|  | // run | 
|  |  | 
|  | //go:build !wasm | 
|  | // +build !wasm | 
|  |  | 
|  | // Copyright 2021 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. | 
|  |  | 
|  | // wasm is excluded because the compiler chatter about register abi pragma ends up | 
|  | // on stdout, and causes the expected output to not match. | 
|  |  | 
|  | package main | 
|  |  | 
|  | import ( | 
|  | "fmt" | 
|  | ) | 
|  |  | 
|  | var sink int = 3 | 
|  |  | 
|  | //go:registerparams | 
|  | //go:noinline | 
|  | func F(a, b, c, d, e, f *int) { | 
|  | G(f, e, d, c, b, a) | 
|  | sink += *a // *a == 6 after swapping in G | 
|  | } | 
|  |  | 
|  | //go:registerparams | 
|  | //go:noinline | 
|  | func G(a, b, c, d, e, f *int) { | 
|  | var scratch [1000 * 100]int | 
|  | scratch[*a] = *f                    // scratch[6] = 1 | 
|  | fmt.Println(*a, *b, *c, *d, *e, *f) // Forces it to spill b | 
|  | sink = scratch[*b+1]                // scratch[5+1] == 1 | 
|  | *f, *a = *a, *f | 
|  | *e, *b = *b, *e | 
|  | *d, *c = *c, *d | 
|  | } | 
|  |  | 
|  | func main() { | 
|  | a, b, c, d, e, f := 1, 2, 3, 4, 5, 6 | 
|  | F(&a, &b, &c, &d, &e, &f) | 
|  | fmt.Println(a, b, c, d, e, f) | 
|  | fmt.Println(sink) | 
|  | } |