From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rock.gnat.com (rock.gnat.com [205.232.38.15]) by sourceware.org (Postfix) with ESMTPS id AA2693858D3C for ; Tue, 27 Dec 2022 04:30:09 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org AA2693858D3C Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=adacore.com Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 7DC3D1162A6; Mon, 26 Dec 2022 23:30:09 -0500 (EST) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id x8Tbz2gYLg1O; Mon, 26 Dec 2022 23:30:09 -0500 (EST) Received: from free.home (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by rock.gnat.com (Postfix) with ESMTPS id 1CFB811628F; Mon, 26 Dec 2022 23:30:08 -0500 (EST) Received: from livre (livre.home [172.31.160.2]) by free.home (8.15.2/8.15.2) with ESMTPS id 2BR4U0lW712370 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 27 Dec 2022 01:30:00 -0300 From: Alexandre Oliva To: gcc-patches@gcc.gnu.org Cc: Jason Merrill , Nathan Sidwell Subject: [09/13] [C++] constexpr: request insert iff depth is ok Organization: Free thinker, does not speak for AdaCore References: Errors-To: aoliva@lxoliva.fsfla.org Date: Tue, 27 Dec 2022 01:30:00 -0300 In-Reply-To: (Alexandre Oliva's message of "Tue, 27 Dec 2022 01:07:35 -0300") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00,GIT_PATCH_0,KAM_DMARC_STATUS,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: cxx_eval_call_expression requests an INSERT even in cases when it would later decide not to insert. This could break double-hashing chains. Arrange for it to use NO_INSERT when the insertion would not be completed. Regstrapped on x86_64-linux-gnu. Ok to install? for gcc/cp/ChangeLog * constexpr.cc (cxx_eval_call_expression): Do not request an INSERT that would not be completed. --- gcc/cp/constexpr.cc | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index d99c49bdbe282..6d20ffa2cdeb6 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -3000,13 +3000,15 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, /* If we have seen this call before, we are done. */ maybe_initialize_constexpr_call_table (); + bool insert = depth_ok < constexpr_cache_depth; constexpr_call **slot - = constexpr_call_table->find_slot (&new_call, INSERT); - entry = *slot; + = constexpr_call_table->find_slot (&new_call, + insert ? INSERT : NO_INSERT); + entry = slot ? *slot : NULL; if (entry == NULL) { /* Only cache up to constexpr_cache_depth to limit memory use. */ - if (depth_ok < constexpr_cache_depth) + if (insert) { /* We need to keep a pointer to the entry, not just the slot, as the slot can move during evaluation of the body. */ -- Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ Free Software Activist GNU Toolchain Engineer Disinformation flourishes because many people care deeply about injustice but very few check the facts. Ask me about