From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk1-x736.google.com (mail-qk1-x736.google.com [IPv6:2607:f8b0:4864:20::736]) by sourceware.org (Postfix) with ESMTPS id 25E37385828E for ; Sun, 10 Jul 2022 18:05:43 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 25E37385828E Received: by mail-qk1-x736.google.com with SMTP id p22so2495018qkj.4 for ; Sun, 10 Jul 2022 11:05:43 -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=0Q3IsAlPnxR0OZlMkPyy901NMSuicuncc3YNCvoDaC8=; b=s8KsrwE5pK/JcDaFBplZuGMzr12w4l7hV7yFEaWf8fTkjK5m1HeU5NLyXNF6qhvL4S SO3P0fvUwoSvHOWnB5zEK3DQvJvTJUEkoaFSD8/RogCMFUIF56HgnG8OhjA2jbmRXmzh n3IP1wEPuL3n7NFQAqticWvR4mAos5281fWlFH2cxyOT0Xjrd5X9HkjBHOWKkFVaYrii Tn8qg7gogUyZUzorrbMwpMgYMkUiMWCfaYKtAD/z7KxUnEXAEiZ6f2gAj9mYz7j+QWWG nlWdHpguqS7oXRNUhfT/Kx2WRvXqTO7O1BXlxsYYnj0XDtpMD1ke2laU8BWPncBPAYFs c67A== X-Gm-Message-State: AJIora98DhW3zVm0XJmd9pcjd7TPjkJolzZ5AB2qOC/FvUO7E7GXgyKY 2E1LBtzuYiv/t3r6k6S96h1IJ5y6uO5du/2K7GI= X-Google-Smtp-Source: AGRyM1sUR7pbxrQJOuomSDBkk0Mgp6BlxSVr2poHJBwnJ1p/PN0l8HPQLIFdWsE8CtEFINxoskvRNHD/2RguIaZF21Y= X-Received: by 2002:a05:620a:1242:b0:6b5:77b1:8449 with SMTP id a2-20020a05620a124200b006b577b18449mr4062979qkl.180.1657476342312; Sun, 10 Jul 2022 11:05:42 -0700 (PDT) MIME-Version: 1.0 References: <000901d8938d$ead4dc40$c07e94c0$@nextmovesoftware.com> In-Reply-To: <000901d8938d$ead4dc40$c07e94c0$@nextmovesoftware.com> From: Uros Bizjak Date: Sun, 10 Jul 2022 20:05:31 +0200 Message-ID: Subject: Re: [x86_64 PATCH] Improved Scalar-To-Vector (STV) support for TImode to V1TImode. To: Roger Sayle Cc: "gcc-patches@gcc.gnu.org" , "H. J. Lu" Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-2.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE 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: Sun, 10 Jul 2022 18:05:45 -0000 On Sat, Jul 9, 2022 at 2:17 PM Roger Sayle wrote: > > > This patch upgrades x86_64's scalar-to-vector (STV) pass to more > aggressively transform 128-bit scalar TImode operations into vector > V1TImode operations performed on SSE registers. TImode functionality > already exists in STV, but only for move operations, this changes > brings support for logical operations (AND, IOR, XOR, NOT and ANDN) > and comparisons. > > The effect of these changes are conveniently demonstrated by the new > sse4_1-stv-5.c test case: > > __int128 a[16]; > __int128 b[16]; > __int128 c[16]; > > void foo() > { > for (unsigned int i=0; i<16; i++) > a[i] = b[i] & ~c[i]; > } > > which when currently compiled on mainline wtih -O2 -msse4 produces: > > foo: xorl %eax, %eax > .L2: movq c(%rax), %rsi > movq c+8(%rax), %rdi > addq $16, %rax > notq %rsi > notq %rdi > andq b-16(%rax), %rsi > andq b-8(%rax), %rdi > movq %rsi, a-16(%rax) > movq %rdi, a-8(%rax) > cmpq $256, %rax > jne .L2 > ret > > but with this patch now produces: > > foo: xorl %eax, %eax > .L2: movdqa c(%rax), %xmm0 > pandn b(%rax), %xmm0 > addq $16, %rax > movaps %xmm0, a-16(%rax) > cmpq $256, %rax > jne .L2 > ret > > Technically, the STV pass is implemented by three C++ classes, a common > abstract base class "scalar_chain" that contains common functionality, > and two derived classes: general_scalar_chain (which handles SI and > DI modes) and timode_scalar_chain (which handles TI modes). As > mentioned previously, because only TI mode moves were handled the > two worker classes behaved significantly differently. These changes > bring the functionality of these two classes closer together, which > is reflected by refactoring more shared code from general_scalar_chain > to the parent scalar_chain and reusing it from timode. There still > remain significant differences (and simplifications) so the existing > division of classes (as specializations) continues to make sense. Please note that there are in fact two STV passes, one before combine and the other after combine. The TImode pass that previously handled only loads and stores is positioned before combine (there was a reason for this decision, but I don't remember the details - let's ask HJ...). However, DImode STV pass transforms much more instructions and the reason it was positioned after the combine pass was that STV pass transforms optimized insn stream where forward propagation was already performed. What is not clear to me from the above explanation is: is the new TImode STV pass positioned after the combine pass, and if this is the case, how the change affects current load/store TImode STV pass. I must admit, I don't like two separate STV passess, so if TImode is now similar to DImode, I suggest we abandon STV1 pass and do everything concerning TImode after the combine pass. HJ, what is your opinion on this? Other than the above, the patch LGTM to me. Uros. > Obviously, there are more changes to come (shifts and rotates), > and compute_convert_gain doesn't yet have its final (tuned) form, > but is already an improvement over the "return 1;" used previously. > > This patch has been tested on x86_64-pc-linux-gnu with make boostrap > and make -k check, both with and without --target_board=unix{-m32} > with no new failures. Ok for mainline? > > > 2022-07-09 Roger Sayle > > gcc/ChangeLog > * config/i386/i386-features.h (scalar_chain): Add fields > insns_conv, n_sse_to_integer and n_integer_to_sse to this > parent class, moved from general_scalar_chain. > (scalar_chain::convert_compare): Protected method moved > from general_scalar_chain. > (mark_dual_mode_def): Make protected, not private virtual. > (scalar_chain:convert_op): New private virtual method. > > (general_scalar_chain::general_scalar_chain): Simplify constructor. > (general_scalar_chain::~general_scalar_chain): Delete destructor. > (general_scalar_chain): Move insns_conv, n_sse_to_integer and > n_integer_to_sse fields to parent class, scalar_chain. > (general_scalar_chain::mark_dual_mode_def): Delete prototype. > (general_scalar_chain::convert_compare): Delete prototype. > > (timode_scalar_chain::compute_convert_gain): Remove simplistic > implementation, convert to a method prototype. > (timode_scalar_chain::mark_dual_mode_def): Delete prototype. > (timode_scalar_chain::convert_op): Prototype new virtual method. > > * config/i386/i386-features.cc (scalar_chain::scalar_chain): > Allocate insns_conv and initialize n_sse_to_integer and > n_integer_to_sse fields in constructor. > (scalar_chain::scalar_chain): Free insns_conv in destructor. > > (general_scalar_chain::general_scalar_chain): Delete > constructor, now defined in the class declaration. > (general_scalar_chain::~general_scalar_chain): Delete destructor. > > (scalar_chain::mark_dual_mode_def): Renamed from > general_scalar_chain::mark_dual_mode_def. > (timode_scalar_chain::mark_dual_mode_def): Delete. > (scalar_chain::convert_compare): Renamed from > general_scalar_chain::convert_compare. > > (timode_scalar_chain::compute_convert_gain): New method to > determine the gain from converting a TImode chain to V1TImode. > (timode_scalar_chain::convert_op): New method to convert an > operand from TImode to V1TImode. > > (timode_scalar_chain::convert_insn) : Only PUT_MODE > on REG_EQUAL notes that were originally TImode (not CONST_INT). > Handle AND, ANDN, XOR, IOR, NOT and COMPARE. > (timode_mem_p): Helper predicate to check where operand is > memory reference with sufficient alignment for TImode STV. > (timode_scalar_to_vector_candidate_p): Use convertible_comparison_p > to check whether COMPARE is convertible. Handle SET_DESTs that > that are REG_P or MEM_P and SET_SRCs that are REG, CONST_INT, > CONST_WIDE_INT, MEM, AND, ANDN, IOR, XOR or NOT. > > gcc/testsuite/ChangeLog > * gcc.target/i386/sse4_1-stv-2.c: New test case, pand. > * gcc.target/i386/sse4_1-stv-3.c: New test case, por. > * gcc.target/i386/sse4_1-stv-4.c: New test case, pxor. > * gcc.target/i386/sse4_1-stv-5.c: New test case, pandn. > * gcc.target/i386/sse4_1-stv-6.c: New test case, ptest. > > Roger > -- >