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From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug math/18803] hypot missing underflows Date: Thu, 24 Sep 2015 23:44:00 -0000 [thread overview] Message-ID: <bug-18803-131-u4aq8XfjfL@http.sourceware.org/bugzilla/> (raw) In-Reply-To: <bug-18803-131@http.sourceware.org/bugzilla/> https://sourceware.org/bugzilla/show_bug.cgi?id=18803 --- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> --- This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU C Library master sources". The branch, master has been updated via f6987f5aa4c2ef7270bcb0a828808bd3db53520b (commit) from 2fd9177c92328e5c861c60ec9d0c4588cf0d9376 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f6987f5aa4c2ef7270bcb0a828808bd3db53520b commit f6987f5aa4c2ef7270bcb0a828808bd3db53520b Author: Joseph Myers <joseph@codesourcery.com> Date: Thu Sep 24 23:43:57 2015 +0000 Fix hypot missing underflows (bug 18803). Similar to various other bugs in this area, hypot functions can fail to raise the underflow exception when the result is tiny and inexact but one or more low bits of the intermediate result that is scaled down (or, in the i386 case, converted from a wider evaluation format) are zero. This patch forces the exception in a similar way to previous fixes. Note that this issue cannot arise for implementations of hypotf using double (or wider) for intermediate evaluation (if hypotf should underflow, that means the double square root is being computed of some number of the form N*2^-298, for 0 < N < 2^46, which is exactly represented as a double, and whatever the rounding mode such a square root cannot have a mantissa with all zeroes after the initial 23 bits). Thus no changes are made to hypotf implementations in this patch, only to hypot and hypotl. Tested for x86_64, x86, mips64 and powerpc. [BZ #18803] * sysdeps/i386/fpu/e_hypot.S: Use DEFINE_DBL_MIN. (MO): New macro. (__ieee754_hypot) [PIC]: Load PIC register. (__ieee754_hypot): Use DBL_NARROW_EVAL_UFLOW_NONNEG instead of DBL_NARROW_EVAL. * sysdeps/ieee754/dbl-64/e_hypot.c (__ieee754_hypot): Use math_check_force_underflow_nonneg in case where result might be tiny. * sysdeps/ieee754/ldbl-128/e_hypotl.c (__ieee754_hypotl): Likewise. * sysdeps/ieee754/ldbl-128ibm/e_hypotl.c (__ieee754_hypotl): Likewise. * sysdeps/ieee754/ldbl-96/e_hypotl.c (__ieee754_hypotl): Likewise. * sysdeps/powerpc/fpu/e_hypot.c (__ieee754_hypot): Likewise. * math/auto-libm-test-in: Add more tests of hypot. * math/auto-libm-test-out: Regenerated. ----------------------------------------------------------------------- Summary of changes: ChangeLog | 20 + NEWS | 6 +- math/auto-libm-test-in | 7 + math/auto-libm-test-out | 1342 ++++++++++++++++++++++++++++++++ sysdeps/i386/fpu/e_hypot.S | 13 +- sysdeps/ieee754/dbl-64/e_hypot.c | 4 +- sysdeps/ieee754/ldbl-128/e_hypotl.c | 4 +- sysdeps/ieee754/ldbl-128ibm/e_hypotl.c | 6 +- sysdeps/ieee754/ldbl-96/e_hypotl.c | 4 +- sysdeps/powerpc/fpu/e_hypot.c | 4 +- 10 files changed, 1401 insertions(+), 9 deletions(-) -- You are receiving this mail because: You are on the CC list for the bug.
next prev parent reply other threads:[~2015-09-24 23:44 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-08-11 0:38 [Bug math/18803] New: [i386] " jsm28 at gcc dot gnu.org 2015-08-13 23:08 ` [Bug math/18803] " jsm28 at gcc dot gnu.org 2015-09-24 23:44 ` cvs-commit at gcc dot gnu.org [this message] 2015-09-24 23:45 ` jsm28 at gcc dot gnu.org
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