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| author | Joseph Myers <joseph@codesourcery.com> | 2015-06-24 15:12:03 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-06-24 15:12:03 +0000 |
| commit | 8475ab16848cf2adb6ce3446749c2f1d10233286 (patch) | |
| tree | ce32b378b0e67c8d52f6a6a63347ae4b3711d159 | |
| parent | 36870482d2a33e3b703bd74b52063594389e827a (diff) | |
| download | glibc-8475ab16848cf2adb6ce3446749c2f1d10233286.tar.gz glibc-8475ab16848cf2adb6ce3446749c2f1d10233286.tar.xz glibc-8475ab16848cf2adb6ce3446749c2f1d10233286.zip | |
Fix ldbl-128 expl missing underflows (bug 18586).
Similar to various other bugs in this area, the ldbl-128 expl implementation does not raise the underflow exception for all subnormal results, if the scaling down is exact although the actual result is inexact. This patch fixes this by forcing the exception in this case (the tests that failed before and pass after the test are already in the testsuite). Tested for mips64. [BZ #18586] * sysdeps/ieee754/ldbl-128/e_expl.c (__ieee754_expl): Force underflow exception for small results.
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | NEWS | 2 | ||||
| -rw-r--r-- | sysdeps/ieee754/ldbl-128/e_expl.c | 10 |
3 files changed, 16 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog index b5e19b1817..b103dcdc26 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2015-06-24 Joseph Myers <joseph@codesourcery.com> + + [BZ #18586] + * sysdeps/ieee754/ldbl-128/e_expl.c (__ieee754_expl): Force + underflow exception for small results. + 2015-06-24 Andrew Senkevich <andrew.senkevich@intel.com> * sysdeps/x86_64/fpu/Makefile (libmvec-support): Fixed files list. diff --git a/NEWS b/NEWS index aacd894c82..e8c84b88e0 100644 --- a/NEWS +++ b/NEWS @@ -24,7 +24,7 @@ Version 2.22 18444, 18468, 18469, 18470, 18479, 18483, 18495, 18496, 18497, 18498, 18507, 18512, 18513, 18519, 18520, 18522, 18527, 18528, 18529, 18530, 18532, 18533, 18534, 18536, 18539, 18540, 18542, 18544, 18545, 18546, - 18547, 18553, 18558, 18569, 18583. + 18547, 18553, 18558, 18569, 18583, 18586. * Cache information can be queried via sysconf() function on s390 e.g. with _SC_LEVEL1_ICACHE_SIZE as argument. diff --git a/sysdeps/ieee754/ldbl-128/e_expl.c b/sysdeps/ieee754/ldbl-128/e_expl.c index b4b789658a..1cd095cb77 100644 --- a/sysdeps/ieee754/ldbl-128/e_expl.c +++ b/sysdeps/ieee754/ldbl-128/e_expl.c @@ -230,7 +230,15 @@ __ieee754_expl (long double x) if (!unsafe) return result; else - return result * scale_u.d; + { + result *= scale_u.d; + if (result < LDBL_MIN) + { + long double force_underflow = result * result; + math_force_eval (force_underflow); + } + return result; + } } /* Exceptional cases: */ else if (isless (x, himark)) |