}
y := x
gx = x
x[1], y[0] = f(0), f(1)
check(x, 2, 1, 3)
}
func p4() {
x := []int{1, 2, 3}
y := x
gx = x
x[1], y[0] = gx[0], gx[1]
check(x, 2, 1, 3)
}
func p5() {
x := []int{1, 2, 3}
y := x
p := &x[0]
q := &x[1]
*p, *q = x[1], y[0]
check(x, 2, 1, 3)
}
func p6() {
x := 1
y := 2
z := 3
px := &x
py := &y
*px, *py = y, x
check3(x, y, z, 2, 1, 3)
}
func f1(x, y, z int) (xx, yy, zz int) {
return x, y, z
}
func f2() (x, y, z int) {
return f1(2, 1, 3)
}
func p7() {
x, y, z := f2()
check3(x, y, z, 2, 1, 3)
}
func p8() {
m := make(map[int]int)
m[0] = len(m)
if m[0] != 0 {
panic(m[0])
}
}
// Issue #13433: Left-to-right assignment of OAS2XXX nodes.
func p9() {
var x bool
// OAS2FUNC
x, x = fn()
checkOAS2XXX(x, "x, x = fn()")
// OAS2RECV
var c = make(chan bool, 10)
c <- false
x, x = <-c
checkOAS2XXX(x, "x, x <-c")
// OAS2MAPR
var m = map[int]bool{0: false}
x, x = m[0]
checkOAS2XXX(x, "x, x = m[0]")
// OAS2DOTTYPE
var i interface{} = false
x, x = i.(bool)
checkOAS2XXX(x, "x, x = i.(bool)")
}
//go:noinline
func fn() (bool, bool) { return false, true }
// checks the order of OAS2XXX.
func checkOAS2XXX(x bool, s string) {
if !x {
fmt.Printf("%s; got=(false); want=(true)\n", s)
panic("failed")
}
}
//go:noinline
func fp() (*int, int) { return nil, 42 }
func p10() {
p := new(int)
p, *p = fp()
}
func p11() {
var i interface{}
p := new(bool)
p, *p = i.(*bool)
}