From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oo1-xc36.google.com (mail-oo1-xc36.google.com [IPv6:2607:f8b0:4864:20::c36]) by sourceware.org (Postfix) with ESMTPS id 21EF43858C53 for ; Fri, 1 Apr 2022 07:14:59 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 21EF43858C53 Received: by mail-oo1-xc36.google.com with SMTP id v19-20020a056820101300b0032488bb70f5so384725oor.5 for ; Fri, 01 Apr 2022 00:14:59 -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=pL6BHdAPKrV6mLbvEkS09irEq1/MLP8lrMrQKnnXqoU=; b=VJpIOLS6UkleDXMYKeu5rWuc13gJDtzVcqR/NNM/5QtR7kYwfZfXVRZBO2GAD96OWO 3lKD2EF39ZzZqx8OkNTJUjn2VyBc2SGL5c69Z2GRnn4vvqQxJt+LYHCPMRVJVbsPEIPQ gof2rYPHRwYPY1kuTzj9Ee0b0UHhT2e6FxBQ7IzPlvQRXy7lZmO7PMnOUQ69neOU3I3f jf67jjWe37xpnllb6I27PN6LuYZFZ7hxEHjOwhWDDFZfh0GaWI3hUuT72LeWe+LBZ1L+ /9FMl6to/m82MaP0W4bWd7IPbmOkPK1mq/Xek3yq/1vWWy+4oJ29PyDxRACriwfbdcJd xrnQ== X-Gm-Message-State: AOAM5336T70K2DoDwtTVy6Jji1xumYdZG0P4oAzvooL/JAdCvd+oOZYs KmsQdvKNX6odLr+yzWBxpTTSa/rr+LqT8TknMSw= X-Google-Smtp-Source: ABdhPJwJaS5Abt0z6mUwGUmW1Zfy/N1wR1QBPcJvr1xj5dlvS8/4xG3DSPz6IN1wWk1jRYTP2teTD6POmqUZmXsCjGk= X-Received: by 2002:a4a:1ec1:0:b0:324:76e1:c37f with SMTP id 184-20020a4a1ec1000000b0032476e1c37fmr6376637ooq.53.1648797298409; Fri, 01 Apr 2022 00:14:58 -0700 (PDT) MIME-Version: 1.0 References: <20220401064634.16091-1-hongtao.liu@intel.com> In-Reply-To: From: Hongtao Liu Date: Fri, 1 Apr 2022 15:14:47 +0800 Message-ID: Subject: Re: [PATCH] Split vector load from parm_del to elemental loads to avoid STLF stalls. To: Richard Biener Cc: liuhongt , Jan Hubicka , GCC Patches Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-8.3 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, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Fri, 01 Apr 2022 07:15:02 -0000 On Fri, Apr 1, 2022 at 2:54 PM Richard Biener via Gcc-patches wrote: > > On Fri, Apr 1, 2022 at 8:47 AM liuhongt via Gcc-patches > wrote: > > > > Update in V2: > > 1. Use get_insns instead of FOR_EACH_BB_CFUN and FOR_BB_INSNS. > > 2. Return for any_uncondjump_p and ANY_RETURN_P. > > 3. Add dump info for spliting instruction. > > 4. Restrict ix86_split_stlf_stall_load under TARGET_SSE2. > > > > Since cfg is freed before machine_reorg, just do a rough calculation > > of the window according to the layout. > > Also according to an experiment on CLX, set window size to 64. > > > > Currently only handle V2DFmode load since it doesn't need any scratch > > registers, and it's sufficient to recover cray performance for -O2 > > compared to GCC11. > > > > gcc/ChangeLog: > > > > PR target/101908 > > * config/i386/i386.cc (ix86_split_stlf_stall_load): New > > function > > (ix86_reorg): Call ix86_split_stlf_stall_load. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.target/i386/pr101908-1.c: New test. > > * gcc.target/i386/pr101908-2.c: New test. > > --- > > gcc/config/i386/i386.cc | 60 ++++++++++++++++++++++ > > gcc/testsuite/gcc.target/i386/pr101908-1.c | 12 +++++ > > gcc/testsuite/gcc.target/i386/pr101908-2.c | 12 +++++ > > 3 files changed, 84 insertions(+) > > create mode 100644 gcc/testsuite/gcc.target/i386/pr101908-1.c > > create mode 100644 gcc/testsuite/gcc.target/i386/pr101908-2.c > > > > diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc > > index 5a561966eb4..c88a689f32b 100644 > > --- a/gcc/config/i386/i386.cc > > +++ b/gcc/config/i386/i386.cc > > @@ -21933,6 +21933,64 @@ ix86_seh_fixup_eh_fallthru (void) > > emit_insn_after (gen_nops (const1_rtx), insn); > > } > > } > > +/* Split vector load from parm_decl to elemental loads to avoid STLF > > + stalls. */ > > +static void > > +ix86_split_stlf_stall_load () > > +{ > > + rtx_insn* insn, *start = get_insns (); > > + unsigned window = 0; > > + > > + for (insn = start; insn; insn = NEXT_INSN (insn)) > > + { > > + if (!NONDEBUG_INSN_P (insn)) > > + continue; > > + window++; > > + /* Insert 64 vaddps %xmm18, %xmm19, %xmm20(no dependence between each > > + other, just emulate for pipeline) before stalled load, stlf stall > > + case is as fast as no stall cases on CLX. > > + Since CFG is freed before machine_reorg, just do a rough > > + calculation of the window according to the layout. */ > > + if (window > 64) > > I think we want to turn the '64' into a --param at least. You can add > > -param=x86-stlf-window-ninsns= > > into i386.opt (see -param= examples in aarch64/ for example). Sure. > > > + return; > > + > > + if (any_uncondjump_p (insn) > > + || ANY_RETURN_P (PATTERN (insn))) > > You made a point about calls - does any_uncondjump_p cover them? > No, I prefer excluding calls which could take sufficient time to compensate for the STLF stall. > otherwise I think this is fine, Honza, do you agree? > > Thanks, > Richard. > > > + return; > > + > > + rtx set = single_set (insn); > > + if (!set) > > + continue; > > + rtx src = SET_SRC (set); > > + if (!MEM_P (src) > > + /* Only handle V2DFmode load since it doesn't need any scratch > > + register. */ > > + || GET_MODE (src) != E_V2DFmode > > + || !MEM_EXPR (src) > > + || TREE_CODE (get_base_address (MEM_EXPR (src))) != PARM_DECL > > + continue; > > + > > + rtx zero = CONST0_RTX (V2DFmode); > > + rtx dest = SET_DEST (set); > > + rtx m = adjust_address (src, DFmode, 0); > > + rtx loadlpd = gen_sse2_loadlpd (dest, zero, m); > > + emit_insn_before (loadlpd, insn); > > + m = adjust_address (src, DFmode, 8); > > + rtx loadhpd = gen_sse2_loadhpd (dest, dest, m); > > + if (dump_file && (dump_flags & TDF_DETAILS)) > > + { > > + fputs ("Due to potential STLF stall, split instruction:\n", > > + dump_file); > > + print_rtl_single (dump_file, insn); > > + fputs ("To:\n", dump_file); > > + print_rtl_single (dump_file, loadlpd); > > + print_rtl_single (dump_file, loadhpd); > > + } > > + PATTERN (insn) = loadhpd; > > + INSN_CODE (insn) = -1; > > + gcc_assert (recog_memoized (insn) != -1); > > + } > > +} > > > > /* Implement machine specific optimizations. We implement padding of returns > > for K8 CPUs and pass to avoid 4 jumps in the single 16 byte window. */ > > @@ -21948,6 +22006,8 @@ ix86_reorg (void) > > > > if (optimize && optimize_function_for_speed_p (cfun)) > > { > > + if (TARGET_SSE2) > > + ix86_split_stlf_stall_load (); > > if (TARGET_PAD_SHORT_FUNCTION) > > ix86_pad_short_function (); > > else if (TARGET_PAD_RETURNS) > > diff --git a/gcc/testsuite/gcc.target/i386/pr101908-1.c b/gcc/testsuite/gcc.target/i386/pr101908-1.c > > new file mode 100644 > > index 00000000000..33d9684f0ad > > --- /dev/null > > +++ b/gcc/testsuite/gcc.target/i386/pr101908-1.c > > @@ -0,0 +1,12 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-O2 -msse2 -mno-avx" } */ > > +/* { dg-final { scan-assembler-not {(?n)movhpd[ \t]} } } */ > > + > > +struct X { double x[2]; }; > > +typedef double v2df __attribute__((vector_size(16))); > > + > > +v2df __attribute__((noipa)) > > +foo (struct X* x, struct X* y) > > +{ > > + return (v2df) {x->x[1], x->x[0] } + (v2df) { y->x[1], y->x[0] }; > > +} > > diff --git a/gcc/testsuite/gcc.target/i386/pr101908-2.c b/gcc/testsuite/gcc.target/i386/pr101908-2.c > > new file mode 100644 > > index 00000000000..45060b73c06 > > --- /dev/null > > +++ b/gcc/testsuite/gcc.target/i386/pr101908-2.c > > @@ -0,0 +1,12 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-O2 -msse2 -mno-avx" } */ > > +/* { dg-final { scan-assembler-times {(?n)movhpd[ \t]+} "2" } } */ > > + > > +struct X { double x[4]; }; > > +typedef double v2df __attribute__((vector_size(16))); > > + > > +v2df __attribute__((noipa)) > > +foo (struct X x, struct X y) > > +{ > > + return (v2df) {x.x[1], x.x[0] } + (v2df) { y.x[1], y.x[0] }; > > +} > > -- > > 2.18.1 > > -- BR, Hongtao