From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id DA9173858291; Thu, 1 Sep 2022 14:32:42 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DA9173858291 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1662042762; bh=fyHQKAH1R0s4Z57XwQRhkXQvOtV6hmRREMdVv2mDRwM=; h=From:To:Subject:Date:In-Reply-To:References:From; b=WSD7Omk+EXQFMINwxumNZ6OZSxoWIhSF/0kWDWyG2Xx6MtlTj/9xo8690w/mbyyv6 FxACdicvh9Ag31HiI9X247zlB9PpDjuIwzhVJEJfQmFNyWvmHaBpIWpuLcwNJ5z4j+ dkRbbyFx76TY140trwfRX9Kwt4tsHO+5TYNLqcaQ= From: "rearnsha at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/106763] Armv8.2 vmov.f16 instruction sometimes causes SIGILL Date: Thu, 01 Sep 2022 14:32:42 +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: 12.2.1 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: rearnsha at gcc dot gnu.org X-Bugzilla-Status: RESOLVED X-Bugzilla-Resolution: INVALID 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=3D106763 --- Comment #13 from Richard Earnshaw --- I don't think it would hurt. With this change, a float-16 instruction that= was encountered on older cores would enable the VFP unit if it wasn't previously enabled and then fault again when the retried instruction failed. That's w= hat likely already happens today if you have an instruction that isn't legal but still falls in the top-level decoding space for 32-bit and 64-bit FP instructions. Perviously we would unconditionally raise a SIGILL, which is what you're seeing right now. However, I'm not a kernel expert and I haven't tested any of the above, so = all the caveats that that implies should be assumed.=