From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 559E93858D33; Mon, 25 Mar 2024 18:19:56 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 559E93858D33 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1711390796; bh=Rr7JmhfHkEj2Ic5hCXompxjtN9Iq93hfJnyUQPFfy/c=; h=From:To:Subject:Date:In-Reply-To:References:From; b=BlBF8hRhZTNnc4dI4G7YJ6GnabnSf/+TEfRQkAQY0TtC8zJYpc8LOtErhc/yrXi22 u1VkccgvN/35VxxleTDVnlgFFvtGCLQW7r88stKKSjAjf3OaBwm6kY8VNoplffEVFO Xa84gSDJo6eJxcxlNw8XHx2BR9NU0FnkDHgQ1UHk= From: "jsm28 at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/114469] gcc.dg/torture/bitint-64.c failure with -O2 -flto -std=c23 -fwrapv Date: Mon, 25 Mar 2024 18:19:56 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: jsm28 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: 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=3D114469 --- Comment #1 from Joseph S. Myers --- I'd expect _Atomic _BitInt(5) to follow the same ABI (regarding upper bits being defined or not) as plain _BitInt(5), and any simplification needs to = deal with that. (In principle for atomics with _BitInt with padding bits there are the same concerns as for any types with padding bits - any compare-and-exchange loop needs to succeed eventually when the underlying memory isn't being modified, rather than failing in comparison of padding bits that might not have been consistently loaded / preserved. My guess is this is unlikely to be a conce= rn in practice for _BitInt the way it is e.g. for x86 long double where the padding bits only exist in memory and not in registers.)=