From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id C1DA5385C41B; Thu, 25 Aug 2022 12:55:58 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C1DA5385C41B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1661432158; bh=zORan3qkNCHEUpSrq7+5m5WvrSNQYwJpjSwUSGKAYTw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Q/uOq2Mjl6WPuNwDiHlpaWK0Yuz37zk4XkXI07bc/WHP7S96vq+zNao/pqWkUxu9f KrnQsnXdJ3nbbv+D2ml6AdXaiOCRIg3CPIL+BwfCh/fH+uMw/hT+UDejQYmITV/lni EEVLtQsb8TrOPlyeTkqXpuNEbatW83qZASrhrUuI= From: "jakub at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/106652] [C++23] P1467 - Extended floating-point types and standard names Date: Thu, 25 Aug 2022 12:55:58 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: unknown X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: jakub at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: attachments.created Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106652 --- Comment #6 from Jakub Jelinek --- Created attachment 53507 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D53507&action=3Dedit gcc13-pr106652-bf16.patch And if the answer to 1) is that it is ok for std::bfloat16_t to be __bf16 with u6__bf16 mangling, incremental patch for that. This one doesn't work though, because apparently on none of the 3 targets that do support __bf16 we actually support conversions between __bf16 and other floating point typ= es (most importantly float), nor arithmetic operations (that is quite fatal). So, the important question is if we are ok to add arithmetic operation supp= ort to __bf16 and ditto conversions (where arithmetic operations presumably wou= ld be implemented by cast to float, arithmetic on float and conversion back?),= or if that should be done only on some separate type, whether it is _BFloat16 = or __bfloat16_t or whatever else.=