1// run
2
3// Copyright 2015 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// Issue 12577: Test that there are no -0 floating-point constants.
8
9package main
10
11import "math"
12
13const (
14	z0 = 0.0
15	z1 = -0.0
16	z2 = -z0
17	z3 = -z2
18)
19
20var (
21	x0 float32 = z0
22	x1 float32 = z1
23	x2 float32 = z2
24	x3 float32 = z3
25
26	y0 float64 = z0
27	y1 float64 = z1
28	y2 float64 = z2
29	y3 float64 = z3
30)
31
32func test32(f float32) {
33	if f != 0 || math.Signbit(float64(f)) {
34		println("BUG: got", f, "want 0.0")
35		return
36	}
37}
38
39func test64(f float64) {
40	if f != 0 || math.Signbit(f) {
41		println("BUG: got", f, "want 0.0")
42		return
43	}
44}
45
46func main() {
47	if f := -x0; f != 0 || !math.Signbit(float64(f)) {
48		println("BUG: got", f, "want -0.0")
49	}
50
51	test32(-0.0)
52	test32(x0)
53	test32(x1)
54	test32(x2)
55	test32(x3)
56
57	if f := -y0; f != 0 || !math.Signbit(f) {
58		println("BUG: got", f, "want -0.0")
59	}
60
61	test64(-0.0)
62	test64(y0)
63	test64(y1)
64	test64(y2)
65	test64(y3)
66}
67