From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by sourceware.org (Postfix) with ESMTP id CF9A63855160 for ; Mon, 28 Nov 2022 23:03:55 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CF9A63855160 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=kernel.crashing.org Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 2ASN2s55018161; Mon, 28 Nov 2022 17:02:55 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 2ASN2sSg018160; Mon, 28 Nov 2022 17:02:54 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 28 Nov 2022 17:02:54 -0600 From: Segher Boessenkool To: Richard Biener Cc: HAO CHEN GUI , gcc-patches , David , Peter Bergner , "Kewen.Lin" Subject: Re: Ping [PATCH] Change the behavior of predicate check failure on cbranchcc4 operand0 in prepare_cmp_insn Message-ID: <20221128230254.GP25951@gate.crashing.org> References: <4a052a62-7861-ed6f-9801-3b58ac384f81@linux.ibm.com> <20221128175629.GO25951@gate.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-Spam-Status: No, score=-3.0 required=5.0 tests=BAYES_00,JMQ_SPF_NEUTRAL,KAM_DMARC_STATUS,SPF_HELO_PASS,SPF_PASS,TXREP 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: On Mon, Nov 28, 2022 at 07:46:07PM +0100, Richard Biener wrote: > Anyhow - my question still stands - what's the fallback for the callers > that do not check for failure? How are we sure we're not running into > these when relaxing the requirement that a MODE_CC prepare_cmp_insn > must not fail? This will work the same as with any other define_expand? If the caller of gen_blablabla does not check for failure, you end up with a NULL_RTX in the instruction stream, which will ICE sooner or later. Not pretty, sure, but at least it is a reliable ICE :-) Segher