/* SSA-PRE for trees.
- Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
<stevenb@suse.de>
along with GCC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
+
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "errors.h"
#include "ggc.h"
#include "tree.h"
-
-/* These RTL headers are needed for basic-block.h. */
-#include "rtl.h"
-#include "tm_p.h"
-#include "hard-reg-set.h"
#include "basic-block.h"
#include "diagnostic.h"
#include "tree-inline.h"
#include "alloc-pool.h"
#include "tree-pass.h"
#include "flags.h"
-#include "splay-tree.h"
#include "bitmap.h"
#include "langhooks.h"
+#include "cfgloop.h"
+
/* TODO:
- 1. Implement load value numbering.
- 2. Speed up insert_aux so that we can use it all the time. It
- spends most of it's time in quadratic value replacement.
- 3. Avail sets can be shared by making an avail_find_leader that
+ 1. Avail sets can be shared by making an avail_find_leader that
walks up the dominator tree and looks in those avail sets.
This might affect code optimality, it's unclear right now.
- 4. Load motion can be performed by value numbering the loads the
+ 2. Load motion can be performed by value numbering the loads the
same as we do other expressions. This requires iterative
hashing the vuses into the values. Right now we simply assign
a new value every time we see a statement with a vuse.
- 5. Strength reduction can be performed by anticipating expressions
+ 3. Strength reduction can be performed by anticipating expressions
we can repair later on.
+ 4. We can do back-substitution or smarter value numbering to catch
+ commutative expressions split up over multiple statements.
*/
/* For ease of terminology, "expression node" in the below refers to
/* Basic algorithm
- First we walk the statements to generate the AVAIL sets, the EXP_GEN
- sets, and the tmp_gen sets. AVAIL is a forward dataflow
- problem. EXP_GEN sets represent the generation of
- values/expressions by a given block. We use them when computing
- the ANTIC sets. The AVAIL sets consist of SSA_NAME's that
- represent values, so we know what values are available in what
- blocks. In SSA, values are never killed, so we don't need a kill
- set, or a fixpoint iteration, in order to calculate the AVAIL sets.
- In traditional parlance, AVAIL sets tell us the downsafety of the
+ First we walk the statements to generate the AVAIL sets, the
+ EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
+ generation of values/expressions by a given block. We use them
+ when computing the ANTIC sets. The AVAIL sets consist of
+ SSA_NAME's that represent values, so we know what values are
+ available in what blocks. AVAIL is a forward dataflow problem. In
+ SSA, values are never killed, so we don't need a kill set, or a
+ fixpoint iteration, in order to calculate the AVAIL sets. In
+ traditional parlance, AVAIL sets tell us the downsafety of the
expressions/values.
- Next, we generate the ANTIC sets. ANTIC is a backwards dataflow
- problem. These sets represent the anticipatable expressions. An
- expression is anticipatable in a given block if it could be
- generated in that block. This means that if we had to perform an
- insertion in that block, of the value of that expression, we could.
- Calculating the ANTIC sets requires phi translation of expressions,
- because the flow goes backwards through phis. We must iterate to a
- fixpoint of the ANTIC sets, because we have a kill set.
- Even in SSA form, values are not live over the entire function,
- only from their definition point onwards. So we have to remove
- values from the ANTIC set once we go past the definition point of
- the leaders that make them up. compute_antic/compute_antic_aux
- performs this computation.
+ Next, we generate the ANTIC sets. These sets represent the
+ anticipatable expressions. ANTIC is a backwards dataflow
+ problem.An expression is anticipatable in a given block if it could
+ be generated in that block. This means that if we had to perform
+ an insertion in that block, of the value of that expression, we
+ could. Calculating the ANTIC sets requires phi translation of
+ expressions, because the flow goes backwards through phis. We must
+ iterate to a fixpoint of the ANTIC sets, because we have a kill
+ set. Even in SSA form, values are not live over the entire
+ function, only from their definition point onwards. So we have to
+ remove values from the ANTIC set once we go past the definition
+ point of the leaders that make them up.
+ compute_antic/compute_antic_aux performs this computation.
Third, we perform insertions to make partially redundant
expressions fully redundant.
Value numbers are represented using the "value handle" approach.
This means that each SSA_NAME (and for other reasons to be
- disclosed in a moment, expression nodes and constant nodes) has a
- value handle that can be retrieved through get_value_handle. This
- value handle, *is* the value number of the SSA_NAME. You can
- pointer compare the value handles for equivalence purposes.
+ disclosed in a moment, expression nodes) has a value handle that
+ can be retrieved through get_value_handle. This value handle, *is*
+ the value number of the SSA_NAME. You can pointer compare the
+ value handles for equivalence purposes.
For debugging reasons, the value handle is internally more than
just a number, it is a VAR_DECL named "value.x", where x is a
Expression nodes have value handles associated with them as a
cache. Otherwise, we'd have to look them up again in the hash
table This makes significant difference (factor of two or more) on
- some test cases. They can be thrown away after the Constants have
- value handles associated with them so that they aren't special
- cased everywhere, and for consistency sake. This may be changed
- depending on memory usage vs code maintenance tradeoff. */
+ some test cases. They can be thrown away after the pass is
+ finished. */
/* Representation of expressions on value numbers:
/* Representation of sets:
- Sets are represented as doubly linked lists kept in topological
+ There are currently two types of sets used, hopefully to be unified soon.
+ The AVAIL sets do not need to be sorted in any particular order,
+ and thus, are simply represented as two bitmaps, one that keeps
+ track of values present in the set, and one that keeps track of
+ expressions present in the set.
+
+ The other sets are represented as doubly linked lists kept in topological
order, with an optional supporting bitmap of values present in the
- set. The sets represent values, and the elements can be constants,
- values, or expressions. The elements can appear in different sets,
- but each element can only appear once in each set.
+ set. The sets represent values, and the elements can be values or
+ expressions. The elements can appear in different sets, but each
+ element can only appear once in each set.
Since each node in the set represents a value, we also want to be
able to map expression, set pairs to something that tells us
/* A value set element. Basically a single linked list of
- expressions/constants/values. */
+ expressions/values. */
typedef struct value_set_node
{
/* An expression. */
} *value_set_t;
-/* 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. */
+/* An unordered bitmap set. One bitmap tracks values, the other,
+ expressions. */
+typedef struct bitmap_set
+{
+ bitmap expressions;
+ bitmap values;
+} *bitmap_set_t;
+
+/* Sets that we need to keep track of. */
typedef struct bb_value_sets
{
/* The EXP_GEN set, which represents expressions/values generated in
/* The PHI_GEN set, which represents PHI results generated in a
basic block. */
- value_set_t phi_gen;
+ bitmap_set_t phi_gen;
- /* The TMP_GEN set, which represents results/temporaries genererated
+ /* The TMP_GEN set, which represents results/temporaries generated
in a basic block. IE the LHS of an expression. */
- value_set_t tmp_gen;
+ bitmap_set_t tmp_gen;
/* The AVAIL_OUT set, which represents which values are available in
a given basic block. */
- value_set_t avail_out;
+ bitmap_set_t avail_out;
/* The ANTIC_IN set, which represents which values are anticiptable
in a given basic block. */
/* 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;
+ bitmap_set_t new_sets;
} *bb_value_sets_t;
#define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
/* The number of new PHI nodes added by PRE. */
int phis;
+
+ /* The number of values found constant. */
+ int constified;
+
} pre_stats;
+
+static tree bitmap_find_leader (bitmap_set_t, tree);
static tree find_leader (value_set_t, tree);
static void value_insert_into_set (value_set_t, tree);
+static void bitmap_value_insert_into_set (bitmap_set_t, tree);
+static void bitmap_value_replace_in_set (bitmap_set_t, tree);
static void insert_into_set (value_set_t, tree);
-static void add_to_value (tree, tree);
+static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
+static bool bitmap_set_contains_value (bitmap_set_t, tree);
+static bitmap_set_t bitmap_set_new (void);
static value_set_t set_new (bool);
static bool is_undefined_value (tree);
-static bool expressions_equal_p (tree, tree);
+static tree create_expression_by_pieces (basic_block, tree, tree);
+
/* We can add and remove elements and entries to and from sets
and hash tables, so we use alloc pools for them. */
static alloc_pool value_set_pool;
+static alloc_pool bitmap_set_pool;
static alloc_pool value_set_node_pool;
static alloc_pool binary_node_pool;
static alloc_pool unary_node_pool;
+static alloc_pool reference_node_pool;
+static bitmap_obstack grand_bitmap_obstack;
-/* The value table that maps expressions to values. */
-
-static htab_t value_table;
+/* Set of blocks with statements that have had its EH information
+ cleaned up. */
+static bitmap need_eh_cleanup;
/* 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
- 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
-{
- tree v, e;
- hashval_t hashcode;
-} *val_expr_pair_t;
-
-
-/* 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)
-{
- 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 true;
-
- return false;
-}
-
-
-/* Get the value handle of EXPR. This is the only correct way to get
- the value handle for a "thing".
- Returns NULL if the value handle does not exist. */
-
-tree
-get_value_handle (tree expr)
-{
- /* We should never see these. */
- if (DECL_P (expr))
- abort ();
- else if (TREE_CODE (expr) == SSA_NAME)
- {
- return SSA_NAME_VALUE (expr);
- }
- else if (TREE_CODE_CLASS (TREE_CODE (expr)) == 'c')
- {
- cst_ann_t ann = cst_ann (expr);
- if (ann)
- return ann->common.value_handle;
- return NULL;
- }
- else if (EXPR_P (expr))
- {
- expr_ann_t ann = expr_ann (expr);
- if (ann)
- return ann->common.value_handle;
- return NULL;
- }
- abort ();
-}
-
-
-/* Set the value handle for expression E to value V */
-
-void
-set_value_handle (tree e, tree v)
-{
- if (DECL_P (e))
- abort ();
- else if (TREE_CODE (e) == SSA_NAME)
- SSA_NAME_VALUE (e) = v;
- else if (TREE_CODE_CLASS (TREE_CODE (e)) == 'c')
- get_cst_ann (e)->common.value_handle = v;
- else if (EXPR_P (e))
- get_expr_ann (e)->common.value_handle = v;
-}
-
/* A three tuple {e, pred, v} used to cache phi translations in the
phi_translate_table. */
typedef struct expr_pred_trans_d
{
- /* The expression. */
+ /* The expression. */
tree e;
/* The predecessor block along which we translated the expression. */
return false;
/* If they are for the same basic block, determine if the
- expressions are equal. */
+ expressions are equal. */
if (expressions_equal_p (ve1->e, ve2->e))
return true;
/* Search in the phi translation table for the translation of
expression E in basic block PRED. Return the translated value, if
- found, NULL otherwise. */
+ found, NULL otherwise. */
static inline tree
phi_trans_lookup (tree e, basic_block pred)
struct expr_pred_trans_d ept;
ept.e = e;
ept.pred = pred;
- ept.hashcode = iterative_hash_expr (e, (unsigned long) pred);
+ ept.hashcode = vn_compute (e, (unsigned long) pred, NULL);
slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
NO_INSERT);
if (!slot)
new_pair->e = e;
new_pair->pred = pred;
new_pair->v = v;
- new_pair->hashcode = iterative_hash_expr (e, (unsigned long) pred);
+ new_pair->hashcode = vn_compute (e, (unsigned long) pred, NULL);
slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
new_pair->hashcode, INSERT);
if (*slot)
*slot = (void *) new_pair;
}
-/* Search in TABLE for an existing instance of expression E,
- and return its value, or NULL if none has been set. */
-
-static inline tree
-lookup (htab_t table, tree e)
-{
- void **slot;
- 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 expression E to the expression set of value V. */
-static inline void
+void
add_to_value (tree v, tree e)
{
-#if DEBUG_VALUE_EXPRESSIONS
- var_ann_t va = var_ann (v);
-#endif
- /* For values representing numerical constants, we mark
- TREE_CONSTANT as true and set the tree chain to the actual
- constant. This is because unlike values involving expressions,
- which are only available to use where the expressions are live, a
- constant can be remade anywhere, and thus, is available
- everywhere. */
- if (TREE_CODE_CLASS (TREE_CODE (e)) == 'c')
- {
- TREE_CONSTANT (v) = true;
- TREE_CHAIN (v) = e;
- }
- else if (is_gimple_min_invariant (e))
- {
- TREE_CONSTANT (v) = true;
- TREE_CHAIN (v) = e;
- }
-#if DEBUG_VALUE_EXPRESSIONS
- if (va->expr_set == NULL)
- va->expr_set = set_new (false);
- insert_into_set (va->expr_set, e);
-#endif
-}
-
-/* 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)
-{
-
- void **slot;
- val_expr_pair_t new_pair = xmalloc (sizeof (struct val_expr_pair_d));
- new_pair->e = e;
- new_pair->v = v;
- new_pair->hashcode = iterative_hash_expr (e, 0);
- slot = htab_find_slot_with_hash (table, new_pair, new_pair->hashcode,
- INSERT);
- if (*slot)
- free (*slot);
- *slot = (void *) new_pair;
- set_value_handle (e, v);
-
- add_to_value (v, e);
-
-}
-
-/* A unique counter that is incremented every time we create a new
- value. */
-static int pre_uid;
-
-/* Create a new value handle for expression EXPR. */
+ /* Constants have no expression sets. */
+ if (is_gimple_min_invariant (v))
+ return;
-static tree
-create_new_value (tree expr)
-{
- tree a = create_tmp_var_raw (TREE_TYPE (expr), "value");
- create_var_ann (a);
- var_ann (a)->uid = pre_uid++;
+ if (VALUE_HANDLE_EXPR_SET (v) == NULL)
+ VALUE_HANDLE_EXPR_SET (v) = set_new (false);
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Created value ");
- print_generic_expr (dump_file, a, dump_flags);
- fprintf (dump_file, " for ");
- print_generic_expr (dump_file, expr, dump_flags);
- fprintf (dump_file, "\n");
- }
- return a;
+ insert_into_set (VALUE_HANDLE_EXPR_SET (v), e);
}
-/* 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)
-{
- tree x = lookup (table, e);
- if (x == NULL_TREE)
- {
- tree v;
- v = create_new_value (e);
- add (table, e, v);
- x = v;
- }
- set_value_handle (e, x);
- return x;
-}
-
/* Return true if value V exists in the bitmap for SET. */
static inline bool
value_exists_in_set_bitmap (value_set_t set, tree v)
{
- if (TREE_CODE (v) != VAR_DECL)
- abort ();
-
if (!set->values)
return false;
- return bitmap_bit_p (set->values, get_var_ann (v)->uid);
+
+ return bitmap_bit_p (set->values, VALUE_HANDLE_ID (v));
}
+
/* Remove value V from the bitmap for SET. */
static void
value_remove_from_set_bitmap (value_set_t set, tree v)
{
- if (TREE_CODE (v) != VAR_DECL)
- abort ();
-#ifdef ENABLE_CHECKING
- if (!set->indexed)
- abort ();
-#endif
+ gcc_assert (set->indexed);
+
if (!set->values)
return;
- bitmap_clear_bit (set->values, get_var_ann (v)->uid);
+
+ bitmap_clear_bit (set->values, VALUE_HANDLE_ID (v));
}
static inline void
value_insert_into_set_bitmap (value_set_t set, tree v)
{
- if (TREE_CODE (v) != VAR_DECL)
- abort ();
-#ifdef ENABLE_CHECKING
- if (!set->indexed)
- abort ();
-#endif
+ gcc_assert (set->indexed);
+
if (set->values == NULL)
- {
- set->values = BITMAP_GGC_ALLOC ();
- bitmap_clear (set->values);
- }
- bitmap_set_bit (set->values, get_var_ann (v)->uid);
+ set->values = BITMAP_ALLOC (&grand_bitmap_obstack);
+
+ bitmap_set_bit (set->values, VALUE_HANDLE_ID (v));
+}
+
+
+/* Create a new bitmap set and return it. */
+
+static bitmap_set_t
+bitmap_set_new (void)
+{
+ bitmap_set_t ret = pool_alloc (bitmap_set_pool);
+ ret->expressions = BITMAP_ALLOC (&grand_bitmap_obstack);
+ ret->values = BITMAP_ALLOC (&grand_bitmap_obstack);
+ return ret;
}
/* Create a new set. */
return ret;
}
+/* Insert an expression EXPR into a bitmapped set. */
+
+static void
+bitmap_insert_into_set (bitmap_set_t set, tree expr)
+{
+ tree val;
+ /* XXX: For now, we only let SSA_NAMES into the bitmap sets. */
+ gcc_assert (TREE_CODE (expr) == SSA_NAME);
+ val = get_value_handle (expr);
+
+ gcc_assert (val);
+ if (!is_gimple_min_invariant (val))
+ {
+ bitmap_set_bit (set->values, VALUE_HANDLE_ID (val));
+ bitmap_set_bit (set->expressions, SSA_NAME_VERSION (expr));
+ }
+}
/* Insert EXPR into SET. */
{
value_set_node_t newnode = pool_alloc (value_set_node_pool);
tree val = get_value_handle (expr);
- if (DECL_P (expr))
- abort ();
+ gcc_assert (val);
- if (val == NULL)
- abort ();
+ if (is_gimple_min_invariant (val))
+ return;
/* For indexed sets, insert the value into the set value bitmap.
For all sets, add it to the linked list and increment the list
}
}
+/* Copy a bitmapped set ORIG, into bitmapped set DEST. */
+
+static void
+bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
+{
+ bitmap_copy (dest->expressions, orig->expressions);
+ bitmap_copy (dest->values, orig->values);
+}
+
/* Copy the set ORIG to the set DEST. */
static void
static bool
set_contains_value (value_set_t set, tree val)
{
- /* This is only referring to the flag above that we set on
- values referring to numerical constants, because we know that we
- are dealing with one of the value handles we created. */
- if (TREE_CONSTANT (val))
+ /* All constants are in every set. */
+ if (is_gimple_min_invariant (val))
return true;
if (set->length == 0)
return value_exists_in_set_bitmap (set, val);
}
-/* Replace the leader for the value LOOKFOR in SET with EXPR. */
-
-static void
-set_replace_value (value_set_t set, tree lookfor, tree expr)
+/* Return true if bitmapped set SET contains the expression EXPR. */
+static bool
+bitmap_set_contains (bitmap_set_t set, tree expr)
{
- value_set_node_t node = set->head;
-
- /* The lookup is probably more expensive than walking the linked
- list when we have only a small number of nodes. */
- if (!set_contains_value (set, lookfor))
- return;
+ /* All constants are in every set. */
+ if (is_gimple_min_invariant (get_value_handle (expr)))
+ return true;
- for (node = set->head;
- node;
- node = node->next)
- {
- if (get_value_handle (node->expr) == lookfor)
- {
- node->expr = expr;
- return;
- }
- }
+ /* XXX: Bitmapped sets only contain SSA_NAME's for now. */
+ if (TREE_CODE (expr) != SSA_NAME)
+ return false;
+ return bitmap_bit_p (set->expressions, SSA_NAME_VERSION (expr));
}
-/* Return true if the set contains expression (not value) EXPR. */
+
+/* Return true if bitmapped set SET contains the value VAL. */
static bool
-set_contains (value_set_t set, tree expr)
+bitmap_set_contains_value (bitmap_set_t set, tree val)
+{
+ if (is_gimple_min_invariant (val))
+ return true;
+ return bitmap_bit_p (set->values, VALUE_HANDLE_ID (val));
+}
+
+/* Replace an instance of value LOOKFOR with expression EXPR in SET. */
+
+static void
+bitmap_set_replace_value (bitmap_set_t set, tree lookfor, tree expr)
{
+ value_set_t exprset;
value_set_node_t node;
-
- for (node = set->head;
- node;
- node = node->next)
+ if (is_gimple_min_invariant (lookfor))
+ return;
+ if (!bitmap_set_contains_value (set, lookfor))
+ return;
+
+ /* The number of expressions having a given value is usually
+ significantly less than the total number of expressions in SET.
+ Thus, rather than check, for each expression in SET, whether it
+ has the value LOOKFOR, we walk the reverse mapping that tells us
+ what expressions have a given value, and see if any of those
+ expressions are in our set. For large testcases, this is about
+ 5-10x faster than walking the bitmap. If this is somehow a
+ significant lose for some cases, we can choose which set to walk
+ based on the set size. */
+ exprset = VALUE_HANDLE_EXPR_SET (lookfor);
+ for (node = exprset->head; node; node = node->next)
{
- if (operand_equal_p (node->expr, expr, 0))
- return true;
+ if (TREE_CODE (node->expr) == SSA_NAME)
+ {
+ if (bitmap_bit_p (set->expressions, SSA_NAME_VERSION (node->expr)))
+ {
+ bitmap_clear_bit (set->expressions, SSA_NAME_VERSION (node->expr));
+ bitmap_set_bit (set->expressions, SSA_NAME_VERSION (expr));
+ return;
+ }
+ }
}
- return false;
}
-/* Subtract set B from set A, and return the new set. */
+/* Subtract bitmapped set B from value set A, and return the new set. */
static value_set_t
-set_subtract (value_set_t a, value_set_t b, bool indexed)
+bitmap_set_subtract_from_value_set (value_set_t a, bitmap_set_t b,
+ bool indexed)
{
value_set_t ret = set_new (indexed);
value_set_node_t node;
node;
node = node->next)
{
- if (!set_contains (b, node->expr))
+ if (!bitmap_set_contains (b, node->expr))
insert_into_set (ret, node->expr);
}
return ret;
}
-/* Return true if two sets are equal. */
+/* Return true if two sets are equal. */
static bool
set_equal (value_set_t a, value_set_t b)
return true;
}
-/* Replace the value for EXPR in SET with EXPR. */
+/* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
+ and add it otherwise. */
+
static void
-value_replace_in_set (value_set_t set, tree expr)
+bitmap_value_replace_in_set (bitmap_set_t set, tree expr)
{
tree val = get_value_handle (expr);
+ if (bitmap_set_contains_value (set, val))
+ bitmap_set_replace_value (set, val, expr);
+ else
+ bitmap_insert_into_set (set, expr);
+}
- if (set->length == 0)
+/* Insert EXPR into SET if EXPR's value is not already present in
+ SET. */
+
+static void
+bitmap_value_insert_into_set (bitmap_set_t set, tree expr)
+{
+ tree val = get_value_handle (expr);
+
+ if (is_gimple_min_invariant (val))
return;
- set_replace_value (set, val, expr);
+ if (!bitmap_set_contains_value (set, val))
+ bitmap_insert_into_set (set, expr);
}
/* Insert the value for EXPR into SET, if it doesn't exist already. */
{
tree val = get_value_handle (expr);
- /* Constant values exist everywhere. */
- if (TREE_CONSTANT (val))
+ /* Constant and invariant values exist everywhere, and thus,
+ actually keeping them in the sets is pointless. */
+ if (is_gimple_min_invariant (val))
return;
if (!set_contains_value (set, val))
}
+/* Print out SET to OUTFILE. */
+
+static void
+bitmap_print_value_set (FILE *outfile, bitmap_set_t set,
+ const char *setname, int blockindex)
+{
+ fprintf (outfile, "%s[%d] := { ", setname, blockindex);
+ if (set)
+ {
+ bool first = true;
+ unsigned i;
+ bitmap_iterator bi;
+
+ EXECUTE_IF_SET_IN_BITMAP (set->expressions, 0, i, bi)
+ {
+ if (!first)
+ fprintf (outfile, ", ");
+ first = false;
+ print_generic_expr (outfile, ssa_name (i), 0);
+
+ fprintf (outfile, " (");
+ print_generic_expr (outfile, get_value_handle (ssa_name (i)), 0);
+ fprintf (outfile, ") ");
+ }
+ }
+ fprintf (outfile, " }\n");
+}
/* Print out the value_set SET to OUTFILE. */
static void
}
/* Print out the expressions that have VAL to OUTFILE. */
+
void
print_value_expressions (FILE *outfile, tree val)
{
- var_ann_t va = var_ann (val);
- if (va && va->expr_set)
- print_value_set (outfile, va->expr_set,
- IDENTIFIER_POINTER (DECL_NAME (val)), 0);
+ if (VALUE_HANDLE_EXPR_SET (val))
+ {
+ char s[10];
+ sprintf (s, "VH.%04d", VALUE_HANDLE_ID (val));
+ print_value_set (outfile, VALUE_HANDLE_EXPR_SET (val), s, 0);
+ }
}
part of the translated expression. */
static tree
-phi_translate (tree expr, value_set_t set, basic_block pred,
+phi_translate (tree expr, value_set_t set, basic_block pred,
basic_block phiblock)
{
tree phitrans = NULL;
if (expr == NULL)
return NULL;
- /* Phi translations of a given expression don't change, */
+ if (is_gimple_min_invariant (expr))
+ return expr;
+
+ /* Phi translations of a given expression don't change. */
phitrans = phi_trans_lookup (expr, pred);
if (phitrans)
return phitrans;
-
switch (TREE_CODE_CLASS (TREE_CODE (expr)))
{
- case '2':
+ case tcc_reference:
+ /* XXX: Until we have PRE of loads working, none will be ANTIC. */
+ return NULL;
+
+ case tcc_binary:
{
tree oldop1 = TREE_OPERAND (expr, 0);
tree oldop2 = TREE_OPERAND (expr, 1);
{
newexpr = pool_alloc (binary_node_pool);
memcpy (newexpr, expr, tree_size (expr));
- create_expr_ann (newexpr);
+ create_tree_ann (newexpr);
TREE_OPERAND (newexpr, 0) = newop1 == oldop1 ? oldop1 : get_value_handle (newop1);
TREE_OPERAND (newexpr, 1) = newop2 == oldop2 ? oldop2 : get_value_handle (newop2);
- lookup_or_add (value_table, newexpr);
+ vn_lookup_or_add (newexpr, NULL);
expr = newexpr;
phi_trans_add (oldexpr, newexpr, pred);
}
}
- break;
- case '1':
+ return expr;
+
+ case tcc_unary:
{
tree oldop1 = TREE_OPERAND (expr, 0);
tree newop1;
{
newexpr = pool_alloc (unary_node_pool);
memcpy (newexpr, expr, tree_size (expr));
- create_expr_ann (newexpr);
+ create_tree_ann (newexpr);
TREE_OPERAND (newexpr, 0) = get_value_handle (newop1);
- lookup_or_add (value_table, newexpr);
+ vn_lookup_or_add (newexpr, NULL);
expr = newexpr;
phi_trans_add (oldexpr, newexpr, pred);
}
}
- break;
- case 'd':
- abort ();
- case 'x':
+ return expr;
+
+ case tcc_exceptional:
{
tree phi = NULL;
- int i;
- if (TREE_CODE (expr) != SSA_NAME)
- abort ();
+ edge e;
+ gcc_assert (TREE_CODE (expr) == SSA_NAME);
if (TREE_CODE (SSA_NAME_DEF_STMT (expr)) == PHI_NODE)
phi = SSA_NAME_DEF_STMT (expr);
else
return expr;
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
- if (PHI_ARG_EDGE (phi, i)->src == pred)
- {
- tree val;
- if (is_undefined_value (PHI_ARG_DEF (phi, i)))
- return NULL;
- val = lookup_or_add (value_table, PHI_ARG_DEF (phi, i));
- return PHI_ARG_DEF (phi, i);
- }
+ e = find_edge (pred, bb_for_stmt (phi));
+ if (e)
+ {
+ if (is_undefined_value (PHI_ARG_DEF (phi, e->dest_idx)))
+ return NULL;
+ vn_lookup_or_add (PHI_ARG_DEF (phi, e->dest_idx), NULL);
+ return PHI_ARG_DEF (phi, e->dest_idx);
+ }
}
- break;
+ return expr;
+
+ default:
+ gcc_unreachable ();
}
- return expr;
}
static void
}
}
-/* Find the leader for a value (IE the name representing that
+/* Find the leader for a value (i.e., the name representing that
+ value) in a given set, and return it. Return NULL if no leader is
+ found. */
+
+static tree
+bitmap_find_leader (bitmap_set_t set, tree val)
+{
+ if (val == NULL)
+ return NULL;
+
+ if (is_gimple_min_invariant (val))
+ return val;
+ if (bitmap_set_contains_value (set, val))
+ {
+ /* Rather than walk the entire bitmap of expressions, and see
+ whether any of them has the value we are looking for, we look
+ at the reverse mapping, which tells us the set of expressions
+ that have a given value (IE value->expressions with that
+ value) and see if any of those expressions are in our set.
+ The number of expressions per value is usually significantly
+ less than the number of expressions in the set. In fact, for
+ large testcases, doing it this way is roughly 5-10x faster
+ than walking the bitmap.
+ If this is somehow a significant lose for some cases, we can
+ choose which set to walk based on which set is smaller. */
+ value_set_t exprset;
+ value_set_node_t node;
+ exprset = VALUE_HANDLE_EXPR_SET (val);
+ for (node = exprset->head; node; node = node->next)
+ {
+ if (TREE_CODE (node->expr) == SSA_NAME)
+ {
+ if (bitmap_bit_p (set->expressions,
+ SSA_NAME_VERSION (node->expr)))
+ return node->expr;
+ }
+ }
+ }
+ return NULL;
+}
+
+
+/* Find the leader for a value (i.e., the name representing that
value) in a given set, and return it. Return NULL if no leader is
found. */
if (val == NULL)
return NULL;
- if (TREE_CONSTANT (val))
- return TREE_CHAIN (val);
+ /* Constants represent themselves. */
+ if (is_gimple_min_invariant (val))
+ return val;
if (set->length == 0)
return NULL;
return node->expr;
}
}
+
return NULL;
}
{
switch (TREE_CODE_CLASS (TREE_CODE (expr)))
{
- case '2':
+ case tcc_binary:
{
tree op1 = TREE_OPERAND (expr, 0);
tree op2 = TREE_OPERAND (expr, 1);
return set_contains_value (set, op1) && set_contains_value (set, op2);
}
- break;
- case '1':
+
+ case tcc_unary:
{
tree op1 = TREE_OPERAND (expr, 0);
return set_contains_value (set, op1);
}
- break;
- case 'x':
- {
- if (TREE_CODE (expr) == SSA_NAME)
- return true;
- abort ();
- }
- case 'c':
- abort ();
- }
- return false;
+
+ case tcc_reference:
+ /* XXX: Until PRE of loads works, no reference nodes are ANTIC. */
+ return false;
+
+ case tcc_exceptional:
+ gcc_assert (TREE_CODE (expr) == SSA_NAME);
+ return true;
+
+ default:
+ /* No other cases should be encountered. */
+ gcc_unreachable ();
+ }
}
/* Clean the set of expressions that are no longer valid in SET. This
}
}
-/* Compute the ANTIC set for BLOCK.
-
-ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK), if
-succs(BLOCK) > 1
-ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)]) if
-succs(BLOCK) == 1
+DEF_VEC_MALLOC_P (basic_block);
+static sbitmap has_abnormal_preds;
-ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] -
-TMP_GEN[BLOCK])
+/* Compute the ANTIC set for BLOCK.
-Iterate until fixpointed.
+ If succs(BLOCK) > 1 then
+ ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
+ else if succs(BLOCK) == 1 then
+ ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
-XXX: It would be nice to either write a set_clear, and use it for
-antic_out, or to mark the antic_out set as deleted at the end
-of this routine, so that the pool can hand the same memory back out
-again for the next antic_out. */
+ ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
+ XXX: It would be nice to either write a set_clear, and use it for
+ ANTIC_OUT, or to mark the antic_out set as deleted at the end
+ of this routine, so that the pool can hand the same memory back out
+ again for the next ANTIC_OUT. */
static bool
-compute_antic_aux (basic_block block)
+compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
{
basic_block son;
- edge e;
bool changed = false;
value_set_t S, old, ANTIC_OUT;
value_set_node_t node;
-
+
ANTIC_OUT = S = NULL;
- /* If any edges from predecessors are abnormal, antic_in is empty, so
- punt. Remember that the block has an incoming abnormal edge by
- setting the BB_VISITED flag. */
- if (! (block->flags & BB_VISITED))
- {
- for (e = block->pred; e; e = e->pred_next)
- if (e->flags & EDGE_ABNORMAL)
- {
- block->flags |= BB_VISITED;
- break;
- }
- }
- if (block->flags & BB_VISITED)
- {
- S = NULL;
- goto visit_sons;
- }
-
+
+ /* If any edges from predecessors are abnormal, antic_in is empty,
+ so do nothing. */
+ if (block_has_abnormal_pred_edge)
+ goto maybe_dump_sets;
old = set_new (false);
set_copy (old, ANTIC_IN (block));
ANTIC_OUT = set_new (true);
- /* If the block has no successors, ANTIC_OUT is empty, because it is
- the exit block. */
- if (block->succ == NULL);
-
+ /* If the block has no successors, ANTIC_OUT is empty. */
+ if (EDGE_COUNT (block->succs) == 0)
+ ;
/* If we have one successor, we could have some phi nodes to
translate through. */
- else if (block->succ->succ_next == NULL)
+ else if (EDGE_COUNT (block->succs) == 1)
{
- phi_translate_set (ANTIC_OUT, ANTIC_IN(block->succ->dest),
- block, block->succ->dest);
+ phi_translate_set (ANTIC_OUT, ANTIC_IN(EDGE_SUCC (block, 0)->dest),
+ block, EDGE_SUCC (block, 0)->dest);
}
/* If we have multiple successors, we take the intersection of all of
them. */
else
{
- varray_type worklist;
+ VEC (basic_block) * worklist;
edge e;
size_t i;
basic_block bprime, first;
+ edge_iterator ei;
- VARRAY_BB_INIT (worklist, 1, "succ");
- e = block->succ;
- while (e)
- {
- VARRAY_PUSH_BB (worklist, e->dest);
- e = e->succ_next;
- }
- first = VARRAY_BB (worklist, 0);
+ worklist = VEC_alloc (basic_block, 2);
+ FOR_EACH_EDGE (e, ei, block->succs)
+ VEC_safe_push (basic_block, worklist, e->dest);
+ first = VEC_index (basic_block, worklist, 0);
set_copy (ANTIC_OUT, ANTIC_IN (first));
- for (i = 1; i < VARRAY_ACTIVE_SIZE (worklist); i++)
+ for (i = 1; VEC_iterate (basic_block, worklist, i, bprime); i++)
{
- bprime = VARRAY_BB (worklist, i);
node = ANTIC_OUT->head;
while (node)
{
node = next;
}
}
- VARRAY_CLEAR (worklist);
+ VEC_free (basic_block, worklist);
}
- /* Generate ANTIC_OUT - TMP_GEN */
- S = set_subtract (ANTIC_OUT, TMP_GEN (block), false);
+ /* Generate ANTIC_OUT - TMP_GEN. */
+ S = bitmap_set_subtract_from_value_set (ANTIC_OUT, TMP_GEN (block), false);
/* Start ANTIC_IN with EXP_GEN - TMP_GEN */
- ANTIC_IN (block) = set_subtract (EXP_GEN (block),TMP_GEN (block), true);
-
- /* Then union in the ANTIC_OUT - TMP_GEN values, to get ANTIC_OUT U
- EXP_GEN - TMP_GEN */
- for (node = S->head;
- node;
- node = node->next)
- {
- value_insert_into_set (ANTIC_IN (block), node->expr);
- }
- clean (ANTIC_IN (block));
-
+ ANTIC_IN (block) = bitmap_set_subtract_from_value_set (EXP_GEN (block),
+ TMP_GEN (block),
+ true);
+ /* Then union in the ANTIC_OUT - TMP_GEN values,
+ to get ANTIC_OUT U EXP_GEN - TMP_GEN */
+ for (node = S->head; node; node = node->next)
+ value_insert_into_set (ANTIC_IN (block), node->expr);
+
+ clean (ANTIC_IN (block));
if (!set_equal (old, ANTIC_IN (block)))
changed = true;
- visit_sons:
+ maybe_dump_sets:
if (dump_file && (dump_flags & TDF_DETAILS))
{
if (ANTIC_OUT)
print_value_set (dump_file, ANTIC_IN (block), "ANTIC_IN", block->index);
if (S)
print_value_set (dump_file, S, "S", block->index);
-
}
for (son = first_dom_son (CDI_POST_DOMINATORS, block);
son;
son = next_dom_son (CDI_POST_DOMINATORS, son))
{
- changed |= compute_antic_aux (son);
+ changed |= compute_antic_aux (son,
+ TEST_BIT (has_abnormal_preds, son->index));
}
return changed;
}
compute_antic (void)
{
bool changed = true;
- basic_block bb;
int num_iterations = 0;
- FOR_ALL_BB (bb)
+ basic_block block;
+
+ /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
+ We pre-build the map of blocks with incoming abnormal edges here. */
+ has_abnormal_preds = sbitmap_alloc (last_basic_block);
+ sbitmap_zero (has_abnormal_preds);
+ FOR_EACH_BB (block)
{
- ANTIC_IN (bb) = set_new (true);
- bb->flags &= ~BB_VISITED;
+ edge_iterator ei;
+ edge e;
+
+ FOR_EACH_EDGE (e, ei, block->preds)
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ SET_BIT (has_abnormal_preds, block->index);
+ break;
+ }
+
+ /* While we are here, give empty ANTIC_IN sets to each block. */
+ ANTIC_IN (block) = set_new (true);
}
+ /* At the exit block we anticipate nothing. */
+ ANTIC_IN (EXIT_BLOCK_PTR) = set_new (true);
while (changed)
{
num_iterations++;
changed = false;
- changed = compute_antic_aux (EXIT_BLOCK_PTR);
+ changed = compute_antic_aux (EXIT_BLOCK_PTR, false);
}
- if (num_iterations > 2 && dump_file && (dump_flags & TDF_STATS))
+
+ sbitmap_free (has_abnormal_preds);
+
+ if (dump_file && (dump_flags & TDF_STATS))
fprintf (dump_file, "compute_antic required %d iterations\n", num_iterations);
}
+static VEC(tree_on_heap) *inserted_exprs;
+/* Find a leader for an expression, or generate one using
+ create_expression_by_pieces if it's ANTIC but
+ complex.
+ BLOCK is the basic_block we are looking for leaders in.
+ EXPR is the expression to find a leader or generate for.
+ STMTS is the statement list to put the inserted expressions on.
+ Returns the SSA_NAME of the LHS of the generated expression or the
+ leader. */
+
+static tree
+find_or_generate_expression (basic_block block, tree expr, tree stmts)
+{
+ tree genop = bitmap_find_leader (AVAIL_OUT (block), expr);
+
+ /* If it's still NULL, see if it is a complex expression, and if
+ so, generate it recursively, otherwise, abort, because it's
+ not really . */
+ if (genop == NULL)
+ {
+ genop = VALUE_HANDLE_EXPR_SET (expr)->head->expr;
+ gcc_assert (UNARY_CLASS_P (genop)
+ || BINARY_CLASS_P (genop)
+ || REFERENCE_CLASS_P (genop));
+ genop = create_expression_by_pieces (block, genop, stmts);
+ }
+ return genop;
+}
+
+#define NECESSARY(stmt) stmt->common.asm_written_flag
+/* Create an expression in pieces, so that we can handle very complex
+ expressions that may be ANTIC, but not necessary GIMPLE.
+ BLOCK is the basic block the expression will be inserted into,
+ EXPR is the expression to insert (in value form)
+ STMTS is a statement list to append the necessary insertions into.
+
+ This function will abort if we hit some value that shouldn't be
+ ANTIC but is (IE there is no leader for it, or its components).
+ This function may also generate expressions that are themselves
+ partially or fully redundant. Those that are will be either made
+ fully redundant during the next iteration of insert (for partially
+ redundant ones), or eliminated by eliminate (for fully redundant
+ ones). */
+
+static tree
+create_expression_by_pieces (basic_block block, tree expr, tree stmts)
+{
+ tree name = NULL_TREE;
+ tree newexpr = NULL_TREE;
+ tree v;
+
+ switch (TREE_CODE_CLASS (TREE_CODE (expr)))
+ {
+ case tcc_binary:
+ {
+ tree_stmt_iterator tsi;
+ tree genop1, genop2;
+ tree temp;
+ tree op1 = TREE_OPERAND (expr, 0);
+ tree op2 = TREE_OPERAND (expr, 1);
+ genop1 = find_or_generate_expression (block, op1, stmts);
+ genop2 = find_or_generate_expression (block, op2, stmts);
+ temp = create_tmp_var (TREE_TYPE (expr), "pretmp");
+ add_referenced_tmp_var (temp);
+ newexpr = fold (build (TREE_CODE (expr), TREE_TYPE (expr),
+ genop1, genop2));
+ newexpr = build (MODIFY_EXPR, TREE_TYPE (expr),
+ temp, newexpr);
+ NECESSARY (newexpr) = 0;
+ name = make_ssa_name (temp, newexpr);
+ TREE_OPERAND (newexpr, 0) = name;
+ tsi = tsi_last (stmts);
+ tsi_link_after (&tsi, newexpr, TSI_CONTINUE_LINKING);
+ VEC_safe_push (tree_on_heap, inserted_exprs, newexpr);
+ pre_stats.insertions++;
+ break;
+ }
+ case tcc_unary:
+ {
+ tree_stmt_iterator tsi;
+ tree genop1;
+ tree temp;
+ tree op1 = TREE_OPERAND (expr, 0);
+ genop1 = find_or_generate_expression (block, op1, stmts);
+ temp = create_tmp_var (TREE_TYPE (expr), "pretmp");
+ add_referenced_tmp_var (temp);
+ newexpr = fold (build (TREE_CODE (expr), TREE_TYPE (expr),
+ genop1));
+ newexpr = build (MODIFY_EXPR, TREE_TYPE (expr),
+ temp, newexpr);
+ name = make_ssa_name (temp, newexpr);
+ TREE_OPERAND (newexpr, 0) = name;
+ NECESSARY (newexpr) = 0;
+ tsi = tsi_last (stmts);
+ tsi_link_after (&tsi, newexpr, TSI_CONTINUE_LINKING);
+ VEC_safe_push (tree_on_heap, inserted_exprs, newexpr);
+ pre_stats.insertions++;
+
+ break;
+ }
+ default:
+ gcc_unreachable ();
+
+ }
+ v = get_value_handle (expr);
+ vn_add (name, v, NULL);
+
+ /* The value may already exist in either NEW_SETS, or AVAIL_OUT, because
+ we are creating the expression by pieces, and this particular piece of
+ the expression may have been represented. There is no harm in replacing
+ here. */
+ bitmap_value_replace_in_set (NEW_SETS (block), name);
+ bitmap_value_replace_in_set (AVAIL_OUT (block), name);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Inserted ");
+ print_generic_expr (dump_file, newexpr, 0);
+ fprintf (dump_file, " in predecessor %d\n", block->index);
+ }
+ return name;
+}
+
+/* Return the folded version of T if T, when folded, is a gimple
+ min_invariant. Otherwise, return T. */
+
+static tree
+fully_constant_expression (tree t)
+{
+ tree folded;
+ folded = fold (t);
+ if (folded && is_gimple_min_invariant (folded))
+ return folded;
+ return t;
+}
+
+/* Insert the to-be-made-available values of NODE for each predecessor, stored
+ in AVAIL, into the predecessors of BLOCK, and merge the result with a phi
+ node, given the same value handle as NODE. The prefix of the phi node is
+ given with TMPNAME. Return true if we have inserted new stuff. */
+
+static bool
+insert_into_preds_of_block (basic_block block, value_set_node_t node,
+ tree *avail, const char *tmpname)
+{
+ tree val = get_value_handle (node->expr);
+ edge pred;
+ bool insertions = false;
+ bool nophi = false;
+ basic_block bprime;
+ tree eprime;
+ edge_iterator ei;
+ tree type = TREE_TYPE (avail[EDGE_PRED (block, 0)->src->index]);
+ tree temp;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Found partial redundancy for expression ");
+ print_generic_expr (dump_file, node->expr, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ /* Make sure we aren't creating an induction variable. */
+ if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2)
+ {
+ bool firstinsideloop = false;
+ bool secondinsideloop = false;
+ firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
+ EDGE_PRED (block, 0)->src);
+ secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
+ EDGE_PRED (block, 1)->src);
+ /* Induction variables only have one edge inside the loop. */
+ if (firstinsideloop ^ secondinsideloop)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
+ nophi = true;
+ }
+ }
+
+
+ /* Make the necessary insertions. */
+ FOR_EACH_EDGE (pred, ei, block->preds)
+ {
+ tree stmts = alloc_stmt_list ();
+ tree builtexpr;
+ bprime = pred->src;
+ eprime = avail[bprime->index];
+ if (BINARY_CLASS_P (eprime)
+ || UNARY_CLASS_P (eprime))
+ {
+ builtexpr = create_expression_by_pieces (bprime,
+ eprime,
+ stmts);
+ bsi_insert_on_edge (pred, stmts);
+ avail[bprime->index] = builtexpr;
+ insertions = true;
+ }
+ }
+ /* If we didn't want a phi node, and we made insertions, we still have
+ inserted new stuff, and thus return true. If we didn't want a phi node,
+ and didn't make insertions, we haven't added anything new, so return
+ false. */
+ if (nophi && insertions)
+ return true;
+ else if (nophi && !insertions)
+ return false;
+
+ /* Now build a phi for the new variable. */
+ temp = create_tmp_var (type, tmpname);
+ add_referenced_tmp_var (temp);
+ temp = create_phi_node (temp, block);
+ NECESSARY (temp) = 0;
+ VEC_safe_push (tree_on_heap, inserted_exprs, temp);
+ FOR_EACH_EDGE (pred, ei, block->preds)
+ add_phi_arg (temp, avail[pred->src->index], pred);
+
+ vn_add (PHI_RESULT (temp), val, NULL);
+
+ /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
+ this insertion, since we test for the existence of this value in PHI_GEN
+ before proceeding with the partial redundancy checks in insert_aux.
+
+ The value may exist in AVAIL_OUT, in particular, it could be represented
+ by the expression we are trying to eliminate, in which case we want the
+ replacement to occur. If it's not existing in AVAIL_OUT, we want it
+ inserted there.
+
+ Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
+ this block, because if it did, it would have existed in our dominator's
+ AVAIL_OUT, and would have been skipped due to the full redundancy check.
+ */
+
+ bitmap_insert_into_set (PHI_GEN (block),
+ PHI_RESULT (temp));
+ bitmap_value_replace_in_set (AVAIL_OUT (block),
+ PHI_RESULT (temp));
+ bitmap_insert_into_set (NEW_SETS (block),
+ PHI_RESULT (temp));
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Created phi ");
+ print_generic_expr (dump_file, temp, 0);
+ fprintf (dump_file, " in block %d\n", block->index);
+ }
+ pre_stats.phis++;
+ return true;
+}
+
+
+
/* Perform insertion of partially redundant values.
For BLOCK, do the following:
1. Propagate the NEW_SETS of the dominator into the current block.
3. Recursively call ourselves on the dominator children of BLOCK.
*/
+
static bool
insert_aux (basic_block block)
{
if (block)
{
- value_set_node_t e;
basic_block dom;
dom = get_immediate_dominator (CDI_DOMINATORS, block);
if (dom)
{
- e = NEW_SETS (dom)->head;
- while (e)
+ unsigned i;
+ bitmap_iterator bi;
+ bitmap_set_t newset = NEW_SETS (dom);
+ if (newset)
{
- insert_into_set (NEW_SETS (block), e->expr);
- value_replace_in_set (AVAIL_OUT (block), e->expr);
- e = e->next;
+ /* Note that we need to value_replace both NEW_SETS, and
+ AVAIL_OUT. For both the case of NEW_SETS, the value may be
+ represented by some non-simple expression here that we want
+ to replace it with. */
+ EXECUTE_IF_SET_IN_BITMAP (newset->expressions, 0, i, bi)
+ {
+ bitmap_value_replace_in_set (NEW_SETS (block), ssa_name (i));
+ bitmap_value_replace_in_set (AVAIL_OUT (block), ssa_name (i));
+ }
}
- if (block->pred->pred_next)
+ if (EDGE_COUNT (block->preds) > 1)
{
value_set_node_t node;
for (node = ANTIC_IN (block)->head;
node;
node = node->next)
{
- if (TREE_CODE_CLASS (TREE_CODE (node->expr)) == '2'
- || TREE_CODE_CLASS (TREE_CODE (node->expr)) == '1')
+ if (BINARY_CLASS_P (node->expr)
+ || UNARY_CLASS_P (node->expr))
{
tree *avail;
tree val;
tree first_s = NULL;
edge pred;
basic_block bprime;
- tree eprime;
+ tree eprime = NULL_TREE;
+ edge_iterator ei;
val = get_value_handle (node->expr);
- if (set_contains_value (PHI_GEN (block), val))
+ if (bitmap_set_contains_value (PHI_GEN (block), val))
continue;
- if (set_contains_value (AVAIL_OUT (dom), val))
+ if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found fully redundant value\n");
continue;
}
-
+
avail = xcalloc (last_basic_block, sizeof (tree));
- for (pred = block->pred;
- pred;
- pred = pred->pred_next)
+ FOR_EACH_EDGE (pred, ei, block->preds)
{
tree vprime;
tree edoubleprime;
+
+ /* This can happen in the very weird case
+ that our fake infinite loop edges have caused a
+ critical edge to appear. */
+ if (EDGE_CRITICAL_P (pred))
+ {
+ cant_insert = true;
+ break;
+ }
bprime = pred->src;
eprime = phi_translate (node->expr,
ANTIC_IN (block),
break;
}
+ eprime = fully_constant_expression (eprime);
vprime = get_value_handle (eprime);
- if (!vprime)
- abort ();
- edoubleprime = find_leader (AVAIL_OUT (bprime),
- vprime);
+ gcc_assert (vprime);
+ edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
+ vprime);
if (edoubleprime == NULL)
{
avail[bprime->index] = eprime;
by_some = true;
if (first_s == NULL)
first_s = edoubleprime;
- else if (first_s != edoubleprime)
+ else if (!operand_equal_p (first_s, edoubleprime,
+ 0))
all_same = false;
- if (first_s != edoubleprime
- && operand_equal_p (first_s, edoubleprime, 0))
- abort ();
}
}
/* If we can insert it, it's not the same value
partially redundant. */
if (!cant_insert && !all_same && by_some)
{
- tree type = TREE_TYPE (avail[block->pred->src->index]);
- tree temp;
- tree v;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Found partial redundancy for expression ");
- print_generic_expr (dump_file, node->expr, 0);
- fprintf (dump_file, "\n");
- }
-
- /* Make the necessary insertions. */
- for (pred = block->pred;
- pred;
- pred = pred->pred_next)
- {
- bprime = pred->src;
- eprime = avail[bprime->index];
- if (TREE_CODE_CLASS (TREE_CODE (eprime)) == '2')
- {
- tree s1, s2;
- tree newexpr;
- s1 = find_leader (AVAIL_OUT (bprime),
- TREE_OPERAND (eprime, 0));
- /* Depending on the order we process
- DOM branches in, the value may
- not have propagated to all the
- dom children yet during this
- iteration. In this case, the
- value will always be in the
- NEW_SETS for *our* dominator */
- if (!s1)
- s1 = find_leader (NEW_SETS (dom),
- TREE_OPERAND (eprime, 0));
- if (!s1)
- abort ();
-
- s2 = find_leader (AVAIL_OUT (bprime),
- TREE_OPERAND (eprime, 1));
- if (!s2)
- s2 = find_leader (NEW_SETS (dom),
- TREE_OPERAND (eprime, 1));
- if (!s2)
- abort ();
-
- temp = create_tmp_var (TREE_TYPE (eprime),
- "pretmp");
- add_referenced_tmp_var (temp);
- newexpr = build (TREE_CODE (eprime),
- TREE_TYPE (eprime),
- s1, s2);
- newexpr = build (MODIFY_EXPR,
- TREE_TYPE (eprime),
- temp, newexpr);
- temp = make_ssa_name (temp, newexpr);
- TREE_OPERAND (newexpr, 0) = temp;
- bsi_insert_on_edge (pred, newexpr);
- bsi_commit_edge_inserts (NULL);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Inserted ");
- print_generic_expr (dump_file, newexpr, 0);
- fprintf (dump_file, " in predecessor %d\n", pred->src->index);
- }
- pre_stats.insertions++;
- v = lookup_or_add (value_table, eprime);
- add (value_table, temp, v);
- insert_into_set (NEW_SETS (bprime), temp);
- value_insert_into_set (AVAIL_OUT (bprime),
- temp);
- avail[bprime->index] = temp;
- }
- else if (TREE_CODE_CLASS (TREE_CODE (eprime)) == '1')
- {
- tree s1;
- tree newexpr;
- s1 = find_leader (AVAIL_OUT (bprime),
- TREE_OPERAND (eprime, 0));
- /* Depending on the order we process
- DOM branches in, the value may not have
- propagated to all the dom
- children yet in the current
- iteration, but it will be in
- NEW_SETS if it is not yet
- propagated. */
-
- if (!s1)
- s1 = find_leader (NEW_SETS (dom),
- TREE_OPERAND (eprime, 0));
- if (!s1)
- abort ();
-
- temp = create_tmp_var (TREE_TYPE (eprime),
- "pretmp");
- add_referenced_tmp_var (temp);
- newexpr = build (TREE_CODE (eprime),
- TREE_TYPE (eprime),
- s1);
- newexpr = build (MODIFY_EXPR,
- TREE_TYPE (eprime),
- temp, newexpr);
- temp = make_ssa_name (temp, newexpr);
- TREE_OPERAND (newexpr, 0) = temp;
- bsi_insert_on_edge (pred, newexpr);
- bsi_commit_edge_inserts (NULL);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Inserted ");
- print_generic_expr (dump_file, newexpr, 0);
- fprintf (dump_file, " in predecessor %d\n", pred->src->index);
- }
- pre_stats.insertions++;
- v = lookup_or_add (value_table, eprime);
- add (value_table, temp, v);
- insert_into_set (NEW_SETS (bprime), temp);
- value_insert_into_set (AVAIL_OUT (bprime),
- temp);
- avail[bprime->index] = temp;
+ if (insert_into_preds_of_block (block, node, avail,
+ "prephitmp"))
+ new_stuff = true;
+ }
+ /* If all edges produce the same value and that value is
+ an invariant, then the PHI has the same value on all
+ edges. Note this. */
+ else if (all_same && eprime
+ && is_gimple_min_invariant (eprime)
+ && !is_gimple_min_invariant (val))
+ {
+ value_set_t exprset = VALUE_HANDLE_EXPR_SET (val);
+ value_set_node_t node;
+ for (node = exprset->head; node; node = node->next)
+ {
+ if (TREE_CODE (node->expr) == SSA_NAME)
+ {
+ vn_add (node->expr, eprime, NULL);
+ pre_stats.constified++;
}
- }
- /* Now build a phi for the new variable. */
- temp = create_tmp_var (type, "prephitmp");
- add_referenced_tmp_var (temp);
- temp = create_phi_node (temp, block);
- add (value_table, PHI_RESULT (temp), val);
-
-#if 0
- if (!set_contains_value (AVAIL_OUT (block), val))
- insert_into_set (AVAIL_OUT (block),
- PHI_RESULT (temp));
- else
-#endif
- value_replace_in_set (AVAIL_OUT (block),
- PHI_RESULT (temp));
- for (pred = block->pred;
- pred;
- pred = pred->pred_next)
- {
- add_phi_arg (&temp, avail[pred->src->index],
- pred);
- }
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Created phi ");
- print_generic_expr (dump_file, temp, 0);
- fprintf (dump_file, " in block %d\n", block->index);
- }
- pre_stats.phis++;
- new_stuff = true;
- insert_into_set (NEW_SETS (block),
- PHI_RESULT (temp));
- insert_into_set (PHI_GEN (block),
- PHI_RESULT (temp));
+ }
}
-
free (avail);
}
}
bool new_stuff = true;
basic_block bb;
int num_iterations = 0;
-
+
FOR_ALL_BB (bb)
- NEW_SETS (bb) = set_new (true);
+ NEW_SETS (bb) = bitmap_set_new ();
while (new_stuff)
{
fprintf (dump_file, "insert required %d iterations\n", num_iterations);
}
-/* Return true if EXPR has no defining statement in this procedure,
- *AND* isn't a live-on-entry parameter. */
+
+/* Return true if VAR is an SSA variable with no defining statement in
+ this procedure, *AND* isn't a live-on-entry parameter. */
+
static bool
is_undefined_value (tree expr)
-{
-
-#ifdef ENABLE_CHECKING
- /* We should never be handed DECL's */
- if (DECL_P (expr))
- abort ();
-#endif
- if (TREE_CODE (expr) == SSA_NAME)
+{
+ return (TREE_CODE (expr) == SSA_NAME
+ && IS_EMPTY_STMT (SSA_NAME_DEF_STMT (expr))
+ /* PARM_DECLs and hard registers are always defined. */
+ && TREE_CODE (SSA_NAME_VAR (expr)) != PARM_DECL);
+}
+
+
+/* Given an SSA variable VAR and an expression EXPR, compute the value
+ number for EXPR and create a value handle (VAL) for it. If VAR and
+ EXPR are not the same, associate VAL with VAR. Finally, add VAR to
+ S1 and its value handle to S2.
+
+ VUSES represent the virtual use operands associated with EXPR (if
+ any). They are used when computing the hash value for EXPR. */
+
+static inline void
+add_to_sets (tree var, tree expr, vuse_optype vuses, bitmap_set_t s1,
+ bitmap_set_t s2)
+{
+ tree val = vn_lookup_or_add (expr, vuses);
+
+ /* VAR and EXPR may be the same when processing statements for which
+ we are not computing value numbers (e.g., non-assignments, or
+ statements that make aliased stores). In those cases, we are
+ only interested in making VAR available as its own value. */
+ if (var != expr)
+ vn_add (var, val, NULL);
+
+ if (s1)
+ bitmap_insert_into_set (s1, var);
+ bitmap_value_insert_into_set (s2, var);
+}
+
+
+/* Given a unary or binary expression EXPR, create and return a new
+ expression with the same structure as EXPR but with its operands
+ replaced with the value handles of each of the operands of EXPR.
+ Insert EXPR's operands into the EXP_GEN set for BLOCK.
+
+ VUSES represent the virtual use operands associated with EXPR (if
+ any). They are used when computing the hash value for EXPR. */
+
+static inline tree
+create_value_expr_from (tree expr, basic_block block, vuse_optype vuses)
+{
+ int i;
+ enum tree_code code = TREE_CODE (expr);
+ tree vexpr;
+
+ gcc_assert (TREE_CODE_CLASS (code) == tcc_unary
+ || TREE_CODE_CLASS (code) == tcc_binary
+ || TREE_CODE_CLASS (code) == tcc_reference);
+
+ if (TREE_CODE_CLASS (code) == tcc_unary)
+ vexpr = pool_alloc (unary_node_pool);
+ else if (TREE_CODE_CLASS (code) == tcc_reference)
+ vexpr = pool_alloc (reference_node_pool);
+ else
+ vexpr = pool_alloc (binary_node_pool);
+
+ memcpy (vexpr, expr, tree_size (expr));
+
+ for (i = 0; i < TREE_CODE_LENGTH (code); i++)
{
- /* XXX: Is this the correct test? */
- if (TREE_CODE (SSA_NAME_VAR (expr)) == PARM_DECL)
- return false;
- if (IS_EMPTY_STMT (SSA_NAME_DEF_STMT (expr)))
- return true;
+ tree op = TREE_OPERAND (expr, i);
+ if (op != NULL)
+ {
+ tree val = vn_lookup_or_add (op, vuses);
+ if (!is_undefined_value (op))
+ value_insert_into_set (EXP_GEN (block), op);
+ if (TREE_CODE (val) == VALUE_HANDLE)
+ TREE_TYPE (val) = TREE_TYPE (TREE_OPERAND (vexpr, i));
+ TREE_OPERAND (vexpr, i) = val;
+ }
}
- return false;
+
+ return vexpr;
}
-/* Compute the AVAIL set for BLOCK.
- This function performs value numbering of the statements in BLOCK.
- The AVAIL sets are built from information we glean while doing this
- value numbering, since the AVAIL sets contain only entry per
- value.
+/* Compute the AVAIL set for all basic blocks.
+
+ This function performs value numbering of the statements in each basic
+ block. The AVAIL sets are built from information we glean while doing
+ this value numbering, since the AVAIL sets contain only one entry per
+ value.
AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
- AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U
- TMP_GEN[BLOCK].
-*/
+ AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
static void
-compute_avail (basic_block block)
+compute_avail (void)
{
- basic_block son;
-
+ basic_block block, son;
+ basic_block *worklist;
+ size_t sp = 0;
+ tree param;
+
/* For arguments with default definitions, we pretend they are
defined in the entry block. */
- if (block == ENTRY_BLOCK_PTR)
+ for (param = DECL_ARGUMENTS (current_function_decl);
+ param;
+ param = TREE_CHAIN (param))
{
- tree param;
- for (param = DECL_ARGUMENTS (current_function_decl);
- param;
- param = TREE_CHAIN (param))
+ if (default_def (param) != NULL)
{
- if (default_def (param) != NULL)
- {
- tree val;
- tree def = default_def (param);
- val = lookup_or_add (value_table, def);
- insert_into_set (TMP_GEN (block), def);
- value_insert_into_set (AVAIL_OUT (block), def);
- }
+ tree val;
+ tree def = default_def (param);
+ val = vn_lookup_or_add (def, NULL);
+ bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), def);
+ bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), def);
}
}
- else if (block)
+
+ /* Allocate the worklist. */
+ worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
+
+ /* Seed the algorithm by putting the dominator children of the entry
+ block on the worklist. */
+ for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
+ son;
+ son = next_dom_son (CDI_DOMINATORS, son))
+ worklist[sp++] = son;
+
+ /* Loop until the worklist is empty. */
+ while (sp)
{
block_stmt_iterator bsi;
tree stmt, phi;
basic_block dom;
+ /* Pick a block from the worklist. */
+ block = worklist[--sp];
+
+ /* Initially, the set of available values in BLOCK is that of
+ its immediate dominator. */
dom = get_immediate_dominator (CDI_DOMINATORS, block);
if (dom)
- set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
- for (phi = phi_nodes (block); phi; phi = PHI_CHAIN (phi))
- {
- /* Ignore virtual PHIs until we can do PRE on expressions
- with virtual operands. */
- if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
- continue;
-
- lookup_or_add (value_table, PHI_RESULT (phi));
- value_insert_into_set (AVAIL_OUT (block), PHI_RESULT (phi));
- insert_into_set (PHI_GEN (block), PHI_RESULT (phi));
- }
+ bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
+ /* Generate values for PHI nodes. */
+ for (phi = phi_nodes (block); phi; phi = PHI_CHAIN (phi))
+ /* We have no need for virtual phis, as they don't represent
+ actual computations. */
+ if (is_gimple_reg (PHI_RESULT (phi)))
+ add_to_sets (PHI_RESULT (phi), PHI_RESULT (phi), NULL,
+ PHI_GEN (block), AVAIL_OUT (block));
+
+ /* Now compute value numbers and populate value sets with all
+ the expressions computed in BLOCK. */
for (bsi = bsi_start (block); !bsi_end_p (bsi); bsi_next (&bsi))
{
- tree op0, op1;
+ stmt_ann_t ann;
+ size_t j;
+
stmt = bsi_stmt (bsi);
+ ann = stmt_ann (stmt);
get_stmt_operands (stmt);
-
- if (NUM_VUSES (STMT_VUSE_OPS (stmt))
- || NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt))
- || NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt))
- || stmt_ann (stmt)->has_volatile_ops)
+
+ /* We are only interested in assignments of the form
+ X_i = EXPR, where EXPR represents an "interesting"
+ computation, it has no volatile operands and X_i
+ doesn't flow through an abnormal edge. */
+ if (TREE_CODE (stmt) == MODIFY_EXPR
+ && !ann->has_volatile_ops
+ && TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME
+ && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND (stmt, 0)))
{
- size_t j;
- for (j = 0; j < NUM_DEFS (STMT_DEF_OPS (stmt)); j++)
+ tree lhs = TREE_OPERAND (stmt, 0);
+ tree rhs = TREE_OPERAND (stmt, 1);
+ vuse_optype vuses = STMT_VUSE_OPS (stmt);
+
+ STRIP_USELESS_TYPE_CONVERSION (rhs);
+ if (TREE_CODE (rhs) == SSA_NAME
+ || is_gimple_min_invariant (rhs))
{
- tree def = DEF_OP (STMT_DEF_OPS (stmt), j);
- lookup_or_add (value_table, def);
- insert_into_set (TMP_GEN (block), def);
- value_insert_into_set (AVAIL_OUT (block), def);
- }
- for (j = 0; j < NUM_USES (STMT_USE_OPS (stmt)); j++)
+ /* Compute a value number for the RHS of the statement
+ and add its value to the AVAIL_OUT set for the block.
+ Add the LHS to TMP_GEN. */
+ add_to_sets (lhs, rhs, vuses, TMP_GEN (block),
+ AVAIL_OUT (block));
+
+ if (TREE_CODE (rhs) == SSA_NAME
+ && !is_undefined_value (rhs))
+ value_insert_into_set (EXP_GEN (block), rhs);
+ continue;
+ }
+ else if (UNARY_CLASS_P (rhs) || BINARY_CLASS_P (rhs)
+ || TREE_CODE (rhs) == INDIRECT_REF)
{
- tree use = USE_OP (STMT_USE_OPS (stmt), j);
- if (TREE_CODE (use) == SSA_NAME)
- {
- lookup_or_add (value_table, use);
- insert_into_set (TMP_GEN (block), use);
- value_insert_into_set (AVAIL_OUT (block), use);
- }
+ /* For binary, unary, and reference expressions,
+ create a duplicate expression with the operands
+ replaced with the value handles of the original
+ RHS. */
+ tree newt = create_value_expr_from (rhs, block, vuses);
+ add_to_sets (lhs, newt, vuses, TMP_GEN (block),
+ AVAIL_OUT (block));
+ value_insert_into_set (EXP_GEN (block), newt);
+ continue;
}
- continue;
}
- else if (TREE_CODE (stmt) == RETURN_EXPR
- && TREE_OPERAND (stmt, 0)
- && TREE_CODE (TREE_OPERAND (stmt, 0)) == MODIFY_EXPR)
- stmt = TREE_OPERAND (stmt, 0);
-
- if (TREE_CODE (stmt) == MODIFY_EXPR)
+
+ /* For any other statement that we don't recognize, simply
+ make the names generated by the statement available in
+ AVAIL_OUT and TMP_GEN. */
+ for (j = 0; j < NUM_DEFS (STMT_DEF_OPS (stmt)); j++)
{
- op0 = TREE_OPERAND (stmt, 0);
- if (TREE_CODE (op0) != SSA_NAME)
- continue;
- if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
- continue;
- op1 = TREE_OPERAND (stmt, 1);
- STRIP_USELESS_TYPE_CONVERSION (op1);
- if (TREE_CODE_CLASS (TREE_CODE (op1)) == 'c')
- {
- add (value_table, op0, lookup_or_add (value_table, op1));
- insert_into_set (TMP_GEN (block), op0);
- value_insert_into_set (AVAIL_OUT (block), op0);
- }
- else if (TREE_CODE_CLASS (TREE_CODE (op1)) == '2')
- {
- tree bop1, bop2;
- tree val, val1, val2;
- tree newt;
- bop1 = TREE_OPERAND (op1, 0);
- bop2 = TREE_OPERAND (op1, 1);
- val1 = lookup_or_add (value_table, bop1);
- val2 = lookup_or_add (value_table, bop2);
-
- newt = pool_alloc (binary_node_pool);
- memcpy (newt, op1, tree_size (op1));
- TREE_OPERAND (newt, 0) = val1;
- TREE_OPERAND (newt, 1) = val2;
- val = lookup_or_add (value_table, newt);
- add (value_table, op0, val);
- if (!is_undefined_value (bop1))
- value_insert_into_set (EXP_GEN (block), bop1);
- if (!is_undefined_value (bop2))
- value_insert_into_set (EXP_GEN (block), bop2);
- value_insert_into_set (EXP_GEN (block), newt);
- insert_into_set (TMP_GEN (block), op0);
- value_insert_into_set (AVAIL_OUT (block), op0);
- }
- else if (TREE_CODE_CLASS (TREE_CODE (op1)) == '1'
- && !is_gimple_cast (op1))
- {
- tree uop;
- tree val, val1;
- tree newt;
- uop = TREE_OPERAND (op1, 0);
- val1 = lookup_or_add (value_table, uop);
- newt = pool_alloc (unary_node_pool);
- memcpy (newt, op1, tree_size (op1));
- TREE_OPERAND (newt, 0) = val1;
- val = lookup_or_add (value_table, newt);
- add (value_table, op0, val);
- if (!is_undefined_value (uop))
- value_insert_into_set (EXP_GEN (block), uop);
- value_insert_into_set (EXP_GEN (block), newt);
- insert_into_set (TMP_GEN (block), op0);
- value_insert_into_set (AVAIL_OUT (block), op0);
- }
- else if (TREE_CODE (op1) == SSA_NAME)
- {
- tree val = lookup_or_add (value_table, op1);
- add (value_table, op0, val);
- if (!is_undefined_value (op1))
- value_insert_into_set (EXP_GEN (block), op1);
- insert_into_set (TMP_GEN (block), op0);
- value_insert_into_set (AVAIL_OUT (block), op0);
- }
- else
- {
- size_t j;
- for (j = 0; j < NUM_DEFS (STMT_DEF_OPS (stmt)); j++)
- {
- tree def = DEF_OP (STMT_DEF_OPS (stmt), j);
- lookup_or_add (value_table, def);
- insert_into_set (TMP_GEN (block), def);
- value_insert_into_set (AVAIL_OUT (block), def);
- if (def != op0)
- abort ();
- }
- for (j = 0; j < NUM_USES (STMT_USE_OPS (stmt)); j++)
- {
- tree use = USE_OP (STMT_USE_OPS (stmt), j);
- if (TREE_CODE (use) == SSA_NAME)
- {
- lookup_or_add (value_table, use);
- insert_into_set (TMP_GEN (block), use);
- value_insert_into_set (AVAIL_OUT (block), use);
- }
- }
- }
+ tree def = DEF_OP (STMT_DEF_OPS (stmt), j);
+ add_to_sets (def, def, NULL, TMP_GEN (block),
+ AVAIL_OUT (block));
}
- else
+
+ for (j = 0; j < NUM_USES (STMT_USE_OPS (stmt)); j++)
{
- size_t j;
- for (j = 0; j < NUM_DEFS (STMT_DEF_OPS (stmt)); j++)
- {
- tree def = DEF_OP (STMT_DEF_OPS (stmt), j);
- lookup_or_add (value_table, def);
- insert_into_set (TMP_GEN (block), def);
- value_insert_into_set (AVAIL_OUT (block), def);
- }
- for (j = 0; j < NUM_USES (STMT_USE_OPS (stmt)); j++)
- {
- tree use = USE_OP (STMT_USE_OPS (stmt), j);
- if (TREE_CODE (use) == SSA_NAME)
- {
- lookup_or_add (value_table, use);
- insert_into_set (TMP_GEN (block), use);
- value_insert_into_set (AVAIL_OUT (block), use);
- }
- }
+ tree use = USE_OP (STMT_USE_OPS (stmt), j);
+ add_to_sets (use, use, NULL, NULL, AVAIL_OUT (block));
}
}
+
+ /* Put the dominator children of BLOCK on the worklist of blocks
+ to compute available sets for. */
+ for (son = first_dom_son (CDI_DOMINATORS, block);
+ son;
+ son = next_dom_son (CDI_DOMINATORS, son))
+ worklist[sp++] = son;
}
- for (son = first_dom_son (CDI_DOMINATORS, block);
- son;
- son = next_dom_son (CDI_DOMINATORS, son))
- compute_avail (son);
+ free (worklist);
}
+
/* Eliminate fully redundant computations. */
static void
{
tree stmt = bsi_stmt (i);
- if (NUM_VUSES (STMT_VUSE_OPS (stmt))
- || NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt))
- || NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt))
- || stmt_ann (stmt)->has_volatile_ops)
- continue;
- /* Lookup the RHS of the expression, see if we have an
- available computation for it. If so, replace the RHS with
+ /* Lookup the RHS of the expression, see if we have an
+ available computation for it. If so, replace the RHS with
the available computation. */
- if (TREE_CODE (stmt) == MODIFY_EXPR)
- {
- tree t = TREE_OPERAND (stmt, 0);
- tree expr = TREE_OPERAND (stmt, 1);
- tree sprime;
- /* There is no point in eliminating NOP_EXPR, it isn't
- supposed to generate any code. */
- if (TREE_CODE (expr) == NOP_EXPR
- || (TREE_CODE_CLASS (TREE_CODE (expr)) != '2'
- && TREE_CODE_CLASS (TREE_CODE (expr)) != '1'))
- continue;
- sprime = find_leader (AVAIL_OUT (b),
- lookup (value_table, t));
- if (sprime
- && sprime != t
- && may_propagate_copy (sprime, TREE_OPERAND (stmt, 1)))
- {
+ if (TREE_CODE (stmt) == MODIFY_EXPR
+ && TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME
+ && TREE_CODE (TREE_OPERAND (stmt ,1)) != SSA_NAME
+ && !is_gimple_min_invariant (TREE_OPERAND (stmt, 1))
+ && !stmt_ann (stmt)->has_volatile_ops)
+ {
+ tree lhs = TREE_OPERAND (stmt, 0);
+ tree *rhs_p = &TREE_OPERAND (stmt, 1);
+ tree sprime;
+
+ sprime = bitmap_find_leader (AVAIL_OUT (b),
+ vn_lookup (lhs, NULL));
+ if (sprime
+ && sprime != lhs
+ && (TREE_CODE (*rhs_p) != SSA_NAME
+ || may_propagate_copy (*rhs_p, sprime)))
+ {
+ gcc_assert (sprime != *rhs_p);
+
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Replaced ");
- print_generic_expr (dump_file, expr, 0);
+ print_generic_expr (dump_file, *rhs_p, 0);
fprintf (dump_file, " with ");
print_generic_expr (dump_file, sprime, 0);
fprintf (dump_file, " in ");
print_generic_stmt (dump_file, stmt, 0);
}
+ if (TREE_CODE (sprime) == SSA_NAME)
+ NECESSARY (SSA_NAME_DEF_STMT (sprime)) = 1;
pre_stats.eliminations++;
- propagate_value (&TREE_OPERAND (stmt, 1), sprime);
- modify_stmt (stmt);
- }
- }
+ propagate_tree_value (rhs_p, sprime);
+ modify_stmt (stmt);
+ /* If we removed EH side effects from the statement, clean
+ its EH information. */
+ if (maybe_clean_eh_stmt (stmt))
+ {
+ bitmap_set_bit (need_eh_cleanup,
+ bb_for_stmt (stmt)->index);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " Removed EH side effects.\n");
+ }
+ }
+ }
}
}
}
-/* Main entry point to the SSA-PRE pass.
+/* Borrow a bit of tree-ssa-dce.c for the moment.
+ XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
+ this may be a bit faster, and we may want critical edges kept split. */
+
+/* If OP's defining statement has not already been determined to be necessary,
+ mark that statement necessary. and place it on the WORKLIST. */
+
+static inline void
+mark_operand_necessary (tree op, VEC(tree_on_heap) **worklist)
+{
+ tree stmt;
+ int ver;
+
+ gcc_assert (op);
+
+ ver = SSA_NAME_VERSION (op);
+
+ stmt = SSA_NAME_DEF_STMT (op);
+ gcc_assert (stmt);
+
+ if (NECESSARY (stmt)
+ || IS_EMPTY_STMT (stmt))
+ return;
+
+ NECESSARY (stmt) = 1;
+ VEC_safe_push (tree_on_heap, *worklist, stmt);
+}
+
+/* Because we don't follow exactly the standard PRE algorithm, and decide not
+ to insert PHI nodes sometimes, and because value numbering of casts isn't
+ perfect, we sometimes end up inserting dead code. This simple DCE-like
+ pass removes any insertions we made that weren't actually used. */
- PHASE indicates which dump file from the DUMP_FILES array to use when
- dumping debugging information. */
+static void
+remove_dead_inserted_code (void)
+{
+ VEC (tree_on_heap) *worklist = NULL;
+ int i;
+ tree t;
+
+ for (i = 0; VEC_iterate (tree_on_heap, inserted_exprs, i, t); i++)
+ {
+ if (NECESSARY (t))
+ VEC_safe_push (tree_on_heap, worklist, t);
+ }
+ while (VEC_length (tree_on_heap, worklist) > 0)
+ {
+ t = VEC_pop (tree_on_heap, worklist);
+ if (TREE_CODE (t) == PHI_NODE)
+ {
+ /* PHI nodes are somewhat special in that each PHI alternative has
+ data and control dependencies. All the statements feeding the
+ PHI node's arguments are always necessary. In aggressive mode,
+ we also consider the control dependent edges leading to the
+ predecessor block associated with each PHI alternative as
+ necessary. */
+ int k;
+ for (k = 0; k < PHI_NUM_ARGS (t); k++)
+ {
+ tree arg = PHI_ARG_DEF (t, k);
+ if (TREE_CODE (arg) == SSA_NAME)
+ mark_operand_necessary (arg, &worklist);
+ }
+ }
+ else
+ {
+ /* Propagate through the operands. Examine all the USE, VUSE and
+ V_MAY_DEF operands in this statement. Mark all the statements
+ which feed this statement's uses as necessary. */
+ ssa_op_iter iter;
+ tree use;
+
+ get_stmt_operands (t);
+
+ /* The operands of V_MAY_DEF expressions are also needed as they
+ represent potential definitions that may reach this
+ statement (V_MAY_DEF operands allow us to follow def-def
+ links). */
+
+ FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
+ mark_operand_necessary (use, &worklist);
+ }
+ }
+ for (i = 0; VEC_iterate (tree_on_heap, inserted_exprs, i, t); i++)
+ {
+ if (!NECESSARY (t))
+ {
+ block_stmt_iterator bsi;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Removing unnecessary insertion:");
+ print_generic_stmt (dump_file, t, 0);
+ }
+ if (TREE_CODE (t) == PHI_NODE)
+ {
+ remove_phi_node (t, NULL);
+ }
+ else
+ {
+ bsi = bsi_for_stmt (t);
+ bsi_remove (&bsi);
+ }
+ }
+ }
+ VEC_free (tree_on_heap, worklist);
+}
+/* Initialize data structures used by PRE. */
static void
-execute_pre (void)
+init_pre (bool do_fre)
{
- size_t tsize;
basic_block bb;
- pre_uid = num_referenced_vars;
+
+ inserted_exprs = NULL;
+ vn_init ();
+ if (!do_fre)
+ current_loops = loop_optimizer_init (dump_file);
+ connect_infinite_loops_to_exit ();
memset (&pre_stats, 0, sizeof (pre_stats));
+
+ /* If block 0 has more than one predecessor, it means that its PHI
+ nodes will have arguments coming from block -1. This creates
+ problems for several places in PRE that keep local arrays indexed
+ by block number. To prevent this, we split the edge coming from
+ ENTRY_BLOCK_PTR (FIXME, if ENTRY_BLOCK_PTR had an index number
+ different than -1 we wouldn't have to hack this. tree-ssa-dce.c
+ needs a similar change). */
+ if (EDGE_COUNT (EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest->preds) > 1)
+ if (!(EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->flags & EDGE_ABNORMAL))
+ split_edge (EDGE_SUCC (ENTRY_BLOCK_PTR, 0));
+
FOR_ALL_BB (bb)
- {
- bb->aux = xcalloc (1, sizeof (struct bb_value_sets));
- }
+ bb->aux = xcalloc (1, sizeof (struct bb_value_sets));
+
+ bitmap_obstack_initialize (&grand_bitmap_obstack);
phi_translate_table = htab_create (511, expr_pred_trans_hash,
- expr_pred_trans_eq,
- free);
- value_table = htab_create (511, val_expr_pair_hash,
- val_expr_pair_expr_eq, free);
+ expr_pred_trans_eq, free);
value_set_pool = create_alloc_pool ("Value sets",
sizeof (struct value_set), 30);
+ bitmap_set_pool = create_alloc_pool ("Bitmap sets",
+ sizeof (struct bitmap_set), 30);
value_set_node_pool = create_alloc_pool ("Value set nodes",
- sizeof (struct value_set_node), 30);
+ sizeof (struct value_set_node), 30);
calculate_dominance_info (CDI_POST_DOMINATORS);
calculate_dominance_info (CDI_DOMINATORS);
- tsize = tree_size (build (PLUS_EXPR, void_type_node, NULL_TREE,
- NULL_TREE));
- binary_node_pool = create_alloc_pool ("Binary tree nodes", tsize, 30);
- tsize = tree_size (build1 (NEGATE_EXPR, void_type_node, NULL_TREE));
- unary_node_pool = create_alloc_pool ("Unary tree nodes", tsize, 30);
-
+ binary_node_pool = create_alloc_pool ("Binary tree nodes",
+ tree_code_size (PLUS_EXPR), 30);
+ unary_node_pool = create_alloc_pool ("Unary tree nodes",
+ tree_code_size (NEGATE_EXPR), 30);
+ reference_node_pool = create_alloc_pool ("Reference tree nodes",
+ tree_code_size (ARRAY_REF), 30);
FOR_ALL_BB (bb)
{
EXP_GEN (bb) = set_new (true);
- PHI_GEN (bb) = set_new (true);
- TMP_GEN (bb) = set_new (false);
- AVAIL_OUT (bb) = set_new (true);
+ PHI_GEN (bb) = bitmap_set_new ();
+ TMP_GEN (bb) = bitmap_set_new ();
+ AVAIL_OUT (bb) = bitmap_set_new ();
}
- compute_avail (ENTRY_BLOCK_PTR);
+ need_eh_cleanup = BITMAP_ALLOC (NULL);
+}
+
+
+/* Deallocate data structures used by PRE. */
+
+static void
+fini_pre (bool do_fre)
+{
+ basic_block bb;
+ unsigned int i;
+
+ VEC_free (tree_on_heap, inserted_exprs);
+ bitmap_obstack_release (&grand_bitmap_obstack);
+ free_alloc_pool (value_set_pool);
+ free_alloc_pool (bitmap_set_pool);
+ free_alloc_pool (value_set_node_pool);
+ free_alloc_pool (binary_node_pool);
+ free_alloc_pool (reference_node_pool);
+ free_alloc_pool (unary_node_pool);
+ htab_delete (phi_translate_table);
+ remove_fake_exit_edges ();
+
+ FOR_ALL_BB (bb)
+ {
+ free (bb->aux);
+ bb->aux = NULL;
+ }
+
+ free_dominance_info (CDI_POST_DOMINATORS);
+ vn_delete ();
+
+ if (!bitmap_empty_p (need_eh_cleanup))
+ {
+ tree_purge_all_dead_eh_edges (need_eh_cleanup);
+ cleanup_tree_cfg ();
+ }
+
+ BITMAP_FREE (need_eh_cleanup);
+
+ /* Wipe out pointers to VALUE_HANDLEs. In the not terribly distant
+ future we will want them to be persistent though. */
+ for (i = 0; i < num_ssa_names; i++)
+ {
+ tree name = ssa_name (i);
+
+ if (!name)
+ continue;
+
+ if (SSA_NAME_VALUE (name)
+ && TREE_CODE (SSA_NAME_VALUE (name)) == VALUE_HANDLE)
+ SSA_NAME_VALUE (name) = NULL;
+ }
+ if (!do_fre && current_loops)
+ {
+ loop_optimizer_finalize (current_loops, dump_file);
+ current_loops = NULL;
+ }
+}
+
+
+/* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
+ only wants to do full redundancy elimination. */
+
+static void
+execute_pre (bool do_fre)
+{
+ init_pre (do_fre);
+
+ /* Collect and value number expressions computed in each basic block. */
+ compute_avail ();
if (dump_file && (dump_flags & TDF_DETAILS))
{
+ basic_block bb;
+
FOR_ALL_BB (bb)
{
print_value_set (dump_file, EXP_GEN (bb), "exp_gen", bb->index);
- print_value_set (dump_file, TMP_GEN (bb), "tmp_gen", bb->index);
- print_value_set (dump_file, AVAIL_OUT (bb), "avail_out", bb->index);
+ bitmap_print_value_set (dump_file, TMP_GEN (bb), "tmp_gen",
+ bb->index);
+ bitmap_print_value_set (dump_file, AVAIL_OUT (bb), "avail_out",
+ bb->index);
}
}
fixed, don't run it when he have an incredibly large number of
bb's. If we aren't going to run insert, there is no point in
computing ANTIC, either, even though it's plenty fast. */
-
- if (n_basic_blocks < 4000)
+ if (!do_fre && n_basic_blocks < 4000)
{
compute_antic ();
-
insert ();
}
+
+ /* Remove all the redundant expressions. */
eliminate ();
-
+
+
if (dump_file && (dump_flags & TDF_STATS))
{
fprintf (dump_file, "Insertions:%d\n", pre_stats.insertions);
fprintf (dump_file, "New PHIs:%d\n", pre_stats.phis);
fprintf (dump_file, "Eliminated:%d\n", pre_stats.eliminations);
+ fprintf (dump_file, "Constified:%d\n", pre_stats.constified);
}
-
- free_alloc_pool (value_set_pool);
- free_alloc_pool (value_set_node_pool);
- free_alloc_pool (binary_node_pool);
- free_alloc_pool (unary_node_pool);
- htab_delete (value_table);
- htab_delete (phi_translate_table);
- FOR_ALL_BB (bb)
- {
- free (bb->aux);
- bb->aux = NULL;
- }
- free_dominance_info (CDI_POST_DOMINATORS);
+ bsi_commit_edge_inserts ();
+ if (!do_fre)
+ remove_dead_inserted_code ();
+ fini_pre (do_fre);
+
+}
+
+
+/* Gate and execute functions for PRE. */
+
+static void
+do_pre (void)
+{
+ execute_pre (false);
}
static bool
{
"pre", /* name */
gate_pre, /* gate */
- execute_pre, /* execute */
+ do_pre, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_TREE_PRE, /* tv_id */
- PROP_no_crit_edges | PROP_cfg | PROP_ssa,/* properties_required */
+ PROP_no_crit_edges | PROP_cfg
+ | PROP_ssa | PROP_alias, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
+ 0 /* letter */
+};
+
+
+/* Gate and execute functions for FRE. */
+
+static void
+do_fre (void)
+{
+ execute_pre (true);
+}
+
+static bool
+gate_fre (void)
+{
+ return flag_tree_fre != 0;
+}
+
+struct tree_opt_pass pass_fre =
+{
+ "fre", /* name */
+ gate_fre, /* gate */
+ do_fre, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_FRE, /* tv_id */
+ PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */
+ TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
+ 0 /* letter */
};
OSDN Git Service
