github.com/xushiwei/go@v0.0.0-20130601165731-2b9d83f45bc9/test/fixedbugs/bug434.go (about)

     1  // run
     2  
     3  // Copyright 2012 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  // Test that typed and untyped negative zero floating point constants
     8  // are treated as equivalent to zero constants.
     9  
    10  package main
    11  
    12  import "math"
    13  
    14  const zero = 0.0
    15  
    16  func main() {
    17  	x := -zero
    18  	b := math.Float64bits(x)
    19  	if b != 0 {
    20  		panic(b)
    21  	}
    22  	x = -float64(zero)
    23  	b = math.Float64bits(x)
    24  	if b != 0 {
    25  		panic(b)
    26  	}
    27  	v := x
    28  	b = math.Float64bits(-v)
    29  	if b != 0x8000000000000000 {
    30  		panic(b)
    31  	}
    32  }