From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 75C283858C50; Mon, 29 Jan 2024 07:55:43 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 75C283858C50 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1706514943; bh=2e2vYlHazjVTSN8j0qvyQxGC4n5OhUwCJ8XWYZ8VG+c=; h=From:To:Subject:Date:In-Reply-To:References:From; b=aMbyLpzgtLy7dgiQAegsU6+J9Xk2L+NW5y1AP2hpikDEUhUM9IMZvrQVqZGhOXyaQ RWzs8F5kXZt7KimJyJdVMw54qo68sELGyrNTJrnPhE+quY8AYb30e3j4tyiP7mxINm p+aDxQFRXkql2swSb3Q4VH+XBPWxyswH60qkqBIc= From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/113618] [14 Regression] AArch64: memmove idiom regression Date: Mon, 29 Jan 2024 07:55:42 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 14.0 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 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113618 --- Comment #2 from Richard Biener --- It might be good to recognize this pattern in strlenopt or a related pass. A purely local transform would turn it into memcpy (temp, a, 64); memmove (b, a, 64); relying on DSE to eliminate the copy to temp if possible. Not sure if that possibly would be a bad transform if copying to temp is required. stp q30, q31, [sp] ldp q30, q31, [sp] why is CSE not able to catch this?=