/* Value Numbering routines for tree expressions.
- Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org>, Steven Bosscher
<stevenb@suse.de> and Diego Novillo <dnovillo@redhat.com>
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)
+the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
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. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "tree-pass.h"
#include "tree-dump.h"
#include "diagnostic.h"
+#include "tree-ssa-sccvn.h"
-/* The value table that maps expressions to values. */
-static htab_t value_table;
-
-/* Map expressions to values. These are simple pairs of expressions
- and the values they represent. To find the value represented by
- an expression, we use a hash table where the elements are {e,v}
- pairs, and the expression is the key. */
-typedef struct val_expr_pair_d
-{
- /* Value handle. */
- tree v;
-
- /* Associated expression. */
- tree e;
-
- /* For comparing virtual uses in E. */
- VEC (tree, gc) *vuses;
-
- /* E's hash value. */
- hashval_t hashcode;
-} *val_expr_pair_t;
-
-static void set_value_handle (tree e, tree v);
-
+/* 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. */
-static tree
+tree
make_value_handle (tree type)
{
static unsigned int id = 0;
}
-/* Given an expression EXPR, compute a hash value number using the
- code of the expression, its real operands and virtual operands (if
- any).
-
- VAL can be used to iterate by passing previous value numbers (it is
- used by iterative_hash_expr). */
-
-hashval_t
-vn_compute (tree expr, hashval_t val)
-{
- /* EXPR must not be a statement. We are only interested in value
- numbering expressions on the RHS of assignments. */
- gcc_assert (expr);
- gcc_assert (!expr->common.ann
- || expr->common.ann->common.type != STMT_ANN);
-
- val = iterative_hash_expr (expr, val);
- return val;
-}
/* Compare two expressions E1 and E2 and return true if they are
equal. */
expressions_equal_p (tree e1, tree e2)
{
tree te1, te2;
-
+
if (e1 == e2)
return true;
return true;
}
- else if (TREE_CODE (e1) == TREE_CODE (e2)
- && (te1 == te2 || lang_hooks.types_compatible_p (te1, te2))
+ 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;
}
-
-/* Hash a {v,e} pair that is pointed to by P.
- The hashcode is cached in the val_expr_pair, so we just return
- that. */
-
-static hashval_t
-val_expr_pair_hash (const void *p)
-{
- const val_expr_pair_t ve = (val_expr_pair_t) p;
- return ve->hashcode;
-}
-
-
-/* Given two val_expr_pair_t's, return true if they represent the same
- expression, false otherwise.
- P1 and P2 should point to the val_expr_pair_t's to be compared. */
-
-static int
-val_expr_pair_expr_eq (const void *p1, const void *p2)
-{
- int i;
- tree vuse1;
- const val_expr_pair_t ve1 = (val_expr_pair_t) p1;
- const val_expr_pair_t ve2 = (val_expr_pair_t) p2;
-
- if (! expressions_equal_p (ve1->e, ve2->e))
- return false;
-
- if (ve1->vuses == ve2->vuses)
- return true;
-
- if (VEC_length (tree, ve1->vuses) != VEC_length (tree, ve2->vuses))
- return false;
-
- for (i = 0; VEC_iterate (tree, ve1->vuses, i, vuse1); i++)
- {
- if (VEC_index (tree, ve2->vuses, i) != vuse1)
- return false;
- }
- return true;
-}
-
-
/* Set the value handle for expression E to value V. */
-
-static void
+
+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
gcc_assert (is_gimple_min_invariant (e));
}
-/* Copy the virtual uses from STMT into a newly allocated VEC(tree),
- and return the VEC(tree). */
+/* A comparison function for use in qsort to compare vuses. Simply
+ subtracts version numbers. */
-static VEC (tree, gc) *
-copy_vuses_from_stmt (tree stmt)
+static int
+vuses_compare (const void *pa, const void *pb)
{
- ssa_op_iter iter;
- tree vuse;
- VEC (tree, gc) *vuses = NULL;
-
- if (!stmt)
- return NULL;
-
- FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE)
- VEC_safe_push (tree, gc, vuses, vuse);
+ const tree vusea = *((const tree *)pa);
+ const tree vuseb = *((const tree *)pb);
+ int sn = SSA_NAME_VERSION (vusea) - SSA_NAME_VERSION (vuseb);
- return vuses;
+ return sn;
}
-/* Place for shared_vuses_from_stmt to shove vuses. */
-static VEC (tree, gc) *shared_lookup_vuses;
-
-/* Copy the virtual uses from STMT into SHARED_LOOKUP_VUSES.
- This function will overwrite the current SHARED_LOOKUP_VUSES
- variable. */
+/* Print out the "Created value <x> for <Y>" 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 VEC (tree, gc) *
-shared_vuses_from_stmt (tree stmt)
+static void
+print_creation_to_file (tree v, tree expr, VEC (tree, gc) *vuses)
{
- ssa_op_iter iter;
- tree vuse;
+ 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 (!stmt)
- return NULL;
+ if (vuses && VEC_length (tree, vuses) != 0)
+ {
+ size_t i;
+ tree vuse;
- VEC_truncate (tree, shared_lookup_vuses, 0);
+ 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");
+}
- FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE)
- VEC_safe_push (tree, gc, shared_lookup_vuses, vuse);
- if (VEC_length (tree, shared_lookup_vuses) > 1)
- sort_vuses (shared_lookup_vuses);
+/* Sort the VUSE array so that we can do equality comparisons
+ quicker on two vuse vecs. */
- return shared_lookup_vuses;
+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)
{
- vn_add_with_vuses (expr, val, NULL);
+ 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 VALUE_TABLE 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. */
+/* 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)
{
- void **slot;
- val_expr_pair_t new_pair;
-
- new_pair = XNEW (struct val_expr_pair_d);
- new_pair->e = expr;
- new_pair->v = val;
- new_pair->vuses = vuses;
- new_pair->hashcode = vn_compute (expr, 0);
- slot = htab_find_slot_with_hash (value_table, new_pair, new_pair->hashcode,
- INSERT);
- if (*slot)
- free (*slot);
- *slot = (void *) new_pair;
+ if (!vuses)
+ {
+ vn_add (expr, val);
+ return;
+ }
+ vn_reference_insert (expr, val, vuses);
set_value_handle (expr, val);
if (TREE_CODE (val) == VALUE_HANDLE)
}
-/* Search in VALUE_TABLE 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. */
+/* 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 (tree expr, tree stmt)
+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));
}
tree
vn_lookup_with_vuses (tree expr, VEC (tree, gc) *vuses)
{
- void **slot;
- struct val_expr_pair_d vep = {NULL, NULL, NULL, 0};
+ if (!vuses || !VEC_length (tree, vuses))
+ return vn_lookup (expr);
- /* Constants are their own value. */
- if (is_gimple_min_invariant (expr))
+ if (is_gimple_min_invariant (expr) || TREE_CODE (expr) == FIELD_DECL)
return expr;
- vep.e = expr;
- vep.vuses = vuses;
- vep.hashcode = vn_compute (expr, 0);
- slot = htab_find_slot_with_hash (value_table, &vep, vep.hashcode, NO_INSERT);
- if (!slot)
- return NULL_TREE;
- else
- return ((val_expr_pair_t) *slot)->v;
+ return vn_reference_lookup (expr, vuses);
}
-
-/* A comparison function for use in qsort to compare vuses. Simply
- subtracts version numbers. */
-
-static int
-vuses_compare (const void *pa, const void *pb)
+static tree
+create_value_handle_for_expr (tree expr, VEC(tree, gc) *vuses)
{
- const tree vusea = *((const tree *)pa);
- const tree vuseb = *((const tree *)pb);
- int sn = SSA_NAME_VERSION (vusea) - SSA_NAME_VERSION (vuseb);
+ tree v;
- return sn;
+ v = make_value_handle (TREE_TYPE (expr));
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ print_creation_to_file (v, expr, vuses);
+ return v;
}
-/* Print out the "Created value <x> for <Y>" 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. */
+/* Like vn_lookup, but creates a new value for the operation if one
+ does not exist. */
-static void
-print_creation_to_file (tree v, tree expr, VEC (tree, gc) *vuses)
+tree
+vn_lookup_or_add (tree expr)
{
- 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)
+ tree v = vn_lookup (expr);
+
+ if (v == NULL_TREE)
{
- 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");
+ v = create_value_handle_for_expr (expr, NULL);
+ vn_add (expr, v);
+ }
+ 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 VUSES for EXPR. */
+/* Like vn_lookup, but handles reference operations as well by using
+ STMT to get the set of vuses. */
tree
-vn_lookup_or_add (tree expr, tree stmt)
+vn_lookup_or_add_with_stmt (tree expr, tree stmt)
{
- tree v = vn_lookup (expr, 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;
-
- v = make_value_handle (TREE_TYPE (expr));
- vuses = copy_vuses_from_stmt (stmt);
- sort_vuses (vuses);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- print_creation_to_file (v, expr, vuses);
-
- VALUE_HANDLE_VUSES (v) = vuses;
+ VEC (tree, gc) *vuses = copy_vuses_from_stmt (stmt);
+ v = create_value_handle_for_expr (expr, vuses);
vn_add_with_vuses (expr, v, vuses);
}
-
- set_value_handle (expr, v);
+ else
+ set_value_handle (expr, v);
return v;
}
-/* 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);
-}
-
/* 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
tree
vn_lookup_or_add_with_vuses (tree expr, VEC (tree, gc) *vuses)
{
- tree v = vn_lookup_with_vuses (expr, vuses);
- if (v == NULL_TREE)
- {
- v = make_value_handle (TREE_TYPE (expr));
- sort_vuses (vuses);
+ tree v;
- if (dump_file && (dump_flags & TDF_DETAILS))
- print_creation_to_file (v, expr, vuses);
+ if (!vuses || VEC_length (tree, vuses) == 0)
+ return vn_lookup_or_add (expr);
- VALUE_HANDLE_VUSES (v) = vuses;
+ 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);
}
-
- set_value_handle (expr, v);
+ else
+ set_value_handle (expr, v);
return v;
}
-/* Initialize data structures used in value numbering. */
-
-void
-vn_init (void)
-{
- value_table = htab_create (511, val_expr_pair_hash,
- val_expr_pair_expr_eq, free);
- shared_lookup_vuses = NULL;
-}
-
-/* Delete data used for value numbering. */
-
-void
-vn_delete (void)
-{
- htab_delete (value_table);
- VEC_free (tree, gc, shared_lookup_vuses);
- value_table = NULL;
-}
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