From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id B7E86385701F; Tue, 23 Mar 2021 14:32:09 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B7E86385701F From: "kretz at kde dot org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/99728] code pessimization when using wrapper classes around SIMD types Date: Tue, 23 Mar 2021 14:32:09 +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: 10.2.1 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: kretz at kde dot 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 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 23 Mar 2021 14:32:09 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99728 --- Comment #6 from Matthias Kretz (Vir) --- > I guess I need it for unaligned loads/stores, correct? Otherwise __v4df s= hould work everywhere. 1. You can freely reinterpret_cast by value between all the different [[gnu::vector_size(N)]] types (with equal N). 2. I use std::memcpy for loads and stores. Use __builtin_assume_aligned to = get aligned loads & stores.=