From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 1253B3858422; Thu, 25 Nov 2021 22:49:32 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1253B3858422 From: "hjl.tools at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/103393] [12 Regression] Generating 256bit register usage with -mprefer-avx128 -mprefer-vector-width=128 Date: Thu, 25 Nov 2021 22:49:32 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Version: 12.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: hjl.tools at gmail dot com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 12.0 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: Thu, 25 Nov 2021 22:49:33 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103393 --- Comment #14 from H.J. Lu --- (In reply to Richard Earnshaw from comment #13) > Also, note that the comment in gimple-fold.c prior to this change read: >=20 > /* If we can perform the copy efficiently with first doing all loads > and then all stores inline it that way. Currently efficiently > means that we can load all the memory into a single integer > register which is what MOVE_MAX gives us. */ >=20 > Which would imply that the AArch64 definition of MOVE_MAX is the correct = one. The GCC manual has - Macro: MOVE_MAX The maximum number of bytes that a single instruction can move quickly between memory and registers or between two memory locations.=