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From: "amonakov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/111101] -finline-small-functions may invert FP arguments breaking FP bit accuracy in case of NaNs Date: Tue, 22 Aug 2023 14:06:32 +0000 [thread overview] Message-ID: <bug-111101-4-uEtzfAaEwU@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-111101-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111101 Alexander Monakov <amonakov at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID CC| |amonakov at gcc dot gnu.org --- Comment #1 from Alexander Monakov <amonakov at gcc dot gnu.org> --- 0x7fe5ed65 is a quiet NaN, not signaling (it differs from the input 0x7fa5ed65 sNaN by the leading mantissa bit 0x00400000). IEEE-754 does not pin down which of the two payloads should be propagated when both operands are NaNs, and neither do language standards, so for GCC floating-point addition and similar operations are commutative. Observed NaN payloads are not predictable and may change depending on optimization level, choice of x87 vs. SSE instructions, etc. This is not a bug.
prev parent reply other threads:[~2023-08-22 14:06 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-08-22 13:30 [Bug rtl-optimization/111101] New: " pavel.morozkin at gmail dot com 2023-08-22 14:06 ` amonakov at gcc dot gnu.org [this message]
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