> On 10 Jan 2025, at 15:30, Richard Sandiford <richard.sandif...@arm.com> wrote: > > Wilco Dijkstra <wilco.dijks...@arm.com> writes: >> As a minor cleanup remove Cortex-A57 FMA steering pass. Since Cortex-A57 is >> pretty old, there isn't any benefit of keeping this. >> >> Passes regress & bootstrap, OK for commit? >> >> gcc: >> * config.gcc (extra_objs): Remove cortex-a57-fma-steering.o. >> * config/aarch64/aarch64-passes.def: Remove pass_fma_steering. >> * config/aarch64/aarch64-protos.h: Remove make_pass_fma_steering. >> * config/aarch64/aarch64-tuning-flags.def (RENAME_FMA_REGS): Remove. >> * config/aarch64/cortex-a57-fma-steering.cc: Delete file. >> * config/aarch64/t-aarch64: Remove cortex-a57-fma-steering.o rules. >> * config/aarch64/tuning_models/cortexa57.h (cortexa57_tunings): >> Remove RENAME_FMA_REGS tuning. > > This would probably be a reasonable compromise if the pass ever became a > maintenance burden. But I'm not sure the pass is a burden at the moment. > TBH, I don't remember having had to think about it for years :) > > So IMO we should keep the pass, but reconsider removing it if in future > it requires non-trivial effort to keep working. > > That said, the fact the patch requires no testsuite changes suggests > that the pass could easily become ineffective without anyone noticing. > So I won't object if other maintainers are in favour.
We still have Cortex-A57-based products out there that can potentially use newer compilers. So I’d be in favor for keeping the pass in as long as it’s not too much of a maintenance burden. Thanks, Kyrill > > Thanks, > Richard > >> >> --- >> >> diff --git a/gcc/config.gcc b/gcc/config.gcc >> index >> 55e37146ee0356b67b8a1a09d263eccdf69cd91a..97ef3ae77fb97b347ba43e55f7a05f5438a96a43 >> 100644 >> --- a/gcc/config.gcc >> +++ b/gcc/config.gcc >> @@ -350,7 +350,7 @@ aarch64*-*-*) >> c_target_objs="aarch64-c.o" >> cxx_target_objs="aarch64-c.o" >> d_target_objs="aarch64-d.o" >> - extra_objs="aarch64-builtins.o aarch-common.o aarch64-sve-builtins.o >> aarch64-sve-builtins-shapes.o aarch64-sve-builtins-base.o >> aarch64-sve-builtins-sve2.o aarch64-sve-builtins-sme.o >> cortex-a57-fma-steering.o aarch64-speculation.o aarch-bti-insert.o >> aarch64-cc-fusion.o aarch64-early-ra.o aarch64-ldp-fusion.o" >> + extra_objs="aarch64-builtins.o aarch-common.o aarch64-sve-builtins.o >> aarch64-sve-builtins-shapes.o aarch64-sve-builtins-base.o >> aarch64-sve-builtins-sve2.o aarch64-sve-builtins-sme.o aarch64-speculation.o >> aarch-bti-insert.o aarch64-cc-fusion.o aarch64-early-ra.o >> aarch64-ldp-fusion.o" >> target_gtfiles="\$(srcdir)/config/aarch64/aarch64-protos.h >> \$(srcdir)/config/aarch64/aarch64-builtins.h >> \$(srcdir)/config/aarch64/aarch64-builtins.cc >> \$(srcdir)/config/aarch64/aarch64-sve-builtins.h >> \$(srcdir)/config/aarch64/aarch64-sve-builtins.cc" >> target_has_targetm_common=yes >> ;; >> diff --git a/gcc/config/aarch64/aarch64-passes.def >> b/gcc/config/aarch64/aarch64-passes.def >> index >> 9cf9d3e13b2cb0d0bf9c34439785e8ca704230fe..d80b9c6f39c3b56aa6251a81590172f70b31e01e >> 100644 >> --- a/gcc/config/aarch64/aarch64-passes.def >> +++ b/gcc/config/aarch64/aarch64-passes.def >> @@ -19,7 +19,6 @@ >> <http://www.gnu.org/licenses/>. */ >> >> INSERT_PASS_BEFORE (pass_sched, 1, pass_aarch64_early_ra); >> -INSERT_PASS_AFTER (pass_regrename, 1, pass_fma_steering); >> INSERT_PASS_BEFORE (pass_reorder_blocks, 1, pass_track_speculation); >> INSERT_PASS_BEFORE (pass_late_thread_prologue_and_epilogue, 1, >> pass_switch_pstate_sm); >> INSERT_PASS_BEFORE (pass_late_thread_prologue_and_epilogue, 1, >> pass_late_track_speculation); >> diff --git a/gcc/config/aarch64/aarch64-protos.h >> b/gcc/config/aarch64/aarch64-protos.h >> index >> fa7bc8029be04f6530d2aee2ead4d754ba3b2550..afdf7d01adb3bdafd15d0422c3b2dfd680383bef >> 100644 >> --- a/gcc/config/aarch64/aarch64-protos.h >> +++ b/gcc/config/aarch64/aarch64-protos.h >> @@ -1199,7 +1199,6 @@ std::string aarch64_get_extension_string_for_isa_flags >> (aarch64_feature_flags, >> aarch64_feature_flags); >> >> rtl_opt_pass *make_pass_aarch64_early_ra (gcc::context *); >> -rtl_opt_pass *make_pass_fma_steering (gcc::context *); >> rtl_opt_pass *make_pass_track_speculation (gcc::context *); >> rtl_opt_pass *make_pass_late_track_speculation (gcc::context *); >> rtl_opt_pass *make_pass_insert_bti (gcc::context *ctxt); >> diff --git a/gcc/config/aarch64/aarch64-tuning-flags.def >> b/gcc/config/aarch64/aarch64-tuning-flags.def >> index >> 1feff3beb348f45c254c5a7c346a1a9674dee362..b1ab068f4073f459e829503f59c9de236cffb63a >> 100644 >> --- a/gcc/config/aarch64/aarch64-tuning-flags.def >> +++ b/gcc/config/aarch64/aarch64-tuning-flags.def >> @@ -28,8 +28,6 @@ >> INTERNAL_NAME gives the internal name suitable for appending to >> AARCH64_TUNE_ to give an enum name. */ >> >> -AARCH64_EXTRA_TUNING_OPTION ("rename_fma_regs", RENAME_FMA_REGS) >> - >> /* Some of the optional shift to some arthematic instructions are >> considered cheap. Logical shift left <=4 with or without a >> zero extend are considered cheap. Sign extend; non logical shift left >> diff --git a/gcc/config/aarch64/cortex-a57-fma-steering.cc >> b/gcc/config/aarch64/cortex-a57-fma-steering.cc >> deleted file mode 100644 >> index >> fd6da66d855e36cd023b5343c392cd2f7f062d1b..0000000000000000000000000000000000000000 >> --- a/gcc/config/aarch64/cortex-a57-fma-steering.cc >> +++ /dev/null >> @@ -1,1096 +0,0 @@ >> -/* FMA steering optimization pass for Cortex-A57. >> - Copyright (C) 2015-2025 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 >> - <http://www.gnu.org/licenses/>. */ >> - >> -#define IN_TARGET_CODE 1 >> - >> -#include "config.h" >> -#define INCLUDE_LIST >> -#include "system.h" >> -#include "coretypes.h" >> -#include "backend.h" >> -#include "target.h" >> -#include "rtl.h" >> -#include "df.h" >> -#include "insn-config.h" >> -#include "regs.h" >> -#include "memmodel.h" >> -#include "emit-rtl.h" >> -#include "recog.h" >> -#include "cfganal.h" >> -#include "insn-attr.h" >> -#include "context.h" >> -#include "tree-pass.h" >> -#include "function-abi.h" >> -#include "regrename.h" >> -#include "aarch64-protos.h" >> - >> -/* 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.cc 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<fma_root_node *> *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: >> - /* Prohibit copy construction. */ >> - fma_forest (const fma_forest &); >> - >> - /* The list of roots that form this forest. */ >> - std::list<fma_root_node *> *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<fma_node *> *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 *); >> - >> -private: >> - /* Prohibit copy construction. */ >> - fma_node (const fma_node &); >> - >> -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<fma_node *> *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: >> - /* Prohibit copy construction. */ >> - func_fma_steering (const func_fma_steering &); >> - >> - 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<rtx_insn *, fma_node *> *m_insn_fma_head_map; >> - >> - /* A list of all the forests in a given function. */ >> - std::list<fma_forest *> 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.cc. */ >> - >> -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++; >> - *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->call_abis) >> - 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 (regrename_do_replace (head, best_new_reg)) >> - { >> - if (dump_file) >> - fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]); >> - df_set_regs_ever_live (best_new_reg, true); >> - } >> - else >> - { >> - if (dump_file) >> - fprintf (dump_file, ", renaming as %s failed\n", >> - reg_names[best_new_reg]); >> - return false; >> - } >> - 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<fma_root_node *>; >> - 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_root_node *> * >> -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<fma_root_node *> *other_roots; >> - std::list<fma_root_node *>::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); >> - this->m_nb_nodes += other_forest->m_nb_nodes; >> - >> - delete other_forest; >> -} >> - >> -/* 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<fma_node *>; >> - 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<fma_root_node *> (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 *> * >> -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<fma_node *>::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; >> - 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<rtx_insn *, fma_node *>; >> - 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) >> -{ >> - auto_vec<fma_node *> to_process; >> - auto_vec<fma_node *> to_free; >> - std::list<fma_forest *>::iterator forest_iter; >> - >> - /* For each forest. */ >> - for (forest_iter = this->m_fma_forests.begin (); >> - forest_iter != this->m_fma_forests.end (); ++forest_iter) >> - { >> - std::list<fma_root_node *>::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<fma_node *>::iterator child_iter; >> - >> - node = to_process.pop (); >> - >> - if (process_node) >> - process_node (*forest_iter, node); >> - >> - for (child_iter = node->get_children ()->begin (); >> - child_iter != node->get_children ()->end (); ++child_iter) >> - to_process.safe_push (*child_iter); >> - >> - /* Defer freeing so that the process_node callback can access the >> - parent and children of the node being processed. */ >> - if (free) >> - to_free.safe_push (node); >> - } >> - >> - if (free) >> - { >> - delete *forest_iter; >> - >> - while (!to_free.is_empty ()) >> - { >> - fma_node *node = to_free.pop (); >> - if (node->root_p ()) >> - delete static_cast<fma_root_node *> (node); >> - else >> - delete node; >> - } >> - } >> - } >> -} >> - >> -/* 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 = NULL; >> - unsigned dest_regno; >> - fma_forest *forest = NULL; >> - du_head_p head = NULL; >> - 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; >> - } >> - >> - /* Due to implementation of regrename, dest register can slip away >> - from regrename's analysis. As a result, there is no chain for >> - the destination register of insn. We simply skip the insn even >> - it is a fmul/fmac instruction. This can happen when the dest >> - register is also a source register of insn and one of the below >> - conditions is satisfied: >> - 1) the source reg is setup in larger mode than this insn; >> - 2) the source reg is uninitialized; >> - 3) the source reg is passed in as parameter. */ >> - if (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 (aarch64_tune_params.extra_tuning_flags >> - & AARCH64_EXTRA_TUNE_RENAME_FMA_REGS) >> - && 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. */ >> - >> -rtl_opt_pass * >> -make_pass_fma_steering (gcc::context *ctxt) >> -{ >> - return new pass_fma_steering (ctxt); >> -} >> diff --git a/gcc/config/aarch64/t-aarch64 b/gcc/config/aarch64/t-aarch64 >> index >> 5aa7780994834a1ae3424b23e77679d7e1e187ed..0bde167cc043f358fa7131504a44eb185f1864aa >> 100644 >> --- a/gcc/config/aarch64/t-aarch64 >> +++ b/gcc/config/aarch64/t-aarch64 >> @@ -151,15 +151,6 @@ aarch64-d.o: $(srcdir)/config/aarch64/aarch64-d.cc >> >> PASSES_EXTRA += $(srcdir)/config/aarch64/aarch64-passes.def >> >> -cortex-a57-fma-steering.o: >> $(srcdir)/config/aarch64/cortex-a57-fma-steering.cc \ >> - $(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 \ >> - $(srcdir)/config/aarch64/aarch64-protos.h >> - $(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \ >> - $(srcdir)/config/aarch64/cortex-a57-fma-steering.cc >> - >> aarch64-speculation.o: $(srcdir)/config/aarch64/aarch64-speculation.cc \ >> $(CONFIG_H) \ >> $(SYSTEM_H) \ >> diff --git a/gcc/config/aarch64/tuning_models/cortexa57.h >> b/gcc/config/aarch64/tuning_models/cortexa57.h >> index >> 8da7fa9d80df983c640c1870d2f4de6c35808760..8df67f4c512e3e3f38d92d4e18a0763ac9d23648 >> 100644 >> --- a/gcc/config/aarch64/tuning_models/cortexa57.h >> +++ b/gcc/config/aarch64/tuning_models/cortexa57.h >> @@ -99,7 +99,7 @@ static const struct tune_params cortexa57_tunings = >> 2, /* min_div_recip_mul_df. */ >> 0, /* max_case_values. */ >> tune_params::AUTOPREFETCHER_WEAK, /* autoprefetcher_model. */ >> - (AARCH64_EXTRA_TUNE_RENAME_FMA_REGS), /* tune_flags. */ >> + (AARCH64_EXTRA_TUNE_NONE), /* tune_flags. */ >> &generic_prefetch_tune, >> AARCH64_LDP_STP_POLICY_ALWAYS, /* ldp_policy_model. */ >> AARCH64_LDP_STP_POLICY_ALWAYS /* stp_policy_model. */
