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| author | Joseph Myers <joseph@codesourcery.com> | 2014-06-24 21:00:08 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2014-06-24 21:00:08 +0000 |
| commit | 4060283decf711ed95a6c4993ffeaba39f8cd40a (patch) | |
| tree | d303f8bcf7bd9fafbbb5edddc48c7c2be827f84e /ChangeLog | |
| parent | e7dd3c8c1db8c6d293abb995e033893b7328ad19 (diff) | |
| download | glibc-4060283decf711ed95a6c4993ffeaba39f8cd40a.tar.gz glibc-4060283decf711ed95a6c4993ffeaba39f8cd40a.tar.xz glibc-4060283decf711ed95a6c4993ffeaba39f8cd40a.zip | |
Fix x86/x86_64 expm1l spurious underflow exceptions (bug 16539).
This patch fixes bug 16539, spurious underflow exceptions from x86 / x86-64 expm1l. The problem is that the computation of a base-2 exponent with extra precision involves spurious underflows for arguments that are small but not subnormal, so a check is added to just return the argument in those cases. (If the argument *is* subnormal, underflowing is correct and the existing code will always underflow, so it suffices to keep using the existing code in that case; some expm1 implementations have a bug (bug 16353) with missing underflow exceptions, but I don't think there's such a bug in this particular version.) Tested x86_64 and x86; no ulps updates needed. (auto-libm-test-out diffs omitted below.) [BZ #16539] * sysdeps/i386/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Just return the argument for normal arguments with exponent below -64. * sysdeps/x86_64/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Likewise. * math/auto-libm-test-in: Add another test of expm1. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index 8ddb74fff6..ce6c4d8f24 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,13 @@ 2014-06-24 Joseph Myers <joseph@codesourcery.com> + [BZ #16539] + * sysdeps/i386/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Just + return the argument for normal arguments with exponent below -64. + * sysdeps/x86_64/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: + Likewise. + * math/auto-libm-test-in: Add another test of expm1. + * math/auto-libm-test-out: Regenerated. + [BZ #16287] * sysdeps/ieee754/ldbl-128/s_erfl.c (__erfl): Return 1 without calling __erfcl for arguments at least 16. |