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Commit ca072a31 by Daniel Berlin Committed by Daniel Berlin
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tree-ssa-pre.c: Update comments. 

2004-06-17  Daniel Berlin  <dberlin@dberlin.org>

	* tree-ssa-pre.c:  Update comments.
	(val_expr_pair_eq): Factor code from here.
	(expr_pred_trans_eq): and here.
	(expressions_equal_p): To here.
	(print_value_set): Print value for expression.
	(phi_trans_lookup): Rename some variables.
	(lookup): Ditto.
	(value_exists_in_set_bitmap): Ditto.
	(value_remove_from_set_bitmap): Ditto.
	(value_insert_into_set_bitmap): Ditto.

From-SVN: r83290
parent 5bed2809
Showing with 161 additions and 66 deletions
gcc/ChangeLog
2004-06-17 Daniel Berlin <dberlin@dberlin.org>
* tree-ssa-pre.c: Update comments.
(val_expr_pair_eq): Factor code from here.
(expr_pred_trans_eq): and here.
(expressions_equal_p): To here.
(print_value_set): Print value for expression.
(phi_trans_lookup): Rename some variables.
(lookup): Ditto.
(value_exists_in_set_bitmap): Ditto.
(value_remove_from_set_bitmap): Ditto.
(value_insert_into_set_bitmap): Ditto.
2004-06-17 Ulrich Weigand <uweigand@de.ibm.com>
* config/s390/s390-modes.def (CCL3mode): New machine mode.
......
gcc/tree-ssa-pre.c
......@@ -182,19 +182,38 @@ Boston, MA 02111-1307, USA. */
expressions/constants/values. */
typedef struct value_set_node
{
/* An expression. */
tree expr;
/* A pointer to the next element of the value set. */
struct value_set_node *next;
} *value_set_node_t;
/* A value set, which is the head of the linked list, and we also keep
the tail because we have to append for the topolofical sort. */
/* A value set. This is a singly linked list of value_set_node
elements with a possible bitmap that tells us what values exist in
the set. This set must be kept in topologically sorted order. */
typedef struct value_set
{
/* The head of the list. Used for iterating over the list in
order. */
value_set_node_t head;
/* The tail of the list. Used for tail insertions, which are
necessary to keep the set in topologically sorted order because
of how the set is built. */
value_set_node_t tail;
/* The length of the list. */
size_t length;
/* True if the set is indexed, which means it contains a backing
bitmap for quick determination of whether certain values exist in the
set. */
bool indexed;
/* The bitmap of values that exist in the set. May be NULL in an
empty or non-indexed set. */
bitmap values;
} *value_set_t;
......@@ -202,13 +221,32 @@ typedef struct value_set
/* All of the following sets, except for TMP_GEN, are indexed.
TMP_GEN is only ever iterated over, we never check what values
exist in it. */
typedef struct bb_value_sets
{
/* The EXP_GEN set, which represents expressions/values generated in
a basic block. */
value_set_t exp_gen;
/* The PHI_GEN set, which represents PHI results generated in a
basic block. */
value_set_t phi_gen;
/* The TMP_GEN set, which represents results/temporaries genererated
in a basic block. IE the LHS of an expression. */
value_set_t tmp_gen;
/* The AVAIL_OUT set, which represents which values are available in
a given basic block. */
value_set_t avail_out;
/* The ANTIC_IN set, which represents which values are anticiptable
in a given basic block. */
value_set_t antic_in;
/* The NEW_SETS set, which is used during insertion to augment the
AVAIL_OUT set of blocks with the new insertions performed during
the current iteration. */
value_set_t new_sets;
} *bb_value_sets_t;
......@@ -219,10 +257,17 @@ typedef struct bb_value_sets
#define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
#define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
/* This structure is used to keep track of statistics on what
optimization PRE was able to perform. */
static struct
{
/* The number of RHS computations eliminated by PRE. */
int eliminations;
/* The number of new expressions/temporaries generated by PRE. */
int insertions;
/* The number of new PHI nodes added by PRE. */
int phis;
} pre_stats;
......@@ -232,6 +277,7 @@ static void insert_into_set (value_set_t, tree);
static void add_to_value (tree, tree);
static value_set_t set_new (bool);
static bool is_undefined_value (tree);
static bool expressions_equal_p (tree, tree);
/* We can add and remove elements and entries to and from sets
and hash tables, so we use alloc pools for them. */
......@@ -242,12 +288,34 @@ static alloc_pool binary_node_pool;
static alloc_pool unary_node_pool;
/* The value table that maps expressions to values. */
static htab_t value_table;
/* The phi_translate_table caches phi translations for a given
expression and predecessor. */
static htab_t phi_translate_table;
/* Compare two expressions E1 and E2 and return true if they are
equal. */
static 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_CODE (e2)
&& (te1 == te2 || lang_hooks.types_compatible_p (te1, te2))
&& operand_equal_p (e1, e2, 0))
return true;
return false;
}
/* Map expressions to values. These are simple pairs of expressions
and the values they represent. To find the value represented by
......@@ -261,7 +329,9 @@ typedef struct val_expr_pair_d
} *val_expr_pair_t;
/* Hash a {v,e} pair. We really only hash the expression. */
/* 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)
......@@ -271,26 +341,17 @@ val_expr_pair_hash (const void *p)
}
/* Are {e2,v2} and {e1,v1} the same? Again, only the expression
matters. */
/* 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)
{
const val_expr_pair_t ve1 = (val_expr_pair_t) p1;
const val_expr_pair_t ve2 = (val_expr_pair_t) p2;
tree e1 = ve1->e;
tree e2 = ve2->e;
tree te1;
tree te2;
if (e1 == e2)
return true;
te1 = TREE_TYPE (e1);
te2 = TREE_TYPE (e2);
if (TREE_CODE (e1) == TREE_CODE (e2)
&& (te1 == te2 || lang_hooks.types_compatible_p (te1, te2))
&& operand_equal_p (e1, e2, 0))
if (expressions_equal_p (ve1->e, ve2->e))
return true;
return false;
......@@ -298,7 +359,8 @@ val_expr_pair_expr_eq (const void *p1, const void *p2)
/* Get the value handle of EXPR. This is the only correct way to get
the value handle for a "thing". */
the value handle for a "thing".
Returns NULL if the value handle does not exist. */
tree
get_value_handle (tree expr)
......@@ -328,7 +390,7 @@ get_value_handle (tree expr)
}
/* Set the value handle for E to V */
/* Set the value handle for expression E to value V */
void
set_value_handle (tree e, tree v)
......@@ -348,9 +410,17 @@ set_value_handle (tree e, tree v)
typedef struct expr_pred_trans_d
{
/* The expression. */
tree e;
/* The predecessor block along which we translated the expression. */
basic_block pred;
/* The value that resulted from the translation. */
tree v;
/* The hashcode for the expression, pred pair. This is cached for
speed reasons. */
hashval_t hashcode;
} *expr_pred_trans_t;
......@@ -363,49 +433,44 @@ expr_pred_trans_hash (const void *p)
return ve->hashcode;
}
/* Return true if two phi translation table entries are the same. */
/* Return true if two phi translation table entries are the same.
P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
static int
expr_pred_trans_eq (const void *p1, const void *p2)
{
const expr_pred_trans_t ve1 = (expr_pred_trans_t) p1;
const expr_pred_trans_t ve2 = (expr_pred_trans_t) p2;
tree e1 = ve1->e;
tree e2 = ve2->e;
basic_block b1 = ve1->pred;
basic_block b2 = ve2->pred;
tree te1;
tree te2;
/* If they are not translations for the same basic block, they can't
be equal. */
if (b1 != b2)
return false;
if (e1 == e2)
return true;
te1 = TREE_TYPE (e1);
te2 = TREE_TYPE (e2);
if (TREE_CODE (e1) == TREE_CODE (e2)
&& (te1 == te2 || lang_hooks.types_compatible_p (te1, te2))
&& operand_equal_p (e1, e2, 0))
/* If they are for the same basic block, determine if the
expressions are equal. */
if (expressions_equal_p (ve1->e, ve2->e))
return true;
return false;
}
/* Search in the phi translation table for the translation of E in
PRED. Return the translated value, if found, NULL otherwise. */
/* Search in the phi translation table for the translation of
expression E in basic block PRED. Return the translated value, if
found, NULL otherwise. */
static inline tree
phi_trans_lookup (tree e, basic_block pred)
{
void **slot;
struct expr_pred_trans_d ugly;
ugly.e = e;
ugly.pred = pred;
ugly.hashcode = iterative_hash_expr (e, (unsigned long) pred);
slot = htab_find_slot_with_hash (phi_translate_table, &ugly, ugly.hashcode,
struct expr_pred_trans_d ept;
ept.e = e;
ept.pred = pred;
ept.hashcode = iterative_hash_expr (e, (unsigned long) pred);
slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
NO_INSERT);
if (!slot)
return NULL;
......@@ -414,7 +479,8 @@ phi_trans_lookup (tree e, basic_block pred)
}
/* Add the tuple mapping {e, pred}->v to the phi translation table. */
/* Add the tuple mapping from {expression E, basic block PRED} to
value V, to the phi translation table. */
static inline void
phi_trans_add (tree e, tree v, basic_block pred)
......@@ -439,17 +505,17 @@ static inline tree
lookup (htab_t table, tree e)
{
void **slot;
struct val_expr_pair_d ugly = {NULL, NULL, 0};
ugly.e = e;
ugly.hashcode = iterative_hash_expr (e,0);
slot = htab_find_slot_with_hash (table, &ugly, ugly.hashcode, NO_INSERT);
struct val_expr_pair_d vep = {NULL, NULL, 0};
vep.e = e;
vep.hashcode = iterative_hash_expr (e,0);
slot = htab_find_slot_with_hash (table, &vep, vep.hashcode, NO_INSERT);
if (!slot)
return NULL_TREE;
else
return ((val_expr_pair_t) *slot)->v;
}
/* Add E to the expression set of V. */
/* Add expression E to the expression set of value V. */
static inline void
add_to_value (tree v, tree e)
......@@ -480,7 +546,8 @@ add_to_value (tree v, tree e)
#endif
}
/* Insert E into TABLE with value V, and add E to the value set for V. */
/* Insert E into TABLE with value V, and add expression E to the value
set for value V. */
static inline void
add (htab_t table, tree e, tree v)
......@@ -502,9 +569,12 @@ add (htab_t table, tree e, tree v)
}
/* A unique counter that is incremented every time we create a new
value. */
static int pre_uid;
/* Create a new value handle for EXPR. */
/* Create a new value handle for expression EXPR. */
static tree
create_new_value (tree expr)
{
......@@ -523,7 +593,10 @@ create_new_value (tree expr)
return a;
}
/* Like lookup, but adds V as the value for E if E does not have a value. */
/* Like lookup, but creates a new value for expression E if E doesn't
already have a value.
Return the existing/created value for E. */
static inline tree
lookup_or_add (htab_t table, tree e)
{
......@@ -540,25 +613,25 @@ lookup_or_add (htab_t table, tree e)
}
/* Search in the bitmap for SET to see if E exists. */
/* Return true if value V exists in the bitmap for SET. */
static inline bool
value_exists_in_set_bitmap (value_set_t set, tree e)
value_exists_in_set_bitmap (value_set_t set, tree v)
{
if (TREE_CODE (e) != VAR_DECL)
if (TREE_CODE (v) != VAR_DECL)
abort ();
if (!set->values)
return false;
return bitmap_bit_p (set->values, get_var_ann (e)->uid);
return bitmap_bit_p (set->values, get_var_ann (v)->uid);
}
/* Remove E from the bitmap for SET. */
/* Remove value V from the bitmap for SET. */
static void
value_remove_from_set_bitmap (value_set_t set, tree e)
value_remove_from_set_bitmap (value_set_t set, tree v)
{
if (TREE_CODE (e) != VAR_DECL)
if (TREE_CODE (v) != VAR_DECL)
abort ();
#ifdef ENABLE_CHECKING
if (!set->indexed)
......@@ -566,17 +639,17 @@ value_remove_from_set_bitmap (value_set_t set, tree e)
#endif
if (!set->values)
return;
bitmap_clear_bit (set->values, get_var_ann (e)->uid);
bitmap_clear_bit (set->values, get_var_ann (v)->uid);
}
/* Insert the value number E into the bitmap of values existing in
/* Insert the value number V into the bitmap of values existing in
SET. */
static inline void
value_insert_into_set_bitmap (value_set_t set, tree e)
value_insert_into_set_bitmap (value_set_t set, tree v)
{
if (TREE_CODE (e) != VAR_DECL)
if (TREE_CODE (v) != VAR_DECL)
abort ();
#ifdef ENABLE_CHECKING
if (!set->indexed)
......@@ -587,7 +660,7 @@ value_insert_into_set_bitmap (value_set_t set, tree e)
set->values = BITMAP_GGC_ALLOC ();
bitmap_clear (set->values);
}
bitmap_set_bit (set->values, get_var_ann (e)->uid);
bitmap_set_bit (set->values, get_var_ann (v)->uid);
}
/* Create a new set. */
......@@ -824,6 +897,11 @@ print_value_set (FILE *outfile, value_set_t set,
node = node->next)
{
print_generic_expr (outfile, node->expr, 0);
fprintf (outfile, " (");
print_generic_expr (outfile, get_value_handle (node->expr), 0);
fprintf (outfile, ") ");
if (node->next)
fprintf (outfile, ", ");
}
......@@ -1047,9 +1125,9 @@ valid_in_set (value_set_t set, tree expr)
return false;
}
/* Clean the set of expressions that are no longer valid in the
specified set. This means expressions that are made up of values
we have no leaders for in the current set, etc. */
/* Clean the set of expressions that are no longer valid in SET. This
means expressions that are made up of values we have no leaders for
in SET. */
static void
clean (value_set_t set)
......@@ -1180,6 +1258,7 @@ compute_antic_aux (basic_block block)
}
clean (ANTIC_IN (block));
if (!set_equal (old, ANTIC_IN (block)))
changed = true;
......@@ -1274,12 +1353,12 @@ insert_aux (basic_block block)
tree *avail;
tree val;
bool by_some = false;
bool cant_insert = false;
bool all_same = true;
tree first_s = NULL;
edge pred;
basic_block bprime;
tree eprime;
bool cant_insert = false;
val = get_value_handle (node->expr);
if (set_contains_value (PHI_GEN (block), val))
......@@ -1341,11 +1420,14 @@ insert_aux (basic_block block)
abort ();
}
}
/* If we can insert it, it's not the same value
already existing along every predecessor, and
it's defined by some predecessor, it is
partially redundant. */
if (!cant_insert && !all_same && by_some)
{
tree temp;
tree type = TREE_TYPE (avail[block->pred->src->index]);
tree temp;
tree v;
if (dump_file && (dump_flags & TDF_DETAILS))
......
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