2124 lines
60 KiB
C
2124 lines
60 KiB
C
/* SSA-PRE for trees.
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Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
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Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
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<stevenb@suse.de>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "errors.h"
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#include "ggc.h"
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#include "tree.h"
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#include "basic-block.h"
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#include "diagnostic.h"
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#include "tree-inline.h"
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#include "tree-flow.h"
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#include "tree-gimple.h"
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#include "tree-dump.h"
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#include "timevar.h"
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#include "fibheap.h"
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#include "hashtab.h"
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#include "tree-iterator.h"
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#include "real.h"
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#include "alloc-pool.h"
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#include "tree-pass.h"
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#include "flags.h"
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#include "splay-tree.h"
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#include "bitmap.h"
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#include "langhooks.h"
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/* TODO:
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1. Avail sets can be shared by making an avail_find_leader that
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walks up the dominator tree and looks in those avail sets.
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This might affect code optimality, it's unclear right now.
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2. Load motion can be performed by value numbering the loads the
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same as we do other expressions. This requires iterative
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hashing the vuses into the values. Right now we simply assign
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a new value every time we see a statement with a vuse.
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3. Strength reduction can be performed by anticipating expressions
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we can repair later on.
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4. Our canonicalization of expressions during lookups don't take
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constants into account very well. In particular, we don't fold
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anywhere, so we can get situations where we stupidly think
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something is a new value (a + 1 + 1 vs a + 2). This is somewhat
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expensive to fix, but it does expose a lot more eliminations.
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It may or not be worth it, depending on how critical you
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consider PRE vs just plain GRE.
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*/
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/* For ease of terminology, "expression node" in the below refers to
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every expression node but MODIFY_EXPR, because MODIFY_EXPR's represent
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the actual statement containing the expressions we care about, and
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we cache the value number by putting it in the expression. */
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/* Basic algorithm
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First we walk the statements to generate the AVAIL sets, the
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EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
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generation of values/expressions by a given block. We use them
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when computing the ANTIC sets. The AVAIL sets consist of
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SSA_NAME's that represent values, so we know what values are
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available in what blocks. AVAIL is a forward dataflow problem. In
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SSA, values are never killed, so we don't need a kill set, or a
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fixpoint iteration, in order to calculate the AVAIL sets. In
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traditional parlance, AVAIL sets tell us the downsafety of the
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expressions/values.
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Next, we generate the ANTIC sets. These sets represent the
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anticipatable expressions. ANTIC is a backwards dataflow
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problem.An expression is anticipatable in a given block if it could
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be generated in that block. This means that if we had to perform
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an insertion in that block, of the value of that expression, we
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could. Calculating the ANTIC sets requires phi translation of
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expressions, because the flow goes backwards through phis. We must
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iterate to a fixpoint of the ANTIC sets, because we have a kill
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set. Even in SSA form, values are not live over the entire
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function, only from their definition point onwards. So we have to
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remove values from the ANTIC set once we go past the definition
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point of the leaders that make them up.
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compute_antic/compute_antic_aux performs this computation.
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Third, we perform insertions to make partially redundant
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expressions fully redundant.
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An expression is partially redundant (excluding partial
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anticipation) if:
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1. It is AVAIL in some, but not all, of the predecessors of a
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given block.
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2. It is ANTIC in all the predecessors.
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In order to make it fully redundant, we insert the expression into
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the predecessors where it is not available, but is ANTIC.
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insert/insert_aux performs this insertion.
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Fourth, we eliminate fully redundant expressions.
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This is a simple statement walk that replaces redundant
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calculations with the now available values. */
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/* Representations of value numbers:
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Value numbers are represented using the "value handle" approach.
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This means that each SSA_NAME (and for other reasons to be
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disclosed in a moment, expression nodes) has a value handle that
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can be retrieved through get_value_handle. This value handle, *is*
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the value number of the SSA_NAME. You can pointer compare the
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value handles for equivalence purposes.
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For debugging reasons, the value handle is internally more than
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just a number, it is a VAR_DECL named "value.x", where x is a
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unique number for each value number in use. This allows
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expressions with SSA_NAMES replaced by value handles to still be
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pretty printed in a sane way. They simply print as "value.3 *
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value.5", etc.
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Expression nodes have value handles associated with them as a
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cache. Otherwise, we'd have to look them up again in the hash
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table This makes significant difference (factor of two or more) on
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some test cases. They can be thrown away after the pass is
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finished. */
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/* Representation of expressions on value numbers:
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In some portions of this code, you will notice we allocate "fake"
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analogues to the expression we are value numbering, and replace the
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operands with the values of the expression. Since we work on
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values, and not just names, we canonicalize expressions to value
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expressions for use in the ANTIC sets, the EXP_GEN set, etc.
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This is theoretically unnecessary, it just saves a bunch of
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repeated get_value_handle and find_leader calls in the remainder of
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the code, trading off temporary memory usage for speed. The tree
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nodes aren't actually creating more garbage, since they are
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allocated in a special pools which are thrown away at the end of
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this pass.
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All of this also means that if you print the EXP_GEN or ANTIC sets,
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you will see "value.5 + value.7" in the set, instead of "a_55 +
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b_66" or something. The only thing that actually cares about
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seeing the value leaders is phi translation, and it needs to be
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able to find the leader for a value in an arbitrary block, so this
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"value expression" form is perfect for it (otherwise you'd do
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get_value_handle->find_leader->translate->get_value_handle->find_leader).*/
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/* Representation of sets:
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There are currently two types of sets used, hopefully to be unified soon.
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The AVAIL sets do not need to be sorted in any particular order,
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and thus, are simply represented as two bitmaps, one that keeps
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track of values present in the set, and one that keeps track of
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expressions present in the set.
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The other sets are represented as doubly linked lists kept in topological
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order, with an optional supporting bitmap of values present in the
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set. The sets represent values, and the elements can be values or
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expressions. The elements can appear in different sets, but each
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element can only appear once in each set.
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Since each node in the set represents a value, we also want to be
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able to map expression, set pairs to something that tells us
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whether the value is present is a set. We use a per-set bitmap for
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that. The value handles also point to a linked list of the
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expressions they represent via a tree annotation. This is mainly
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useful only for debugging, since we don't do identity lookups. */
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/* A value set element. Basically a single linked list of
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expressions/values. */
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typedef struct value_set_node
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{
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/* An expression. */
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tree expr;
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/* A pointer to the next element of the value set. */
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struct value_set_node *next;
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} *value_set_node_t;
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/* A value set. This is a singly linked list of value_set_node
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elements with a possible bitmap that tells us what values exist in
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the set. This set must be kept in topologically sorted order. */
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typedef struct value_set
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{
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/* The head of the list. Used for iterating over the list in
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order. */
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value_set_node_t head;
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/* The tail of the list. Used for tail insertions, which are
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necessary to keep the set in topologically sorted order because
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of how the set is built. */
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value_set_node_t tail;
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/* The length of the list. */
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size_t length;
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/* True if the set is indexed, which means it contains a backing
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bitmap for quick determination of whether certain values exist in the
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set. */
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bool indexed;
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/* The bitmap of values that exist in the set. May be NULL in an
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empty or non-indexed set. */
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bitmap values;
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} *value_set_t;
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/* An unordered bitmap set. One bitmap tracks values, the other,
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expressions. */
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typedef struct bitmap_set
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{
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bitmap expressions;
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bitmap values;
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} *bitmap_set_t;
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/* Sets that we need to keep track of. */
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typedef struct bb_value_sets
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{
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/* The EXP_GEN set, which represents expressions/values generated in
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a basic block. */
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value_set_t exp_gen;
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/* The PHI_GEN set, which represents PHI results generated in a
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basic block. */
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bitmap_set_t phi_gen;
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/* The TMP_GEN set, which represents results/temporaries generated
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in a basic block. IE the LHS of an expression. */
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bitmap_set_t tmp_gen;
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/* The AVAIL_OUT set, which represents which values are available in
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a given basic block. */
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bitmap_set_t avail_out;
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/* The ANTIC_IN set, which represents which values are anticiptable
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in a given basic block. */
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value_set_t antic_in;
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/* The NEW_SETS set, which is used during insertion to augment the
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AVAIL_OUT set of blocks with the new insertions performed during
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the current iteration. */
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bitmap_set_t new_sets;
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} *bb_value_sets_t;
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#define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
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#define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
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#define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
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#define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
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#define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
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#define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
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/* This structure is used to keep track of statistics on what
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optimization PRE was able to perform. */
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static struct
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{
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/* The number of RHS computations eliminated by PRE. */
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int eliminations;
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/* The number of new expressions/temporaries generated by PRE. */
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int insertions;
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/* The number of new PHI nodes added by PRE. */
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int phis;
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} pre_stats;
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static tree bitmap_find_leader (bitmap_set_t, tree);
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static tree find_leader (value_set_t, tree);
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static void value_insert_into_set (value_set_t, tree);
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static void bitmap_value_insert_into_set (bitmap_set_t, tree);
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static void bitmap_value_replace_in_set (bitmap_set_t, tree);
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static void insert_into_set (value_set_t, tree);
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static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
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static bool bitmap_set_contains_value (bitmap_set_t, tree);
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static bitmap_set_t bitmap_set_new (void);
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static value_set_t set_new (bool);
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static bool is_undefined_value (tree);
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static tree create_expression_by_pieces (basic_block, tree, tree);
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/* We can add and remove elements and entries to and from sets
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and hash tables, so we use alloc pools for them. */
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static alloc_pool value_set_pool;
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static alloc_pool bitmap_set_pool;
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static alloc_pool value_set_node_pool;
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static alloc_pool binary_node_pool;
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static alloc_pool unary_node_pool;
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static alloc_pool reference_node_pool;
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static struct obstack grand_bitmap_obstack;
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/* Set of blocks with statements that have had its EH information
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cleaned up. */
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static bitmap need_eh_cleanup;
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/* The phi_translate_table caches phi translations for a given
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expression and predecessor. */
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static htab_t phi_translate_table;
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/* A three tuple {e, pred, v} used to cache phi translations in the
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phi_translate_table. */
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typedef struct expr_pred_trans_d
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{
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/* The expression. */
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tree e;
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/* The predecessor block along which we translated the expression. */
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basic_block pred;
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/* The value that resulted from the translation. */
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tree v;
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/* The hashcode for the expression, pred pair. This is cached for
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speed reasons. */
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hashval_t hashcode;
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} *expr_pred_trans_t;
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/* Return the hash value for a phi translation table entry. */
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static hashval_t
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expr_pred_trans_hash (const void *p)
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{
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const expr_pred_trans_t ve = (expr_pred_trans_t) p;
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return ve->hashcode;
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}
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/* Return true if two phi translation table entries are the same.
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P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
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static int
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expr_pred_trans_eq (const void *p1, const void *p2)
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{
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const expr_pred_trans_t ve1 = (expr_pred_trans_t) p1;
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const expr_pred_trans_t ve2 = (expr_pred_trans_t) p2;
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basic_block b1 = ve1->pred;
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basic_block b2 = ve2->pred;
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/* If they are not translations for the same basic block, they can't
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be equal. */
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if (b1 != b2)
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return false;
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/* If they are for the same basic block, determine if the
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expressions are equal. */
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if (expressions_equal_p (ve1->e, ve2->e))
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return true;
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return false;
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}
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/* Search in the phi translation table for the translation of
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expression E in basic block PRED. Return the translated value, if
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found, NULL otherwise. */
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static inline tree
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phi_trans_lookup (tree e, basic_block pred)
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{
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void **slot;
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struct expr_pred_trans_d ept;
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ept.e = e;
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ept.pred = pred;
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ept.hashcode = vn_compute (e, (unsigned long) pred, NULL);
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slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
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NO_INSERT);
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if (!slot)
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return NULL;
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else
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return ((expr_pred_trans_t) *slot)->v;
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}
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/* Add the tuple mapping from {expression E, basic block PRED} to
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value V, to the phi translation table. */
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static inline void
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phi_trans_add (tree e, tree v, basic_block pred)
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{
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void **slot;
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expr_pred_trans_t new_pair = xmalloc (sizeof (*new_pair));
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new_pair->e = e;
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new_pair->pred = pred;
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new_pair->v = v;
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new_pair->hashcode = vn_compute (e, (unsigned long) pred, NULL);
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slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
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new_pair->hashcode, INSERT);
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if (*slot)
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free (*slot);
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*slot = (void *) new_pair;
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}
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/* Add expression E to the expression set of value V. */
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void
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add_to_value (tree v, tree e)
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{
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/* Constants have no expression sets. */
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if (is_gimple_min_invariant (v))
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return;
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if (VALUE_HANDLE_EXPR_SET (v) == NULL)
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VALUE_HANDLE_EXPR_SET (v) = set_new (false);
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insert_into_set (VALUE_HANDLE_EXPR_SET (v), e);
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}
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/* Return true if value V exists in the bitmap for SET. */
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static inline bool
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value_exists_in_set_bitmap (value_set_t set, tree v)
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{
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if (!set->values)
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return false;
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return bitmap_bit_p (set->values, VALUE_HANDLE_ID (v));
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}
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/* Remove value V from the bitmap for SET. */
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static void
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value_remove_from_set_bitmap (value_set_t set, tree v)
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{
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gcc_assert (set->indexed);
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if (!set->values)
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return;
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bitmap_clear_bit (set->values, VALUE_HANDLE_ID (v));
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}
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/* Insert the value number V into the bitmap of values existing in
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SET. */
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static inline void
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value_insert_into_set_bitmap (value_set_t set, tree v)
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{
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gcc_assert (set->indexed);
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if (set->values == NULL)
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{
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set->values = BITMAP_OBSTACK_ALLOC (&grand_bitmap_obstack);
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bitmap_clear (set->values);
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}
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bitmap_set_bit (set->values, VALUE_HANDLE_ID (v));
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}
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/* Create a new bitmap set and return it. */
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static bitmap_set_t
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bitmap_set_new (void)
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{
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bitmap_set_t ret = pool_alloc (bitmap_set_pool);
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ret->expressions = BITMAP_OBSTACK_ALLOC (&grand_bitmap_obstack);
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ret->values = BITMAP_OBSTACK_ALLOC (&grand_bitmap_obstack);
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bitmap_clear (ret->expressions);
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bitmap_clear (ret->values);
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return ret;
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}
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/* Create a new set. */
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static value_set_t
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set_new (bool indexed)
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{
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value_set_t ret;
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ret = pool_alloc (value_set_pool);
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ret->head = ret->tail = NULL;
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ret->length = 0;
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ret->indexed = indexed;
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ret->values = NULL;
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return ret;
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}
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/* Insert an expression EXPR into a bitmapped set. */
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static void
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bitmap_insert_into_set (bitmap_set_t set, tree expr)
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{
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tree val;
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/* XXX: For now, we only let SSA_NAMES into the bitmap sets. */
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gcc_assert (TREE_CODE (expr) == SSA_NAME);
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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. */
|
|
|
|
static void
|
|
insert_into_set (value_set_t set, tree expr)
|
|
{
|
|
value_set_node_t newnode = pool_alloc (value_set_node_pool);
|
|
tree val = get_value_handle (expr);
|
|
gcc_assert (val);
|
|
|
|
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
|
|
length. */
|
|
if (set->indexed)
|
|
value_insert_into_set_bitmap (set, val);
|
|
|
|
newnode->next = NULL;
|
|
newnode->expr = expr;
|
|
set->length ++;
|
|
if (set->head == NULL)
|
|
{
|
|
set->head = set->tail = newnode;
|
|
}
|
|
else
|
|
{
|
|
set->tail->next = newnode;
|
|
set->tail = newnode;
|
|
}
|
|
}
|
|
|
|
/* 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
|
|
set_copy (value_set_t dest, value_set_t orig)
|
|
{
|
|
value_set_node_t node;
|
|
|
|
if (!orig || !orig->head)
|
|
return;
|
|
|
|
for (node = orig->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
insert_into_set (dest, node->expr);
|
|
}
|
|
}
|
|
|
|
/* Remove EXPR from SET. */
|
|
|
|
static void
|
|
set_remove (value_set_t set, tree expr)
|
|
{
|
|
value_set_node_t node, prev;
|
|
|
|
/* Remove the value of EXPR from the bitmap, decrement the set
|
|
length, and remove it from the actual double linked list. */
|
|
value_remove_from_set_bitmap (set, get_value_handle (expr));
|
|
set->length--;
|
|
prev = NULL;
|
|
for (node = set->head;
|
|
node != NULL;
|
|
prev = node, node = node->next)
|
|
{
|
|
if (node->expr == expr)
|
|
{
|
|
if (prev == NULL)
|
|
set->head = node->next;
|
|
else
|
|
prev->next= node->next;
|
|
|
|
if (node == set->tail)
|
|
set->tail = prev;
|
|
pool_free (value_set_node_pool, node);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Return true if SET contains the value VAL. */
|
|
|
|
static bool
|
|
set_contains_value (value_set_t set, tree val)
|
|
{
|
|
/* All constants are in every set. */
|
|
if (is_gimple_min_invariant (val))
|
|
return true;
|
|
|
|
if (set->length == 0)
|
|
return false;
|
|
|
|
return value_exists_in_set_bitmap (set, val);
|
|
}
|
|
|
|
/* Return true if bitmapped set SET contains the expression EXPR. */
|
|
static bool
|
|
bitmap_set_contains (bitmap_set_t set, tree expr)
|
|
{
|
|
/* All constants are in every set. */
|
|
if (is_gimple_min_invariant (get_value_handle (expr)))
|
|
return true;
|
|
|
|
/* 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 bitmapped set SET contains the value VAL. */
|
|
|
|
static bool
|
|
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;
|
|
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 (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;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Subtract bitmapped set B from value set A, and return the new set. */
|
|
|
|
static value_set_t
|
|
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;
|
|
for (node = a->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
if (!bitmap_set_contains (b, node->expr))
|
|
insert_into_set (ret, node->expr);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Return true if two sets are equal. */
|
|
|
|
static bool
|
|
set_equal (value_set_t a, value_set_t b)
|
|
{
|
|
value_set_node_t node;
|
|
|
|
if (a->length != b->length)
|
|
return false;
|
|
for (node = a->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
if (!set_contains_value (b, get_value_handle (node->expr)))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/* Replace an instance of EXPR's VALUE with EXPR in SET. */
|
|
|
|
static void
|
|
bitmap_value_replace_in_set (bitmap_set_t set, tree expr)
|
|
{
|
|
tree val = get_value_handle (expr);
|
|
bitmap_set_replace_value (set, val, 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, tree expr)
|
|
{
|
|
tree val = get_value_handle (expr);
|
|
|
|
if (is_gimple_min_invariant (val))
|
|
return;
|
|
|
|
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. */
|
|
|
|
static void
|
|
value_insert_into_set (value_set_t set, tree expr)
|
|
{
|
|
tree val = get_value_handle (expr);
|
|
|
|
/* 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))
|
|
insert_into_set (set, expr);
|
|
}
|
|
|
|
|
|
/* 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)
|
|
{
|
|
unsigned i;
|
|
bitmap_iterator bi;
|
|
|
|
EXECUTE_IF_SET_IN_BITMAP (set->expressions, 0, i, bi)
|
|
{
|
|
print_generic_expr (outfile, ssa_name (i), 0);
|
|
|
|
fprintf (outfile, " (");
|
|
print_generic_expr (outfile, get_value_handle (ssa_name (i)), 0);
|
|
fprintf (outfile, ") ");
|
|
if (bitmap_last_set_bit (set->expressions) != (int)i)
|
|
fprintf (outfile, ", ");
|
|
}
|
|
}
|
|
fprintf (outfile, " }\n");
|
|
}
|
|
/* Print out the value_set SET to OUTFILE. */
|
|
|
|
static void
|
|
print_value_set (FILE *outfile, value_set_t set,
|
|
const char *setname, int blockindex)
|
|
{
|
|
value_set_node_t node;
|
|
fprintf (outfile, "%s[%d] := { ", setname, blockindex);
|
|
if (set)
|
|
{
|
|
for (node = set->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
print_generic_expr (outfile, node->expr, 0);
|
|
|
|
fprintf (outfile, " (");
|
|
print_generic_expr (outfile, get_value_handle (node->expr), 0);
|
|
fprintf (outfile, ") ");
|
|
|
|
if (node->next)
|
|
fprintf (outfile, ", ");
|
|
}
|
|
}
|
|
|
|
fprintf (outfile, " }\n");
|
|
}
|
|
|
|
/* Print out the expressions that have VAL to OUTFILE. */
|
|
|
|
void
|
|
print_value_expressions (FILE *outfile, tree val)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
|
|
|
|
void
|
|
debug_value_expressions (tree val)
|
|
{
|
|
print_value_expressions (stderr, val);
|
|
}
|
|
|
|
|
|
void debug_value_set (value_set_t, const char *, int);
|
|
|
|
void
|
|
debug_value_set (value_set_t set, const char *setname, int blockindex)
|
|
{
|
|
print_value_set (stderr, set, setname, blockindex);
|
|
}
|
|
|
|
/* 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 tree
|
|
phi_translate (tree expr, value_set_t set, basic_block pred,
|
|
basic_block phiblock)
|
|
{
|
|
tree phitrans = NULL;
|
|
tree oldexpr = expr;
|
|
|
|
if (expr == NULL)
|
|
return NULL;
|
|
|
|
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 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);
|
|
tree newop1;
|
|
tree newop2;
|
|
tree newexpr;
|
|
|
|
newop1 = phi_translate (find_leader (set, oldop1),
|
|
set, pred, phiblock);
|
|
if (newop1 == NULL)
|
|
return NULL;
|
|
newop2 = phi_translate (find_leader (set, oldop2),
|
|
set, pred, phiblock);
|
|
if (newop2 == NULL)
|
|
return NULL;
|
|
if (newop1 != oldop1 || newop2 != oldop2)
|
|
{
|
|
newexpr = pool_alloc (binary_node_pool);
|
|
memcpy (newexpr, expr, tree_size (expr));
|
|
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);
|
|
vn_lookup_or_add (newexpr, NULL);
|
|
expr = newexpr;
|
|
phi_trans_add (oldexpr, newexpr, pred);
|
|
}
|
|
}
|
|
return expr;
|
|
|
|
case tcc_unary:
|
|
{
|
|
tree oldop1 = TREE_OPERAND (expr, 0);
|
|
tree newop1;
|
|
tree newexpr;
|
|
|
|
newop1 = phi_translate (find_leader (set, oldop1),
|
|
set, pred, phiblock);
|
|
if (newop1 == NULL)
|
|
return NULL;
|
|
if (newop1 != oldop1)
|
|
{
|
|
newexpr = pool_alloc (unary_node_pool);
|
|
memcpy (newexpr, expr, tree_size (expr));
|
|
create_tree_ann (newexpr);
|
|
TREE_OPERAND (newexpr, 0) = get_value_handle (newop1);
|
|
vn_lookup_or_add (newexpr, NULL);
|
|
expr = newexpr;
|
|
phi_trans_add (oldexpr, newexpr, pred);
|
|
}
|
|
}
|
|
return expr;
|
|
|
|
case tcc_exceptional:
|
|
{
|
|
tree phi = NULL;
|
|
int i;
|
|
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 = vn_lookup_or_add (PHI_ARG_DEF (phi, i), NULL);
|
|
return PHI_ARG_DEF (phi, i);
|
|
}
|
|
}
|
|
return expr;
|
|
|
|
default:
|
|
gcc_unreachable ();
|
|
}
|
|
}
|
|
|
|
static void
|
|
phi_translate_set (value_set_t dest, value_set_t set, basic_block pred,
|
|
basic_block phiblock)
|
|
{
|
|
value_set_node_t node;
|
|
for (node = set->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
tree translated;
|
|
translated = phi_translate (node->expr, set, pred, phiblock);
|
|
phi_trans_add (node->expr, translated, pred);
|
|
|
|
if (translated != NULL)
|
|
value_insert_into_set (dest, translated);
|
|
}
|
|
}
|
|
|
|
/* 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. */
|
|
|
|
static tree
|
|
find_leader (value_set_t set, tree val)
|
|
{
|
|
value_set_node_t node;
|
|
|
|
if (val == NULL)
|
|
return NULL;
|
|
|
|
/* Constants represent themselves. */
|
|
if (is_gimple_min_invariant (val))
|
|
return val;
|
|
|
|
if (set->length == 0)
|
|
return NULL;
|
|
|
|
if (value_exists_in_set_bitmap (set, val))
|
|
{
|
|
for (node = set->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
if (get_value_handle (node->expr) == val)
|
|
return node->expr;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Determine if the expression EXPR is valid in SET. 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.
|
|
|
|
NB: We never should run into a case where we have SSA_NAME +
|
|
SSA_NAME or SSA_NAME + value. The sets valid_in_set is called on,
|
|
the ANTIC sets, will only ever have SSA_NAME's or binary value
|
|
expression (IE VALUE1 + VALUE2) */
|
|
|
|
static bool
|
|
valid_in_set (value_set_t set, tree expr)
|
|
{
|
|
switch (TREE_CODE_CLASS (TREE_CODE (expr)))
|
|
{
|
|
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);
|
|
}
|
|
|
|
case tcc_unary:
|
|
{
|
|
tree op1 = TREE_OPERAND (expr, 0);
|
|
return set_contains_value (set, op1);
|
|
}
|
|
|
|
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
|
|
means expressions that are made up of values we have no leaders for
|
|
in SET. */
|
|
|
|
static void
|
|
clean (value_set_t set)
|
|
{
|
|
value_set_node_t node;
|
|
value_set_node_t next;
|
|
node = set->head;
|
|
while (node)
|
|
{
|
|
next = node->next;
|
|
if (!valid_in_set (set, node->expr))
|
|
set_remove (set, node->expr);
|
|
node = next;
|
|
}
|
|
}
|
|
|
|
DEF_VEC_MALLOC_P (basic_block);
|
|
|
|
/* 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
|
|
|
|
ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] -
|
|
TMP_GEN[BLOCK])
|
|
|
|
Iterate until fixpointed.
|
|
|
|
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)
|
|
{
|
|
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))
|
|
{
|
|
edge_iterator ei;
|
|
FOR_EACH_EDGE (e, ei, block->preds)
|
|
if (e->flags & EDGE_ABNORMAL)
|
|
{
|
|
block->flags |= BB_VISITED;
|
|
break;
|
|
}
|
|
}
|
|
if (block->flags & BB_VISITED)
|
|
{
|
|
S = NULL;
|
|
goto visit_sons;
|
|
}
|
|
|
|
|
|
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 (EDGE_COUNT (block->succs) == 0);
|
|
|
|
/* If we have one successor, we could have some phi nodes to
|
|
translate through. */
|
|
else if (EDGE_COUNT (block->succs) == 1)
|
|
{
|
|
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
|
|
{
|
|
VEC (basic_block) * worklist;
|
|
edge e;
|
|
size_t i;
|
|
basic_block bprime, first;
|
|
edge_iterator ei;
|
|
|
|
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; VEC_iterate (basic_block, worklist, i, bprime); i++)
|
|
{
|
|
node = ANTIC_OUT->head;
|
|
while (node)
|
|
{
|
|
tree val;
|
|
value_set_node_t next = node->next;
|
|
val = get_value_handle (node->expr);
|
|
if (!set_contains_value (ANTIC_IN (bprime), val))
|
|
set_remove (ANTIC_OUT, node->expr);
|
|
node = next;
|
|
}
|
|
}
|
|
VEC_free (basic_block, worklist);
|
|
}
|
|
|
|
/* 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) = 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:
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
if (ANTIC_OUT)
|
|
print_value_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
|
|
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);
|
|
}
|
|
return changed;
|
|
}
|
|
|
|
/* Compute ANTIC sets. */
|
|
|
|
static void
|
|
compute_antic (void)
|
|
{
|
|
bool changed = true;
|
|
basic_block bb;
|
|
int num_iterations = 0;
|
|
FOR_ALL_BB (bb)
|
|
{
|
|
ANTIC_IN (bb) = set_new (true);
|
|
gcc_assert (!(bb->flags & BB_VISITED));
|
|
}
|
|
|
|
while (changed)
|
|
{
|
|
num_iterations++;
|
|
changed = false;
|
|
changed = compute_antic_aux (EXIT_BLOCK_PTR);
|
|
}
|
|
FOR_ALL_BB (bb)
|
|
{
|
|
bb->flags &= ~BB_VISITED;
|
|
}
|
|
if (num_iterations > 2 && dump_file && (dump_flags & TDF_STATS))
|
|
fprintf (dump_file, "compute_antic required %d iterations\n", num_iterations);
|
|
}
|
|
|
|
|
|
/* 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;
|
|
genop = bitmap_find_leader (AVAIL_OUT (block), expr);
|
|
/* 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 us already, having been propagated from our
|
|
dominator. */
|
|
if (genop == NULL)
|
|
genop = bitmap_find_leader (NEW_SETS (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;
|
|
}
|
|
|
|
|
|
/* 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 = build (TREE_CODE (expr), TREE_TYPE (expr),
|
|
genop1, genop2);
|
|
newexpr = build (MODIFY_EXPR, TREE_TYPE (expr),
|
|
temp, newexpr);
|
|
name = make_ssa_name (temp, newexpr);
|
|
TREE_OPERAND (newexpr, 0) = name;
|
|
tsi = tsi_last (stmts);
|
|
tsi_link_after (&tsi, newexpr, TSI_CONTINUE_LINKING);
|
|
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 = 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;
|
|
tsi = tsi_last (stmts);
|
|
tsi_link_after (&tsi, newexpr, TSI_CONTINUE_LINKING);
|
|
pre_stats.insertions++;
|
|
|
|
break;
|
|
}
|
|
default:
|
|
gcc_unreachable ();
|
|
|
|
}
|
|
v = get_value_handle (expr);
|
|
vn_add (name, v, NULL);
|
|
bitmap_insert_into_set (NEW_SETS (block), name);
|
|
bitmap_value_insert_into_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;
|
|
}
|
|
|
|
/* 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.
|
|
|
|
*/
|
|
static bool
|
|
insert_aux (basic_block block)
|
|
{
|
|
basic_block son;
|
|
bool new_stuff = false;
|
|
|
|
if (block)
|
|
{
|
|
basic_block dom;
|
|
dom = get_immediate_dominator (CDI_DOMINATORS, block);
|
|
if (dom)
|
|
{
|
|
unsigned i;
|
|
bitmap_iterator bi;
|
|
|
|
bitmap_set_t newset = NEW_SETS (dom);
|
|
EXECUTE_IF_SET_IN_BITMAP (newset->expressions, 0, i, bi)
|
|
{
|
|
bitmap_insert_into_set (NEW_SETS (block), ssa_name (i));
|
|
bitmap_value_replace_in_set (AVAIL_OUT (block), ssa_name (i));
|
|
}
|
|
if (EDGE_COUNT (block->preds) > 1)
|
|
{
|
|
value_set_node_t node;
|
|
for (node = ANTIC_IN (block)->head;
|
|
node;
|
|
node = node->next)
|
|
{
|
|
if (BINARY_CLASS_P (node->expr)
|
|
|| UNARY_CLASS_P (node->expr))
|
|
{
|
|
tree *avail;
|
|
tree val;
|
|
bool by_some = false;
|
|
bool cant_insert = false;
|
|
bool all_same = true;
|
|
tree first_s = NULL;
|
|
edge pred;
|
|
basic_block bprime;
|
|
tree eprime;
|
|
edge_iterator ei;
|
|
|
|
val = get_value_handle (node->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");
|
|
continue;
|
|
}
|
|
|
|
avail = xcalloc (last_basic_block, sizeof (tree));
|
|
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),
|
|
bprime, block);
|
|
|
|
/* eprime will generally only be NULL if the
|
|
value of the expression, translated
|
|
through the PHI for this predecessor, is
|
|
undefined. If that is the case, we can't
|
|
make the expression fully redundant,
|
|
because its value is undefined along a
|
|
predecessor path. We can thus break out
|
|
early because it doesn't matter what the
|
|
rest of the results are. */
|
|
if (eprime == NULL)
|
|
{
|
|
cant_insert = true;
|
|
break;
|
|
}
|
|
|
|
vprime = get_value_handle (eprime);
|
|
gcc_assert (vprime);
|
|
edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
|
|
vprime);
|
|
if (edoubleprime == NULL)
|
|
{
|
|
avail[bprime->index] = eprime;
|
|
all_same = false;
|
|
}
|
|
else
|
|
{
|
|
avail[bprime->index] = edoubleprime;
|
|
by_some = true;
|
|
if (first_s == NULL)
|
|
first_s = edoubleprime;
|
|
else if (first_s != edoubleprime)
|
|
all_same = false;
|
|
gcc_assert (first_s == edoubleprime
|
|
|| !operand_equal_p
|
|
(first_s, edoubleprime, 0));
|
|
}
|
|
}
|
|
/* If we can insert it, it's not the same value
|
|
already existing along every predecessor, and
|
|
it's defined by some predecessor, it is
|
|
partially redundant. */
|
|
if (!cant_insert && !all_same && by_some)
|
|
{
|
|
tree 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 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;
|
|
}
|
|
}
|
|
/* 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);
|
|
vn_add (PHI_RESULT (temp), val, NULL);
|
|
|
|
#if 0
|
|
if (!set_contains_value (AVAIL_OUT (block), val))
|
|
insert_into_set (AVAIL_OUT (block),
|
|
PHI_RESULT (temp));
|
|
else
|
|
#endif
|
|
bitmap_value_replace_in_set (AVAIL_OUT (block),
|
|
PHI_RESULT (temp));
|
|
FOR_EACH_EDGE (pred, ei, block->preds)
|
|
{
|
|
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;
|
|
bitmap_insert_into_set (NEW_SETS (block),
|
|
PHI_RESULT (temp));
|
|
bitmap_insert_into_set (PHI_GEN (block),
|
|
PHI_RESULT (temp));
|
|
}
|
|
|
|
free (avail);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for (son = first_dom_son (CDI_DOMINATORS, block);
|
|
son;
|
|
son = next_dom_son (CDI_DOMINATORS, son))
|
|
{
|
|
new_stuff |= insert_aux (son);
|
|
}
|
|
|
|
return new_stuff;
|
|
}
|
|
|
|
/* Perform insertion of partially redundant values. */
|
|
|
|
static void
|
|
insert (void)
|
|
{
|
|
bool new_stuff = true;
|
|
basic_block bb;
|
|
int num_iterations = 0;
|
|
|
|
FOR_ALL_BB (bb)
|
|
NEW_SETS (bb) = bitmap_set_new ();
|
|
|
|
while (new_stuff)
|
|
{
|
|
num_iterations++;
|
|
new_stuff = false;
|
|
new_stuff = insert_aux (ENTRY_BLOCK_PTR);
|
|
}
|
|
if (num_iterations > 2 && dump_file && (dump_flags & TDF_STATS))
|
|
fprintf (dump_file, "insert required %d iterations\n", num_iterations);
|
|
}
|
|
|
|
|
|
/* 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)
|
|
{
|
|
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);
|
|
|
|
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++)
|
|
{
|
|
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 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 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]. */
|
|
|
|
static void
|
|
compute_avail (basic_block block)
|
|
{
|
|
basic_block son;
|
|
|
|
/* For arguments with default definitions, we pretend they are
|
|
defined in the entry block. */
|
|
if (block == ENTRY_BLOCK_PTR)
|
|
{
|
|
tree param;
|
|
for (param = DECL_ARGUMENTS (current_function_decl);
|
|
param;
|
|
param = TREE_CHAIN (param))
|
|
{
|
|
if (default_def (param) != NULL)
|
|
{
|
|
tree val;
|
|
tree def = default_def (param);
|
|
val = vn_lookup_or_add (def, NULL);
|
|
bitmap_insert_into_set (TMP_GEN (block), def);
|
|
bitmap_value_insert_into_set (AVAIL_OUT (block), def);
|
|
}
|
|
}
|
|
}
|
|
else if (block)
|
|
{
|
|
block_stmt_iterator bsi;
|
|
tree stmt, phi;
|
|
basic_block dom;
|
|
|
|
/* Initially, the set of available values in BLOCK is that of
|
|
its immediate dominator. */
|
|
dom = get_immediate_dominator (CDI_DOMINATORS, block);
|
|
if (dom)
|
|
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))
|
|
{
|
|
stmt_ann_t ann;
|
|
size_t j;
|
|
|
|
stmt = bsi_stmt (bsi);
|
|
ann = stmt_ann (stmt);
|
|
get_stmt_operands (stmt);
|
|
|
|
/* 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)))
|
|
{
|
|
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))
|
|
{
|
|
/* 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)
|
|
{
|
|
/* 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;
|
|
}
|
|
}
|
|
|
|
/* 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++)
|
|
{
|
|
tree def = DEF_OP (STMT_DEF_OPS (stmt), j);
|
|
add_to_sets (def, def, NULL, TMP_GEN (block),
|
|
AVAIL_OUT (block));
|
|
}
|
|
|
|
for (j = 0; j < NUM_USES (STMT_USE_OPS (stmt)); j++)
|
|
{
|
|
tree use = USE_OP (STMT_USE_OPS (stmt), j);
|
|
add_to_sets (use, use, NULL, TMP_GEN (block),
|
|
AVAIL_OUT (block));
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Compute available sets for the dominator children of BLOCK. */
|
|
for (son = first_dom_son (CDI_DOMINATORS, block);
|
|
son;
|
|
son = next_dom_son (CDI_DOMINATORS, son))
|
|
compute_avail (son);
|
|
}
|
|
|
|
|
|
/* Eliminate fully redundant computations. */
|
|
|
|
static void
|
|
eliminate (void)
|
|
{
|
|
basic_block b;
|
|
|
|
FOR_EACH_BB (b)
|
|
{
|
|
block_stmt_iterator i;
|
|
|
|
for (i = bsi_start (b); !bsi_end_p (i); bsi_next (&i))
|
|
{
|
|
tree stmt = bsi_stmt (i);
|
|
|
|
/* 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_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, *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);
|
|
}
|
|
pre_stats.eliminations++;
|
|
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");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Initialize data structures used by PRE. */
|
|
|
|
static void
|
|
init_pre (void)
|
|
{
|
|
basic_block bb;
|
|
|
|
connect_infinite_loops_to_exit ();
|
|
vn_init ();
|
|
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));
|
|
|
|
gcc_obstack_init (&grand_bitmap_obstack);
|
|
phi_translate_table = htab_create (511, expr_pred_trans_hash,
|
|
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);
|
|
calculate_dominance_info (CDI_POST_DOMINATORS);
|
|
calculate_dominance_info (CDI_DOMINATORS);
|
|
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) = bitmap_set_new ();
|
|
TMP_GEN (bb) = bitmap_set_new ();
|
|
AVAIL_OUT (bb) = bitmap_set_new ();
|
|
}
|
|
|
|
need_eh_cleanup = BITMAP_XMALLOC ();
|
|
}
|
|
|
|
|
|
/* Deallocate data structures used by PRE. */
|
|
|
|
static void
|
|
fini_pre (void)
|
|
{
|
|
basic_block bb;
|
|
unsigned int i;
|
|
|
|
bsi_commit_edge_inserts (NULL);
|
|
|
|
obstack_free (&grand_bitmap_obstack, NULL);
|
|
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_XFREE (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;
|
|
}
|
|
}
|
|
|
|
|
|
/* 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 ();
|
|
|
|
/* Collect and value number expressions computed in each basic
|
|
block. */
|
|
compute_avail (ENTRY_BLOCK_PTR);
|
|
|
|
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);
|
|
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);
|
|
}
|
|
}
|
|
|
|
/* Insert can get quite slow on an incredibly large number of basic
|
|
blocks due to some quadratic behavior. Until this behavior is
|
|
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 (!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);
|
|
}
|
|
|
|
fini_pre ();
|
|
}
|
|
|
|
|
|
/* Gate and execute functions for PRE. */
|
|
|
|
static void
|
|
do_pre (void)
|
|
{
|
|
execute_pre (false);
|
|
}
|
|
|
|
static bool
|
|
gate_pre (void)
|
|
{
|
|
return flag_tree_pre != 0;
|
|
}
|
|
|
|
struct tree_opt_pass pass_pre =
|
|
{
|
|
"pre", /* name */
|
|
gate_pre, /* gate */
|
|
do_pre, /* execute */
|
|
NULL, /* sub */
|
|
NULL, /* next */
|
|
0, /* static_pass_number */
|
|
TV_TREE_PRE, /* tv_id */
|
|
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 */
|
|
0 /* letter */
|
|
};
|