From patchwork Tue Oct 24 17:58:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Sandiford X-Patchwork-Id: 1854588 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=server2.sourceware.org; envelope-from=gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4SFKYZ2CzPz23jn for ; Wed, 25 Oct 2023 04:58:42 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 5F9243858430 for ; Tue, 24 Oct 2023 17:58:40 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id BEABA3858421 for ; Tue, 24 Oct 2023 17:58:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org BEABA3858421 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=arm.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org BEABA3858421 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698170310; cv=none; b=DexueRPIBjDXIZxncM2WpuwX3DDqjJ2qzXoNM3/1cjILI53C7wuDfFTn/h5bsZSJ9PP0PTpgZqsSoPuQFQnTyKlCPY4oau6splyuDFmxBDOInTFLq0VUWa3A/hVcn0F6EtUDzJ1U3oryVKKQY7YAIyZE4YV/i+SallyGSpVd4RQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698170310; c=relaxed/simple; bh=TSpvnq/8AZb0DhMI2CFQg1Wa5X+PPdA2XbyHnWyFQoA=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=QdAKXrh6rFLSxBMsf83XThrFoPlm+fSNvfrlcPZxT18DiMR68nqwrsf6XUfERfnX+skBrMOZS1OKU8rx9biZvC7KUNhOh3CiaerA7X9TegloBnK+LrWCHpXuBhjgrMg7a/VXiuB05pVIcQD5EMBDo9Bg836SWrfUpNtBSMpBsds= ARC-Authentication-Results: i=1; server2.sourceware.org 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 9CA192F4; Tue, 24 Oct 2023 10:59:09 -0700 (PDT) Received: from e121540-lin.manchester.arm.com (e121540-lin.manchester.arm.com [10.32.110.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DF8003F64C; Tue, 24 Oct 2023 10:58:27 -0700 (PDT) From: Richard Sandiford To: jlaw@ventanamicro.com, gcc-patches@gcc.gnu.org Cc: Richard Sandiford Subject: [PATCH 2/3] rtl-ssa: Extend make_uses_available Date: Tue, 24 Oct 2023 18:58:04 +0100 Message-Id: <20231024175805.3359331-3-richard.sandiford@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231024175805.3359331-1-richard.sandiford@arm.com> References: <20231024175805.3359331-1-richard.sandiford@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-23.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_NONE, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, SPF_HELO_NONE, SPF_NONE, 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 X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org The first in-tree use of RTL-SSA was fwprop, and one of the goals was to make the fwprop rewrite preserve the old behaviour as far as possible. The switch to RTL-SSA was supposed to be a pure infrastructure change. So RTL-SSA has various FIXMEs for things that were artifically limited to faciliate the old-fwprop vs. new-fwprop comparison. One of the things that fwprop wants to do is extend live ranges, and function_info::make_use_available tried to keep within the cases that old fwprop could handle. Since the information is built in extended basic blocks, it's easy to handle intra-EBB queries directly. This patch does that, and removes the associated FIXME. To get a flavour for how much difference this makes, I tried compiling the testsuite at -Os for at least one target per supported CPU and OS. For most targets, only a handful of tests changed, but the vast majority of changes were positive. The only target that seemed to benefit significantly was i686-apple-darwin. The main point of the patch is to remove the FIXME and to enable the upcoming post-RA late-combine pass to handle more cases. gcc/ * rtl-ssa/functions.h (function_info::remains_available_at_insn): New member function. * rtl-ssa/accesses.cc (function_info::remains_available_at_insn): Likewise. (function_info::make_use_available): Avoid false negatives for queries within an EBB. --- gcc/rtl-ssa/accesses.cc | 37 +++++++++++++++++++++++++++++++++++-- gcc/rtl-ssa/functions.h | 4 ++++ 2 files changed, 39 insertions(+), 2 deletions(-) diff --git a/gcc/rtl-ssa/accesses.cc b/gcc/rtl-ssa/accesses.cc index c35c7efb73d..1b25ecc3e23 100644 --- a/gcc/rtl-ssa/accesses.cc +++ b/gcc/rtl-ssa/accesses.cc @@ -1303,6 +1303,33 @@ function_info::insert_temp_clobber (obstack_watermark &watermark, return insert_access (watermark, clobber, old_defs); } +// See the comment above the declaration. +bool +function_info::remains_available_at_insn (const set_info *set, + insn_info *insn) +{ + auto *ebb = set->ebb (); + gcc_checking_assert (ebb == insn->ebb ()); + + def_info *next_def = set->next_def (); + if (next_def && *next_def->insn () < *insn) + return false; + + if (HARD_REGISTER_NUM_P (set->regno ()) + && TEST_HARD_REG_BIT (m_clobbered_by_calls, set->regno ())) + for (ebb_call_clobbers_info *call_group : ebb->call_clobbers ()) + { + if (!call_group->clobbers (set->resource ())) + continue; + + insn_info *call_insn = next_call_clobbers (*call_group, insn); + if (call_insn && *call_insn < *insn) + return false; + } + + return true; +} + // See the comment above the declaration. bool function_info::remains_available_on_exit (const set_info *set, bb_info *bb) @@ -1354,14 +1381,20 @@ function_info::make_use_available (use_info *use, bb_info *bb, if (is_single_dominating_def (def)) return use; - // FIXME: Deliberately limited for fwprop compatibility testing. + if (def->ebb () == bb->ebb ()) + { + if (remains_available_at_insn (def, bb->head_insn ())) + return use; + return nullptr; + } + basic_block cfg_bb = bb->cfg_bb (); bb_info *use_bb = use->bb (); if (single_pred_p (cfg_bb) && single_pred (cfg_bb) == use_bb->cfg_bb () && remains_available_on_exit (def, use_bb)) { - if (def->ebb () == bb->ebb () || will_be_debug_use) + if (will_be_debug_use) return use; resource_info resource = use->resource (); diff --git a/gcc/rtl-ssa/functions.h b/gcc/rtl-ssa/functions.h index ab253e750cb..ecb40fdaf57 100644 --- a/gcc/rtl-ssa/functions.h +++ b/gcc/rtl-ssa/functions.h @@ -121,6 +121,10 @@ public: // scope until the change has been aborted or successfully completed. obstack_watermark new_change_attempt () { return &m_temp_obstack; } + // SET and INSN belong to the same EBB, with SET occuring before INSN. + // Return true if SET is still available at INSN. + bool remains_available_at_insn (const set_info *set, insn_info *insn); + // SET either occurs in BB or is known to be available on entry to BB. // Return true if it is also available on exit from BB. (The value // might or might not be live.)