From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by sourceware.org (Postfix) with ESMTPS id 4641A3858C2B for ; Fri, 4 Nov 2022 23:00:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 4641A3858C2B Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=rivosinc.com Received: by mail-pg1-x52e.google.com with SMTP id 78so5552923pgb.13 for ; Fri, 04 Nov 2022 16:00:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:subject:from:cc:to:content-language :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=GDtNnx9LUnNpdSogm2gVe6ocHGZXfHJOSMTwVeNrKG8=; b=GJoD0ZLnKWQU3HbWkb3mnkyXhvfWvpy7MeS33YYmevhstH/dpg0DQJzr4GilXFuBxM K2Ydpt+uG+8cSRHKjdcKE/M9urMQ2IS3V2jv8PdcAyThhnj8UQeHA809QYP3KQKxe7Gs OTmLygFgxzp2IHmJGCVR5USdug0VP8hrxuS1OLKJ22MJWJmegQRWnTcI9lHabcxOtdcv 6iSmBMqVCQbhGxFdkPIlmHZk6lxAS8hHCUT4/FxMn/zhfJzQuRIfdFpT6m9EVdsigCl1 C5MGX9XUyKObS3TsiSK0qfAaq6of91dPFE5qtC5G12mPSoYv8DlNp/qVNfWQ1uYwSGSe 6NkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:subject:from:cc:to:content-language :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=GDtNnx9LUnNpdSogm2gVe6ocHGZXfHJOSMTwVeNrKG8=; b=E7pEEqNAz9UPcwmtc8/wwCCVk8KqHT+AMhlQWdlPgRf6BuGaEnGPMFcdXcK4GKpRJ5 y0UIYVWI0L858reD6uCMmYPyHedAQYlHq+lqDvuHnQHEG0OSjQE7dqifEnAJ6Wr4NeWG nQ98RPEkqH7xoJXJZG6+JZyCJfTg5xny5+tXHUh/pAHsjOFlkA3xwuCBxpxJ7TTWks6M KG+B9Gd1sdtxUtAXNsUvwfDQOmqz1QDRsZv7uipMXAuJpIZzVL/tXP8qAbrbrMNZI6p+ Eszm3cpP3LiKYjSrdW0RTqIud7ce3jst8hnwSemetx9QqOjI/OmnGLq5rD/8+dCqUvVP BVrQ== X-Gm-Message-State: ACrzQf3s41Mh/kdHp4TlL70gJtre3Rmfr2Le85b4UihuAjYhPdwPtB0K LPH9fJr3xmnCVwrwS3+dc263yw== X-Google-Smtp-Source: AMsMyM4fOJdBf0AHasyOm2i/NF0KxjM6IGVky6J9d7ztWJFlAo1hwMGds3B6CfI4z9A1zRGFeHAN+Q== X-Received: by 2002:a63:d503:0:b0:46e:9bac:6d9f with SMTP id c3-20020a63d503000000b0046e9bac6d9fmr32597283pgg.217.1667602800231; Fri, 04 Nov 2022 16:00:00 -0700 (PDT) Received: from [192.168.50.116] (c-24-4-73-83.hsd1.ca.comcast.net. [24.4.73.83]) by smtp.gmail.com with ESMTPSA id n5-20020a170902e54500b00186c54188b4sm249687plf.240.2022.11.04.15.59.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 04 Nov 2022 15:59:59 -0700 (PDT) Message-ID: <23ac9d02-c687-7680-493b-8ace1558a4cb@rivosinc.com> Date: Fri, 4 Nov 2022 15:59:58 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 X-Mozilla-News-Host: news://news.gmane.io:119 Content-Language: en-US To: Jakub Jelinek Cc: gcc@gcc.gnu.org, Michael Collison , Jeff Law From: Vineet Gupta Subject: query about commit 666fdc46bc8489 ("RISC-V: Fix bad insn splits with paradoxical subregs") Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,KAM_SHORT,RCVD_IN_BARRACUDACENTRAL,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,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: Hi Jakub, I had a question about the aforementioned commit in RV backend. (define_split [(set (match_operand:GPR 0 "register_operand") (and:GPR (match_operand:GPR 1 "register_operand") (match_operand:GPR 2 "p2m1_shift_operand"))) + (clobber (match_operand:GPR 3 "register_operand"))] "" - [(set (match_dup 0) + [(set (match_dup 3) (ashift:GPR (match_dup 1) (match_dup 2))) Is there something specific to this split which warrants this or so any split patterns involving shifts have this to avoid the shifting by more than SUBREG_REG problem. Also could you please explain where the clobber itself is allocated ? This came up when discussing the solution to PR/106602 [1] Thx, -Vineet [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106602