1// run
2
3//go:build !wasm
4
5// Copyright 2021 The Go Authors. All rights reserved.
6// Use of this source code is governed by a BSD-style
7// license that can be found in the LICENSE file.
8
9// wasm is excluded because the compiler chatter about register abi pragma ends up
10// on stdout, and causes the expected output to not match.
11
12package main
13
14import (
15	"fmt"
16)
17
18var sink int = 3
19
20//go:registerparams
21//go:noinline
22func F(a, b, c, d, e, f *int) {
23	G(f, e, d, c, b, a)
24	sink += *a // *a == 6 after swapping in G
25}
26
27//go:registerparams
28//go:noinline
29func G(a, b, c, d, e, f *int) {
30	var scratch [1000 * 100]int
31	scratch[*a] = *f                    // scratch[6] = 1
32	fmt.Println(*a, *b, *c, *d, *e, *f) // Forces it to spill b
33	sink = scratch[*b+1]                // scratch[5+1] == 1
34	*f, *a = *a, *f
35	*e, *b = *b, *e
36	*d, *c = *c, *d
37}
38
39func main() {
40	a, b, c, d, e, f := 1, 2, 3, 4, 5, 6
41	F(&a, &b, &c, &d, &e, &f)
42	fmt.Println(a, b, c, d, e, f)
43	fmt.Println(sink)
44}
45