From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by sourceware.org (Postfix) with ESMTPS id 70F1F385842B for ; Thu, 23 Feb 2023 22:33:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 70F1F385842B Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-pj1-x102b.google.com with SMTP id nw10-20020a17090b254a00b00233d7314c1cso819477pjb.5 for ; Thu, 23 Feb 2023 14:33:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=G9egPN1j/a9GkbcAZ+2Bn8oS+iZC+k9FejvgVwHFtDE=; b=R/X4PbJKjIsBE/yrV0S99jigTxgi87LviIAYvzp1RyKGK+bbv2XN2VP2TrHheSvcWA pILlqeIHylXGXBr9vg/Pju421oBoS+9V2auEzIS3Qpd7yhXwTNE8Pxhi5PWQkSKVu0qY SNQhTSYXdkc+HOP1nXSk71xNbhggO63YQU3smBy2/gec+AGBwHZhwZbAWBTCuyIVQyjB LqSZlFW3MReBxLO8e1nNv8wbUYebHdnJ9Zo42DNn047j6hcAdG1xZvvAuq8OGqwhrjO2 8Z1C92sCzaA4psbQ/MfhP0PlYbnb+OUfaTU9F9M438F9RERo9Kxh8QWV5dFYf9wp6t4g lm2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=G9egPN1j/a9GkbcAZ+2Bn8oS+iZC+k9FejvgVwHFtDE=; b=B7cPS/cstb/77RGK7gASA854UoMDaliPMJmd3Mb17ytnBlq0TMpi97ldJ/SNAWLnO0 Uk3i81M8ts/L0rrIe8s1vg7870vbYzjpTR23U0KRs8KFWSLzJSiNOnHY5g+Aejk+17HR 4B/dRuNjK2Jtt29Rhc8mWP97qjvFllNXcZahPrm/a6qDwqlJ6Pfczt7xzgIVTUV9Ehm9 cuu27w124IXdshDuFRIxlZcz02yBhiw8JDe/G3t7Ix+ZQWhBFpnq7FN4OWy/PjjazvYk WAOoPYYND90C4tcCLzdo9stDHwkJrGpiDGRVCaHy5irbt/RwjTV5vttGqJ6/JVhKVwHB oneQ== X-Gm-Message-State: AO0yUKWy9B6cpYDvgeiR3kBa/uDUZZHajZZ50n6N5A6jJPX6QTyOCjWo 78hIfgLBVju9oMYzaM79XZ7Y/HKk4oh4fpQ+a2M= X-Google-Smtp-Source: AK7set8ncdQhyUyj1PhYmGu3Qx0llnAkKi65sa/z+6/XNe1eMwPxlN8jBKq/NuR0IKZMjt1SBxXuWJVk3fMojXdaXQs= X-Received: by 2002:a17:903:2986:b0:199:6e3:187a with SMTP id lm6-20020a170903298600b0019906e3187amr3175994plb.6.1677191633384; Thu, 23 Feb 2023 14:33:53 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Max Filippov Date: Thu, 23 Feb 2023 14:33:41 -0800 Message-ID: Subject: Re: [PATCH v5] xtensa: Eliminate unnecessary general-purpose reg-reg moves To: "Takayuki 'January June' Suwa" Cc: GCC Patches Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-0.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,FROM_LOCAL_NOVOWEL,HK_RANDOM_ENVFROM,HK_RANDOM_FROM,KAM_SHORT,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: On Fri, Feb 17, 2023 at 8:43 PM Takayuki 'January June' Suwa wrote: > > Register-register move instructions that can be easily seen as > unnecessary by the human eye may remain in the compiled result. > For example: > > /* example */ > double test(double a, double b) { > return __builtin_copysign(a, b); > } > > test: > add.n a3, a3, a3 > extui a5, a5, 31, 1 > ssai 1 > ;; Be in the same BB > src a7, a5, a3 ;; Replacing the destination doesn't > ;; violate any constraints of the > ;; operands > ;; No CALL insns in this span > ;; Both A3 and A7 are irrelevant to > ;; insns in this span > mov.n a3, a7 ;; An unnecessary reg-reg move > ;; A7 is not used after this > ret.n > > The last two instructions above, excluding the return instruction, > could be done like this: > > src a3, a5, a3 > > This symptom often occurs when handling DI/DFmode values with SImode > instructions. This patch solves the above problem using peephole2 > pattern. > > gcc/ChangeLog: > > * config/xtensa/xtensa.md: New peephole2 pattern that eliminates > the occurrence of general-purpose register used only once and for > transferring intermediate value. > > gcc/testsuite/ChangeLog: > > * gcc.target/xtensa/elim_GP_regmove_[01].c: New. > --- > gcc/config/xtensa/xtensa.md | 46 +++++++++++++++++++ > .../gcc.target/xtensa/elim_GP_regmove_0.c | 23 ++++++++++ > .../gcc.target/xtensa/elim_GP_regmove_1.c | 10 ++++ > 3 files changed, 79 insertions(+) > create mode 100644 gcc/testsuite/gcc.target/xtensa/elim_GP_regmove_0.c > create mode 100644 gcc/testsuite/gcc.target/xtensa/elim_GP_regmove_1.c Regtested for target=xtensa-linux-uclibc, no new regressions. Committed to master. -- Thanks. -- Max