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| author | Joseph Myers <joseph@codesourcery.com> | 2015-06-29 16:52:16 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-06-29 16:52:16 +0000 |
| commit | 63dbe5f32238858c7b953b867ed0588c7808dd4f (patch) | |
| tree | 05aff3104a86894353a10f5ddc0c32deef550977 /sysdeps/ieee754/flt-32 | |
| parent | 31545c23277cd54a1edd41c85d8255fb589158e3 (diff) | |
| download | glibc-63dbe5f32238858c7b953b867ed0588c7808dd4f.tar.gz glibc-63dbe5f32238858c7b953b867ed0588c7808dd4f.tar.xz glibc-63dbe5f32238858c7b953b867ed0588c7808dd4f.zip | |
Fix j1, jn missing underflows (bug 16559).
Similar to various other bugs in this area, j1 and jn implementations can fail to raise the underflow exception when the internal computation is exact although the actual function is inexact. This patch forces the exception in a similar way to other such fixes. (The ldbl-128 / ldbl-128ibm j1l implementation is different and doesn't need a change for this until spurious underflows in it are fixed.) Tested for x86_64, x86, mips64 and powerpc. [BZ #16559] * sysdeps/ieee754/dbl-64/e_j1.c: Include <float.h>. (__ieee754_j1): Force underflow exception for small results. * sysdeps/ieee754/dbl-64/e_jn.c (__ieee754_jn): Likewise. * sysdeps/ieee754/flt-32/e_j1f.c: Include <float.h>. (__ieee754_j1f): Force underflow exception for small results. * sysdeps/ieee754/flt-32/e_jnf.c (__ieee754_jnf): Likewise. * sysdeps/ieee754/ldbl-128/e_jnl.c (__ieee754_jnl): Likewise. * sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Likewise. * sysdeps/ieee754/ldbl-96/e_j1l.c: Include <float.h>. (__ieee754_j1l): Force underflow exception for small results. * sysdeps/ieee754/ldbl-96/e_jnl.c (__ieee754_jnl): Likewise. * math/auto-libm-test-in: Add more tests of j1 and jn. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'sysdeps/ieee754/flt-32')
| -rw-r--r-- | sysdeps/ieee754/flt-32/e_j1f.c | 10 | ||||
| -rw-r--r-- | sysdeps/ieee754/flt-32/e_jnf.c | 4 |
2 files changed, 13 insertions, 1 deletions
diff --git a/sysdeps/ieee754/flt-32/e_j1f.c b/sysdeps/ieee754/flt-32/e_j1f.c index 7ffb57e806..63de21f609 100644 --- a/sysdeps/ieee754/flt-32/e_j1f.c +++ b/sysdeps/ieee754/flt-32/e_j1f.c @@ -14,6 +14,7 @@ */ #include <errno.h> +#include <float.h> #include <math.h> #include <math_private.h> @@ -69,7 +70,14 @@ __ieee754_j1f(float x) else return z; } if(__builtin_expect(ix<0x32000000, 0)) { /* |x|<2**-27 */ - if(huge+x>one) return (float)0.5*x;/* inexact if x!=0 necessary */ + if(huge+x>one) { /* inexact if x!=0 necessary */ + float ret = (float) 0.5 * x; + if (fabsf (ret) < FLT_MIN) { + float force_underflow = ret * ret; + math_force_eval (force_underflow); + } + return ret; + } } z = x*x; r = z*(r00+z*(r01+z*(r02+z*r03))); diff --git a/sysdeps/ieee754/flt-32/e_jnf.c b/sysdeps/ieee754/flt-32/e_jnf.c index ec5a81b653..44a3761adb 100644 --- a/sysdeps/ieee754/flt-32/e_jnf.c +++ b/sysdeps/ieee754/flt-32/e_jnf.c @@ -170,6 +170,10 @@ __ieee754_jnf(int n, float x) } if (ret == 0) ret = __copysignf (FLT_MIN, ret) * FLT_MIN; + else if (fabsf (ret) < FLT_MIN) { + float force_underflow = ret * ret; + math_force_eval (force_underflow); + } return ret; } strong_alias (__ieee754_jnf, __jnf_finite) |