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gnu / gcc / cd99b30c7cf1e68ef76ed2af7a41ac74c78116fe / . / gcc / tree-ssa-pre.c
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/* SSA-PRE for trees.
Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
<stevenb@suse.de>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "ggc.h"
#include "tree.h"
#include "basic-block.h"
#include "diagnostic.h"
#include "tree-inline.h"
#include "tree-flow.h"
#include "gimple.h"
#include "tree-dump.h"
#include "timevar.h"
#include "fibheap.h"
#include "hashtab.h"
#include "tree-iterator.h"
#include "real.h"
#include "alloc-pool.h"
#include "obstack.h"
#include "tree-pass.h"
#include "flags.h"
#include "bitmap.h"
#include "langhooks.h"
#include "cfgloop.h"
#include "tree-ssa-sccvn.h"
#include "params.h"
#include "dbgcnt.h"
/* TODO:
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.
2. Strength reduction can be performed by anticipating expressions
we can repair later on.
3. 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
every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
represent the actual statement containing the expressions we care about,
and we cache the value number by putting it in the expression. */
/* Basic algorithm
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. 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.
An expression is partially redundant (excluding partial
anticipation) if:
1. It is AVAIL in some, but not all, of the predecessors of a
given block.
2. It is ANTIC in all the predecessors.
In order to make it fully redundant, we insert the expression into
the predecessors where it is not available, but is ANTIC.
For the partial anticipation case, we only perform insertion if it
is partially anticipated in some block, and fully available in all
of the predecessors.
insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
performs these steps.
Fourth, we eliminate fully redundant expressions.
This is a simple statement walk that replaces redundant
calculations with the now available values. */
/* Representations of value numbers:
Value numbers are represented by a representative SSA_NAME. We
will create fake SSA_NAME's in situations where we need a
representative but do not have one (because it is a complex
expression). In order to facilitate storing the value numbers in
bitmaps, and keep the number of wasted SSA_NAME's down, we also
associate a value_id with each value number, and create full blown
ssa_name's only where we actually need them (IE in operands of
existing expressions).
Theoretically you could replace all the value_id's with
SSA_NAME_VERSION, but this would allocate a large number of
SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
It would also require an additional indirection at each point we
use the value id. */
/* Representation of expressions on value numbers:
Expressions consisting of value numbers are represented the same
way as our VN internally represents them, with an additional
"pre_expr" wrapping around them in order to facilitate storing all
of the expressions in the same sets. */
/* Representation of sets:
The dataflow sets do not need to be sorted in any particular order
for the majority of their lifetime, 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.
When we need them in topological order, we produce it on demand by
transforming the bitmap into an array and sorting it into topo
order. */
/* Type of expression, used to know which member of the PRE_EXPR union
is valid. */
enum pre_expr_kind
{
NAME,
NARY,
REFERENCE,
CONSTANT
};
typedef union pre_expr_union_d
{
tree name;
tree constant;
vn_nary_op_t nary;
vn_reference_t reference;
} pre_expr_union;
typedef struct pre_expr_d
{
enum pre_expr_kind kind;
unsigned int id;
pre_expr_union u;
} *pre_expr;
#define PRE_EXPR_NAME(e) (e)->u.name
#define PRE_EXPR_NARY(e) (e)->u.nary
#define PRE_EXPR_REFERENCE(e) (e)->u.reference
#define PRE_EXPR_CONSTANT(e) (e)->u.constant
static int
pre_expr_eq (const void *p1, const void *p2)
{
const struct pre_expr_d *e1 = (const struct pre_expr_d *) p1;
const struct pre_expr_d *e2 = (const struct pre_expr_d *) p2;
if (e1->kind != e2->kind)
return false;
switch (e1->kind)
{
case CONSTANT:
return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1),
PRE_EXPR_CONSTANT (e2));
case NAME:
return PRE_EXPR_NAME (e1) == PRE_EXPR_NAME (e2);
case NARY:
return vn_nary_op_eq (PRE_EXPR_NARY (e1), PRE_EXPR_NARY (e2));
case REFERENCE:
return vn_reference_eq (PRE_EXPR_REFERENCE (e1),
PRE_EXPR_REFERENCE (e2));
default:
abort();
}
}
static hashval_t
pre_expr_hash (const void *p1)
{
const struct pre_expr_d *e = (const struct pre_expr_d *) p1;
switch (e->kind)
{
case CONSTANT:
return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
case NAME:
return iterative_hash_hashval_t (SSA_NAME_VERSION (PRE_EXPR_NAME (e)), 0);
case NARY:
return PRE_EXPR_NARY (e)->hashcode;
case REFERENCE:
return PRE_EXPR_REFERENCE (e)->hashcode;
default:
abort ();
}
}
/* Next global expression id number. */
static unsigned int next_expression_id;
/* Mapping from expression to id number we can use in bitmap sets. */
DEF_VEC_P (pre_expr);
DEF_VEC_ALLOC_P (pre_expr, heap);
static VEC(pre_expr, heap) *expressions;
static htab_t expression_to_id;
/* Allocate an expression id for EXPR. */
static inline unsigned int
alloc_expression_id (pre_expr expr)
{
void **slot;
/* Make sure we won't overflow. */
gcc_assert (next_expression_id + 1 > next_expression_id);
expr->id = next_expression_id++;
VEC_safe_push (pre_expr, heap, expressions, expr);
slot = htab_find_slot (expression_to_id, expr, INSERT);
gcc_assert (!*slot);
*slot = expr;
return next_expression_id - 1;
}
/* Return the expression id for tree EXPR. */
static inline unsigned int
get_expression_id (const pre_expr expr)
{
return expr->id;
}
static inline unsigned int
lookup_expression_id (const pre_expr expr)
{
void **slot;
slot = htab_find_slot (expression_to_id, expr, NO_INSERT);
if (!slot)
return 0;
return ((pre_expr)*slot)->id;
}
/* Return the existing expression id for EXPR, or create one if one
does not exist yet. */
static inline unsigned int
get_or_alloc_expression_id (pre_expr expr)
{
unsigned int id = lookup_expression_id (expr);
if (id == 0)
return alloc_expression_id (expr);
return expr->id = id;
}
/* Return the expression that has expression id ID */
static inline pre_expr
expression_for_id (unsigned int id)
{
return VEC_index (pre_expr, expressions, id);
}
/* Free the expression id field in all of our expressions,
and then destroy the expressions array. */
static void
clear_expression_ids (void)
{
VEC_free (pre_expr, heap, expressions);
}
static alloc_pool pre_expr_pool;
/* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
static pre_expr
get_or_alloc_expr_for_name (tree name)
{
pre_expr result = (pre_expr) pool_alloc (pre_expr_pool);
unsigned int result_id;
result->kind = NAME;
result->id = 0;
PRE_EXPR_NAME (result) = name;
result_id = lookup_expression_id (result);
if (result_id != 0)
{
pool_free (pre_expr_pool, result);
result = expression_for_id (result_id);
return result;
}
get_or_alloc_expression_id (result);
return result;
}
static bool in_fre = false;
/* An unordered bitmap set. One bitmap tracks values, the other,
expressions. */
typedef struct bitmap_set
{
bitmap expressions;
bitmap values;
} *bitmap_set_t;
#define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
#define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
/* Mapping from value id to expressions with that value_id. */
DEF_VEC_P (bitmap_set_t);
DEF_VEC_ALLOC_P (bitmap_set_t, heap);
static VEC(bitmap_set_t, heap) *value_expressions;
/* Sets that we need to keep track of. */
typedef struct bb_bitmap_sets
{
/* The EXP_GEN set, which represents expressions/values generated in
a basic block. */
bitmap_set_t exp_gen;
/* The PHI_GEN set, which represents PHI results generated in a
basic block. */
bitmap_set_t phi_gen;
/* The TMP_GEN set, which represents results/temporaries generated
in a basic block. IE the LHS of an expression. */
bitmap_set_t tmp_gen;
/* The AVAIL_OUT set, which represents which values are available in
a given basic block. */
bitmap_set_t avail_out;
/* The ANTIC_IN set, which represents which values are anticipatable
in a given basic block. */
bitmap_set_t antic_in;
/* The PA_IN set, which represents which values are
partially anticipatable in a given basic block. */
bitmap_set_t pa_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. */
bitmap_set_t new_sets;
/* True if we have visited this block during ANTIC calculation. */
unsigned int visited:1;
/* True we have deferred processing this block during ANTIC
calculation until its successor is processed. */
unsigned int deferred : 1;
} *bb_value_sets_t;
#define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
#define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
#define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
#define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
#define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
#define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
#define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
#define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
#define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
/* Basic block list in postorder. */
static int *postorder;
/* 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 inserts found due to partial anticipation */
int pa_insert;
/* The number of new PHI nodes added by PRE. */
int phis;
/* The number of values found constant. */
int constified;
} pre_stats;
static bool do_partial_partial;
static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int, gimple);
static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr, bool);
static bitmap_set_t bitmap_set_new (void);
static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
gimple, tree);
static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
gimple);
static unsigned int get_expr_value_id (pre_expr);
/* 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 bitmap_set_pool;
static bitmap_obstack grand_bitmap_obstack;
/* To avoid adding 300 temporary variables when we only need one, we
only create one temporary variable, on demand, and build ssa names
off that. We do have to change the variable if the types don't
match the current variable's type. */
static tree pretemp;
static tree storetemp;
static tree prephitemp;
/* Set of blocks with statements that have had its EH information
cleaned up. */
static bitmap need_eh_cleanup;
/* Which expressions have been seen during a given phi translation. */
static bitmap seen_during_translate;
/* The phi_translate_table caches phi translations for a given
expression and predecessor. */
static htab_t phi_translate_table;
/* A three tuple {e, pred, v} used to cache phi translations in the
phi_translate_table. */
typedef struct expr_pred_trans_d
{
/* The expression. */
pre_expr e;
/* The predecessor block along which we translated the expression. */
basic_block pred;
/* The value that resulted from the translation. */
pre_expr v;
/* The hashcode for the expression, pred pair. This is cached for
speed reasons. */
hashval_t hashcode;
} *expr_pred_trans_t;
typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;
/* Return the hash value for a phi translation table entry. */
static hashval_t
expr_pred_trans_hash (const void *p)
{
const_expr_pred_trans_t const ve = (const_expr_pred_trans_t) p;
return ve->hashcode;
}
/* 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 const ve1 = (const_expr_pred_trans_t) p1;
const_expr_pred_trans_t const ve2 = (const_expr_pred_trans_t) p2;
basic_block b1 = ve1->pred;
basic_block b2 = ve2->pred;
/* If they are not translations for the same basic block, they can't
be equal. */
if (b1 != b2)
return false;
return pre_expr_eq (ve1->e, ve2->e);
}
/* 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 pre_expr
phi_trans_lookup (pre_expr e, basic_block pred)
{
void **slot;
struct expr_pred_trans_d ept;
ept.e = e;
ept.pred = pred;
ept.hashcode = iterative_hash_hashval_t (pre_expr_hash (e), pred->index);
slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
NO_INSERT);
if (!slot)
return NULL;
else
return ((expr_pred_trans_t) *slot)->v;
}
/* Add the tuple mapping from {expression E, basic block PRED} to
value V, to the phi translation table. */
static inline void
phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
{
void **slot;
expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
new_pair->e = e;
new_pair->pred = pred;
new_pair->v = v;
new_pair->hashcode = iterative_hash_hashval_t (pre_expr_hash (e),
pred->index);
slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
new_pair->hashcode, INSERT);
if (*slot)
free (*slot);
*slot = (void *) new_pair;
}
/* Add expression E to the expression set of value id V. */
void
add_to_value (unsigned int v, pre_expr e)
{
bitmap_set_t set;
gcc_assert (get_expr_value_id (e) == v);
if (v >= VEC_length (bitmap_set_t, value_expressions))
{
VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
v + 1);
}
set = VEC_index (bitmap_set_t, value_expressions, v);
if (!set)
{
set = bitmap_set_new ();
VEC_replace (bitmap_set_t, value_expressions, v, set);
}
bitmap_insert_into_set_1 (set, e, true);
}
/* Create a new bitmap set and return it. */
static bitmap_set_t
bitmap_set_new (void)
{
bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
ret->expressions = BITMAP_ALLOC (&grand_bitmap_obstack);
ret->values = BITMAP_ALLOC (&grand_bitmap_obstack);
return ret;
}
/* Return the value id for a PRE expression EXPR. */
static unsigned int
get_expr_value_id (pre_expr expr)
{
switch (expr->kind)
{
case CONSTANT:
{
unsigned int id;
id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
if (id == 0)
{
id = get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr));
add_to_value (id, expr);
}
return id;
}
case NAME:
return VN_INFO (PRE_EXPR_NAME (expr))->value_id;
case NARY:
return PRE_EXPR_NARY (expr)->value_id;
case REFERENCE:
return PRE_EXPR_REFERENCE (expr)->value_id;
default:
gcc_unreachable ();
}
}
/* Remove an expression EXPR from a bitmapped set. */
static void
bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
{
unsigned int val = get_expr_value_id (expr);
if (!value_id_constant_p (val))
{
bitmap_clear_bit (set->values, val);
bitmap_clear_bit (set->expressions, get_expression_id (expr));
}
}
static void
bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
bool allow_constants)
{
unsigned int val = get_expr_value_id (expr);
if (allow_constants || !value_id_constant_p (val))
{
/* We specifically expect this and only this function to be able to
insert constants into a set. */
bitmap_set_bit (set->values, val);
bitmap_set_bit (set->expressions, get_or_alloc_expression_id (expr));
}
}
/* Insert an expression EXPR into a bitmapped set. */
static void
bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
{
bitmap_insert_into_set_1 (set, expr, false);
}
/* 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);
}
/* Free memory used up by SET. */
static void
bitmap_set_free (bitmap_set_t set)
{
BITMAP_FREE (set->expressions);
BITMAP_FREE (set->values);
}
/* Generate an topological-ordered array of bitmap set SET. */
static VEC(pre_expr, heap) *
sorted_array_from_bitmap_set (bitmap_set_t set)
{
unsigned int i, j;
bitmap_iterator bi, bj;
VEC(pre_expr, heap) *result = NULL;
FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
{
/* The number of expressions having a given value is usually
relatively small. Thus, rather than making a vector of all
the expressions and sorting it by value-id, we walk the values
and check in the reverse mapping that tells us what expressions
have a given value, to filter those in our set. As a result,
the expressions are inserted in value-id order, which means
topological order.
If this is somehow a significant lose for some cases, we can
choose which set to walk based on the set size. */
bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
{
if (bitmap_bit_p (set->expressions, j))
VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
}
}
return result;
}
/* Perform bitmapped set operation DEST &= ORIG. */
static void
bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
{
bitmap_iterator bi;
unsigned int i;
if (dest != orig)
{
bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
bitmap_and_into (dest->values, orig->values);
bitmap_copy (temp, dest->expressions);
EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
{
pre_expr expr = expression_for_id (i);
unsigned int value_id = get_expr_value_id (expr);
if (!bitmap_bit_p (dest->values, value_id))
bitmap_clear_bit (dest->expressions, i);
}
BITMAP_FREE (temp);
}
}
/* Subtract all values and expressions contained in ORIG from DEST. */
static bitmap_set_t
bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
{
bitmap_set_t result = bitmap_set_new ();
bitmap_iterator bi;
unsigned int i;
bitmap_and_compl (result->expressions, dest->expressions,
orig->expressions);
FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
{
pre_expr expr = expression_for_id (i);
unsigned int value_id = get_expr_value_id (expr);
bitmap_set_bit (result->values, value_id);
}
return result;
}
/* Subtract all the values in bitmap set B from bitmap set A. */
static void
bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
{
unsigned int i;
bitmap_iterator bi;
bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
bitmap_copy (temp, a->expressions);
EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
{
pre_expr expr = expression_for_id (i);
if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
bitmap_remove_from_set (a, expr);
}
BITMAP_FREE (temp);
}
/* Return true if bitmapped set SET contains the value VALUE_ID. */
static bool
bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
{
if (value_id_constant_p (value_id))
return true;
if (!set || bitmap_empty_p (set->expressions))
return false;
return bitmap_bit_p (set->values, value_id);
}
static inline bool
bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
{
return bitmap_bit_p (set->expressions, get_expression_id (expr));
}
/* Replace an instance of value LOOKFOR with expression EXPR in SET. */
static void
bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
const pre_expr expr)
{
bitmap_set_t exprset;
unsigned int i;
bitmap_iterator bi;
if (value_id_constant_p (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 = VEC_index (bitmap_set_t, value_expressions, lookfor);
FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
{
if (bitmap_bit_p (set->expressions, i))
{
bitmap_clear_bit (set->expressions, i);
bitmap_set_bit (set->expressions, get_expression_id (expr));
return;
}
}
}
/* Return true if two bitmap sets are equal. */
static bool
bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
{
return bitmap_equal_p (a->values, b->values);
}
/* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
and add it otherwise. */
static void
bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
{
unsigned int val = get_expr_value_id (expr);
if (bitmap_set_contains_value (set, val))
bitmap_set_replace_value (set, val, expr);
else
bitmap_insert_into_set (set, expr);
}
/* 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, pre_expr expr)
{
unsigned int val = get_expr_value_id (expr);
if (value_id_constant_p (val))
return;
if (!bitmap_set_contains_value (set, val))
bitmap_insert_into_set (set, expr);
}
/* Print out EXPR to outfile. */
static void
print_pre_expr (FILE *outfile, const pre_expr expr)
{
switch (expr->kind)
{
case CONSTANT:
print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
break;
case NAME:
print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
break;
case NARY:
{
unsigned int i;
vn_nary_op_t nary = PRE_EXPR_NARY (expr);
fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
for (i = 0; i < nary->length; i++)
{
print_generic_expr (outfile, nary->op[i], 0);
if (i != (unsigned) nary->length - 1)
fprintf (outfile, ",");
}
fprintf (outfile, "}");
}
break;
case REFERENCE:
{
vn_reference_op_t vro;
unsigned int i;
vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
fprintf (outfile, "{");
for (i = 0;
VEC_iterate (vn_reference_op_s, ref->operands, i, vro);
i++)
{
if (vro->opcode != SSA_NAME
&& TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
fprintf (outfile, "%s ", tree_code_name [vro->opcode]);
if (vro->op0)
{
if (vro->op1)
fprintf (outfile, "<");
print_generic_expr (outfile, vro->op0, 0);
if (vro->op1)
{
fprintf (outfile, ",");
print_generic_expr (outfile, vro->op1, 0);
}
if (vro->op1)
fprintf (outfile, ">");
}
if (i != VEC_length (vn_reference_op_s, ref->operands) - 1)
fprintf (outfile, ",");
}
fprintf (outfile, "}");
}
break;
}
}
void debug_pre_expr (pre_expr);
/* Like print_pre_expr but always prints to stderr. */
void
debug_pre_expr (pre_expr e)
{
print_pre_expr (stderr, e);
fprintf (stderr, "\n");
}
/* Print out SET to OUTFILE. */
static void
print_bitmap_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;
FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
{
const pre_expr expr = expression_for_id (i);
if (!first)
fprintf (outfile, ", ");
first = false;
print_pre_expr (outfile, expr);
fprintf (outfile, " (%04d)", get_expr_value_id (expr));
}
}
fprintf (outfile, " }\n");
}
void debug_bitmap_set (bitmap_set_t);
void
debug_bitmap_set (bitmap_set_t set)
{
print_bitmap_set (stderr, set, "debug", 0);
}
/* Print out the expressions that have VAL to OUTFILE. */
void
print_value_expressions (FILE *outfile, unsigned int val)
{
bitmap_set_t set = VEC_index (bitmap_set_t, value_expressions, val);
if (set)
{
char s[10];
sprintf (s, "%04d", val);
print_bitmap_set (outfile, set, s, 0);
}
}
void
debug_value_expressions (unsigned int val)
{
print_value_expressions (stderr, val);
}
/* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
represent it. */
static pre_expr
get_or_alloc_expr_for_constant (tree constant)
{
unsigned int result_id;
unsigned int value_id;
pre_expr newexpr = (pre_expr) pool_alloc (pre_expr_pool);
newexpr->kind = CONSTANT;
PRE_EXPR_CONSTANT (newexpr) = constant;
result_id = lookup_expression_id (newexpr);
if (result_id != 0)
{
pool_free (pre_expr_pool, newexpr);
newexpr = expression_for_id (result_id);
return newexpr;
}
value_id = get_or_alloc_constant_value_id (constant);
get_or_alloc_expression_id (newexpr);
add_to_value (value_id, newexpr);
return newexpr;
}
/* Given a value id V, find the actual tree representing the constant
value if there is one, and return it. Return NULL if we can't find
a constant. */
static tree
get_constant_for_value_id (unsigned int v)
{
if (value_id_constant_p (v))
{
unsigned int i;
bitmap_iterator bi;
bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, v);
FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
{
pre_expr expr = expression_for_id (i);
if (expr->kind == CONSTANT)
return PRE_EXPR_CONSTANT (expr);
}
}
return NULL;
}
/* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
Currently only supports constants and SSA_NAMES. */
static pre_expr
get_or_alloc_expr_for (tree t)
{
if (TREE_CODE (t) == SSA_NAME)
return get_or_alloc_expr_for_name (t);
else if (is_gimple_min_invariant (t))
return get_or_alloc_expr_for_constant (t);
else
{
/* More complex expressions can result from SCCVN expression
simplification that inserts values for them. As they all
do not have VOPs the get handled by the nary ops struct. */
vn_nary_op_t result;
unsigned int result_id;
vn_nary_op_lookup (t, &result);
if (result != NULL)
{
pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
e->kind = NARY;
PRE_EXPR_NARY (e) = result;
result_id = lookup_expression_id (e);
if (result_id != 0)
{
pool_free (pre_expr_pool, e);
e = expression_for_id (result_id);
return e;
}
alloc_expression_id (e);
return e;
}
}
return NULL;
}
/* Return the folded version of T if T, when folded, is a gimple
min_invariant. Otherwise, return T. */
static pre_expr
fully_constant_expression (pre_expr e)
{
switch (e->kind)
{
case CONSTANT:
return e;
case NARY:
{
vn_nary_op_t nary = PRE_EXPR_NARY (e);
switch (TREE_CODE_CLASS (nary->opcode))
{
case tcc_expression:
if (nary->opcode == TRUTH_NOT_EXPR)
goto do_unary;
if (nary->opcode != TRUTH_AND_EXPR
&& nary->opcode != TRUTH_OR_EXPR
&& nary->opcode != TRUTH_XOR_EXPR)
return e;
/* Fallthrough. */
case tcc_binary:
case tcc_comparison:
{
/* We have to go from trees to pre exprs to value ids to
constants. */
tree naryop0 = nary->op[0];
tree naryop1 = nary->op[1];
tree result;
if (!is_gimple_min_invariant (naryop0))
{
pre_expr rep0 = get_or_alloc_expr_for (naryop0);
unsigned int vrep0 = get_expr_value_id (rep0);
tree const0 = get_constant_for_value_id (vrep0);
if (const0)
naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
}
if (!is_gimple_min_invariant (naryop1))
{
pre_expr rep1 = get_or_alloc_expr_for (naryop1);
unsigned int vrep1 = get_expr_value_id (rep1);
tree const1 = get_constant_for_value_id (vrep1);
if (const1)
naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
}
result = fold_binary (nary->opcode, nary->type,
naryop0, naryop1);
if (result && is_gimple_min_invariant (result))
return get_or_alloc_expr_for_constant (result);
/* We might have simplified the expression to a
SSA_NAME for example from x_1 * 1. But we cannot
insert a PHI for x_1 unconditionally as x_1 might
not be available readily. */
return e;
}
case tcc_reference:
if (nary->opcode != REALPART_EXPR
&& nary->opcode != IMAGPART_EXPR
&& nary->opcode != VIEW_CONVERT_EXPR)
return e;
/* Fallthrough. */
case tcc_unary:
do_unary:
{
/* We have to go from trees to pre exprs to value ids to
constants. */
tree naryop0 = nary->op[0];
tree const0, result;
if (is_gimple_min_invariant (naryop0))
const0 = naryop0;
else
{
pre_expr rep0 = get_or_alloc_expr_for (naryop0);
unsigned int vrep0 = get_expr_value_id (rep0);
const0 = get_constant_for_value_id (vrep0);
}
result = NULL;
if (const0)
{
tree type1 = TREE_TYPE (nary->op[0]);
const0 = fold_convert (type1, const0);
result = fold_unary (nary->opcode, nary->type, const0);
}
if (result && is_gimple_min_invariant (result))
return get_or_alloc_expr_for_constant (result);
return e;
}
default:
return e;
}
}
case REFERENCE:
{
vn_reference_t ref = PRE_EXPR_REFERENCE (e);
VEC (vn_reference_op_s, heap) *operands = ref->operands;
vn_reference_op_t op;
/* Try to simplify the translated expression if it is
a call to a builtin function with at most two arguments. */
op = VEC_index (vn_reference_op_s, operands, 0);
if (op->opcode == CALL_EXPR
&& TREE_CODE (op->op0) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (op->op0, 0)) == FUNCTION_DECL
&& DECL_BUILT_IN (TREE_OPERAND (op->op0, 0))
&& VEC_length (vn_reference_op_s, operands) >= 2
&& VEC_length (vn_reference_op_s, operands) <= 3)
{
vn_reference_op_t arg0, arg1 = NULL;
bool anyconst = false;
arg0 = VEC_index (vn_reference_op_s, operands, 1);
if (VEC_length (vn_reference_op_s, operands) > 2)
arg1 = VEC_index (vn_reference_op_s, operands, 2);
if (TREE_CODE_CLASS (arg0->opcode) == tcc_constant
|| (arg0->opcode == ADDR_EXPR
&& is_gimple_min_invariant (arg0->op0)))
anyconst = true;
if (arg1
&& (TREE_CODE_CLASS (arg1->opcode) == tcc_constant
|| (arg1->opcode == ADDR_EXPR
&& is_gimple_min_invariant (arg1->op0))))
anyconst = true;
if (anyconst)
{
tree folded = build_call_expr (TREE_OPERAND (op->op0, 0),
arg1 ? 2 : 1,
arg0->op0,
arg1 ? arg1->op0 : NULL);
if (folded
&& TREE_CODE (folded) == NOP_EXPR)
folded = TREE_OPERAND (folded, 0);
if (folded
&& is_gimple_min_invariant (folded))
return get_or_alloc_expr_for_constant (folded);
}
}
return e;
}
default:
return e;
}
return e;
}
/* Translate the vuses in the VUSES vector backwards through phi nodes
in PHIBLOCK, so that they have the value they would have in
BLOCK. */
static VEC(tree, gc) *
translate_vuses_through_block (VEC (tree, gc) *vuses,
basic_block phiblock,
basic_block block)
{
tree oldvuse;
VEC(tree, gc) *result = NULL;
int i;
for (i = 0; VEC_iterate (tree, vuses, i, oldvuse); i++)
{
gimple phi = SSA_NAME_DEF_STMT (oldvuse);
if (gimple_code (phi) == GIMPLE_PHI
&& gimple_bb (phi) == phiblock)
{
edge e = find_edge (block, gimple_bb (phi));
if (e)
{
tree def = PHI_ARG_DEF (phi, e->dest_idx);
if (def != oldvuse)
{
if (!result)
result = VEC_copy (tree, gc, vuses);
VEC_replace (tree, result, i, def);
}
}
}
}
/* We avoid creating a new copy of the vuses unless something
actually changed, so result can be NULL. */
if (result)
{
sort_vuses (result);
return result;
}
return vuses;
}
/* Like find_leader, but checks for the value existing in SET1 *or*
SET2. This is used to avoid making a set consisting of the union
of PA_IN and ANTIC_IN during insert. */
static inline pre_expr
find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
{
pre_expr result;
result = bitmap_find_leader (set1, val, NULL);
if (!result && set2)
result = bitmap_find_leader (set2, val, NULL);
return result;
}
/* Get the tree type for our PRE expression e. */
static tree
get_expr_type (const pre_expr e)
{
switch (e->kind)
{
case NAME:
return TREE_TYPE (PRE_EXPR_NAME (e));
case CONSTANT:
return TREE_TYPE (PRE_EXPR_CONSTANT (e));
case REFERENCE:
{
vn_reference_op_t vro;
gcc_assert (PRE_EXPR_REFERENCE (e)->operands);
vro = VEC_index (vn_reference_op_s,
PRE_EXPR_REFERENCE (e)->operands,
0);
/* We don't store type along with COMPONENT_REF because it is
always the same as FIELD_DECL's type. */
if (!vro->type)
{
gcc_assert (vro->opcode == COMPONENT_REF);
return TREE_TYPE (vro->op0);
}
return vro->type;
}
case NARY:
return PRE_EXPR_NARY (e)->type;
}
gcc_unreachable();
}
/* Get a representative SSA_NAME for a given expression.
Since all of our sub-expressions are treated as values, we require
them to be SSA_NAME's for simplicity.
Prior versions of GVNPRE used to use "value handles" here, so that
an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
either case, the operands are really values (IE we do not expect
them to be usable without finding leaders). */
static tree
get_representative_for (const pre_expr e)
{
tree exprtype;
tree name;
unsigned int value_id = get_expr_value_id (e);
switch (e->kind)
{
case NAME:
return PRE_EXPR_NAME (e);
case CONSTANT:
return PRE_EXPR_CONSTANT (e);
case NARY:
case REFERENCE:
{
/* Go through all of the expressions representing this value
and pick out an SSA_NAME. */
unsigned int i;
bitmap_iterator bi;
bitmap_set_t exprs = VEC_index (bitmap_set_t, value_expressions,
value_id);
FOR_EACH_EXPR_ID_IN_SET (exprs, i, bi)
{
pre_expr rep = expression_for_id (i);
if (rep->kind == NAME)
return PRE_EXPR_NAME (rep);
}
}
break;
}
/* If we reached here we couldn't find an SSA_NAME. This can
happen when we've discovered a value that has never appeared in
the program as set to an SSA_NAME, most likely as the result of
phi translation. */
if (dump_file)
{
fprintf (dump_file,
"Could not find SSA_NAME representative for expression:");
print_pre_expr (dump_file, e);
fprintf (dump_file, "\n");
}
exprtype = get_expr_type (e);
/* Build and insert the assignment of the end result to the temporary
that we will return. */
if (!pretemp || exprtype != TREE_TYPE (pretemp))
{
pretemp = create_tmp_var (exprtype, "pretmp");
get_var_ann (pretemp);
}
name = make_ssa_name (pretemp, gimple_build_nop ());
VN_INFO_GET (name)->value_id = value_id;
if (e->kind == CONSTANT)
VN_INFO (name)->valnum = PRE_EXPR_CONSTANT (e);
else
VN_INFO (name)->valnum = name;
add_to_value (value_id, get_or_alloc_expr_for_name (name));
if (dump_file)
{
fprintf (dump_file, "Created SSA_NAME representative ");
print_generic_expr (dump_file, name, 0);
fprintf (dump_file, " for expression:");
print_pre_expr (dump_file, e);
fprintf (dump_file, "\n");
}
return name;
}
/* Translate EXPR using phis in PHIBLOCK, so that it has the values of
the phis in PRED. SEEN is a bitmap saying which expression we have
translated since we started translation of the toplevel expression.
Return NULL if we can't find a leader for each part of the
translated expression. */
static pre_expr
phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
basic_block pred, basic_block phiblock, bitmap seen)
{
pre_expr oldexpr = expr;
pre_expr phitrans;
if (!expr)
return NULL;
if (value_id_constant_p (get_expr_value_id (expr)))
return expr;
phitrans = phi_trans_lookup (expr, pred);
if (phitrans)
return phitrans;
/* Prevent cycles when we have recursively dependent leaders. This
can only happen when phi translating the maximal set. */
if (seen)
{
unsigned int expr_id = get_expression_id (expr);
if (bitmap_bit_p (seen, expr_id))
return NULL;
bitmap_set_bit (seen, expr_id);
}
switch (expr->kind)
{
/* Constants contain no values that need translation. */
case CONSTANT:
return expr;
case NARY:
{
unsigned int i;
bool changed = false;
vn_nary_op_t nary = PRE_EXPR_NARY (expr);
struct vn_nary_op_s newnary;
/* The NARY structure is only guaranteed to have been
allocated to the nary->length operands. */
memcpy (&newnary, nary, (sizeof (struct vn_nary_op_s)
- sizeof (tree) * (4 - nary->length)));
for (i = 0; i < newnary.length; i++)
{
if (TREE_CODE (newnary.op[i]) != SSA_NAME)
continue;
else
{
unsigned int op_val_id = VN_INFO (newnary.op[i])->value_id;
pre_expr leader = find_leader_in_sets (op_val_id, set1, set2);
pre_expr result = phi_translate_1 (leader, set1, set2,
pred, phiblock, seen);
if (result && result != leader)
{
tree name = get_representative_for (result);
if (!name)
return NULL;
newnary.op[i] = name;
}
else if (!result)
return NULL;
changed |= newnary.op[i] != nary->op[i];
}
}
if (changed)
{
pre_expr constant;
tree result = vn_nary_op_lookup_pieces (newnary.length,
newnary.opcode,
newnary.type,
newnary.op[0],
newnary.op[1],
newnary.op[2],
newnary.op[3],
&nary);
unsigned int new_val_id;
expr = (pre_expr) pool_alloc (pre_expr_pool);
expr->kind = NARY;
expr->id = 0;
if (result && is_gimple_min_invariant (result))
return get_or_alloc_expr_for_constant (result);
if (nary)
{
PRE_EXPR_NARY (expr) = nary;
constant = fully_constant_expression (expr);
if (constant != expr)
return constant;
new_val_id = nary->value_id;
get_or_alloc_expression_id (expr);
}
else
{
new_val_id = get_next_value_id ();
VEC_safe_grow_cleared (bitmap_set_t, heap,
value_expressions,
get_max_value_id() + 1);
nary = vn_nary_op_insert_pieces (newnary.length,
newnary.opcode,
newnary.type,
newnary.op[0],
newnary.op[1],
newnary.op[2],
newnary.op[3],
result, new_val_id);
PRE_EXPR_NARY (expr) = nary;
constant = fully_constant_expression (expr);
if (constant != expr)
return constant;
get_or_alloc_expression_id (expr);
}
add_to_value (new_val_id, expr);
}
phi_trans_add (oldexpr, expr, pred);
return expr;
}
break;
case REFERENCE:
{
vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
VEC (vn_reference_op_s, heap) *operands = ref->operands;
VEC (tree, gc) *vuses = ref->vuses;
VEC (tree, gc) *newvuses = vuses;
VEC (vn_reference_op_s, heap) *newoperands = NULL;
bool changed = false;
unsigned int i;
vn_reference_op_t operand;
vn_reference_t newref;
for (i = 0; VEC_iterate (vn_reference_op_s, operands, i, operand); i++)
{
pre_expr opresult;
pre_expr leader;
tree oldop0 = operand->op0;
tree oldop1 = operand->op1;
tree oldop2 = operand->op2;
tree op0 = oldop0;
tree op1 = oldop1;
tree op2 = oldop2;
tree type = operand->type;
vn_reference_op_s newop = *operand;
if (op0 && TREE_CODE (op0) == SSA_NAME)
{
unsigned int op_val_id = VN_INFO (op0)->value_id;
leader = find_leader_in_sets (op_val_id, set1, set2);
opresult = phi_translate_1 (leader, set1, set2,
pred, phiblock, seen);
if (opresult && opresult != leader)
{
tree name = get_representative_for (opresult);
if (!name)
break;
op0 = name;
}
else if (!opresult)
break;
}
changed |= op0 != oldop0;
if (op1 && TREE_CODE (op1) == SSA_NAME)
{
unsigned int op_val_id = VN_INFO (op1)->value_id;
leader = find_leader_in_sets (op_val_id, set1, set2);
opresult = phi_translate_1 (leader, set1, set2,
pred, phiblock, seen);
if (opresult && opresult != leader)
{
tree name = get_representative_for (opresult);
if (!name)
break;
op1 = name;
}
else if (!opresult)
break;
}
changed |= op1 != oldop1;
if (op2 && TREE_CODE (op2) == SSA_NAME)
{
unsigned int op_val_id = VN_INFO (op2)->value_id;
leader = find_leader_in_sets (op_val_id, set1, set2);
opresult = phi_translate_1 (leader, set1, set2,
pred, phiblock, seen);
if (opresult && opresult != leader)
{
tree name = get_representative_for (opresult);
if (!name)
break;
op2 = name;
}
else if (!opresult)
break;
}
changed |= op2 != oldop2;
if (!newoperands)
newoperands = VEC_copy (vn_reference_op_s, heap, operands);
/* We may have changed from an SSA_NAME to a constant */
if (newop.opcode == SSA_NAME && TREE_CODE (op0) != SSA_NAME)
newop.opcode = TREE_CODE (op0);
newop.type = type;
newop.op0 = op0;
newop.op1 = op1;
newop.op2 = op2;
VEC_replace (vn_reference_op_s, newoperands, i, &newop);
}
if (i != VEC_length (vn_reference_op_s, operands))
{
if (newoperands)
VEC_free (vn_reference_op_s, heap, newoperands);
return NULL;
}
newvuses = translate_vuses_through_block (vuses, phiblock, pred);
changed |= newvuses != vuses;
if (changed)
{
unsigned int new_val_id;
pre_expr constant;
tree result = vn_reference_lookup_pieces (newvuses,
newoperands,
&newref, true);
if (newref)
VEC_free (vn_reference_op_s, heap, newoperands);
if (result && is_gimple_min_invariant (result))
{
gcc_assert (!newoperands);
return get_or_alloc_expr_for_constant (result);
}
expr = (pre_expr) pool_alloc (pre_expr_pool);
expr->kind = REFERENCE;
expr->id = 0;
if (newref)
{
PRE_EXPR_REFERENCE (expr) = newref;
constant = fully_constant_expression (expr);
if (constant != expr)
return constant;
new_val_id = newref->value_id;
get_or_alloc_expression_id (expr);
}
else
{
new_val_id = get_next_value_id ();
VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
get_max_value_id() + 1);
newref = vn_reference_insert_pieces (newvuses,
newoperands,
result, new_val_id);
newoperands = NULL;
PRE_EXPR_REFERENCE (expr) = newref;
constant = fully_constant_expression (expr);
if (constant != expr)
return constant;
get_or_alloc_expression_id (expr);
}
add_to_value (new_val_id, expr);
}
VEC_free (vn_reference_op_s, heap, newoperands);
phi_trans_add (oldexpr, expr, pred);
return expr;
}
break;
case NAME:
{
gimple phi = NULL;
edge e;
gimple def_stmt;
tree name = PRE_EXPR_NAME (expr);
def_stmt = SSA_NAME_DEF_STMT (name);
if (gimple_code (def_stmt) == GIMPLE_PHI
&& gimple_bb (def_stmt) == phiblock)
phi = def_stmt;
else
return expr;
e = find_edge (pred, gimple_bb (phi));
if (e)
{
tree def = PHI_ARG_DEF (phi, e->dest_idx);
pre_expr newexpr;
if (TREE_CODE (def) == SSA_NAME)
def = VN_INFO (def)->valnum;
/* Handle constant. */
if (is_gimple_min_invariant (def))
return get_or_alloc_expr_for_constant (def);
if (TREE_CODE (def) == SSA_NAME && ssa_undefined_value_p (def))
return NULL;
newexpr = get_or_alloc_expr_for_name (def);
return newexpr;
}
}
return expr;
default:
gcc_unreachable ();
}
}
/* Translate EXPR using phis in PHIBLOCK, so that it has the values of
the phis in PRED.
Return NULL if we can't find a leader for each part of the
translated expression. */
static pre_expr
phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
basic_block pred, basic_block phiblock)
{
bitmap_clear (seen_during_translate);
return phi_translate_1 (expr, set1, set2, pred, phiblock,
seen_during_translate);
}
/* For each expression in SET, translate the values through phi nodes
in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
expressions in DEST. */
static void
phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
basic_block phiblock)
{
VEC (pre_expr, heap) *exprs;
pre_expr expr;
int i;
if (!phi_nodes (phiblock))
{
bitmap_set_copy (dest, set);
return;
}
exprs = sorted_array_from_bitmap_set (set);
for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
{
pre_expr translated;
translated = phi_translate (expr, set, NULL, pred, phiblock);
/* Don't add empty translations to the cache */
if (translated)
phi_trans_add (expr, translated, pred);
if (translated != NULL)
bitmap_value_insert_into_set (dest, translated);
}
VEC_free (pre_expr, heap, exprs);
}
/* Find the leader for a value (i.e., the name representing that
value) in a given set, and return it. If STMT is non-NULL it
makes sure the defining statement for the leader dominates it.
Return NULL if no leader is found. */
static pre_expr
bitmap_find_leader (bitmap_set_t set, unsigned int val, gimple stmt)
{
if (value_id_constant_p (val))
{
unsigned int i;
bitmap_iterator bi;
bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
{
pre_expr expr = expression_for_id (i);
if (expr->kind == CONSTANT)
return expr;
}
}
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. */
unsigned int i;
bitmap_iterator bi;
bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
EXECUTE_IF_AND_IN_BITMAP (exprset->expressions,
set->expressions, 0, i, bi)
{
pre_expr val = expression_for_id (i);
/* At the point where stmt is not null, there should always
be an SSA_NAME first in the list of expressions. */
if (stmt)
{
gimple def_stmt = SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val));
if (gimple_code (def_stmt) != GIMPLE_PHI
&& gimple_bb (def_stmt) == gimple_bb (stmt)
&& gimple_uid (def_stmt) >= gimple_uid (stmt))
continue;
}
return val;
}
}
return NULL;
}
/* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
BLOCK by seeing if it is not killed in the block. Note that we are
only determining whether there is a store that kills it. Because
of the order in which clean iterates over values, we are guaranteed
that altered operands will have caused us to be eliminated from the
ANTIC_IN set already. */
static bool
value_dies_in_block_x (pre_expr expr, basic_block block)
{
int i;
tree vuse;
VEC (tree, gc) *vuses = PRE_EXPR_REFERENCE (expr)->vuses;
/* Conservatively, a value dies if it's vuses are defined in this
block, unless they come from phi nodes (which are merge operations,
rather than stores. */
for (i = 0; VEC_iterate (tree, vuses, i, vuse); i++)
{
gimple def = SSA_NAME_DEF_STMT (vuse);
if (gimple_bb (def) != block)
continue;
if (gimple_code (def) == GIMPLE_PHI)
continue;
return true;
}
return false;
}
#define union_contains_value(SET1, SET2, VAL) \
(bitmap_set_contains_value ((SET1), (VAL)) \
|| ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
/* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
*/
static bool
vro_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2,
vn_reference_op_t vro)
{
if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
{
struct pre_expr_d temp;
temp.kind = NAME;
temp.id = 0;
PRE_EXPR_NAME (&temp) = vro->op0;
temp.id = lookup_expression_id (&temp);
if (temp.id == 0)
return false;
if (!union_contains_value (set1, set2,
get_expr_value_id (&temp)))
return false;
}
if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
{
struct pre_expr_d temp;
temp.kind = NAME;
temp.id = 0;
PRE_EXPR_NAME (&temp) = vro->op1;
temp.id = lookup_expression_id (&temp);
if (temp.id == 0)
return false;
if (!union_contains_value (set1, set2,
get_expr_value_id (&temp)))
return false;
}
if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
{
struct pre_expr_d temp;
temp.kind = NAME;
temp.id = 0;
PRE_EXPR_NAME (&temp) = vro->op2;
temp.id = lookup_expression_id (&temp);
if (temp.id == 0)
return false;
if (!union_contains_value (set1, set2,
get_expr_value_id (&temp)))
return false;
}
return true;
}
/* Determine if the expression EXPR is valid in SET1 U SET2.
ONLY SET2 CAN BE NULL.
This means that we have a leader for each part of the expression
(if it consists of values), or the expression is an SSA_NAME.
For loads/calls, we also see if the vuses are killed in this block.
*/
static bool
valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
basic_block block)
{
switch (expr->kind)
{
case NAME:
return bitmap_set_contains_expr (AVAIL_OUT (block), expr);
case NARY:
{
unsigned int i;
vn_nary_op_t nary = PRE_EXPR_NARY (expr);
for (i = 0; i < nary->length; i++)
{
if (TREE_CODE (nary->op[i]) == SSA_NAME)
{
struct pre_expr_d temp;
temp.kind = NAME;
temp.id = 0;
PRE_EXPR_NAME (&temp) = nary->op[i];
temp.id = lookup_expression_id (&temp);
if (temp.id == 0)
return false;
if (!union_contains_value (set1, set2,
get_expr_value_id (&temp)))
return false;
}
}
return true;
}
break;
case REFERENCE:
{
vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
vn_reference_op_t vro;
unsigned int i;
for (i = 0; VEC_iterate (vn_reference_op_s, ref->operands, i, vro); i++)
{
if (!vro_valid_in_sets (set1, set2, vro))
return false;
}
return !value_dies_in_block_x (expr, block);
}
default:
gcc_unreachable ();
}
}
/* Clean the set of expressions that are no longer valid in SET1 or
SET2. This means expressions that are made up of values we have no
leaders for in SET1 or SET2. This version is used for partial
anticipation, which means it is not valid in either ANTIC_IN or
PA_IN. */
static void
dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
{
VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set1);
pre_expr expr;
int i;
for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
{
if (!valid_in_sets (set1, set2, expr, block))
bitmap_remove_from_set (set1, expr);
}
VEC_free (pre_expr, heap, exprs);
}
/* 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 (bitmap_set_t set, basic_block block)
{
VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
pre_expr expr;
int i;
for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
{
if (!valid_in_sets (set, NULL, expr, block))
bitmap_remove_from_set (set, expr);
}
VEC_free (pre_expr, heap, exprs);
}
static sbitmap has_abnormal_preds;
/* List of blocks that may have changed during ANTIC computation and
thus need to be iterated over. */
static sbitmap changed_blocks;
/* Decide whether to defer a block for a later iteration, or PHI
translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
should defer the block, and true if we processed it. */
static bool
defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
basic_block block, basic_block phiblock)
{
if (!BB_VISITED (phiblock))
{
SET_BIT (changed_blocks, block->index);
BB_VISITED (block) = 0;
BB_DEFERRED (block) = 1;
return false;
}
else
phi_translate_set (dest, source, block, phiblock);
return true;
}
/* Compute the ANTIC set for BLOCK.
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)])
ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
*/
static bool
compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
{
bool changed = false;
bitmap_set_t S, old, ANTIC_OUT;
bitmap_iterator bi;
unsigned int bii;
edge e;
edge_iterator ei;
old = ANTIC_OUT = S = NULL;
BB_VISITED (block) = 1;
/* 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 = ANTIC_IN (block);
ANTIC_OUT = bitmap_set_new ();
/* 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 (single_succ_p (block))
{
basic_block succ_bb = single_succ (block);
/* We trade iterations of the dataflow equations for having to
phi translate the maximal set, which is incredibly slow
(since the maximal set often has 300+ members, even when you
have a small number of blocks).
Basically, we defer the computation of ANTIC for this block
until we have processed it's successor, which will inevitably
have a *much* smaller set of values to phi translate once
clean has been run on it.
The cost of doing this is that we technically perform more
iterations, however, they are lower cost iterations.
Timings for PRE on tramp3d-v4:
without maximal set fix: 11 seconds
with maximal set fix/without deferring: 26 seconds
with maximal set fix/with deferring: 11 seconds
*/
if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
block, succ_bb))
{
changed = true;
goto maybe_dump_sets;
}
}
/* If we have multiple successors, we take the intersection of all of
them. Note that in the case of loop exit phi nodes, we may have
phis to translate through. */
else
{
VEC(basic_block, heap) * worklist;
size_t i;
basic_block bprime, first = NULL;
worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
FOR_EACH_EDGE (e, ei, block->succs)
{
if (!first
&& BB_VISITED (e->dest))
first = e->dest;
else if (BB_VISITED (e->dest))
VEC_quick_push (basic_block, worklist, e->dest);
}
/* Of multiple successors we have to have visited one already. */
if (!first)
{
SET_BIT (changed_blocks, block->index);
BB_VISITED (block) = 0;
BB_DEFERRED (block) = 1;
changed = true;
VEC_free (basic_block, heap, worklist);
goto maybe_dump_sets;
}
if (phi_nodes (first))
phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
else
bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
{
if (phi_nodes (bprime))
{
bitmap_set_t tmp = bitmap_set_new ();
phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
bitmap_set_and (ANTIC_OUT, tmp);
bitmap_set_free (tmp);
}
else
bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
}
VEC_free (basic_block, heap, worklist);
}
/* Generate ANTIC_OUT - TMP_GEN. */
S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
/* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
TMP_GEN (block));
/* Then union in the ANTIC_OUT - TMP_GEN values,
to get ANTIC_OUT U EXP_GEN - TMP_GEN */
FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
bitmap_value_insert_into_set (ANTIC_IN (block),
expression_for_id (bii));
clean (ANTIC_IN (block), block);
/* !old->expressions can happen when we deferred a block. */
if (!old->expressions || !bitmap_set_equal (old, ANTIC_IN (block)))
{
changed = true;
SET_BIT (changed_blocks, block->index);
FOR_EACH_EDGE (e, ei, block->preds)
SET_BIT (changed_blocks, e->src->index);
}
else
RESET_BIT (changed_blocks, block->index);
maybe_dump_sets:
if (dump_file && (dump_flags & TDF_DETAILS))
{
if (!BB_DEFERRED (block) || BB_VISITED (block))
{
if (ANTIC_OUT)
print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
block->index);
if (S)
print_bitmap_set (dump_file, S, "S", block->index);
}
else
{
fprintf (dump_file,
"Block %d was deferred for a future iteration.\n",
block->index);
}
}
if (old)
bitmap_set_free (old);
if (S)
bitmap_set_free (S);
if (ANTIC_OUT)
bitmap_set_free (ANTIC_OUT);
return changed;
}
/* Compute PARTIAL_ANTIC for BLOCK.
If succs(BLOCK) > 1 then
PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
in ANTIC_OUT for all succ(BLOCK)
else if succs(BLOCK) == 1 then
PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
- ANTIC_IN[BLOCK])
*/
static bool
compute_partial_antic_aux (basic_block block,
bool block_has_abnormal_pred_edge)
{
bool changed = false;
bitmap_set_t old_PA_IN;
bitmap_set_t PA_OUT;
edge e;
edge_iterator ei;
unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);
old_PA_IN = PA_OUT = NULL;
/* If any edges from predecessors are abnormal, antic_in is empty,
so do nothing. */
if (block_has_abnormal_pred_edge)
goto maybe_dump_sets;
/* If there are too many partially anticipatable values in the
block, phi_translate_set can take an exponential time: stop
before the translation starts. */
if (max_pa
&& single_succ_p (block)
&& bitmap_count_bits (PA_IN (single_succ (block))->values) > max_pa)
goto maybe_dump_sets;
old_PA_IN = PA_IN (block);
PA_OUT = bitmap_set_new ();
/* 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. Note that we can't phi translate across DFS
back edges in partial antic, because it uses a union operation on
the successors. For recurrences like IV's, we will end up
generating a new value in the set on each go around (i + 3 (VH.1)
VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
else if (single_succ_p (block))
{
basic_block succ = single_succ (block);
if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
}
/* If we have multiple successors, we take the union of all of
them. */
else
{
VEC(basic_block, heap) * worklist;
size_t i;
basic_block bprime;
worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
FOR_EACH_EDGE (e, ei, block->succs)
{
if (e->flags & EDGE_DFS_BACK)
continue;
VEC_quick_push (basic_block, worklist, e->dest);
}
if (VEC_length (basic_block, worklist) > 0)
{
for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
{
unsigned int i;
bitmap_iterator bi;
FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
bitmap_value_insert_into_set (PA_OUT,
expression_for_id (i));
if (phi_nodes (bprime))
{
bitmap_set_t pa_in = bitmap_set_new ();
phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
bitmap_value_insert_into_set (PA_OUT,
expression_for_id (i));
bitmap_set_free (pa_in);
}
else
FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
bitmap_value_insert_into_set (PA_OUT,
expression_for_id (i));
}
}
VEC_free (basic_block, heap, worklist);
}
/* PA_IN starts with PA_OUT - TMP_GEN.
Then we subtract things from ANTIC_IN. */
PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
/* For partial antic, we want to put back in the phi results, since
we will properly avoid making them partially antic over backedges. */
bitmap_ior_into (PA_IN (block)->values, PHI_GEN (block)->values);
bitmap_ior_into (PA_IN (block)->expressions, PHI_GEN (block)->expressions);
/* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));
dependent_clean (PA_IN (block), ANTIC_IN (block), block);
if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
{
changed = true;
SET_BIT (changed_blocks, block->index);
FOR_EACH_EDGE (e, ei, block->preds)
SET_BIT (changed_blocks, e->src->index);
}
else
RESET_BIT (changed_blocks, block->index);
maybe_dump_sets:
if (dump_file && (dump_flags & TDF_DETAILS))
{
if (PA_OUT)
print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);
print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
}
if (old_PA_IN)
bitmap_set_free (old_PA_IN);
if (PA_OUT)
bitmap_set_free (PA_OUT);
return changed;
}
/* Compute ANTIC and partial ANTIC sets. */
static void
compute_antic (void)
{
bool changed = true;
int num_iterations = 0;
basic_block block;
int i;
/* 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)
{
edge_iterator ei;
edge e;
FOR_EACH_EDGE (e, ei, block->preds)
{
e->flags &= ~EDGE_DFS_BACK;
if (e->flags & EDGE_ABNORMAL)
{
SET_BIT (has_abnormal_preds, block->index);
break;
}
}
BB_VISITED (block) = 0;
BB_DEFERRED (block) = 0;
/* While we are here, give empty ANTIC_IN sets to each block. */
ANTIC_IN (block) = bitmap_set_new ();
PA_IN (block) = bitmap_set_new ();
}
/* At the exit block we anticipate nothing. */
ANTIC_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
BB_VISITED (EXIT_BLOCK_PTR) = 1;
PA_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
changed_blocks = sbitmap_alloc (last_basic_block + 1);
sbitmap_ones (changed_blocks);
while (changed)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Starting iteration %d\n", num_iterations);
num_iterations++;
changed = false;
for (i = 0; i < n_basic_blocks - NUM_FIXED_BLOCKS; i++)
{
if (TEST_BIT (changed_blocks, postorder[i]))
{
basic_block block = BASIC_BLOCK (postorder[i]);
changed |= compute_antic_aux (block,
TEST_BIT (has_abnormal_preds,
block->index));
}
}
#ifdef ENABLE_CHECKING
/* Theoretically possible, but *highly* unlikely. */
gcc_assert (num_iterations < 500);
#endif
}
statistics_histogram_event (cfun, "compute_antic iterations",
num_iterations);
if (do_partial_partial)
{
sbitmap_ones (changed_blocks);
mark_dfs_back_edges ();
num_iterations = 0;
changed = true;
while (changed)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Starting iteration %d\n", num_iterations);
num_iterations++;
changed = false;
for (i = 0; i < n_basic_blocks - NUM_FIXED_BLOCKS; i++)
{
if (TEST_BIT (changed_blocks, postorder[i]))
{
basic_block block = BASIC_BLOCK (postorder[i]);
changed
|= compute_partial_antic_aux (block,
TEST_BIT (has_abnormal_preds,
block->index));
}
}
#ifdef ENABLE_CHECKING
/* Theoretically possible, but *highly* unlikely. */
gcc_assert (num_iterations < 500);
#endif
}
statistics_histogram_event (cfun, "compute_partial_antic iterations",
num_iterations);
}
sbitmap_free (has_abnormal_preds);
sbitmap_free (changed_blocks);
}
/* Return true if we can value number the call in STMT. This is true
if we have a pure or constant call. */
static bool
can_value_number_call (gimple stmt)
{
if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
return true;
return false;
}
/* Return true if OP is an exception handler related operation, such as
FILTER_EXPR or EXC_PTR_EXPR. */
static bool
is_exception_related (gimple stmt)
{
return (is_gimple_assign (stmt)
&& (gimple_assign_rhs_code (stmt) == FILTER_EXPR
|| gimple_assign_rhs_code (stmt) == EXC_PTR_EXPR));
}
/* Return true if OP is a tree which we can perform PRE on
on. This may not match the operations we can value number, but in
a perfect world would. */
static bool
can_PRE_operation (tree op)
{
return UNARY_CLASS_P (op)
|| BINARY_CLASS_P (op)
|| COMPARISON_CLASS_P (op)
|| TREE_CODE (op) == INDIRECT_REF
|| TREE_CODE (op) == COMPONENT_REF
|| TREE_CODE (op) == VIEW_CONVERT_EXPR
|| TREE_CODE (op) == CALL_EXPR
|| TREE_CODE (op) == ARRAY_REF;
}
/* Inserted expressions are placed onto this worklist, which is used
for performing quick dead code elimination of insertions we made
that didn't turn out to be necessary. */
static VEC(gimple,heap) *inserted_exprs;
/* Pool allocated fake store expressions are placed onto this
worklist, which, after performing dead code elimination, is walked
to see which expressions need to be put into GC'able memory */
static VEC(gimple, heap) *need_creation;
/* The actual worker for create_component_ref_by_pieces. */
static tree
create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
unsigned int *operand, gimple_seq *stmts,
gimple domstmt)
{
vn_reference_op_t currop = VEC_index (vn_reference_op_s, ref->operands,
*operand);
tree genop;
++*operand;
switch (currop->opcode)
{
case CALL_EXPR:
{
tree folded, sc = currop->op1;
unsigned int nargs = 0;
tree *args = XNEWVEC (tree, VEC_length (vn_reference_op_s,
ref->operands) - 1);
while (*operand < VEC_length (vn_reference_op_s, ref->operands))
{
args[nargs] = create_component_ref_by_pieces_1 (block, ref,
operand, stmts,
domstmt);
nargs++;
}
folded = build_call_array (currop->type,
TREE_CODE (currop->op0) == FUNCTION_DECL
? build_fold_addr_expr (currop->op0)
: currop->op0,
nargs, args);
free (args);
if (sc)
{
pre_expr scexpr = get_or_alloc_expr_for (sc);
sc = find_or_generate_expression (block, scexpr, stmts, domstmt);
if (!sc)
return NULL_TREE;
CALL_EXPR_STATIC_CHAIN (folded) = sc;
}
return folded;
}
break;
case ADDR_EXPR:
if (currop->op0)
{
gcc_assert (is_gimple_min_invariant (currop->op0));
return currop->op0;
}
/* Fallthrough. */
case REALPART_EXPR:
case IMAGPART_EXPR:
case VIEW_CONVERT_EXPR:
{
tree folded;
tree genop0 = create_component_ref_by_pieces_1 (block, ref,
operand,
stmts, domstmt);
if (!genop0)
return NULL_TREE;
folded = fold_build1 (currop->opcode, currop->type,
genop0);
return folded;
}
break;
case ALIGN_INDIRECT_REF:
case MISALIGNED_INDIRECT_REF:
case INDIRECT_REF:
{
tree folded;
tree genop1 = create_component_ref_by_pieces_1 (block, ref,
operand,
stmts, domstmt);
if (!genop1)
return NULL_TREE;
genop1 = fold_convert (build_pointer_type (currop->type),
genop1);
if (currop->opcode == MISALIGNED_INDIRECT_REF)
folded = fold_build2 (currop->opcode, currop->type,
genop1, currop->op1);
else
folded = fold_build1 (currop->opcode, currop->type,
genop1);
return folded;
}
break;
case BIT_FIELD_REF:
{
tree folded;
tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
stmts, domstmt);
pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
pre_expr op2expr = get_or_alloc_expr_for (currop->op1);
tree genop1;
tree genop2;
if (!genop0)
return NULL_TREE;
genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
if (!genop1)
return NULL_TREE;
genop2 = find_or_generate_expression (block, op2expr, stmts, domstmt);
if (!genop2)
return NULL_TREE;
folded = fold_build3 (BIT_FIELD_REF, currop->type, genop0, genop1,
genop2);
return folded;
}
/* For array ref vn_reference_op's, operand 1 of the array ref
is op0 of the reference op and operand 3 of the array ref is
op1. */
case ARRAY_RANGE_REF:
case ARRAY_REF:
{
tree genop0;
tree genop1 = currop->op0;
pre_expr op1expr;
tree genop2 = currop->op1;
pre_expr op2expr;
tree genop3;
genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
stmts, domstmt);
if (!genop0)
return NULL_TREE;
op1expr = get_or_alloc_expr_for (genop1);
genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
if (!genop1)
return NULL_TREE;
if (genop2)
{
op2expr = get_or_alloc_expr_for (genop2);
genop2 = find_or_generate_expression (block, op2expr, stmts,
domstmt);
if (!genop2)
return NULL_TREE;
}
genop3 = currop->op2;
return build4 (currop->opcode, currop->type, genop0, genop1,
genop2, genop3);
}
case COMPONENT_REF:
{
tree op0;
tree op1;
tree genop2 = currop->op1;
pre_expr op2expr;
op0 = create_component_ref_by_pieces_1 (block, ref, operand,
stmts, domstmt);
if (!op0)
return NULL_TREE;
/* op1 should be a FIELD_DECL, which are represented by
themselves. */
op1 = currop->op0;
if (genop2)
{
op2expr = get_or_alloc_expr_for (genop2);
genop2 = find_or_generate_expression (block, op2expr, stmts,
domstmt);
if (!genop2)
return NULL_TREE;
}
return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1,
genop2);
}
break;
case SSA_NAME:
{
pre_expr op0expr = get_or_alloc_expr_for (currop->op0);
genop = find_or_generate_expression (block, op0expr, stmts, domstmt);
return genop;
}
case STRING_CST:
case INTEGER_CST:
case COMPLEX_CST:
case VECTOR_CST:
case REAL_CST:
case CONSTRUCTOR:
case VAR_DECL:
case PARM_DECL:
case CONST_DECL:
case RESULT_DECL:
case FUNCTION_DECL:
return currop->op0;
default:
gcc_unreachable ();
}
}
/* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
trying to rename aggregates into ssa form directly, which is a no no.
Thus, this routine doesn't create temporaries, it just builds a
single access expression for the array, calling
find_or_generate_expression to build the innermost pieces.
This function is a subroutine of create_expression_by_pieces, and
should not be called on it's own unless you really know what you
are doing. */
static tree
create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
gimple_seq *stmts, gimple domstmt)
{
unsigned int op = 0;
return create_component_ref_by_pieces_1 (block, ref, &op, stmts, domstmt);
}
/* 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.
DOMSTMT if non-NULL is a statement that should be dominated by
all uses in the generated expression. If DOMSTMT is non-NULL this
routine can fail and return NULL_TREE. Otherwise it will assert
on failure. */
static tree
find_or_generate_expression (basic_block block, pre_expr expr,
gimple_seq *stmts, gimple domstmt)
{
pre_expr leader = bitmap_find_leader (AVAIL_OUT (block),
get_expr_value_id (expr), domstmt);
tree genop = NULL;
if (leader)
{
if (leader->kind == NAME)
genop = PRE_EXPR_NAME (leader);
else if (leader->kind == CONSTANT)
genop = PRE_EXPR_CONSTANT (leader);
}
/* If it's still NULL, it must be a complex expression, so generate
it recursively. Not so for FRE though. */
if (genop == NULL
&& !in_fre)
{
bitmap_set_t exprset;
unsigned int lookfor = get_expr_value_id (expr);
bool handled = false;
bitmap_iterator bi;
unsigned int i;
exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
{
pre_expr temp = expression_for_id (i);
if (temp->kind != NAME)
{
handled = true;
genop = create_expression_by_pieces (block, temp, stmts,
domstmt,
get_expr_type (expr));
break;
}
}
if (!handled && domstmt)
return NULL_TREE;
gcc_assert (handled);
}
return genop;
}
#define NECESSARY GF_PLF_1
/* 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 die 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).
If DOMSTMT is non-NULL then we make sure that all uses in the
expressions dominate that statement. In this case the function
can return NULL_TREE to signal failure. */
static tree
create_expression_by_pieces (basic_block block, pre_expr expr,
gimple_seq *stmts, gimple domstmt, tree type)
{
tree temp, name;
tree folded, newexpr;
gimple_seq forced_stmts;
unsigned int value_id;
gimple_stmt_iterator gsi;
tree exprtype = type ? type : get_expr_type (expr);
pre_expr nameexpr;
gimple newstmt;
switch (expr->kind)
{
/* We may hit the NAME/CONSTANT case if we have to convert types
that value numbering saw through. */
case NAME:
folded = PRE_EXPR_NAME (expr);
break;
case CONSTANT:
folded = PRE_EXPR_CONSTANT (expr);
break;
case REFERENCE:
{
vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
folded = create_component_ref_by_pieces (block, ref, stmts, domstmt);
}
break;
case NARY:
{
vn_nary_op_t nary = PRE_EXPR_NARY (expr);
switch (nary->length)
{
case 2:
{
pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
pre_expr op2 = get_or_alloc_expr_for (nary->op[1]);
tree genop1 = find_or_generate_expression (block, op1,
stmts, domstmt);
tree genop2 = find_or_generate_expression (block, op2,
stmts, domstmt);
if (!genop1 || !genop2)
return NULL_TREE;
genop1 = fold_convert (TREE_TYPE (nary->op[0]),
genop1);
/* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
may be a constant with the wrong type. */
if (nary->opcode == POINTER_PLUS_EXPR)
genop2 = fold_convert (sizetype, genop2);
else
genop2 = fold_convert (TREE_TYPE (nary->op[1]), genop2);
folded = fold_build2 (nary->opcode, nary->type,
genop1, genop2);
}
break;
case 1:
{
pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
tree genop1 = find_or_generate_expression (block, op1,
stmts, domstmt);
if (!genop1)
return NULL_TREE;
genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
folded = fold_build1 (nary->opcode, nary->type,
genop1);
}
break;
default:
return NULL_TREE;
}
}
break;
default:
return NULL_TREE;
}
folded = fold_convert (exprtype, folded);
/* Force the generated expression to be a sequence of GIMPLE
statements.
We have to call unshare_expr because force_gimple_operand may
modify the tree we pass to it. */
newexpr = force_gimple_operand (unshare_expr (folded), &forced_stmts,
false, NULL);
/* If we have any intermediate expressions to the value sets, add them
to the value sets and chain them in the instruction stream. */
if (forced_stmts)
{
gsi = gsi_start (forced_stmts);
for (; !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
tree forcedname = gimple_get_lhs (stmt);
pre_expr nameexpr;
VEC_safe_push (gimple, heap, inserted_exprs, stmt);
if (TREE_CODE (forcedname) == SSA_NAME)
{
VN_INFO_GET (forcedname)->valnum = forcedname;
VN_INFO (forcedname)->value_id = get_next_value_id ();
nameexpr = get_or_alloc_expr_for_name (forcedname);
add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
if (!in_fre)
bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
}
mark_symbols_for_renaming (stmt);
}
gimple_seq_add_seq (stmts, forced_stmts);
}
/* Build and insert the assignment of the end result to the temporary
that we will return. */
if (!pretemp || exprtype != TREE_TYPE (pretemp))
{
pretemp = create_tmp_var (exprtype, "pretmp");
get_var_ann (pretemp);
}
temp = pretemp;
add_referenced_var (temp);
if (TREE_CODE (exprtype) == COMPLEX_TYPE
|| TREE_CODE (exprtype) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (temp) = 1;
newstmt = gimple_build_assign (temp, newexpr);
name = make_ssa_name (temp, newstmt);
gimple_assign_set_lhs (newstmt, name);
gimple_set_plf (newstmt, NECESSARY, false);
gimple_seq_add_stmt (stmts, newstmt);
VEC_safe_push (gimple, heap, inserted_exprs, newstmt);
/* All the symbols in NEWEXPR should be put into SSA form. */
mark_symbols_for_renaming (newstmt);
/* Add a value number to the temporary.
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. */
VN_INFO_GET (name)->valnum = name;
value_id = get_expr_value_id (expr);
VN_INFO (name)->value_id = value_id;
nameexpr = get_or_alloc_expr_for_name (name);
add_to_value (value_id, nameexpr);
if (!in_fre)
bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
pre_stats.insertions++;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Inserted ");
print_gimple_stmt (dump_file, newstmt, 0, 0);
fprintf (dump_file, " in predecessor %d\n", block->index);
}
return name;
}
/* Insert the to-be-made-available values of expression EXPRNUM for each
predecessor, stored in AVAIL, into the predecessors of BLOCK, and
merge the result with a phi node, given the same value number as
NODE. Return true if we have inserted new stuff. */
static bool
insert_into_preds_of_block (basic_block block, unsigned int exprnum,
pre_expr *avail)
{
pre_expr expr = expression_for_id (exprnum);
pre_expr newphi;
unsigned int val = get_expr_value_id (expr);
edge pred;
bool insertions = false;
bool nophi = false;
basic_block bprime;
pre_expr eprime;
edge_iterator ei;
tree type = get_expr_type (expr);
tree temp;
gimple phi;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Found partial redundancy for expression ");
print_pre_expr (dump_file, expr);
fprintf (dump_file, " (%04d)\n", val);
}
/* Make sure we aren't creating an induction variable. */
if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2
&& expr->kind != REFERENCE)
{
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 sure we are not inserting trapping expressions. */
FOR_EACH_EDGE (pred, ei, block->preds)
{
bprime = pred->src;
eprime = avail[bprime->index];
if (eprime->kind == NARY
&& vn_nary_may_trap (PRE_EXPR_NARY (eprime)))
return false;
}
/* Make the necessary insertions. */
FOR_EACH_EDGE (pred, ei, block->preds)
{
gimple_seq stmts = NULL;
tree builtexpr;
bprime = pred->src;
eprime = avail[bprime->index];
if (eprime->kind != NAME && eprime->kind != CONSTANT)
{
builtexpr = create_expression_by_pieces (bprime,
eprime,
&stmts, NULL,
type);
gcc_assert (!(pred->flags & EDGE_ABNORMAL));
gsi_insert_seq_on_edge (pred, stmts);
avail[bprime->index] = get_or_alloc_expr_for_name (builtexpr);
insertions = true;
}
else if (eprime->kind == CONSTANT)
{
/* Constants may not have the right type, fold_convert
should give us back a constant with the right type.
*/
tree constant = PRE_EXPR_CONSTANT (eprime);
if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
{
tree builtexpr = fold_convert (type, constant);
if (!is_gimple_min_invariant (builtexpr))
{
tree forcedexpr = force_gimple_operand (builtexpr,
&stmts, true,
NULL);
if (!is_gimple_min_invariant (forcedexpr))
{
if (forcedexpr != builtexpr)
{
VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
}
if (stmts)
{
gimple_stmt_iterator gsi;
gsi = gsi_start (stmts);
for (; !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
VEC_safe_push (gimple, heap, inserted_exprs, stmt);
gimple_set_plf (stmt, NECESSARY, false);
}
gsi_insert_seq_on_edge (pred, stmts);
}
avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
}
}
}
}
else if (eprime->kind == NAME)
{
/* We may have to do a conversion because our value
numbering can look through types in certain cases, but
our IL requires all operands of a phi node have the same
type. */
tree name = PRE_EXPR_NAME (eprime);
if (!useless_type_conversion_p (type, TREE_TYPE (name)))
{
tree builtexpr;
tree forcedexpr;
builtexpr = fold_convert (type, name);
forcedexpr = force_gimple_operand (builtexpr,
&stmts, true,
NULL);
if (forcedexpr != name)
{
VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
}
if (stmts)
{
gimple_stmt_iterator gsi;
gsi = gsi_start (stmts);
for (; !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
VEC_safe_push (gimple, heap, inserted_exprs, stmt);
gimple_set_plf (stmt, NECESSARY, false);
}
gsi_insert_seq_on_edge (pred, stmts);
}
avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
}
}
}
/* 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. */
if (!prephitemp || TREE_TYPE (prephitemp) != type)
{
prephitemp = create_tmp_var (type, "prephitmp");
get_var_ann (prephitemp);
}
temp = prephitemp;
add_referenced_var (temp);
if (TREE_CODE (type) == COMPLEX_TYPE
|| TREE_CODE (type) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (temp) = 1;
phi = create_phi_node (temp, block);
gimple_set_plf (phi, NECESSARY, false);
VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
VN_INFO (gimple_phi_result (phi))->value_id = val;
VEC_safe_push (gimple, heap, inserted_exprs, phi);
FOR_EACH_EDGE (pred, ei, block->preds)
{
pre_expr ae = avail[pred->src->index];
gcc_assert (get_expr_type (ae) == type
|| useless_type_conversion_p (type, get_expr_type (ae)));
if (ae->kind == CONSTANT)
add_phi_arg (phi, PRE_EXPR_CONSTANT (ae), pred);
else
add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred);
}
newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
add_to_value (val, newphi);
/* 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), newphi);
bitmap_value_replace_in_set (AVAIL_OUT (block),
newphi);
bitmap_insert_into_set (NEW_SETS (block),
newphi);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Created phi ");
print_gimple_stmt (dump_file, phi, 0, 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.
If the block has multiple predecessors,
2a. Iterate over the ANTIC expressions for the block to see if
any of them are partially redundant.
2b. If so, insert them into the necessary predecessors to make
the expression fully redundant.
2c. Insert a new PHI merging the values of the predecessors.
2d. Insert the new PHI, and the new expressions, into the
NEW_SETS set.
3. Recursively call ourselves on the dominator children of BLOCK.
Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
do_regular_insertion and do_partial_insertion.
*/
static bool
do_regular_insertion (basic_block block, basic_block dom)
{
bool new_stuff = false;
VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
pre_expr expr;
int i;
for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
{
if (expr->kind != NAME)
{
pre_expr *avail;
unsigned int val;
bool by_some = false;
bool cant_insert = false;
bool all_same = true;
pre_expr first_s = NULL;
edge pred;
basic_block bprime;
pre_expr eprime = NULL;
edge_iterator ei;
pre_expr edoubleprime = NULL;
val = get_expr_value_id (expr);
if (bitmap_set_contains_value (PHI_GEN (block), val))
continue;
if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found fully redundant value\n");