From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id DDFD03857033 for ; Mon, 12 Sep 2022 09:38:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org DDFD03857033 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D81DF113E; Mon, 12 Sep 2022 02:38:42 -0700 (PDT) Received: from localhost (e121540-lin.manchester.arm.com [10.32.98.62]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6FEFB3F73D; Mon, 12 Sep 2022 02:38:35 -0700 (PDT) From: Richard Sandiford To: Jan Beulich Mail-Followup-To: Jan Beulich ,Shaokun Zhang via Binutils , Shaokun Zhang , Jingtao Cai , Bo Dong , Richard Earnshaw , Marcus Shawcroft , richard.sandiford@arm.com Cc: Shaokun Zhang via Binutils , Shaokun Zhang , Jingtao Cai , Bo Dong , Richard Earnshaw , Marcus Shawcroft Subject: Re: [PATCH RESEND v2] Aarch64: Allow explicit size specifier for predicate operand of {sq, uq, }{incp, decp} References: <20220216005311.26184-1-zhangshaokun@hisilicon.com> <94c21b51-5872-1e16-8d15-027c21c59112@suse.com> Date: Mon, 12 Sep 2022 10:38:34 +0100 In-Reply-To: <94c21b51-5872-1e16-8d15-027c21c59112@suse.com> (Jan Beulich's message of "Mon, 12 Sep 2022 10:27:47 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-42.8 required=5.0 tests=BAYES_00,KAM_DMARC_NONE,KAM_DMARC_STATUS,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Jan Beulich writes: > On 12.09.2022 10:17, Richard Sandiford via Binutils wrote: >> It's extremely unlikely that the old syntax would be repurposed to mean >> something else. Therefore, Richard and I thought that it might be better >> to continue to accept the old syntax alongside the new syntax in the GNU >> tools, as a GNU extension to the official assembler spec, without the >> deprecation message. Sorry to raise this after so long, and after you'd >> already done the work. > > Isn't it the case already that the old syntax will continue to be accepte= d, > by there being new insn entries added without removing the original ones? Yes, for now. But the point of deprecation is that it anticipates removing the old syntax in future. The suggestion here was instead to keep the old syntax alongside the new one, without any intention of removing it. > IOW is it perhaps that you're asking for the old syntax to remain accepted > _silently_ (and don't claim this behavior will be removed)? If so, I'd li= ke > to suggest to perhaps allow for diagnostics, but require a command line > option to turn them on. Richard suggested having a =E2=80=9Cstrict=E2=80=9D flag that (IIUC) would = make gas stick more rigidly to the ISA definition. But I think that would be separate work and would affect quite a few more instructions. E.g. it should probably insist on curly brackets around the Z registers in SVE LD1 and ST1 instructions. Perhaps it should even insist on # for immediate operands. I don't think it's worth having an option specifically for these instructions in isolation. And if we did add the strict flag, I think we should try to make the first implementation relatively complete, so that its behaviour is somewhat predictable between releases. Thanks, Richard