126 lines
4.5 KiB
C
126 lines
4.5 KiB
C
/* Data structures and function declarations for the SSA value propagation
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engine.
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Copyright (C) 2004, 2005 Free Software Foundation, Inc.
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Contributed by Diego Novillo <dnovillo@redhat.com>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#ifndef _TREE_SSA_PROPAGATE_H
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#define _TREE_SSA_PROPAGATE_H 1
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/* Use the TREE_VISITED bitflag to mark statements and PHI nodes that
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have been deemed varying and should not be simulated again. */
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#define DONT_SIMULATE_AGAIN(T) TREE_VISITED (T)
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/* Lattice values used for propagation purposes. Specific instances
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of a propagation engine must return these values from the statement
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and PHI visit functions to direct the engine. */
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enum ssa_prop_result {
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/* The statement produces nothing of interest. No edges will be
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added to the work lists. */
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SSA_PROP_NOT_INTERESTING,
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/* The statement produces an interesting value. The set SSA_NAMEs
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returned by SSA_PROP_VISIT_STMT should be added to
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INTERESTING_SSA_EDGES. If the statement being visited is a
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conditional jump, SSA_PROP_VISIT_STMT should indicate which edge
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out of the basic block should be marked executable. */
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SSA_PROP_INTERESTING,
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/* The statement produces a varying (i.e., useless) value and
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should not be simulated again. If the statement being visited
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is a conditional jump, all the edges coming out of the block
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will be considered executable. */
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SSA_PROP_VARYING
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};
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struct prop_value_d {
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/* Lattice value. Each propagator is free to define its own
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lattice and this field is only meaningful while propagating.
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It will not be used by substitute_and_fold. */
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unsigned lattice_val;
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/* Propagated value. */
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tree value;
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/* If this value is held in an SSA name for a non-register
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variable, this field holds the actual memory reference
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associated with this value. This field is taken from
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the LHS of the assignment that generated the associated SSA
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name. However, in the case of PHI nodes, this field is copied
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from the PHI arguments (assuming that all the arguments have
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the same memory reference). See replace_vuses_in for a more
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detailed description. */
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tree mem_ref;
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};
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typedef struct prop_value_d prop_value_t;
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/* Type of value ranges. See value_range_d for a description of these
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types. */
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enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
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/* Range of values that can be associated with an SSA_NAME after VRP
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has executed. */
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struct value_range_d
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{
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/* Lattice value represented by this range. */
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enum value_range_type type;
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/* Minimum and maximum values represented by this range. These
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values should be interpreted as follows:
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- If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
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be NULL.
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- If TYPE == VR_RANGE then MIN holds the minimum value and
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MAX holds the maximum value of the range [MIN, MAX].
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- If TYPE == ANTI_RANGE the variable is known to NOT
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take any values in the range [MIN, MAX]. */
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tree min;
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tree max;
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/* Set of SSA names whose value ranges are equivalent to this one.
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This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
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bitmap equiv;
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};
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typedef struct value_range_d value_range_t;
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/* Call-back functions used by the value propagation engine. */
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typedef enum ssa_prop_result (*ssa_prop_visit_stmt_fn) (tree, edge *, tree *);
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typedef enum ssa_prop_result (*ssa_prop_visit_phi_fn) (tree);
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/* In tree-ssa-propagate.c */
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void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn);
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tree get_rhs (tree);
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bool set_rhs (tree *, tree);
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tree first_vdef (tree);
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bool stmt_makes_single_load (tree);
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bool stmt_makes_single_store (tree);
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prop_value_t *get_value_loaded_by (tree, prop_value_t *);
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bool replace_uses_in (tree, bool *, prop_value_t *);
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void substitute_and_fold (prop_value_t *, bool);
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#endif /* _TREE_SSA_PROPAGATE_H */
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