math: fix special cases in Nextafter
Nextafter(0, -1) != -0.
R=rsc, golang-dev
CC=golang-dev
https://golang.org/cl/5467060
diff --git a/src/pkg/math/all_test.go b/src/pkg/math/all_test.go
index 7256ca4..98a4df0 100644
--- a/src/pkg/math/all_test.go
+++ b/src/pkg/math/all_test.go
@@ -1328,12 +1328,26 @@
}
var vfnextafterSC = [][2]float64{
+ {0, 0},
+ {0, Copysign(0, -1)},
+ {0, -1},
{0, NaN()},
+ {Copysign(0, -1), 1},
+ {Copysign(0, -1), 0},
+ {Copysign(0, -1), Copysign(0, -1)},
+ {Copysign(0, -1), -1},
{NaN(), 0},
{NaN(), NaN()},
}
var nextafterSC = []float64{
+ 0,
+ 0,
+ -4.9406564584124654418e-324, // Float64frombits(0x8000000000000001)
NaN(),
+ 4.9406564584124654418e-324, // Float64frombits(0x0000000000000001)
+ Copysign(0, -1),
+ Copysign(0, -1),
+ -4.9406564584124654418e-324, // Float64frombits(0x8000000000000001)
NaN(),
NaN(),
}
@@ -2259,7 +2273,7 @@
t.Errorf("Nextafter(%g, %g) = %g want %g", vf[i], 10.0, f, nextafter[i])
}
}
- for i := 0; i < len(vfmodfSC); i++ {
+ for i := 0; i < len(vfnextafterSC); i++ {
if f := Nextafter(vfnextafterSC[i][0], vfnextafterSC[i][1]); !alike(nextafterSC[i], f) {
t.Errorf("Nextafter(%g, %g) = %g want %g", vfnextafterSC[i][0], vfnextafterSC[i][1], f, nextafterSC[i])
}
