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// run
//go: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"
// This test is designed to provoke a stack growth
// in a way that very likely leaves junk in the
// parameter save area if they aren't saved or spilled
// there, as appropriate.
//go:registerparams
//go:noinline
func f(x int, xm1, xm2, p *int) {
var y = [2]int{x - 4, 0}
if x < 2 {
*p += x
return
}
x -= 3
g(*xm1, xm2, &x, p) // xm1 is no longer live.
h(*xm2, &x, &y[0], p) // xm2 is no longer live, but was spilled.
}
//go:registerparams
//go:noinline
func g(x int, xm1, xm2, p *int) {
var y = [3]int{x - 4, 0, 0}
if x < 2 {
*p += x
return
}
x -= 3
k(*xm2, &x, &y[0], p)
h(*xm1, xm2, &x, p)
}
//go:registerparams
//go:noinline
func h(x int, xm1, xm2, p *int) {
var y = [4]int{x - 4, 0, 0, 0}
if x < 2 {
*p += x
return
}
x -= 3
k(*xm1, xm2, &x, p)
f(*xm2, &x, &y[0], p)
}
//go:registerparams
//go:noinline
func k(x int, xm1, xm2, p *int) {
var y = [5]int{x - 4, 0, 0, 0, 0}
if x < 2 {
*p += x
return
}
x -= 3
f(*xm2, &x, &y[0], p)
g(*xm1, xm2, &x, p)
}
func main() {
x := 40
var y int
xm1 := x - 1
xm2 := x - 2
f(x, &xm1, &xm2, &y)
fmt.Printf("Fib(%d)=%d\n", x, y)
}
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