https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254911
--- Comment #4 from [email protected] --- A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=3b00222f156dca5700c839d73e36daf479fa640c commit 3b00222f156dca5700c839d73e36daf479fa640c Author: Dimitry Andric <[email protected]> AuthorDate: 2021-04-09 23:07:54 +0000 Commit: Dimitry Andric <[email protected]> CommitDate: 2021-04-10 11:59:57 +0000 Avoid raising unexpected floating point exceptions in libm When using clang with x86_64 CPUs that support AVX, some floating point transformations may raise exceptions that would not have been raised by the original code. To avoid this, use the -fp-exception-behavior=maytrap flag, introduced in clang 10.0.0. In particular, this fixes a number of test failures with ctanhf(3) and ctanf(3), when libm is compiled with -mavx. An unexpected FE_INVALID exception is then raised, because clang emits vdivps instructions to perform certain divides. (The vdivps instruction operates on multiple single-precision float operands simultaneously, but the exceptions may be influenced by unused parts of the XMM registers. In this particular case, it was calculating 0 / 0, which results in FE_INVALID.) If -fp-exception-behavior=maytrap is specified however, clang uses vdivss instructions instead, which work on one operand, and should not raise unexpected exceptions. Reported by: olivier Reviewed by: arichardson PR: 254911 MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D29686 lib/msun/Makefile | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) -- You are receiving this mail because: You are the assignee for the bug. _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "[email protected]"
