Inheritance diagram for dom_opt_dom_walker:

Collaboration diagram for dom_opt_dom_walker:

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Public Types
enum	reachability { ALL_BLOCKS , REACHABLE_BLOCKS , REACHABLE_BLOCKS_PRESERVING_FLAGS }

Public Member Functions
	dom_opt_dom_walker (cdi_direction direction, jump_threader threader, dom_jt_state state, gimple_ranger ranger, const_and_copies const_and_copies, avail_exprs_stack *avail_exprs_stack)
edge	before_dom_children (basic_block) final override
void	after_dom_children (basic_block) final override
void	walk (basic_block)

Static Public Attributes
static const edge	STOP = (edge)-1

Private Member Functions
edge	optimize_stmt (basic_block, gimple_stmt_iterator , bool )
void	set_global_ranges_from_unreachable_edges (basic_block)
void	fold_cond (gimple *)
void	record_equivalences_from_incoming_edge (basic_block)
void	eliminate_redundant_computations (gimple_stmt_iterator *)
void	record_equivalences_from_stmt (gimple *, int)
tree	const_or_copy_of_stmt (gimple *)
bool	bb_reachable (struct function *, basic_block)
void	propagate_unreachable_to_edges (basic_block, FILE *, dump_flags_t)

Private Attributes
class const_and_copies *	m_const_and_copies
class avail_exprs_stack *	m_avail_exprs_stack
jump_threader *	m_threader
gimple_ranger *	m_ranger
dom_jt_state *	m_state
enum cdi_direction	m_dom_direction: 2
enum reachability	m_reachability: 2
bool	m_user_bb_to_rpo
basic_block	m_unreachable_dom
int *	m_bb_to_rpo

Member Enumeration Documentation

◆ reachability

enum dom_walker::reachability

inherited

Enumerator
ALL_BLOCKS
REACHABLE_BLOCKS
REACHABLE_BLOCKS_PRESERVING_FLAGS

Constructor & Destructor Documentation

◆ dom_opt_dom_walker()

dom_opt_dom_walker::dom_opt_dom_walker	(	cdi_direction	direction,
		jump_threader *	threader,
		dom_jt_state *	state,
		gimple_ranger *	ranger,
		const_and_copies *	const_and_copies,
		avail_exprs_stack *	avail_exprs_stack )

inline

References dom_walker::dom_walker(), m_avail_exprs_stack, m_const_and_copies, m_ranger, m_state, m_threader, and dom_walker::REACHABLE_BLOCKS.

Member Function Documentation

◆ after_dom_children()

void dom_opt_dom_walker::after_dom_children ( basic_block bb )

finaloverridevirtual

We have finished processing the dominator children of BB, perform
any finalization actions in preparation for leaving this node in
the dominator tree.

Reimplemented from dom_walker.

References bitmap_clear_bit(), basic_block_def::index, m_avail_exprs_stack, m_const_and_copies, m_state, and m_threader.

◆ bb_reachable()

bool dom_walker::bb_reachable	(	struct function *	fun,
		basic_block	bb )

privateinherited

Return TRUE if BB is reachable, false otherwise.

References ALL_BLOCKS, CDI_DOMINATORS, dominated_by_p(), ENTRY_BLOCK_PTR_FOR_FN, FOR_EACH_EDGE, m_reachability, m_unreachable_dom, and basic_block_def::preds.

Referenced by walk().

◆ before_dom_children()

edge dom_opt_dom_walker::before_dom_children ( basic_block bb )

finaloverridevirtual

◆ const_or_copy_of_stmt()

tree dom_opt_dom_walker::const_or_copy_of_stmt ( gimple * stmt )

private

Return the constant STMT computes, and barring that, an operand its
result is equivalent to.  NULL if neither.

References gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_rhs2(), gimple_assign_rhs_class(), GIMPLE_BINARY_RHS, is_gimple_assign(), m_ranger, NULL_TREE, and VREL_EQ.

Referenced by eliminate_redundant_computations().

◆ eliminate_redundant_computations()

void dom_opt_dom_walker::eliminate_redundant_computations ( gimple_stmt_iterator * gsi )

private

Search for redundant computations in STMT.  If any are found, then
replace them with the variable holding the result of the computation.

If safe, record this expression into the tables.

References boolean_type_node, const_or_copy_of_stmt(), dump_file, dump_flags, dyn_cast(), fold_convert, gcc_assert, gcc_checking_assert, gcc_unreachable, gimple_assign_lhs(), gimple_call_lhs(), gimple_get_lhs(), gimple_phi_result(), gimple_set_modified(), gimple_switch_index(), gimple_vdef(), gsi_stmt(), is_gimple_assign(), is_gimple_call(), is_gimple_min_invariant(), m_avail_exprs_stack, m_const_and_copies, may_propagate_copy_into_stmt(), opt_stats_d::num_exprs_considered, opt_stats_d::num_re, opt_stats, print_generic_expr(), print_gimple_expr(), propagate_tree_value_into_stmt(), simple_iv_increment_p(), SSA_NAME_OCCURS_IN_ABNORMAL_PHI, TDF_DETAILS, TREE_CODE, TREE_TYPE, and useless_type_conversion_p().

Referenced by before_dom_children(), and optimize_stmt().

◆ fold_cond()

void dom_opt_dom_walker::fold_cond ( gimple * stmt )

private

Fold the conditional STMT with range info.

References dyn_cast(), gimple_set_modified(), m_ranger, and simplify::simplify().

Referenced by optimize_stmt().

◆ optimize_stmt()

edge dom_opt_dom_walker::optimize_stmt	(	basic_block	bb,
		gimple_stmt_iterator *	si,
		bool *	removed_p )

private

Optimize the statement in block BB pointed to by iterator SI.

We try to perform some simplistic global redundancy elimination and
constant propagation:

1- To detect global redundancy, we keep track of expressions that have
   been computed in this block and its dominators.  If we find that the
   same expression is computed more than once, we eliminate repeated
   computations by using the target of the first one.

2- Constant values and copy assignments.  This is used to do very
   simplistic constant and copy propagation.  When a constant or copy
   assignment is found, we map the value on the RHS of the assignment to
   the variable in the LHS in the CONST_AND_COPIES table.

3- Very simple redundant store elimination is performed.

4- We can simplify a condition to a constant or from a relational
   condition to an equality condition.

References as_a(), bitmap_set_bit, boolean_type_node, cfg_altered, cprop_into_stmt(), DECL_HARD_REGISTER, dom_valueize(), dump_file, dump_flags, dyn_cast(), eliminate_redundant_computations(), expr_hash_elt::expr(), EXPR_SINGLE, find_taken_edge(), fndecl_built_in_p(), fold_binary_loc(), fold_cond(), fold_stmt(), gcc_unreachable, gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_single_p(), gimple_bb(), gimple_build_assign(), gimple_call_fndecl(), gimple_call_lhs(), gimple_call_noreturn_p(), gimple_cond_code(), gimple_cond_lhs(), gimple_cond_make_false(), gimple_cond_make_true(), gimple_cond_rhs(), gimple_goto_dest(), gimple_has_side_effects(), gimple_location(), gimple_modified_p(), gimple_set_modified(), gimple_set_vuse(), gimple_switch_index(), gimple_vuse(), gsi_remove(), gsi_stmt(), basic_block_def::index, integer_onep(), integer_zero_node, integer_zerop(), is_gimple_assign(), is_gimple_call(), hashable_expr::kind, m_avail_exprs_stack, m_ranger, maybe_clean_or_replace_eh_stmt(), need_eh_cleanup, need_noreturn_fixup, NULL, NULL_TREE, opt_stats_d::num_stmts, operand_equal_p(), hashable_expr::ops, opt_stats, print_gimple_stmt(), propagate_tree_value_into_stmt(), recompute_tree_invariant_for_addr_expr(), record_equivalences_from_stmt(), reduce_vector_comparison_to_scalar_comparison(), refs_same_for_tbaa_p(), release_defs(), si, SSA_NAME_DEF_STMT, TDF_DETAILS, TDF_SLIM, TREE_CODE, unlink_stmt_vdef(), and update_stmt_if_modified().

Referenced by before_dom_children().

◆ propagate_unreachable_to_edges()

void dom_walker::propagate_unreachable_to_edges	(	basic_block	bb,
		FILE *	dump_file,
		dump_flags_t	dump_flags )

privateinherited

BB has been determined to be unreachable.  Propagate that property
to incoming and outgoing edges of BB as appropriate.

References CDI_DOMINATORS, dominated_by_p(), dump_file, dump_flags, FOR_EACH_EDGE, basic_block_def::index, m_unreachable_dom, basic_block_def::preds, basic_block_def::succs, and TDF_DETAILS.

Referenced by walk().

◆ record_equivalences_from_incoming_edge()

void dom_opt_dom_walker::record_equivalences_from_incoming_edge ( basic_block bb )

private

Record any equivalences created by the incoming edge to BB.  If BB
has more than one incoming edge, then no equivalence is created.

References CDI_DOMINATORS, get_immediate_dominator(), m_avail_exprs_stack, m_const_and_copies, m_state, record_temporary_equivalences(), and single_pred_edge_ignoring_loop_edges().

Referenced by before_dom_children().

◆ record_equivalences_from_stmt()

void dom_opt_dom_walker::record_equivalences_from_stmt	(	gimple *	stmt,
		int	may_optimize_p )

private

STMT, a GIMPLE_ASSIGN, may create certain equivalences, in either
the available expressions table or the const_and_copies table.
Detect and record those equivalences.

We handle only very simple copy equivalences here.  The heavy
lifing is done by eliminate_redundant_computations.

References build1(), dom_valueize(), dump_file, dump_flags, fold_build2, fold_convert, gcc_assert, gimple_assign_lhs(), gimple_assign_rhs1(), gimple_assign_rhs2(), gimple_assign_rhs_code(), gimple_assign_single_p(), gimple_build_assign(), gimple_has_volatile_ops(), gimple_references_memory_p(), gimple_set_vuse(), gimple_vdef(), is_gimple_assign(), is_gimple_min_invariant(), is_gimple_reg(), m_avail_exprs_stack, print_generic_expr(), ptr_type_node, set_ssa_name_value(), SSA_NAME_DEF_STMT, TDF_DETAILS, TREE_CODE, TREE_TYPE, and unshare_expr().

Referenced by optimize_stmt().

◆ set_global_ranges_from_unreachable_edges()

void dom_opt_dom_walker::set_global_ranges_from_unreachable_edges ( basic_block bb )

private

Set global ranges that can be determined from the C->M edge:

  <bb C>:
  ...
  if (something)
    goto <bb N>;
  else
    goto <bb M>;
  <bb N>:
  __builtin_unreachable ();
  <bb M>:

References all_uses_feed_or_dominated_by_stmt(), assert_unreachable_fallthru_edge_p(), FOR_EACH_GORI_EXPORT_NAME, gimple_bb(), gimple_cond_lhs(), gimple_cond_rhs(), gsi_last_bb(), m_ranger, maybe_set_nonzero_bits(), r, set_range_info(), single_pred_edge_ignoring_loop_edges(), SSA_NAME_DEF_STMT, SSA_NAME_IS_DEFAULT_DEF, TREE_CODE, and TREE_TYPE.

Referenced by before_dom_children().

◆ walk()

void dom_walker::walk ( basic_block bb )

inherited

Recursively walk the dominator tree.
BB is the basic block we are currently visiting.

References after_dom_children(), bb_reachable(), before_dom_children(), CDI_DOMINATORS, cfun, dump_file, dump_flags, EDGE_COUNT, ENTRY_BLOCK_PTR_FOR_FN, EXIT_BLOCK_PTR_FOR_FN, first_dom_son(), FOR_EACH_EDGE, free(), i, last_basic_block_for_fn, m_bb_to_rpo, m_dom_direction, m_reachability, m_unreachable_dom, m_user_bb_to_rpo, n_basic_blocks_for_fn, next_dom_son(), NULL, pre_and_rev_post_order_compute(), basic_block_def::preds, propagate_unreachable_to_edges(), REACHABLE_BLOCKS, set_all_edges_as_executable(), sort_bbs_postorder(), STOP, and basic_block_def::succs.

Referenced by eliminate_with_rpo_vn(), ipcp_transform_function(), and substitute_and_fold_engine::substitute_and_fold().

Field Documentation

◆ m_avail_exprs_stack

class avail_exprs_stack* dom_opt_dom_walker::m_avail_exprs_stack

private

Referenced by after_dom_children(), before_dom_children(), dom_opt_dom_walker(), eliminate_redundant_computations(), optimize_stmt(), record_equivalences_from_incoming_edge(), and record_equivalences_from_stmt().

◆ m_bb_to_rpo

int* dom_walker::m_bb_to_rpo

privateinherited

Referenced by dom_walker(), walk(), and ~dom_walker().

◆ m_const_and_copies

class const_and_copies* dom_opt_dom_walker::m_const_and_copies

private

Referenced by after_dom_children(), before_dom_children(), dom_opt_dom_walker(), eliminate_redundant_computations(), and record_equivalences_from_incoming_edge().

◆ m_dom_direction

enum cdi_direction dom_walker::m_dom_direction

privateinherited

Referenced by dom_walker(), and walk().

◆ m_ranger

gimple_ranger* dom_opt_dom_walker::m_ranger

private

Referenced by const_or_copy_of_stmt(), dom_opt_dom_walker(), fold_cond(), optimize_stmt(), and set_global_ranges_from_unreachable_edges().

◆ m_reachability

enum reachability dom_walker::m_reachability

privateinherited

Referenced by bb_reachable(), dom_walker(), and walk().

◆ m_state

dom_jt_state* dom_opt_dom_walker::m_state

private

Referenced by after_dom_children(), before_dom_children(), dom_opt_dom_walker(), and record_equivalences_from_incoming_edge().

◆ m_threader

jump_threader* dom_opt_dom_walker::m_threader

private

Referenced by after_dom_children(), and dom_opt_dom_walker().

◆ m_unreachable_dom

basic_block dom_walker::m_unreachable_dom

privateinherited

Referenced by bb_reachable(), dom_walker(), propagate_unreachable_to_edges(), and walk().

◆ m_user_bb_to_rpo

bool dom_walker::m_user_bb_to_rpo

privateinherited

Referenced by dom_walker(), walk(), and ~dom_walker().

◆ STOP

const edge dom_walker::STOP = (edge)-1

staticinherited

Referenced by rewrite_update_dom_walker::before_dom_children(), and walk().

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

tree-ssa-dom.cc

Public Types

Public Member Functions

Static Public Attributes

Private Member Functions

Private Attributes

Member Enumeration Documentation

◆ reachability

Constructor & Destructor Documentation

◆ dom_opt_dom_walker()

Member Function Documentation

◆ after_dom_children()

◆ bb_reachable()

◆ before_dom_children()

◆ const_or_copy_of_stmt()

◆ eliminate_redundant_computations()

◆ fold_cond()

◆ optimize_stmt()

◆ propagate_unreachable_to_edges()

◆ record_equivalences_from_incoming_edge()

◆ record_equivalences_from_stmt()

◆ set_global_ranges_from_unreachable_edges()

◆ walk()

Field Documentation

◆ m_avail_exprs_stack

◆ m_bb_to_rpo

◆ m_const_and_copies

◆ m_dom_direction

◆ m_ranger

◆ m_reachability

◆ m_state

◆ m_threader

◆ m_unreachable_dom

◆ m_user_bb_to_rpo

◆ STOP