From patchwork Thu Jan 20 13:58:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Biener X-Patchwork-Id: 50280 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 81FD93857C48 for ; Thu, 20 Jan 2022 13:59:34 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 81FD93857C48 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1642687174; bh=7dh9SM/xPQsKYsMqiHvnF7b4/a2KSjVDO77c66cZ+0g=; h=Date:To:Subject:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=sIRzc8OROGxpiD6yajY8+OqWXbuR7tbqmgah87tfk1GizAdOt+/D2BaTYFPz1R66Z E2WjPZVi6Lau5qFQb7px42XUbjAuMxq2BSLrKjgdgi1PVl8bjojTdvBlu0V7JSMuay uiec1XwvcNY8fMDTAMOQ9pbSEt7uesTYAoGggCvI= X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by sourceware.org (Postfix) with ESMTPS id AAD02385781D for ; Thu, 20 Jan 2022 13:58:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org AAD02385781D 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-out2.suse.de (Postfix) with ESMTPS id 50F801F3AA for ; Thu, 20 Jan 2022 13:58:22 +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 397BE13BCC for ; Thu, 20 Jan 2022 13:58:22 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id aZblDH5q6WErDAAAMHmgww (envelope-from ) for ; Thu, 20 Jan 2022 13:58:22 +0000 Date: Thu, 20 Jan 2022 14:58:21 +0100 (CET) To: gcc-patches@gcc.gnu.org Subject: [PATCH] middle-end/100786 - constant folding from incompatible alias Message-ID: <3158023-8523-n61r-460-r7n98r84q57@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" The following avoids us ICEing doing constant folding from variables with aliases of different types. The formerly used fold_convert wasn't entirely correct even for the cases it handled and using a VIEW_CONVERT_EXPR avoids the ICE. Reading from a larger alias will cause unfolded constants to appear but appearantly we handle that just "fine". b.0_1 = VIEW_CONVERT_EXPR(1); There is no obvious spot and way to just disable the constant folding so I've not attempted to do that. Boostrapped on x86_64-unknown-linux-gnu, testing in progress. 2022-01-20 Richard Biener PR middle-end/100786 * gimple-fold.cc (fold_stmt_1): Use a VIEW_CONVERT_EXPR on type mismatches. * gcc.dg/torture/pr100786.c: New testcase. --- gcc/gimple-fold.cc | 2 +- gcc/testsuite/gcc.dg/torture/pr100786.c | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr100786.c diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc index 08d3cc214ff..a4f1fdabc18 100644 --- a/gcc/gimple-fold.cc +++ b/gcc/gimple-fold.cc @@ -6264,7 +6264,7 @@ fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace, tree (*valueize) (tree)) if (new_rhs && !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (new_rhs))) - new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); + new_rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), new_rhs); if (new_rhs && (!inplace || get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops)) diff --git a/gcc/testsuite/gcc.dg/torture/pr100786.c b/gcc/testsuite/gcc.dg/torture/pr100786.c new file mode 100644 index 00000000000..42f4e485593 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr100786.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ + +const double a = 0; +extern int b __attribute__((alias("a"))); +void inc() { b++; } + +const int a2 = 0; +extern double b2 __attribute__((alias("a2"))); +void inc2() { b2+=1; }