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| author | ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4> | 2012-04-27 16:32:42 +0000 |
|---|---|---|
| committer | ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4> | 2012-04-27 16:32:42 +0000 |
| commit | 3ff40a6bf4310e9e5bb398be2e590e3998fb203a (patch) | |
| tree | 8a6aa1b0241651d494e4bbac70e2c0cd0613f1de | |
| parent | 1a3dd03cc70c25851dc19f53ba6d2d087e247b2c (diff) | |
| download | gcc-3ff40a6bf4310e9e5bb398be2e590e3998fb203a.tar.gz | |
PR go/52358
math: Work around bug in Solaris 9 implementation of ldexp.
The bug is that ldexp(-1, -1075) should return -0, but the
Solaris 9 implementation returns +0.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@186913 138bc75d-0d04-0410-961f-82ee72b054a4
| -rw-r--r-- | libgo/go/math/ldexp.go | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/libgo/go/math/ldexp.go b/libgo/go/math/ldexp.go index 32c9853204d..4c63edd7319 100644 --- a/libgo/go/math/ldexp.go +++ b/libgo/go/math/ldexp.go @@ -16,7 +16,18 @@ package math func libc_ldexp(float64, int) float64 func Ldexp(frac float64, exp int) float64 { - return libc_ldexp(frac, exp) + r := libc_ldexp(frac, exp) + + // Work around a bug in the implementation of ldexp on Solaris + // 9. If multiplying a negative number by 2 raised to a + // negative exponent underflows, we want to return negative + // zero, but the Solaris 9 implementation returns positive + // zero. This workaround can be removed when and if we no + // longer care about Solaris 9. + if r == 0 && frac < 0 && exp < 0 { + r = Copysign(0, frac) + } + return r } func ldexp(frac float64, exp int) float64 { |