From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22387 invoked by alias); 16 Jan 2015 18:02:51 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 22371 invoked by uid 89); 16 Jan 2015 18:02:48 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.4 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-lb0-f174.google.com Received: from mail-lb0-f174.google.com (HELO mail-lb0-f174.google.com) (209.85.217.174) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Fri, 16 Jan 2015 18:02:43 +0000 Received: by mail-lb0-f174.google.com with SMTP id 10so19741483lbg.5 for ; Fri, 16 Jan 2015 10:02:40 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.112.90.170 with SMTP id bx10mr16994178lbb.69.1421431359906; Fri, 16 Jan 2015 10:02:39 -0800 (PST) Received: by 10.25.21.9 with HTTP; Fri, 16 Jan 2015 10:02:39 -0800 (PST) In-Reply-To: <000401d03192$4901b7e0$db0527a0$@arm.com> References: <000401d03192$4901b7e0$db0527a0$@arm.com> Date: Fri, 16 Jan 2015 18:10:00 -0000 Message-ID: Subject: Re: [PATCH, Aarch64] Add FMA steering pass for Cortex-A57 From: Andrew Pinski To: "Thomas Preud'homme" Cc: GCC Patches Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2015-01/txt/msg01453.txt.bz2 On Fri, Jan 16, 2015 at 5:42 AM, Thomas Preud'homme wrote: > Hi all, > > Quoting the patch: > > For better performance, the destination of FMADD/FMSUB instructions should > have the same parity as their accumulator register if the accumulator contains > the result of a previous FMUL or FMADD/FMSUB instruction if targeting > Cortex-A57 processors. Performance is also increased by otherwise keeping a > good balance in the parity of the destination register of FMUL or FMADD/FMSUB. > > This pass ensure that registers are renamed so that these conditions hold. We > reuse the existing register renaming facility from regrename.c to build > dependency chains and expose candidate registers for renaming. > > ChangeLog entry is as follow: > > gcc/ChangeLog > > 2015-01-14 Thomas Preud'homme thomas.preudhomme@arm.com > > * config.gcc: Add fma_steering.o to extra_objs for aarch64-*-*. > * config/aarch64/t-aarch64: Add a rule for fma_steering.o. > * config/aarch64/aarch64.h (AARCH64_FL_USE_FMA_STEERING_PASS): Define. > (AARCH64_TUNE_FMA_STEERING): Likewise. > * config/aarch64/aarch64-cores.def: Set > AARCH64_FL_USE_FMA_STEERING_PASS for cores with dynamic steering of > FMUL/FMADD instructions. > * config/aarch64/aarch64.c (aarch64_register_fma_steering): Declare. > (aarch64_override_options): Call aarch64_register_fma_steering () if > AARCH64_TUNE_FMA_STEERING is true. > * config/aarch64/fma_steering.c: New file. > > > Patch can be found below and is also attached to this email for convenience. > > diff --git a/gcc/config.gcc b/gcc/config.gcc > index 0dfc08f..7acc5b6 100644 > --- a/gcc/config.gcc > +++ b/gcc/config.gcc > @@ -302,7 +302,7 @@ m32c*-*-*) > aarch64*-*-*) > cpu_type=aarch64 > extra_headers="arm_neon.h arm_acle.h" > - extra_objs="aarch64-builtins.o aarch-common.o" > + extra_objs="aarch64-builtins.o aarch-common.o cortex-a57-fma-steering.o" > target_gtfiles="\$(srcdir)/config/aarch64/aarch64-builtins.c" > target_has_targetm_common=yes > ;; > diff --git a/gcc/config/aarch64/aarch64-cores.def b/gcc/config/aarch64/aarch64-cores.def > index 18f5c48..fc770f3 100644 > --- a/gcc/config/aarch64/aarch64-cores.def > +++ b/gcc/config/aarch64/aarch64-cores.def > @@ -35,9 +35,9 @@ > /* V8 Architecture Processors. */ > > AARCH64_CORE("cortex-a53", cortexa53, cortexa53, 8, AARCH64_FL_FOR_ARCH8 | AARCH64_FL_CRC, cortexa53) > -AARCH64_CORE("cortex-a57", cortexa15, cortexa15, 8, AARCH64_FL_FOR_ARCH8 | AARCH64_FL_CRC, cortexa57) > +AARCH64_CORE("cortex-a57", cortexa15, cortexa15, 8, AARCH64_FL_FOR_ARCH8 | AARCH64_FL_CRC | AARCH64_FL_USE_FMA_STEERING_PASS, cortexa57) > AARCH64_CORE("thunderx", thunderx, thunderx, 8, AARCH64_FL_FOR_ARCH8 | AARCH64_FL_CRC | AARCH64_FL_CRYPTO, thunderx) > > /* V8 big.LITTLE implementations. */ > > -AARCH64_CORE("cortex-a57.cortex-a53", cortexa57cortexa53, cortexa53, 8, AARCH64_FL_FOR_ARCH8 | AARCH64_FL_CRC, cortexa57) > +AARCH64_CORE("cortex-a57.cortex-a53", cortexa57cortexa53, cortexa53, 8, AARCH64_FL_FOR_ARCH8 | AARCH64_FL_CRC | AARCH64_FL_USE_FMA_STEERING_PASS, cortexa57) > diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h > index eed86f7..f749811 100644 > --- a/gcc/config/aarch64/aarch64.h > +++ b/gcc/config/aarch64/aarch64.h > @@ -200,6 +200,8 @@ extern unsigned aarch64_architecture_version; > #define AARCH64_FL_CRYPTO (1 << 2) /* Has crypto. */ > #define AARCH64_FL_SLOWMUL (1 << 3) /* A slow multiply core. */ > #define AARCH64_FL_CRC (1 << 4) /* Has CRC. */ > +/* Has static dispatch of FMA. */ > +#define AARCH64_FL_USE_FMA_STEERING_PASS (1 << 5) > > /* Has FP and SIMD. */ > #define AARCH64_FL_FPSIMD (AARCH64_FL_FP | AARCH64_FL_SIMD) > @@ -220,6 +222,8 @@ extern unsigned long aarch64_isa_flags; > /* Macros to test tuning flags. */ > extern unsigned long aarch64_tune_flags; > #define AARCH64_TUNE_SLOWMUL (aarch64_tune_flags & AARCH64_FL_SLOWMUL) > +#define AARCH64_TUNE_FMA_STEERING \ > + (aarch64_tune_flags & AARCH64_FL_USE_FMA_STEERING_PASS) > > /* Crypto is an optional extension to AdvSIMD. */ > #define TARGET_CRYPTO (TARGET_SIMD && AARCH64_ISA_CRYPTO) > diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c > index 5100532..566ac2d 100644 > --- a/gcc/config/aarch64/aarch64.c > +++ b/gcc/config/aarch64/aarch64.c > @@ -6716,6 +6716,11 @@ aarch64_parse_tune (void) > } > > > +/* Defined in config/aarch64/fma_steering.c. */ > + > +void > +aarch64_register_fma_steering (void); This is really bad form. Can you add a header file for this declaration and maybe future declarations too? Maybe called aarch64-internal.h and include this header file both in aarch64.c and fma_steering.c. Thanks, Andrew Pinski > + > /* Implement TARGET_OPTION_OVERRIDE. */ > > static void > @@ -6798,6 +6803,9 @@ aarch64_override_options (void) > align_functions = aarch64_tune_params->function_align; > } > > + if (AARCH64_TUNE_FMA_STEERING) > + aarch64_register_fma_steering (); > + > aarch64_override_options_after_change (); > } > > diff --git a/gcc/config/aarch64/cortex-a57-fma-steering.c b/gcc/config/aarch64/cortex-a57-fma-steering.c > new file mode 100644 > index 0000000..84b939e > --- /dev/null > +++ b/gcc/config/aarch64/cortex-a57-fma-steering.c > @@ -0,0 +1,1087 @@ > +/* FMA steering optimization pass for Cortex-A57. > + Copyright (C) 2015 Free Software Foundation, Inc. > + Contributed by ARM Ltd. > + > + This file is part of GCC. > + > + GCC is free software; you can redistribute it and/or modify it > + under the terms of the GNU General Public License as published by > + the Free Software Foundation; either version 3, or (at your option) > + any later version. > + > + GCC is distributed in the hope that it will be useful, but > + WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + General Public License for more details. > + > + You should have received a copy of the GNU General Public License > + along with GCC; see the file COPYING3. If not see > + . */ > + > +#include "config.h" > +#include "system.h" > +#include "coretypes.h" > +#include "tm.h" > +#include "regs.h" > +#include "insn-config.h" > +#include "hard-reg-set.h" > +#include "dominance.h" > +#include "cfg.h" > +#include "cfganal.h" > +#include "predict.h" > +#include "basic-block.h" > +#include "insn-attr.h" > +#include "machmode.h" > +#include "recog.h" > +#include "output.h" > +#include "vec.h" > +#include "hash-map.h" > +#include "bitmap.h" > +#include "obstack.h" > +#include "df.h" > +#include "target.h" > +#include "rtl.h" > +#include "context.h" > +#include "tree-pass.h" > +#include "regrename.h" > + > +#include > + > +/* For better performance, the destination of FMADD/FMSUB instructions should > + have the same parity as their accumulator register if the accumulator > + contains the result of a previous FMUL or FMADD/FMSUB instruction if > + targetting Cortex-A57 processors. Performance is also increased by > + otherwise keeping a good balance in the parity of the destination register > + of FMUL or FMADD/FMSUB. > + > + This pass ensure that registers are renamed so that these conditions hold. > + We reuse the existing register renaming facility from regrename.c to build > + dependency chains and expose candidate registers for renaming. > + > + > + The algorithm has three steps: > + > + First, the functions of the register renaming pass are called. These > + analyze the instructions and produce a list of def/use chains of > + instructions. > + > + Next, this information is used to build trees of multiply and > + multiply-accumulate instructions. The roots of these trees are any > + multiply, or any multiply-accumulate whose accumulator is not dependent on > + a multiply or multiply-accumulate instruction. A child is added to the > + tree where a dependency chain exists between the result of the parent > + instruction and the accumulator operand of the child, as in the diagram > + below: > + > + fmul s2, s0, s1 > + / \ > + fmadd s0, s1, s1, s2 fmadd s4, s1, s1 s2 > + | > + fmadd s3, s1, s1, s0 > + > + Trees made of a single instruction are permitted. > + > + Finally, renaming is performed. The parity of the destination register at > + the root of a tree is checked against the current balance of multiply and > + multiply-accumulate on each pipeline. If necessary, the root of a tree is > + renamed, in which case the rest of the tree is then renamed to keep the same > + parity in the destination registers of all instructions in the tree. */ > + > + > + > +/* Forward declarations. */ > +class fma_node; > +class fma_root_node; > +class func_fma_steering; > + > +/* Dependencies between FMUL or FMADD/FMSUB instructions and subsequent > + FMADD/FMSUB instructions form a graph. This is because alternatives can > + make a register be set by several FMUL or FMADD/FMSUB instructions in > + different basic blocks and because of loops. For ease of browsing, the > + connected components of this graph are broken up into forests of trees. > + Forests are represented by fma_forest objects, contained in the fma_forests > + list. Using a separate object for the forests allows for a better use of > + memory as there is some information that is global to each forest, such as > + the number of FMSUB and FMADD/FMSUB instructions currently scheduled on each > + floating-point execution pipelines. */ > + > +class fma_forest > +{ > +public: > + fma_forest (func_fma_steering *, fma_root_node *, int); > + ~fma_forest (); > + > + int get_id (); > + std::list *get_roots (); > + func_fma_steering *get_globals (); > + int get_target_parity (); > + void fma_node_created (fma_node *); > + void merge_forest (fma_forest *); > + void dump_info (); > + void dispatch (); > + > +private: > + /* The list of roots that form this forest. */ > + std::list *m_roots; > + > + /* Target parity the destination register of all FMUL and FMADD/FMSUB > + instructions in this forest should have. */ > + int m_target_parity; > + > + /* Link to the instance of func_fma_steering holding data related to the > + FMA steering of the current function (cfun). */ > + func_fma_steering *m_globals; > + > + /* Identifier for the forest (used for dumps). */ > + int m_id; > + > + /* Total number of nodes in the forest (for statistics). */ > + int m_nb_nodes; > +}; > + > +class fma_node > +{ > +public: > + fma_node (fma_node *parent, du_chain *chain); > + ~fma_node (); > + > + bool root_p (); > + fma_forest *get_forest (); > + std::list *get_children (); > + rtx_insn *get_insn (); > + void add_child (fma_node *); > + int get_parity (); > + void set_head (du_head *); > + void rename (fma_forest *); > + void dump_info (fma_forest *); > + > +protected: > + /* Root node that lead to this node. */ > + fma_root_node *m_root; > + > + /* The parent node of this node. If the node belong to a chain with several > + parent nodes, the first one encountered in a depth-first search is chosen > + as canonical parent. */ > + fma_node *m_parent; > + > + /* The list of child nodes. If a chain contains several parent nodes, one is > + chosen as canonical parent and the others will have no children. */ > + std::list *m_children; > + > + /* The associated DU_HEAD chain that the insn represented by this object > + is (one of) the root of. When a chain contains several roots, the non > + canonical ones have this field set to NULL. */ > + struct du_head *m_head; > + > + /* The FMUL or FMADD/FMSUB instruction this object corresponds to. */ > + rtx_insn *m_insn; > +}; > + > +class fma_root_node : public fma_node > +{ > +public: > + fma_root_node (func_fma_steering *, du_chain *, int); > + > + fma_forest *get_forest (); > + void set_forest (fma_forest *); > + void dump_info (fma_forest *); > + > +private: > + /* The forest this node belonged to when it was created. */ > + fma_forest *m_forest; > +}; > + > +/* Class holding all data and methods relative to the FMA steering of a given > + function. The FMA steering pass could then run in parallel for different > + functions. */ > + > +class func_fma_steering > +{ > +public: > + func_fma_steering (); > + ~func_fma_steering (); > + > + int get_fpu_balance (); > + void remove_forest (fma_forest *); > + bool put_node (fma_node *); > + void update_balance (int); > + fma_node *get_fma_node (rtx_insn *); > + void analyze_fma_fmul_insn (fma_forest *, du_chain *, du_head_p); > + void execute_fma_steering (); > + > +private: > + void dfs (void (*) (fma_forest *), void (*) (fma_forest *, fma_root_node *), > + void (*) (fma_forest *, fma_node *), bool); > + void analyze (); > + void rename_fma_trees (); > + > + /* Mapping between FMUL or FMADD/FMSUB instructions and the associated > + fma_node object. Used when analyzing an instruction that is a root of > + a chain to find if such an object was created because this instruction > + is also a use in another chain. */ > + hash_map *m_insn_fma_head_map; > + > + /* A list of all the forests in a given function. */ > + std::list m_fma_forests; > + > + /* Balance of FMUL and FMADD/FMSUB instructions between the two FPU > + pipelines: > + < 0: more instruction dispatched to the first pipeline > + == 0: perfect balance > + > 0: more instruction dispatched to the second pipeline. */ > + int m_fpu_balance; > + > + /* Identifier for the next forest created. */ > + int m_next_forest_id; > +}; > + > +/* Rename the register HEAD->regno in all the insns in the chain HEAD to any > + register not in the set UNAVAILABLE. Adapted from rename_chains in > + regrename.c. */ > + > +static bool > +rename_single_chain (du_head_p head, HARD_REG_SET *unavailable) > +{ > + int best_new_reg; > + int n_uses = 0; > + struct du_chain *tmp; > + int reg = head->regno; > + enum reg_class super_class = NO_REGS; > + > + if (head->cannot_rename) > + return false; > + > + if (fixed_regs[reg] || global_regs[reg] > + || (frame_pointer_needed && reg == HARD_FRAME_POINTER_REGNUM)) > + return false; > + > + /* Iterate over elements in the chain in order to: > + 1. Count number of uses, and narrow the set of registers we can > + use for renaming. > + 2. Compute the superunion of register classes in this chain. */ > + for (tmp = head->first; tmp; tmp = tmp->next_use) > + { > + if (DEBUG_INSN_P (tmp->insn)) > + continue; > + n_uses++; > + IOR_COMPL_HARD_REG_SET (*unavailable, reg_class_contents[tmp->cl]); > + super_class = reg_class_superunion[(int) super_class][(int) tmp->cl]; > + } > + > + if (n_uses < 1) > + return false; > + > + best_new_reg = find_rename_reg (head, super_class, unavailable, reg, > + false); > + > + if (dump_file) > + { > + fprintf (dump_file, "Register %s in insn %d", reg_names[reg], > + INSN_UID (head->first->insn)); > + if (head->need_caller_save_reg) > + fprintf (dump_file, " crosses a call"); > + } > + > + if (best_new_reg == reg) > + { > + if (dump_file) > + fprintf (dump_file, "; no available better choice\n"); > + return false; > + } > + > + if (dump_file) > + fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]); > + > + regrename_do_replace (head, best_new_reg); > + df_set_regs_ever_live (best_new_reg, true); > + return true; > +} > + > +/* Return whether T is the attribute of a FMADD/FMSUB-like instruction. */ > + > +static bool > +is_fmac_op (enum attr_type t) > +{ > + return (t == TYPE_FMACS) || (t == TYPE_FMACD) || (t == TYPE_NEON_FP_MLA_S); > +} > + > +/* Return whether T is the attribute of a FMUL instruction. */ > + > +static bool > +is_fmul_op (enum attr_type t) > +{ > + return (t == TYPE_FMULS) || (t == TYPE_FMULD) || (t == TYPE_NEON_FP_MUL_S); > +} > + > +/* Return whether INSN is an FMUL (if FMUL_OK is true) or FMADD/FMSUB > + instruction. */ > + > +static bool > +is_fmul_fmac_insn (rtx_insn *insn, bool fmul_ok) > +{ > + enum attr_type t; > + > + if (!NONDEBUG_INSN_P (insn)) > + return false; > + > + if (recog_memoized (insn) < 0) > + return false; > + > + /* Only consider chain(s) this instruction is a root of if this is an FMUL or > + FMADD/FMSUB instruction. This allows to avoid browsing chains of all > + instructions for FMUL or FMADD/FMSUB in them. */ > + t = get_attr_type (insn); > + return is_fmac_op (t) || (fmul_ok && is_fmul_op (t)); > +} > + > + > +/* > + * Class fma_forest method definitions. > + */ > + > +fma_forest::fma_forest (func_fma_steering *fma_steer, fma_root_node *fma_root, > + int id) > +{ > + memset (this, 0, sizeof (*this)); > + this->m_globals = fma_steer; > + this->m_roots = new std::list; > + this->m_roots->push_back (fma_root); > + this->m_id = id; > +} > + > +fma_forest::~fma_forest () > +{ > + delete this->m_roots; > +} > + > +int > +fma_forest::get_id () > +{ > + return this->m_id; > +} > + > +std::list * > +fma_forest::get_roots () > +{ > + return this->m_roots; > +} > + > +func_fma_steering * > +fma_forest::get_globals () > +{ > + return this->m_globals; > +} > + > +int > +fma_forest::get_target_parity () > +{ > + return this->m_target_parity; > +} > + > +/* Act on the creation of NODE by updating statistics in FOREST and adding an > + entry for it in the func_fma_steering hashmap. */ > + > +void fma_forest::fma_node_created (fma_node *node) > +{ > + bool created = !this->m_globals->put_node (node); > + > + gcc_assert (created); > + this->m_nb_nodes++; > +} > + > +/* Merge REF_FOREST and OTHER_FOREST together, making REF_FOREST the canonical > + fma_forest object to represent both. */ > + > +void > +fma_forest::merge_forest (fma_forest *other_forest) > +{ > + std::list *other_roots; > + std::list::iterator other_root_iter; > + > + if (this == other_forest) > + return; > + > + other_roots = other_forest->m_roots; > + > + /* Update root nodes' pointer to forest. */ > + for (other_root_iter = other_roots->begin (); > + other_root_iter != other_roots->end (); other_root_iter++) > + (*other_root_iter)->set_forest (this); > + > + /* Remove other_forest from the list of forests and move its tree roots in > + the list of tree roots of ref_forest. */ > + this->m_globals->remove_forest (other_forest); > + this->m_roots->splice (this->m_roots->begin (), *other_roots); > + delete other_forest; > + > + this->m_nb_nodes += other_forest->m_nb_nodes; > +} > + > +/* Dump information about the forest FOREST. */ > + > +void > +fma_forest::dump_info () > +{ > + gcc_assert (dump_file); > + > + fprintf (dump_file, "Forest #%d has %d nodes\n", this->m_id, > + this->m_nb_nodes); > +} > + > +/* Wrapper around fma_forest::dump_info for use as parameter of function > + pointer type in func_fma_steering::dfs. */ > + > +static void > +dump_forest_info (fma_forest *forest) > +{ > + forest->dump_info (); > +} > + > +/* Dispatch forest to the least utilized pipeline. */ > + > +void > +fma_forest::dispatch () > +{ > + this->m_target_parity = this->m_roots->front ()->get_parity (); > + int fpu_balance = this->m_globals->get_fpu_balance (); > + if (fpu_balance != 0) > + this->m_target_parity = (fpu_balance < 0); > + > + if (dump_file) > + fprintf (dump_file, "Target parity for forest #%d: %s\n", this->m_id, > + this->m_target_parity ? "odd" : "even"); > +} > + > +/* Wrapper around fma_forest::dispatch for use as parameter of function pointer > + type in func_fma_steering::dfs. */ > + > +static void > +dispatch_forest (fma_forest *forest) > +{ > + forest->dispatch (); > +} > + > +fma_node::fma_node (fma_node *parent, du_chain *chain) > +{ > + memset (this, 0, sizeof (*this)); > + this->m_parent = parent; > + this->m_children = new std::list; > + this->m_insn = chain->insn; > + /* root_p () cannot be used to check for root before root is set. */ > + if (this->m_parent == this) > + this->m_root = static_cast (parent); > + else > + { > + this->m_root = parent->m_root; > + this->get_forest ()->fma_node_created (this); > + } > +} > + > +fma_node::~fma_node () > +{ > + delete this->m_children; > +} > + > +std::list * > +fma_node::get_children () > +{ > + return this->m_children; > +} > + > +rtx_insn * > +fma_node::get_insn () > +{ > + return this->m_insn; > +} > + > +void > +fma_node::set_head (du_head *head) > +{ > + gcc_assert (!this->m_head); > + this->m_head = head; > +} > + > +/* Add a child to this node in the list of children. */ > + > +void > +fma_node::add_child (fma_node *child) > +{ > + this->m_children->push_back (child); > +} > + > +/* Return the parity of the destination register of the instruction represented > + by this node. */ > + > +int > +fma_node::get_parity () > +{ > + return this->m_head->regno % 2; > +} > + > +/* Get the actual forest associated with a non root node as the one the node > + points to might have been merged into another one. In that case the pointer > + in the root nodes are updated so we return the forest pointer of a root node > + pointed to by the initial forest. Despite being a oneliner, this method is > + defined here as it references a method from fma_root_node. */ > + > +fma_forest * > +fma_node::get_forest () > +{ > + return this->m_root->get_forest (); > +} > + > +/* Return whether a node is a root node. */ > + > +bool > +fma_node::root_p () > +{ > + return this->m_root == this; > +} > + > +/* Dump information about the children of node FMA_NODE in forest FOREST. */ > + > +void > +fma_node::dump_info (ATTRIBUTE_UNUSED fma_forest *forest) > +{ > + struct du_chain *chain; > + std::list::iterator fma_child; > + > + gcc_assert (dump_file); > + > + if (this->get_children ()->empty ()) > + return; > + > + fprintf (dump_file, "Instruction(s)"); > + for (chain = this->m_head->first; chain; chain = chain->next_use) > + { > + if (!is_fmul_fmac_insn (chain->insn, true)) > + continue; > + > + if (chain->loc != &SET_DEST (PATTERN (chain->insn))) > + continue; > + > + fprintf (dump_file, " %d", INSN_UID (chain->insn)); > + } > + > + fprintf (dump_file, " is(are) accumulator dependency of instructions"); > + for (fma_child = this->get_children ()->begin (); > + fma_child != this->get_children ()->end (); fma_child++) > + fprintf (dump_file, " %d", INSN_UID ((*fma_child)->m_insn)); > + fprintf (dump_file, "\n"); > +} > + > +/* Wrapper around fma_node::dump_info for use as parameter of function pointer > + type in func_fma_steering::dfs. */ > + > +static void > +dump_tree_node_info (fma_forest *forest, fma_node *node) > +{ > + node->dump_info (forest); > +} > + > +/* Rename the destination register of a single FMUL or FMADD/FMSUB instruction > + represented by FMA_NODE to a register that respect the target parity for > + FOREST or with same parity of the instruction represented by its parent node > + if it has one. */ > + > +void > +fma_node::rename (fma_forest *forest) > +{ > + int cur_parity, target_parity; > + > + /* This is alternate root of a chain and thus has no children. It will be > + renamed when processing the canonical root for that chain. */ > + if (!this->m_head) > + return; > + > + target_parity = forest->get_target_parity (); > + if (this->m_parent) > + target_parity = this->m_parent->get_parity (); > + cur_parity = this->get_parity (); > + > + /* Rename if parity differs. */ > + if (cur_parity != target_parity) > + { > + rtx_insn *insn = this->m_insn; > + HARD_REG_SET unavailable; > + enum machine_mode mode; > + int reg; > + > + if (dump_file) > + { > + unsigned cur_dest_reg = this->m_head->regno; > + > + fprintf (dump_file, "FMA or FMUL at insn %d but destination " > + "register (%s) has different parity from expected to " > + "maximize FPU pipeline utilization\n", INSN_UID (insn), > + reg_names[cur_dest_reg]); > + } > + > + /* Don't clobber traceback for noreturn functions. */ > + CLEAR_HARD_REG_SET (unavailable); > + if (frame_pointer_needed) > + { > + add_to_hard_reg_set (&unavailable, Pmode, FRAME_POINTER_REGNUM); > + add_to_hard_reg_set (&unavailable, Pmode, HARD_FRAME_POINTER_REGNUM); > + } > + > + /* Exclude registers with wrong parity. */ > + mode = GET_MODE (SET_DEST (PATTERN (insn))); > + for (reg = cur_parity; reg < FIRST_PSEUDO_REGISTER; reg += 2) > + add_to_hard_reg_set (&unavailable, mode, reg); > + > + if (!rename_single_chain (this->m_head, &unavailable)) > + { > + if (dump_file) > + fprintf (dump_file, "Destination register of insn %d could not be " > + "renamed. Dependent FMA insns will use this parity from " > + "there on.\n", INSN_UID (insn)); > + } > + else > + cur_parity = target_parity; > + } > + > + forest->get_globals ()->update_balance (cur_parity); > +} > + > +/* Wrapper around fma_node::dump_info for use as parameter of function pointer > + type in func_fma_steering::dfs. */ > + > +static void > +rename_fma_node (fma_forest *forest, fma_node *node) > +{ > + node->rename (forest); > +} > + > +fma_root_node::fma_root_node (func_fma_steering *globals, du_chain *chain, > + int id) : fma_node (this, chain) > +{ > + this->m_forest = new fma_forest (globals, this, id); > + this->m_forest->fma_node_created (this); > +} > + > +fma_forest * > +fma_root_node::get_forest () > +{ > + return this->m_forest; > +} > + > +void > +fma_root_node::set_forest (fma_forest *ref_forest) > +{ > + this->m_forest = ref_forest; > +} > + > +/* Dump information about the roots of forest FOREST. */ > + > +void > +fma_root_node::dump_info (fma_forest *forest) > +{ > + gcc_assert (dump_file); > + > + if (this == forest->get_roots ()->front ()) > + fprintf (dump_file, "Instruction(s) at root of forest #%d:", > + forest->get_id ()); > + fprintf (dump_file, " %d", INSN_UID (this->m_insn)); > + if (this == forest->get_roots ()->back ()) > + fprintf (dump_file, "\n"); > +} > + > +/* Wrapper around fma_root_node::dump_info for use as parameter of function > + pointer type in func_fma_steering::dfs. */ > + > +static void > +dump_tree_root_info (fma_forest *forest, fma_root_node *node) > +{ > + node->dump_info (forest); > +} > + > +func_fma_steering::func_fma_steering () : m_fpu_balance (0) > +{ > + this->m_insn_fma_head_map = new hash_map; > + this->m_fma_forests.clear (); > + this->m_next_forest_id = 0; > +} > + > +func_fma_steering::~func_fma_steering () > +{ > + delete this->m_insn_fma_head_map; > +} > + > +int > +func_fma_steering::get_fpu_balance () > +{ > + return this->m_fpu_balance; > +} > + > +void > +func_fma_steering::remove_forest (fma_forest *forest) > +{ > + this->m_fma_forests.remove (forest); > +} > + > +/* Memorize the mapping of this instruction to its fma_node object and return > + whether such a mapping existed. */ > + > +bool > +func_fma_steering::put_node (fma_node *node) > +{ > + return this->m_insn_fma_head_map->put (node->get_insn (), node); > +} > + > +/* Update the current balance considering a node with the given PARITY. */ > + > +void > +func_fma_steering::update_balance (int parity) > +{ > + this->m_fpu_balance = parity ? this->m_fpu_balance + 1 > + : this->m_fpu_balance - 1; > +} > + > +/* Return whether an fma_node object exists for instruction INSN and, if not, > + allocate one in *RET. */ > + > +fma_node * > +func_fma_steering::get_fma_node (rtx_insn *insn) > +{ > + fma_node **fma_slot; > + > + fma_slot = this->m_insn_fma_head_map->get (insn); > + if (fma_slot) > + return *fma_slot; > + return NULL; > +} > + > +/* Allocate and initialize fma_node objects for the FMUL or FMADD/FMSUB > + instruction in CHAIN->insn and its dependent FMADD/FMSUB instructions, all > + part of FOREST. For the children, the associated head is left untouched > + (and thus null) as this function will be called again when considering the > + chain where they are def. For the parent, the chain is given in HEAD. */ > + > +void > +func_fma_steering::analyze_fma_fmul_insn (fma_forest *ref_forest, > + du_chain *chain, du_head_p head) > +{ > + fma_forest *forest; > + fma_node *node = this->get_fma_node (chain->insn); > + > + /* This is a root node. */ > + if (!node) > + { > + fma_root_node *root_node; > + > + root_node = new fma_root_node (this, chain, this->m_next_forest_id++); > + forest = root_node->get_forest (); > + node = root_node; > + > + /* Until proved otherwise, assume this root is not part of an existing > + forest and thus add its forest to the list of forests. */ > + this->m_fma_forests.push_back (forest); > + } > + else > + forest = node->get_forest (); > + > + node->set_head (head); > + > + /* fma_node is part of a chain with several defs, one of them having already > + been processed. The root of that already processed def is the canonical > + one and the root of fma_node is added to its forest. No need to process > + the children nodes as they were already processed when the other def was > + processed. */ > + if (ref_forest) > + { > + ref_forest->merge_forest (forest); > + return; > + } > + > + for (chain = head->first; chain; chain = chain->next_use) > + { > + fma_node *child_fma; > + rtx fma_rtx, *accum_rtx_p; > + > + if (!is_fmul_fmac_insn (chain->insn, false)) > + continue; > + > + /* Get FMA rtx. */ > + fma_rtx = SET_SRC (PATTERN (chain->insn)); > + /* FMA is negated. */ > + if (GET_CODE (fma_rtx) == NEG) > + fma_rtx = XEXP (fma_rtx, 0); > + /* Get accumulator rtx. */ > + accum_rtx_p = &XEXP (fma_rtx, 2); > + /* Accumulator is negated. */ > + if (!REG_P (*accum_rtx_p)) > + accum_rtx_p = &XEXP (*accum_rtx_p, 0); > + > + /* This du_chain structure is not for the accumulator register. */ > + if (accum_rtx_p != chain->loc) > + continue; > + > + /* If object already created, this is a loop carried dependency. We > + don't include this object in the children as we want trees for > + rename_fma_trees to not be an infinite loop. */ > + if (this->get_fma_node (chain->insn)) > + continue; > + > + child_fma = new fma_node (node, chain); > + > + /* Memorize the mapping of this instruction to its fma_node object > + as it will be processed for the chain starting at its destination > + register later. */ > + > + /* Link to siblings. */ > + node->add_child (child_fma); > + } > +} > + > +/* Perform a depth-first search of the forests of fma_node in > + THIS->m_fma_forests, calling PROCESS_FOREST () on each fma_forest object in > + THIS->m_fma_forests list, PROCESS_ROOT () on each tree root and > + PROCESS_NODE () on each node. If FREE is true, free all std::list in the > + same dfs. */ > + > +void > +func_fma_steering::dfs (void (*process_forest) (fma_forest *), > + void (*process_root) (fma_forest *, fma_root_node *), > + void (*process_node) (fma_forest *, fma_node *), > + bool free) > +{ > + vec to_process; > + std::list::iterator forest_iter; > + > + to_process.create (0); > + > + /* For each forest. */ > + for (forest_iter = this->m_fma_forests.begin (); > + forest_iter != this->m_fma_forests.end (); forest_iter++) > + { > + std::list::iterator root_iter; > + > + if (process_forest) > + process_forest (*forest_iter); > + > + /* For each tree root in this forest. */ > + for (root_iter = (*forest_iter)->get_roots ()->begin (); > + root_iter != (*forest_iter)->get_roots ()->end (); root_iter++) > + { > + if (process_root) > + process_root (*forest_iter, *root_iter); > + to_process.safe_push (*root_iter); > + } > + > + /* For each tree node in this forest. */ > + while (!to_process.is_empty ()) > + { > + fma_node *node; > + std::list::iterator child_iter; > + > + node = to_process.pop (); > + > + if (process_node) > + process_node (*forest_iter, node); > + > + /* Absence of children might indicate an alternate root of a *chain*. > + It's ok to skip it here as the chain will be renamed when > + processing the canonical root for that chain. */ > + if (node->get_children ()->empty ()) > + continue; > + > + for (child_iter = node->get_children ()->begin (); > + child_iter != node->get_children ()->end (); child_iter++) > + to_process.safe_push (*child_iter); > + if (free) > + { > + if (node->root_p ()) > + delete static_cast (node); > + else > + delete node; > + } > + } > + if (free) > + delete *forest_iter; > + } > + > + to_process.release (); > +} > + > +/* Build the dependency trees of FMUL and FMADD/FMSUB instructions. */ > + > +void > +func_fma_steering::analyze () > +{ > + int i, n_blocks, *bb_dfs_preorder; > + basic_block bb; > + rtx_insn *insn; > + > + bb_dfs_preorder = XNEWVEC (int, last_basic_block_for_fn (cfun)); > + n_blocks = pre_and_rev_post_order_compute (bb_dfs_preorder, NULL, false); > + > + /* Browse the graph of basic blocks looking for FMUL or FMADD/FMSUB > + instructions. */ > + for (i = 0; i < n_blocks; i++) > + { > + bb = BASIC_BLOCK_FOR_FN (cfun, bb_dfs_preorder[i]); > + FOR_BB_INSNS (bb, insn) > + { > + operand_rr_info *dest_op_info; > + struct du_chain *chain; > + unsigned dest_regno; > + fma_forest *forest; > + du_head_p head; > + int i; > + > + if (!is_fmul_fmac_insn (insn, true)) > + continue; > + > + /* Search the chain where this instruction is (one of) the root. */ > + dest_op_info = insn_rr[INSN_UID (insn)].op_info; > + dest_regno = REGNO (SET_DEST (PATTERN (insn))); > + for (i = 0; i < dest_op_info->n_chains; i++) > + { > + /* The register tracked by this chain does not match the > + destination register of insn. */ > + if (dest_op_info->heads[i]->regno != dest_regno) > + continue; > + > + head = dest_op_info->heads[i]; > + /* The chain was merged in another, find the new head. */ > + if (!head->first) > + head = regrename_chain_from_id (head->id); > + > + /* Search the chain element for this instruction and, if another > + FMUL or FMADD/FMSUB instruction was already processed, note > + the forest of its tree. */ > + forest = NULL; > + for (chain = head->first; chain; chain = chain->next_use) > + { > + fma_node **fma_slot; > + > + if (!is_fmul_fmac_insn (chain->insn, true)) > + continue; > + > + /* This is a use, continue. */ > + if (chain->loc != &SET_DEST (PATTERN (chain->insn))) > + continue; > + > + if (chain->insn == insn) > + break; > + > + fma_slot = this->m_insn_fma_head_map->get (chain->insn); > + if (fma_slot && (*fma_slot)->get_children ()) > + forest = (*fma_slot)->get_forest (); > + } > + if (chain) > + break; > + } > + > + /* We didn't find a chain with a def for this instruction. */ > + gcc_assert (i < dest_op_info->n_chains); > + > + this->analyze_fma_fmul_insn (forest, chain, head); > + } > + } > + free (bb_dfs_preorder); > + > + if (dump_file) > + this->dfs (dump_forest_info, dump_tree_root_info, dump_tree_node_info, > + false); > +} > + > +/* Perform the renaming of all chains with FMUL or FMADD/FMSUB involved with > + the objective of keeping FPU pipeline balanced in term of instructions and > + having FMADD/FMSUB with dependencies on previous FMUL or FMADD/FMSUB be > + scheduled on the same pipeline. */ > + > +void > +func_fma_steering::rename_fma_trees () > +{ > + this->dfs (dispatch_forest, NULL, rename_fma_node, true); > + > + if (dump_file && !this->m_fma_forests.empty ()) > + { > + fprintf (dump_file, "Function %s has ", current_function_name ()); > + if (this->m_fpu_balance == 0) > + fprintf (dump_file, "perfect balance of FMUL/FMA chains between the " > + "two FPU pipelines\n"); > + else if (this->m_fpu_balance > 0) > + fprintf (dump_file, "%d more FMUL/FMA chains scheduled on the second " > + "FPU pipeline\n", this->m_fpu_balance); > + else /* this->m_fpu_balance < 0 */ > + fprintf (dump_file, "%d more FMUL/FMA chains scheduled on the first " > + "FPU pipeline\n", - this->m_fpu_balance); > + } > +} > + > +/* Execute FMA steering pass. */ > + > +void > +func_fma_steering::execute_fma_steering () > +{ > + df_set_flags (DF_LR_RUN_DCE); > + df_note_add_problem (); > + df_analyze (); > + df_set_flags (DF_DEFER_INSN_RESCAN); > + > + regrename_init (true); > + regrename_analyze (NULL); > + this->analyze (); > + this->rename_fma_trees (); > + regrename_finish (); > +} > + > +const pass_data pass_data_fma_steering = > +{ > + RTL_PASS, /* type */ > + "fma_steering", /* name */ > + OPTGROUP_NONE, /* optinfo_flags */ > + TV_NONE, /* tv_id */ > + 0, /* properties_required */ > + 0, /* properties_provided */ > + 0, /* properties_destroyed */ > + 0, /* todo_flags_start */ > + TODO_df_finish, /* todo_flags_finish */ > +}; > + > +class pass_fma_steering : public rtl_opt_pass > +{ > +public: > + pass_fma_steering (gcc::context *ctxt) > + : rtl_opt_pass (pass_data_fma_steering, ctxt) > + {} > + > + /* opt_pass methods: */ > + virtual bool gate (function *) > + { > + return optimize >= 2; > + } > + > + virtual unsigned int execute (function *) > + { > + func_fma_steering *fma_steering = new func_fma_steering; > + fma_steering->execute_fma_steering (); > + delete fma_steering; > + return 0; > + } > + > +}; // class pass_fma_steering > + > +/* Create a new fma steering pass instance. */ > + > +static rtl_opt_pass * > +make_pass_fma_steering (gcc::context *ctxt) > +{ > + return new pass_fma_steering (ctxt); > +} > + > +/* Register the FMA steering pass to the pass manager. */ > + > +void > +aarch64_register_fma_steering () > +{ > + opt_pass *pass_fma_steering = make_pass_fma_steering (g); > + > + static struct register_pass_info fma_steering_info > + = { pass_fma_steering, "rnreg", 1, PASS_POS_INSERT_AFTER }; > + > + register_pass (&fma_steering_info); > +} > diff --git a/gcc/config/aarch64/t-aarch64 b/gcc/config/aarch64/t-aarch64 > index e410bc9..3c358a2 100644 > --- a/gcc/config/aarch64/t-aarch64 > +++ b/gcc/config/aarch64/t-aarch64 > @@ -48,6 +48,14 @@ aarch-common.o: $(srcdir)/config/arm/aarch-common.c $(CONFIG_H) $(SYSTEM_H) \ > $(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \ > $(srcdir)/config/arm/aarch-common.c > > +cortex-a57-fma-steering.o: $(srcdir)/config/aarch64/cortex-a57-fma-steering.c \ > + $(CONFIG_H) $(SYSTEM_H) $(TM_H) $(REGS_H) insn-config.h $(RTL_BASE_H) \ > + dominance.h cfg.h cfganal.h $(BASIC_BLOCK_H) $(INSN_ATTR_H) $(RECOG_H) \ > + output.h hash-map.h $(DF_H) $(OBSTACK_H) $(TARGET_H) $(RTL_H) \ > + $(CONTEXT_H) $(TREE_PASS_H) regrename.h > + $(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \ > + $(srcdir)/config/aarch64/cortex-a57-fma-steering.c > + > comma=, > MULTILIB_OPTIONS = $(subst $(comma),/, $(patsubst %, mabi=%, $(subst $(comma),$(comma)mabi=,$(TM_MULTILIB_CONFIG)))) > MULTILIB_DIRNAMES = $(subst $(comma), ,$(TM_MULTILIB_CONFIG)) > > > Bootstrapped on Cortex-A57 and ran against big benchmark without any regression. > > Is this ok for trunk? > > Best regards, > > Thomas