From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x62f.google.com (mail-ej1-x62f.google.com [IPv6:2a00:1450:4864:20::62f]) by sourceware.org (Postfix) with ESMTPS id 7A49A385AC3F for ; Thu, 21 Jul 2022 09:33:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 7A49A385AC3F Received: by mail-ej1-x62f.google.com with SMTP id va17so2218115ejb.0 for ; Thu, 21 Jul 2022 02:33:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PowBVetvnDtHt8WcQQceRC2vj+kaMPsKuk69GwaG6Is=; b=bzODTIYb2S9o4gAo67orOxrE6T0Ky03PYNuUjfcyP2NMapGySor5oYUMUlO3pyGTim /3qEMgXODeR6XXv6MJcDyN1AheamiaCKW0d3Z+gpDLuV66SoxRcmrPXjSObgfJtStgkz 23RI2UPzRM7Nx9jMbVXUnh+BT8Q5xnU3xKYqMU9IRQq6S5OfFbaBu0KJ77GpTMjY0N6T AIqXj+wiC2TKyiEwgAR2ZhaCHgGZARQgydwWvg8fkGYaqp/U2EdyU7uf0HcA5u7BAFHO kAfQ5JIE4r1yzx4fN3v5RSH39hdNCiTCc2dKWQXH9rKdxeKByD4njH1bZfEmJ8S++YN1 yFRw== X-Gm-Message-State: AJIora9YtwsY47gbL04tclcGAEiCCRnVr3+pH4TfeSAJjZ+pl+C03Jt9 gQARpFBIxrM7t+JxNjX0IF+MKQeoZrH2fjcBDq4= X-Google-Smtp-Source: AGRyM1tOW3qk31TdPCzNsX5YS36jVHBjuDG9tnL7qoEcQN4sq/8ueNaD0hWQ4BUllg0XTGcTdgRq8u8XAOmf4NPJh7Q= X-Received: by 2002:a17:907:c14:b0:72b:6762:de34 with SMTP id ga20-20020a1709070c1400b0072b6762de34mr39327404ejc.94.1658396007051; Thu, 21 Jul 2022 02:33:27 -0700 (PDT) MIME-Version: 1.0 References: <20220524225156.4026293-1-philipp.tomsich@vrull.eu> In-Reply-To: From: Kito Cheng Date: Thu, 21 Jul 2022 17:33:15 +0800 Message-ID: Subject: Re: [PATCH v1 1/3] RISC-V: Split "(a & (1 << BIT_NO)) ? 0 : -1" to bexti + addi To: Philipp Tomsich Cc: GCC Patches , Andrew Waterman , Vineet Gupta Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-8.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, 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 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-List-Received-Date: Thu, 21 Jul 2022 09:33:30 -0000 Hi Philipp: This patch series is LGTM, but plz introduce new pseudo when can_create_pseudo_p like what we discussed in https://gcc.gnu.org/pipermail/gcc-patches/2022-June/596305.html, you can commit with the change with a [committed] patch mail :) On Thu, Jun 16, 2022 at 5:32 PM Philipp Tomsich wrote: > > Kito, > > Looks like this series fell by the wayside (possibly, because it > didn't have a cover-letter and was easier to miss)? > > Thanks, > Philipp. > > On Wed, 25 May 2022 at 00:52, Philipp Tomsich wrote: > > > > Consider creating a polarity-reversed mask from a set-bit (i.e., if > > the bit is set, produce all-ones; otherwise: all-zeros). Using Zbb, > > this can be expressed as bexti, followed by an addi of minus-one. To > > enable the combiner to discover this opportunity, we need to split the > > canonical expression for "(a & (1 << BIT_NO)) ? 0 : -1" into a form > > combinable into bexti. > > > > Consider the function: > > long f(long a) > > { > > return (a & (1 << BIT_NO)) ? 0 : -1; > > } > > This produces the following sequence prior to this change: > > andi a0,a0,16 > > seqz a0,a0 > > neg a0,a0 > > ret > > Following this change, it results in: > > bexti a0,a0,4 > > addi a0,a0,-1 > > ret > > > > Signed-off-by: Philipp Tomsich > > > > gcc/ChangeLog: > > > > * config/riscv/bitmanip.md: Add a splitter to generate > > polarity-reversed masks from a set bit using bexti + addi. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.target/riscv/zbs-bexti.c: New test. > > > > --- > > > > gcc/config/riscv/bitmanip.md | 13 +++++++++++++ > > gcc/testsuite/gcc.target/riscv/zbs-bexti.c | 14 ++++++++++++++ > > 2 files changed, 27 insertions(+) > > create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-bexti.c > > > > diff --git a/gcc/config/riscv/bitmanip.md b/gcc/config/riscv/bitmanip.md > > index 0ab9ffe3c0b..ea5dea13cfb 100644 > > --- a/gcc/config/riscv/bitmanip.md > > +++ b/gcc/config/riscv/bitmanip.md > > @@ -340,3 +340,16 @@ (define_insn "*bexti" > > "TARGET_ZBS" > > "bexti\t%0,%1,%2" > > [(set_attr "type" "bitmanip")]) > > + > > +;; We can create a polarity-reversed mask (i.e. bit N -> { set = 0, clear = -1 }) > > +;; using a bext(i) followed by an addi instruction. > > +;; This splits the canonical representation of "(a & (1 << BIT_NO)) ? 0 : -1". > > +(define_split > > + [(set (match_operand:GPR 0 "register_operand") > > + (neg:GPR (eq:GPR (zero_extract:GPR (match_operand:GPR 1 "register_operand") > > + (const_int 1) > > + (match_operand 2)) > > + (const_int 0))))] > > + "TARGET_ZBS" > > + [(set (match_dup 0) (zero_extract:GPR (match_dup 1) (const_int 1) (match_dup 2))) > > + (set (match_dup 0) (plus:GPR (match_dup 0) (const_int -1)))]) > > diff --git a/gcc/testsuite/gcc.target/riscv/zbs-bexti.c b/gcc/testsuite/gcc.target/riscv/zbs-bexti.c > > new file mode 100644 > > index 00000000000..99e3b58309c > > --- /dev/null > > +++ b/gcc/testsuite/gcc.target/riscv/zbs-bexti.c > > @@ -0,0 +1,14 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-march=rv64gc_zbs -mabi=lp64 -O2" } */ > > + > > +/* bexti */ > > +#define BIT_NO 4 > > + > > +long > > +foo0 (long a) > > +{ > > + return (a & (1 << BIT_NO)) ? 0 : -1; > > +} > > + > > +/* { dg-final { scan-assembler "bexti" } } */ > > +/* { dg-final { scan-assembler "addi" } } */ > > -- > > 2.34.1 > >