From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 63A9B38582BE; Wed, 24 Aug 2022 07:21:32 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 63A9B38582BE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1661325692; bh=CyNGYSghzQfRXZAsjwNZmzu+F7fVBANrAhcDaZP/RZc=; h=From:To:Subject:Date:In-Reply-To:References:From; b=emaGK34viMHf/iunAp/0gt/qKd33TjIiDGpBPhsRDio1IZbI7M8K8flrSVk/o0sww 6mY0VILlk9KKl6fUH9ub4Ti3BM4XPCNRhGL7hG7rSIOk30WFQv7CAsSoEumQ+uOAaB XqEx9m+HctR5G6ek4cu48+X7WAlwk73Tt+qdK3Ro= From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/106727] Missed fold / canonicalization for checking if a number is a power of 2 Date: Wed, 24 Aug 2022 07:21:32 +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: 12.1.1 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement 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: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: keywords bug_status everconfirmed cf_reconfirmed_on 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=3D106727 Richard Biener changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Status|UNCONFIRMED |NEW Ever confirmed|0 |1 Last reconfirmed| |2022-08-24 --- Comment #1 from Richard Biener --- Confirmed. Expanding __builtin_popcount (n) <=3D 1 as (n & (n - 1)) =3D=3D= 0 might be already done. The canonicalization could be applied if .POPCOUNT is available.=