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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/109294] Inconsistent exp function implementations for compile time and run time evaluation Date: Mon, 27 Mar 2023 13:38:31 +0000 [thread overview] Message-ID: <bug-109294-4-pfZeGr5F7s@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-109294-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109294 Xi Ruoyao <xry111 at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |xry111 at gcc dot gnu.org --- Comment #1 from Xi Ruoyao <xry111 at gcc dot gnu.org> --- Here GCC produces more precise value at compile time (as MPFR is used for floating evaluation), while Glibc produces less precise value at runtime. The C standard allows exp to be not correctly rounded (N3054 F.5 para 1), i. e. several ULPs of error is allowed. So there is no way to predict what Glibc (or another Glibc) will produce at runtime. I see nothing we can do here.
next prev parent reply other threads:[~2023-03-27 13:38 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-27 9:54 [Bug c++/109294] New: " jdavidpeter at gmail dot com 2023-03-27 13:38 ` xry111 at gcc dot gnu.org [this message] 2023-03-27 13:55 ` [Bug c++/109294] " redi at gcc dot gnu.org 2023-03-27 15:21 ` pinskia at gcc dot gnu.org
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