1 /* Data structures and function declarations for the SSA value propagation 2 engine. 3 Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc. 4 Contributed by Diego Novillo <dnovillo@redhat.com> 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3, or (at your option) 11 any later version. 12 13 GCC is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 #ifndef _TREE_SSA_PROPAGATE_H 23 #define _TREE_SSA_PROPAGATE_H 1 24 25 /* If SIM_P is true, statement S will be simulated again. */ 26 27 static inline void 28 prop_set_simulate_again (gimple s, bool visit_p) 29 { 30 gimple_set_visited (s, visit_p); 31 } 32 33 /* Return true if statement T should be simulated again. */ 34 35 static inline bool 36 prop_simulate_again_p (gimple s) 37 { 38 return gimple_visited_p (s); 39 } 40 41 /* Lattice values used for propagation purposes. Specific instances 42 of a propagation engine must return these values from the statement 43 and PHI visit functions to direct the engine. */ 44 enum ssa_prop_result { 45 /* The statement produces nothing of interest. No edges will be 46 added to the work lists. */ 47 SSA_PROP_NOT_INTERESTING, 48 49 /* The statement produces an interesting value. The set SSA_NAMEs 50 returned by SSA_PROP_VISIT_STMT should be added to 51 INTERESTING_SSA_EDGES. If the statement being visited is a 52 conditional jump, SSA_PROP_VISIT_STMT should indicate which edge 53 out of the basic block should be marked executable. */ 54 SSA_PROP_INTERESTING, 55 56 /* The statement produces a varying (i.e., useless) value and 57 should not be simulated again. If the statement being visited 58 is a conditional jump, all the edges coming out of the block 59 will be considered executable. */ 60 SSA_PROP_VARYING 61 }; 62 63 64 struct prop_value_d { 65 /* Lattice value. Each propagator is free to define its own 66 lattice and this field is only meaningful while propagating. 67 It will not be used by substitute_and_fold. */ 68 unsigned lattice_val; 69 70 /* Propagated value. */ 71 tree value; 72 }; 73 74 typedef struct prop_value_d prop_value_t; 75 76 77 /* Type of value ranges. See value_range_d for a description of these 78 types. */ 79 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING }; 80 81 /* Range of values that can be associated with an SSA_NAME after VRP 82 has executed. */ 83 struct value_range_d 84 { 85 /* Lattice value represented by this range. */ 86 enum value_range_type type; 87 88 /* Minimum and maximum values represented by this range. These 89 values should be interpreted as follows: 90 91 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must 92 be NULL. 93 94 - If TYPE == VR_RANGE then MIN holds the minimum value and 95 MAX holds the maximum value of the range [MIN, MAX]. 96 97 - If TYPE == ANTI_RANGE the variable is known to NOT 98 take any values in the range [MIN, MAX]. */ 99 tree min; 100 tree max; 101 102 /* Set of SSA names whose value ranges are equivalent to this one. 103 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */ 104 bitmap equiv; 105 }; 106 107 typedef struct value_range_d value_range_t; 108 109 110 /* Call-back functions used by the value propagation engine. */ 111 typedef enum ssa_prop_result (*ssa_prop_visit_stmt_fn) (gimple, edge *, tree *); 112 typedef enum ssa_prop_result (*ssa_prop_visit_phi_fn) (gimple); 113 typedef bool (*ssa_prop_fold_stmt_fn) (gimple_stmt_iterator *gsi); 114 115 116 /* In tree-ssa-propagate.c */ 117 void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn); 118 bool valid_gimple_rhs_p (tree); 119 bool valid_gimple_call_p (tree); 120 void move_ssa_defining_stmt_for_defs (gimple, gimple); 121 bool update_call_from_tree (gimple_stmt_iterator *, tree); 122 bool stmt_makes_single_store (gimple); 123 bool substitute_and_fold (prop_value_t *, ssa_prop_fold_stmt_fn, bool); 124 125 #endif /* _TREE_SSA_PROPAGATE_H */ 126