From patchwork Thu Dec 2 12:35:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Biener X-Patchwork-Id: 48390 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id A8B803858003 for ; Thu, 2 Dec 2021 12:35:44 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A8B803858003 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1638448544; bh=fL25yPHshBVhOvgyEqW5PH6A2FtzDVWEWiTBXTwZVyc=; h=Date:To:Subject:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=uI/DY4tUtIKQi1VoRC+zFd7wDAGaHYVXR/7Gj8TRfgJfKeQcvjS8IbCU1qKMjeH07 z3B4Iqm5w4aRIkoDfsGR77AIUsbATQa5Q0lEnK+umuiQv7iyF+8+DV93kSvMvLD+9m ZcP2yITDaehOUQSlMW5psNykcZRWxFGh0mN07EyA= X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id B45CD3858D28 for ; Thu, 2 Dec 2021 12:35:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B45CD3858D28 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id B8EC7212BB for ; Thu, 2 Dec 2021 12:35:13 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id A243C13E65 for ; Thu, 2 Dec 2021 12:35:13 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id qydqJoG9qGHkJAAAMHmgww (envelope-from ) for ; Thu, 02 Dec 2021 12:35:13 +0000 Date: Thu, 2 Dec 2021 13:35:13 +0100 (CET) To: gcc-patches@gcc.gnu.org Subject: [PATCH] middle-end/103271 - avoid VLA init of register Message-ID: <6r68q34-s4n8-4912-s2r-23705o929651@fhfr.qr> MIME-Version: 1.0 X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Biener via Gcc-patches From: Richard Biener Reply-To: Richard Biener Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Sender: "Gcc-patches" This avoids using VLA types to initalize a register with -ftrivial-auto-var-init in some cases. Bootstrapped and tested on x86_64-unknown-linux-gnu, also tested on the case riscv ICEd on. Pushed. 2021-12-02 Richard Biener PR middle-end/103271 * internal-fn.c (expand_DEFERRED_INIT): When the base of the LHS is a decl with matching constant size use that as the initialization target instead of an eventual VLA typed one. --- gcc/internal-fn.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c index 6ac3460d538..08f94b7a17a 100644 --- a/gcc/internal-fn.c +++ b/gcc/internal-fn.c @@ -3050,6 +3050,23 @@ expand_DEFERRED_INIT (internal_fn, gcall *stmt) lhs_base = TREE_OPERAND (lhs_base, 0); reg_lhs = (mem_ref_refers_to_non_mem_p (lhs_base) || non_mem_decl_p (lhs_base)); + /* If this expands to a register and the underlying decl is wrapped in + a MEM_REF that just serves as an access type change expose the decl + if it is of correct size. This avoids a situation as in PR103271 + if the target does not support a direct move to the registers mode. */ + if (reg_lhs + && TREE_CODE (lhs_base) == MEM_REF + && TREE_CODE (TREE_OPERAND (lhs_base, 0)) == ADDR_EXPR + && DECL_P (TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0)) + && integer_zerop (TREE_OPERAND (lhs_base, 1)) + && tree_fits_uhwi_p (var_size) + && tree_int_cst_equal + (var_size, + DECL_SIZE_UNIT (TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0)))) + { + lhs = TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0); + var_type = TREE_TYPE (lhs); + } } if (!reg_lhs)