#include <tree-ssa-threadupdate.h>

Inheritance diagram for fwd_jt_path_registry:

Collaboration diagram for fwd_jt_path_registry:

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Public Member Functions
	fwd_jt_path_registry ()

	~fwd_jt_path_registry ()

void	remove_jump_threads_including (edge)

bool	register_jump_thread (vec< jump_thread_edge * > *)

bool	thread_through_all_blocks (bool peel_loop_headers)

void	push_edge (vec< jump_thread_edge * > *path, edge, jump_thread_edge_type)

vec< jump_thread_edge * > *	allocate_thread_path ()

void	debug ()

Protected Member Functions
void	debug_path (FILE *, int pathno)

Protected Attributes
vec< vec< jump_thread_edge * > * >	m_paths

unsigned long	m_num_threaded_edges

Private Member Functions
bool	update_cfg (bool peel_loop_headers) override

void	mark_threaded_blocks (bitmap threaded_blocks)

bool	thread_block_1 (basic_block, bool noloop_only, bool joiners)

bool	thread_block (basic_block, bool noloop_only)

bool	thread_through_loop_header (class loop *loop, bool may_peel_loop_headers)

class redirection_data *	lookup_redirection_data (edge e, enum insert_option)

bool	cancel_invalid_paths (vec< jump_thread_edge * > &path)

	DISABLE_COPY_AND_ASSIGN (jt_path_registry)

Private Attributes
hash_table< struct removed_edges > *	m_removed_edges

hash_table< redirection_data > *	m_redirection_data

jump_thread_path_allocator	m_allocator

bool	m_backedge_threads

Constructor & Destructor Documentation

◆ fwd_jt_path_registry()

fwd_jt_path_registry::fwd_jt_path_registry ( )

References m_redirection_data, m_removed_edges, and NULL.

◆ ~fwd_jt_path_registry()

fwd_jt_path_registry::~fwd_jt_path_registry ( )

References m_removed_edges.

Member Function Documentation

◆ allocate_thread_path()

vec< jump_thread_edge * > * jt_path_registry::allocate_thread_path ( )

inherited

References jump_thread_path_allocator::allocate_thread_path(), and jt_path_registry::m_allocator.

Referenced by back_threader_registry::register_path(), and jump_threader::thread_across_edge().

◆ cancel_invalid_paths()

bool jt_path_registry::cancel_invalid_paths ( vec< jump_thread_edge * > & path )

privateinherited

References cancel_thread(), cfun, curr_loop, empty_block_p(), flow_loop_nested_p(), gcc_assert, gcc_checking_assert, i, loop::latch, jt_path_registry::m_backedge_threads, NULL, and PROP_loop_opts_done.

Referenced by jt_path_registry::register_jump_thread().

◆ debug()

void jt_path_registry::debug ( )

inherited

References jt_path_registry::debug_path(), i, and jt_path_registry::m_paths.

◆ debug_path()

void jt_path_registry::debug_path	(	FILE *	dump_file,
		int	pathno )

protectedinherited

References dump_file, i, and jt_path_registry::m_paths.

Referenced by back_jt_path_registry::adjust_paths_after_duplication(), and jt_path_registry::debug().

◆ DISABLE_COPY_AND_ASSIGN()

jt_path_registry::DISABLE_COPY_AND_ASSIGN ( jt_path_registry )

privateinherited

◆ lookup_redirection_data()

redirection_data * fwd_jt_path_registry::lookup_redirection_data	(	edge	e,
		enum	insert_option )

private

Given an outgoing edge E lookup and return its entry in our hash table.

If INSERT is true, then we insert the entry into the hash table if
it is not already present.  INCOMING_EDGE is added to the list of incoming
edges associated with E in the hash table.

References redirection_data::dup_blocks, el::e, hash_table< Descriptor, Lazy, Allocator >::find_slot(), free(), redirection_data::incoming_edges, insert(), m_redirection_data, el::next, NULL, path, redirection_data::path, and THREAD_PATH.

Referenced by thread_block_1().

◆ mark_threaded_blocks()

void fwd_jt_path_registry::mark_threaded_blocks ( bitmap threaded_blocks )

private

Walk through the registered jump threads and convert them into a
form convenient for this pass.

Any block which has incoming edges threaded to outgoing edges
will have its entry in THREADED_BLOCK set.

Any threaded edge will have its new outgoing edge stored in the
original edge's AUX field.

This form avoids the need to walk all the edges in the CFG to
discover blocks which need processing and avoids unnecessary
hash table lookups to map from threaded edge to new target.

References BASIC_BLOCK_FOR_FN, bitmap_copy(), bitmap_set_bit, cancel_thread(), cfun, count_stmts_and_phis_in_block(), EDGE_COPY_SRC_BLOCK, EDGE_COPY_SRC_JOINER_BLOCK, estimate_threading_killed_stmts(), EXECUTE_IF_SET_IN_BITMAP, find_edge(), basic_block_def::flags, flow_loop_nested_p(), FOR_EACH_EDGE, gcc_assert, i, basic_block_def::loop_father, LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS, loops_state_satisfies_p(), jt_path_registry::m_paths, NULL, optimize_function_for_size_p(), path, phi_args_equal_on_edges(), basic_block_def::preds, redirection_block_p(), THREAD_PATH, and vect_free_loop_info_assumptions().

Referenced by update_cfg().

◆ push_edge()

void jt_path_registry::push_edge	(	vec< jump_thread_edge * > *	path,
		edge	e,
		jump_thread_edge_type	type )

inherited

References jump_thread_path_allocator::allocate_thread_edge(), and jt_path_registry::m_allocator.

Referenced by back_threader_registry::register_path(), jump_threader::thread_across_edge(), jump_threader::thread_around_empty_blocks(), and jump_threader::thread_through_normal_block().

◆ register_jump_thread()

bool jt_path_registry::register_jump_thread ( vec< jump_thread_edge * > * path )

inherited

Register a jump threading opportunity.  We queue up all the jump
threading opportunities discovered by a pass and update the CFG
and SSA form all at once.

E is the edge we can thread, E2 is the new target edge, i.e., we
are effectively recording that E->dest can be changed to E2->dest
after fixing the SSA graph.

Return TRUE if PATH was successfully threaded.

References jt_path_registry::cancel_invalid_paths(), dbg_cnt(), dump_file, dump_flags, dump_jump_thread_path(), gcc_checking_assert, jt_path_registry::m_paths, and TDF_DETAILS.

Referenced by back_threader_registry::register_path(), and jump_threader::thread_across_edge().

◆ remove_jump_threads_including()

void fwd_jt_path_registry::remove_jump_threads_including ( edge )

Remove any queued jump threads that include edge E.

We don't actually remove them here, just record the edges into ax
hash table.  That way we can do the search once per iteration of
DOM/VRP rather than for every case where DOM optimizes away a COND_EXPR.

References hash_table< Descriptor, Lazy, Allocator >::find_slot(), jt_path_registry::m_paths, and m_removed_edges.

Referenced by jump_threader::remove_jump_threads_including().

◆ thread_block()

bool fwd_jt_path_registry::thread_block	(	basic_block	bb,
		bool	noloop_only )

private

Wrapper for thread_block_1 so that we can first handle jump
thread paths which do not involve copying joiner blocks, then
handle jump thread paths which have joiner blocks.

By doing things this way we can be as aggressive as possible and
not worry that copying a joiner block will create a jump threading
opportunity.

References thread_block_1().

Referenced by thread_through_loop_header(), and update_cfg().

◆ thread_block_1()

bool fwd_jt_path_registry::thread_block_1	(	basic_block	bb,
		bool	noloop_only,
		bool	joiners )

private

BB is a block which ends with a COND_EXPR or SWITCH_EXPR and when BB
is reached via one or more specific incoming edges, we know which
outgoing edge from BB will be traversed.

We want to redirect those incoming edges to the target of the
appropriate outgoing edge.  Doing so avoids a conditional branch
and may expose new optimization opportunities.  Note that we have
to update dominator tree and SSA graph after such changes.

The key to keeping the SSA graph update manageable is to duplicate
the side effects occurring in BB so that those side effects still
occur on the paths which bypass BB after redirecting edges.

We accomplish this by creating duplicates of BB and arranging for
the duplicates to unconditionally pass control to one specific
successor of BB.  We then revector the incoming edges into BB to
the appropriate duplicate of BB.

If NOLOOP_ONLY is true, we only perform the threading as long as it
does not affect the structure of the loops in a nontrivial way.

If JOINERS is true, then thread through joiner blocks as well.

References ssa_local_info_t::bb, BITMAP_ALLOC, BITMAP_FREE, cancel_thread(), CDI_DOMINATORS, ssa_local_info_t::duplicate_blocks, EDGE_COPY_SRC_BLOCK, EDGE_COPY_SRC_JOINER_BLOCK, EDGE_COUNT, EDGE_NO_COPY_SRC_BLOCK, flow_loop_nested_p(), FOR_EACH_EDGE, free_dominance_info(), gsi_end_p(), gsi_start_nondebug_bb(), gsi_stmt(), loop::header, i, is_ctrl_stmt(), ssa_local_info_t::jumps_threaded, last, lookup_redirection_data(), loop_exit_edge_p(), loop_exits_from_bb_p(), basic_block_def::loop_father, loop_outer(), jt_path_registry::m_num_threaded_edges, m_redirection_data, ssa_local_info_t::need_profile_correction, NULL, ssa_local_info_t::num_threaded_edges, basic_block_def::preds, set_loop_copy(), ssa_create_duplicates(), ssa_fixup_template_block(), ssa_redirect_edges(), basic_block_def::succs, ssa_local_info_t::template_block, THREAD_PATH, and hash_table< Descriptor, Lazy, Allocator >::traverse().

Referenced by thread_block().

◆ thread_through_all_blocks()

bool jt_path_registry::thread_through_all_blocks ( bool peel_loop_headers )

inherited

Thread all paths that have been queued for jump threading, and
update the CFG accordingly.

It is the caller's responsibility to fix the dominance information
and rewrite duplicated SSA_NAMEs back into SSA form.

If PEEL_LOOP_HEADERS is false, avoid threading edges through loop
headers if it does not simplify the loop.

Returns true if one or more edges were threaded.

References cfun, LOOPS_NEED_FIXUP, loops_state_set(), jt_path_registry::m_num_threaded_edges, jt_path_registry::m_paths, statistics_counter_event(), and jt_path_registry::update_cfg().

Referenced by back_threader::thread_blocks(), and jump_threader::thread_through_all_blocks().

◆ thread_through_loop_header()

bool fwd_jt_path_registry::thread_through_loop_header	(	class loop *	loop,
		bool	may_peel_loop_headers )

private

Thread jumps through the header of LOOP.  Returns true if cfg changes.
If MAY_PEEL_LOOP_HEADERS is false, we avoid threading from entry edges
to the inside of the loop.

References cancel_thread(), create_preheader(), determine_bb_domination_status(), DOMST_LOOP_BROKEN, DOMST_NONDOMINATING, EDGE_COPY_SRC_JOINER_BLOCK, EDGE_COUNT, empty_block_p(), FOR_EACH_EDGE, gcc_assert, header, loop::header, loop::latch, basic_block_def::loop_father, loop_latch_edge(), loop_outer(), make_forwarder_block(), mark_loop_for_removal(), mfb_keep_just(), mfb_kj_edge, NULL, basic_block_def::preds, redirection_block_p(), set_loop_copy(), single_succ_edge(), single_succ_p(), split_edge(), thread_block(), and THREAD_PATH.

Referenced by update_cfg().

◆ update_cfg()

bool fwd_jt_path_registry::update_cfg ( bool may_peel_loop_headers )

overrideprivatevirtual

This is the forward threader version of thread_through_all_blocks,
using a custom BB copier.

Implements jt_path_registry.

References BASIC_BLOCK_FOR_FN, bitmap_bit_p, bitmap_empty_p(), can_duplicate_block_p(), cancel_thread(), cfun, EDGE_COPY_SRC_BLOCK, EDGE_COPY_SRC_JOINER_BLOCK, hash_table< Descriptor, Lazy, Allocator >::find_slot(), FOR_EACH_BB_FN, FOR_EACH_EDGE, free(), free_original_copy_tables(), gcc_assert, loop::header, i, basic_block_def::index, initialize_original_copy_tables(), LI_FROM_INNERMOST, jt_path_registry::m_paths, m_removed_edges, mark_threaded_blocks(), n_basic_blocks_for_fn, NULL, post_order_compute(), basic_block_def::preds, thread_block(), and thread_through_loop_header().

Field Documentation

◆ m_allocator

jump_thread_path_allocator jt_path_registry::m_allocator

privateinherited

Referenced by jt_path_registry::allocate_thread_path(), and jt_path_registry::push_edge().

◆ m_backedge_threads

bool jt_path_registry::m_backedge_threads

privateinherited

Referenced by jt_path_registry::cancel_invalid_paths(), and jt_path_registry::jt_path_registry().

◆ m_num_threaded_edges

unsigned long jt_path_registry::m_num_threaded_edges

protectedinherited

Referenced by jt_path_registry::jt_path_registry(), thread_block_1(), jt_path_registry::thread_through_all_blocks(), and back_jt_path_registry::update_cfg().

◆ m_paths

vec<vec<jump_thread_edge *> *> jt_path_registry::m_paths

protectedinherited

Referenced by back_jt_path_registry::adjust_paths_after_duplication(), jt_path_registry::debug(), jt_path_registry::debug_path(), jt_path_registry::jt_path_registry(), mark_threaded_blocks(), jt_path_registry::register_jump_thread(), remove_jump_threads_including(), back_jt_path_registry::rewire_first_differing_edge(), jt_path_registry::thread_through_all_blocks(), back_jt_path_registry::update_cfg(), update_cfg(), and jt_path_registry::~jt_path_registry().

◆ m_redirection_data

hash_table<redirection_data>* fwd_jt_path_registry::m_redirection_data

private

Referenced by fwd_jt_path_registry(), lookup_redirection_data(), and thread_block_1().

◆ m_removed_edges

hash_table<struct removed_edges>* fwd_jt_path_registry::m_removed_edges

private

Referenced by fwd_jt_path_registry(), remove_jump_threads_including(), update_cfg(), and ~fwd_jt_path_registry().

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ fwd_jt_path_registry()

◆ ~fwd_jt_path_registry()

Member Function Documentation

◆ allocate_thread_path()

◆ cancel_invalid_paths()

◆ debug()

◆ debug_path()

◆ DISABLE_COPY_AND_ASSIGN()

◆ lookup_redirection_data()

◆ mark_threaded_blocks()

◆ push_edge()

◆ register_jump_thread()

◆ remove_jump_threads_including()

◆ thread_block()

◆ thread_block_1()

◆ thread_through_all_blocks()

◆ thread_through_loop_header()

◆ update_cfg()

Field Documentation

◆ m_allocator

◆ m_backedge_threads

◆ m_num_threaded_edges

◆ m_paths

◆ m_redirection_data

◆ m_removed_edges