/* Value Numbering routines for tree expressions. Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. Contributed by Daniel Berlin , Steven Bosscher and Diego Novillo 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 2, 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 COPYING. If not, write to the Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "ggc.h" #include "tree.h" #include "tree-flow.h" #include "hashtab.h" #include "langhooks.h" #include "tree-pass.h" #include "tree-dump.h" #include "diagnostic.h" #include "tree-ssa-sccvn.h" /* Most of this is PRE specific. The real grunt work is done in tree-ssa-sccvn.c. This is where the lookup and insertion functions, etc, can be found */ /* Create and return a new value handle node of type TYPE. */ tree make_value_handle (tree type) { static unsigned int id = 0; tree vh; vh = build0 (VALUE_HANDLE, type); VALUE_HANDLE_ID (vh) = id++; return vh; } /* Compare two expressions E1 and E2 and return true if they are equal. */ bool expressions_equal_p (tree e1, tree e2) { tree te1, te2; if (e1 == e2) return true; te1 = TREE_TYPE (e1); te2 = TREE_TYPE (e2); if (TREE_CODE (e1) == TREE_LIST && TREE_CODE (e2) == TREE_LIST) { tree lop1 = e1; tree lop2 = e2; for (lop1 = e1, lop2 = e2; lop1 || lop2; lop1 = TREE_CHAIN (lop1), lop2 = TREE_CHAIN (lop2)) { if (!lop1 || !lop2) return false; if (!expressions_equal_p (TREE_VALUE (lop1), TREE_VALUE (lop2))) return false; } return true; } else if (TREE_CODE (e1) == TREE_CODE (e2) && (te1 == te2 || types_compatible_p (te1, te2)) && operand_equal_p (e1, e2, OEP_PURE_SAME)) return true; return false; } /* Set the value handle for expression E to value V. */ void set_value_handle (tree e, tree v) { if (TREE_CODE (e) == SSA_NAME) SSA_NAME_VALUE (e) = v; else if (EXPR_P (e) || DECL_P (e) || TREE_CODE (e) == TREE_LIST || GIMPLE_STMT_P (e) || TREE_CODE (e) == CONSTRUCTOR) get_tree_common_ann (e)->value_handle = v; else /* Do nothing. Constants are their own value handles. */ gcc_assert (is_gimple_min_invariant (e)); } /* A comparison function for use in qsort to compare vuses. Simply subtracts version numbers. */ static int vuses_compare (const void *pa, const void *pb) { const tree vusea = *((const tree *)pa); const tree vuseb = *((const tree *)pb); int sn = SSA_NAME_VERSION (vusea) - SSA_NAME_VERSION (vuseb); return sn; } /* Print out the "Created value for " statement to the dump_file. This is factored because both versions of lookup use it, and it obscures the real work going on in those functions. */ static void print_creation_to_file (tree v, tree expr, VEC (tree, gc) *vuses) { fprintf (dump_file, "Created value "); print_generic_expr (dump_file, v, dump_flags); fprintf (dump_file, " for "); print_generic_expr (dump_file, expr, dump_flags); if (vuses && VEC_length (tree, vuses) != 0) { size_t i; tree vuse; fprintf (dump_file, " vuses: ("); for (i = 0; VEC_iterate (tree, vuses, i, vuse); i++) { print_generic_expr (dump_file, vuse, dump_flags); if (VEC_length (tree, vuses) - 1 != i) fprintf (dump_file, ","); } fprintf (dump_file, ")"); } fprintf (dump_file, "\n"); } /* Sort the VUSE array so that we can do equality comparisons quicker on two vuse vecs. */ void sort_vuses (VEC (tree,gc) *vuses) { if (VEC_length (tree, vuses) > 1) qsort (VEC_address (tree, vuses), VEC_length (tree, vuses), sizeof (tree), vuses_compare); } /* Sort the VUSE array so that we can do equality comparisons quicker on two vuse vecs. */ void sort_vuses_heap (VEC (tree,heap) *vuses) { if (VEC_length (tree, vuses) > 1) qsort (VEC_address (tree, vuses), VEC_length (tree, vuses), sizeof (tree), vuses_compare); } /* Insert EXPR into VALUE_TABLE with value VAL, and add expression EXPR to the value set for value VAL. */ void vn_add (tree expr, tree val) { switch (TREE_CODE_CLASS (TREE_CODE (expr))) { case tcc_comparison: case tcc_binary: vn_binary_op_insert (expr, val); break; case tcc_unary: vn_unary_op_insert (expr, val); break; /* In the case of array-refs of constants, for example, we can end up with no vuses. */ case tcc_reference: vn_reference_insert (expr, val, NULL); break; /* The *only* time CALL_EXPR should appear here is when it has no vuses. */ case tcc_vl_exp: case tcc_exceptional: case tcc_expression: case tcc_declaration: if (TREE_CODE (expr) == CALL_EXPR || DECL_P (expr)) { vn_reference_insert (expr, val, NULL); break; } else if (TREE_CODE (expr) == SSA_NAME) { SSA_NAME_VALUE (expr) = val; break; } else if (TREE_CODE (expr) == ADDR_EXPR) { vn_unary_op_insert (expr, val); break; } /* FALLTHROUGH */ default: gcc_unreachable (); } set_value_handle (expr, val); if (TREE_CODE (val) == VALUE_HANDLE) add_to_value (val, expr); } /* Insert EXPR into the value numbering tables. with value VAL, and add expression EXPR to the value set for value VAL. VUSES represents the virtual use operands associated with EXPR. It is used when computing a hash value for EXPR. */ void vn_add_with_vuses (tree expr, tree val, VEC (tree, gc) *vuses) { if (!vuses) { vn_add (expr, val); return; } vn_reference_insert (expr, val, vuses); set_value_handle (expr, val); if (TREE_CODE (val) == VALUE_HANDLE) add_to_value (val, expr); } /* Lookup EXPR in the value numbering tables and return the result, if we have one. */ tree vn_lookup (tree expr) { /* Constants are their own value. */ if (is_gimple_min_invariant (expr) || TREE_CODE (expr) == FIELD_DECL) return expr; switch (TREE_CODE_CLASS (TREE_CODE (expr))) { case tcc_comparison: case tcc_binary: return vn_binary_op_lookup (expr); case tcc_unary: return vn_unary_op_lookup (expr); break; /* In the case of array-refs of constants, for example, we can end up with no vuses. */ case tcc_reference: return vn_reference_lookup (expr, NULL); break; /* It is possible to have CALL_EXPR with no vuses for things like "cos", and these will fall into vn_lookup. */ case tcc_vl_exp: case tcc_exceptional: case tcc_expression: case tcc_declaration: if (TREE_CODE (expr) == CALL_EXPR || DECL_P (expr)) return vn_reference_lookup (expr, NULL); else if (TREE_CODE (expr) == SSA_NAME) return SSA_NAME_VALUE (expr); else if (TREE_CODE (expr) == ADDR_EXPR) return vn_unary_op_lookup (expr); /* FALLTHROUGH */ default: gcc_unreachable (); } return NULL; } /* Search in the value numbering tables for an existing instance of expression EXPR, and return its value, or NULL if none has been set. STMT represents the stmt associated with EXPR. It is used when computing the hash value for EXPR for reference operations. */ tree vn_lookup_with_stmt (tree expr, tree stmt) { if (stmt == NULL) return vn_lookup (expr); /* Constants are their own value. */ if (is_gimple_min_invariant (expr) || TREE_CODE (expr) == FIELD_DECL) return expr; return vn_lookup_with_vuses (expr, shared_vuses_from_stmt (stmt)); } /* Search in VALUE_TABLE for an existing instance of expression EXPR, and return its value, or NULL if none has been set. VUSES is the list of virtual use operands associated with EXPR. It is used when computing the hash value for EXPR. */ tree vn_lookup_with_vuses (tree expr, VEC (tree, gc) *vuses) { if (!vuses || !VEC_length (tree, vuses)) return vn_lookup (expr); if (is_gimple_min_invariant (expr) || TREE_CODE (expr) == FIELD_DECL) return expr; return vn_reference_lookup (expr, vuses); } static tree create_value_handle_for_expr (tree expr, VEC (tree, gc) *vuses) { tree v; v = make_value_handle (TREE_TYPE (expr)); if (dump_file && (dump_flags & TDF_DETAILS)) print_creation_to_file (v, expr, vuses); if (vuses) VALUE_HANDLE_VUSES (v) = vuses; return v; } /* Like vn_lookup, but creates a new value for the operation if one does not exist. */ tree vn_lookup_or_add (tree expr) { tree v = vn_lookup (expr); if (v == NULL_TREE) { v = create_value_handle_for_expr (expr, NULL); vn_add (expr, v); } else set_value_handle (expr, v); return v; } /* Like vn_lookup, but handles reference operations as well by using STMT to get the set of vuses. */ tree vn_lookup_or_add_with_stmt (tree expr, tree stmt) { tree v; if (!stmt) return vn_lookup_or_add (expr); v = vn_lookup_with_stmt (expr, stmt); if (v == NULL_TREE) { VEC (tree, gc) *vuses = copy_vuses_from_stmt (stmt); v = create_value_handle_for_expr (expr, vuses); vn_add_with_vuses (expr, v, vuses); } else set_value_handle (expr, v); return v; } /* Like vn_lookup, but creates a new value for expression EXPR, if EXPR doesn't already have a value. Return the existing/created value for EXPR. STMT represents the stmt associated with EXPR. It is used when computing the hash value for EXPR. */ tree vn_lookup_or_add_with_vuses (tree expr, VEC (tree, gc) *vuses) { tree v; if (!vuses || VEC_length (tree, vuses) == 0) return vn_lookup_or_add (expr); v = vn_lookup_with_vuses (expr, vuses); if (v == NULL_TREE) { v = create_value_handle_for_expr (expr, vuses); vn_add_with_vuses (expr, v, vuses); } else set_value_handle (expr, v); return v; }