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author | Joseph Myers <joseph@codesourcery.com> | 2015-08-07 23:10:35 +0000 |
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committer | Joseph Myers <joseph@codesourcery.com> | 2015-08-07 23:10:35 +0000 |
commit | 37550cb3d6591a8f443467707ec80b4ab5c2e157 (patch) | |
tree | 934ef1da0ab3a2cd9d0a23b1645392914e95afcc /sysdeps/ieee754/ldbl-128/k_tanl.c | |
parent | db2bcbcb631f1c1aa023ef9f23a968e1ac288423 (diff) | |
download | glibc-37550cb3d6591a8f443467707ec80b4ab5c2e157.tar.gz glibc-37550cb3d6591a8f443467707ec80b4ab5c2e157.tar.xz glibc-37550cb3d6591a8f443467707ec80b4ab5c2e157.zip |
Fix tan missing underflows (bug 16517).
Similar to various other bugs in this area, some tan implementations do not raise the underflow exception for subnormal arguments, when the result is tiny and inexact. This patch forces the exception in a similar way to previous fixes. Tested for x86_64, x86, mips64 and powerpc. [BZ #16517] * sysdeps/ieee754/dbl-64/s_tan.c: Include <float.h>. (tan): Force underflow exception for arguments with small absolute value. * sysdeps/ieee754/flt-32/k_tanf.c: Include <float.h>. (__kernel_tanf): Force underflow exception for arguments with small absolute value. * sysdeps/ieee754/ldbl-128/k_tanl.c: Include <float.h>. (__kernel_tanl): Force underflow exception for arguments with small absolute value. * sysdeps/ieee754/ldbl-128ibm/k_tanl.c: Include <float.h>. (__kernel_tanl): Force underflow exception for arguments with small absolute value. * sysdeps/ieee754/ldbl-96/k_tanl.c: Include <float.h>. (__kernel_tanl): Force underflow exception for arguments with small absolute value. * math/auto-libm-test-in: Add more tests of tan. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'sysdeps/ieee754/ldbl-128/k_tanl.c')
-rw-r--r-- | sysdeps/ieee754/ldbl-128/k_tanl.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/sysdeps/ieee754/ldbl-128/k_tanl.c b/sysdeps/ieee754/ldbl-128/k_tanl.c index dfba2d9a76..6a6fa9f0a6 100644 --- a/sysdeps/ieee754/ldbl-128/k_tanl.c +++ b/sysdeps/ieee754/ldbl-128/k_tanl.c @@ -56,6 +56,7 @@ * = 1 - 2*(tan(y) - (tan(y)^2)/(1+tan(y))) */ +#include <float.h> #include <libc-internal.h> #include <math.h> #include <math_private.h> @@ -98,8 +99,17 @@ __kernel_tanl (long double x, long double y, int iy) if ((ix | u.parts32.w1 | u.parts32.w2 | u.parts32.w3 | (iy + 1)) == 0) return one / fabs (x); + else if (iy == 1) + { + if (fabsl (x) < LDBL_MIN) + { + long double force_underflow = x * x; + math_force_eval (force_underflow); + } + return x; + } else - return (iy == 1) ? x : -one / x; + return -one / x; } } if (ix >= 0x3ffe5942) /* |x| >= 0.6743316650390625 */ |