/* SSA Dominator optimizations for trees
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/* SSA Dominator optimizations for trees
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Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
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Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
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Free Software Foundation, Inc.
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Free Software Foundation, Inc.
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Contributed by Diego Novillo <dnovillo@redhat.com>
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Contributed by Diego Novillo <dnovillo@redhat.com>
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This file is part of GCC.
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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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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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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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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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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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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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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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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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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "config.h"
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#include "system.h"
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#include "system.h"
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#include "coretypes.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tm.h"
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#include "tree.h"
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#include "tree.h"
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#include "flags.h"
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#include "flags.h"
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#include "rtl.h"
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#include "rtl.h"
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#include "tm_p.h"
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#include "tm_p.h"
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#include "ggc.h"
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#include "ggc.h"
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#include "basic-block.h"
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#include "basic-block.h"
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#include "cfgloop.h"
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#include "cfgloop.h"
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#include "output.h"
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#include "output.h"
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#include "expr.h"
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#include "expr.h"
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#include "function.h"
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#include "function.h"
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#include "diagnostic.h"
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#include "diagnostic.h"
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#include "timevar.h"
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#include "timevar.h"
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#include "tree-dump.h"
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#include "tree-dump.h"
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#include "tree-flow.h"
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#include "tree-flow.h"
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#include "domwalk.h"
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#include "domwalk.h"
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#include "real.h"
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#include "real.h"
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#include "tree-pass.h"
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#include "tree-pass.h"
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#include "tree-ssa-propagate.h"
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#include "tree-ssa-propagate.h"
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#include "langhooks.h"
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#include "langhooks.h"
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#include "params.h"
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#include "params.h"
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/* This file implements optimizations on the dominator tree. */
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/* This file implements optimizations on the dominator tree. */
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/* Structure for recording edge equivalences as well as any pending
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/* Structure for recording edge equivalences as well as any pending
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edge redirections during the dominator optimizer.
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edge redirections during the dominator optimizer.
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Computing and storing the edge equivalences instead of creating
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Computing and storing the edge equivalences instead of creating
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them on-demand can save significant amounts of time, particularly
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them on-demand can save significant amounts of time, particularly
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for pathological cases involving switch statements.
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for pathological cases involving switch statements.
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These structures live for a single iteration of the dominator
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These structures live for a single iteration of the dominator
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optimizer in the edge's AUX field. At the end of an iteration we
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optimizer in the edge's AUX field. At the end of an iteration we
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free each of these structures and update the AUX field to point
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free each of these structures and update the AUX field to point
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to any requested redirection target (the code for updating the
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to any requested redirection target (the code for updating the
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CFG and SSA graph for edge redirection expects redirection edge
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CFG and SSA graph for edge redirection expects redirection edge
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targets to be in the AUX field for each edge. */
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targets to be in the AUX field for each edge. */
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struct edge_info
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struct edge_info
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{
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{
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/* If this edge creates a simple equivalence, the LHS and RHS of
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/* If this edge creates a simple equivalence, the LHS and RHS of
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the equivalence will be stored here. */
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the equivalence will be stored here. */
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tree lhs;
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tree lhs;
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tree rhs;
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tree rhs;
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/* Traversing an edge may also indicate one or more particular conditions
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/* Traversing an edge may also indicate one or more particular conditions
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are true or false. The number of recorded conditions can vary, but
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are true or false. The number of recorded conditions can vary, but
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can be determined by the condition's code. So we have an array
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can be determined by the condition's code. So we have an array
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and its maximum index rather than use a varray. */
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and its maximum index rather than use a varray. */
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tree *cond_equivalences;
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tree *cond_equivalences;
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unsigned int max_cond_equivalences;
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unsigned int max_cond_equivalences;
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};
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};
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/* Hash table with expressions made available during the renaming process.
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/* Hash table with expressions made available during the renaming process.
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When an assignment of the form X_i = EXPR is found, the statement is
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When an assignment of the form X_i = EXPR is found, the statement is
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stored in this table. If the same expression EXPR is later found on the
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stored in this table. If the same expression EXPR is later found on the
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RHS of another statement, it is replaced with X_i (thus performing
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RHS of another statement, it is replaced with X_i (thus performing
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global redundancy elimination). Similarly as we pass through conditionals
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global redundancy elimination). Similarly as we pass through conditionals
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we record the conditional itself as having either a true or false value
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we record the conditional itself as having either a true or false value
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in this table. */
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in this table. */
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static htab_t avail_exprs;
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static htab_t avail_exprs;
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/* Stack of available expressions in AVAIL_EXPRs. Each block pushes any
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/* Stack of available expressions in AVAIL_EXPRs. Each block pushes any
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expressions it enters into the hash table along with a marker entry
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expressions it enters into the hash table along with a marker entry
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(null). When we finish processing the block, we pop off entries and
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(null). When we finish processing the block, we pop off entries and
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remove the expressions from the global hash table until we hit the
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remove the expressions from the global hash table until we hit the
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marker. */
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marker. */
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static VEC(tree,heap) *avail_exprs_stack;
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static VEC(tree,heap) *avail_exprs_stack;
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/* Stack of statements we need to rescan during finalization for newly
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/* Stack of statements we need to rescan during finalization for newly
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exposed variables.
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exposed variables.
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Statement rescanning must occur after the current block's available
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Statement rescanning must occur after the current block's available
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expressions are removed from AVAIL_EXPRS. Else we may change the
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expressions are removed from AVAIL_EXPRS. Else we may change the
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hash code for an expression and be unable to find/remove it from
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hash code for an expression and be unable to find/remove it from
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AVAIL_EXPRS. */
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AVAIL_EXPRS. */
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static VEC(tree,heap) *stmts_to_rescan;
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static VEC(tree,heap) *stmts_to_rescan;
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/* Structure for entries in the expression hash table.
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/* Structure for entries in the expression hash table.
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This requires more memory for the hash table entries, but allows us
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This requires more memory for the hash table entries, but allows us
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to avoid creating silly tree nodes and annotations for conditionals,
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to avoid creating silly tree nodes and annotations for conditionals,
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eliminates 2 global hash tables and two block local varrays.
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eliminates 2 global hash tables and two block local varrays.
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It also allows us to reduce the number of hash table lookups we
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It also allows us to reduce the number of hash table lookups we
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have to perform in lookup_avail_expr and finally it allows us to
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have to perform in lookup_avail_expr and finally it allows us to
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significantly reduce the number of calls into the hashing routine
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significantly reduce the number of calls into the hashing routine
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itself. */
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itself. */
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struct expr_hash_elt
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struct expr_hash_elt
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{
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{
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/* The value (lhs) of this expression. */
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/* The value (lhs) of this expression. */
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tree lhs;
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tree lhs;
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/* The expression (rhs) we want to record. */
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/* The expression (rhs) we want to record. */
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tree rhs;
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tree rhs;
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/* The stmt pointer if this element corresponds to a statement. */
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/* The stmt pointer if this element corresponds to a statement. */
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tree stmt;
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tree stmt;
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/* The hash value for RHS/ann. */
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/* The hash value for RHS/ann. */
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hashval_t hash;
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hashval_t hash;
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};
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};
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/* Stack of dest,src pairs that need to be restored during finalization.
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/* Stack of dest,src pairs that need to be restored during finalization.
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A NULL entry is used to mark the end of pairs which need to be
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A NULL entry is used to mark the end of pairs which need to be
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restored during finalization of this block. */
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restored during finalization of this block. */
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static VEC(tree,heap) *const_and_copies_stack;
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static VEC(tree,heap) *const_and_copies_stack;
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/* Track whether or not we have changed the control flow graph. */
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/* Track whether or not we have changed the control flow graph. */
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static bool cfg_altered;
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static bool cfg_altered;
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/* Bitmap of blocks that have had EH statements cleaned. We should
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/* Bitmap of blocks that have had EH statements cleaned. We should
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remove their dead edges eventually. */
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remove their dead edges eventually. */
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static bitmap need_eh_cleanup;
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static bitmap need_eh_cleanup;
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/* Statistics for dominator optimizations. */
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/* Statistics for dominator optimizations. */
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struct opt_stats_d
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struct opt_stats_d
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{
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{
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long num_stmts;
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long num_stmts;
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long num_exprs_considered;
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long num_exprs_considered;
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long num_re;
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long num_re;
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long num_const_prop;
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long num_const_prop;
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long num_copy_prop;
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long num_copy_prop;
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};
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};
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static struct opt_stats_d opt_stats;
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static struct opt_stats_d opt_stats;
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struct eq_expr_value
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struct eq_expr_value
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{
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{
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tree src;
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tree src;
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tree dst;
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tree dst;
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};
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};
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/* Local functions. */
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/* Local functions. */
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static void optimize_stmt (struct dom_walk_data *,
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static void optimize_stmt (struct dom_walk_data *,
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basic_block bb,
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basic_block bb,
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block_stmt_iterator);
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block_stmt_iterator);
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static tree lookup_avail_expr (tree, bool);
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static tree lookup_avail_expr (tree, bool);
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static hashval_t avail_expr_hash (const void *);
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static hashval_t avail_expr_hash (const void *);
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static hashval_t real_avail_expr_hash (const void *);
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static hashval_t real_avail_expr_hash (const void *);
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static int avail_expr_eq (const void *, const void *);
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static int avail_expr_eq (const void *, const void *);
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static void htab_statistics (FILE *, htab_t);
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static void htab_statistics (FILE *, htab_t);
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static void record_cond (tree, tree);
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static void record_cond (tree, tree);
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static void record_const_or_copy (tree, tree);
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static void record_const_or_copy (tree, tree);
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static void record_equality (tree, tree);
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static void record_equality (tree, tree);
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static void record_equivalences_from_phis (basic_block);
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static void record_equivalences_from_phis (basic_block);
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static void record_equivalences_from_incoming_edge (basic_block);
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static void record_equivalences_from_incoming_edge (basic_block);
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static bool eliminate_redundant_computations (tree);
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static bool eliminate_redundant_computations (tree);
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static void record_equivalences_from_stmt (tree, int, stmt_ann_t);
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static void record_equivalences_from_stmt (tree, int, stmt_ann_t);
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static void dom_thread_across_edge (struct dom_walk_data *, edge);
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static void dom_thread_across_edge (struct dom_walk_data *, edge);
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static void dom_opt_finalize_block (struct dom_walk_data *, basic_block);
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static void dom_opt_finalize_block (struct dom_walk_data *, basic_block);
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static void dom_opt_initialize_block (struct dom_walk_data *, basic_block);
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static void dom_opt_initialize_block (struct dom_walk_data *, basic_block);
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static void propagate_to_outgoing_edges (struct dom_walk_data *, basic_block);
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static void propagate_to_outgoing_edges (struct dom_walk_data *, basic_block);
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static void remove_local_expressions_from_table (void);
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static void remove_local_expressions_from_table (void);
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static void restore_vars_to_original_value (void);
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static void restore_vars_to_original_value (void);
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static edge single_incoming_edge_ignoring_loop_edges (basic_block);
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static edge single_incoming_edge_ignoring_loop_edges (basic_block);
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/* Allocate an EDGE_INFO for edge E and attach it to E.
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/* Allocate an EDGE_INFO for edge E and attach it to E.
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Return the new EDGE_INFO structure. */
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Return the new EDGE_INFO structure. */
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static struct edge_info *
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static struct edge_info *
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allocate_edge_info (edge e)
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allocate_edge_info (edge e)
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{
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{
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struct edge_info *edge_info;
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struct edge_info *edge_info;
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edge_info = XCNEW (struct edge_info);
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edge_info = XCNEW (struct edge_info);
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e->aux = edge_info;
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e->aux = edge_info;
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return edge_info;
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return edge_info;
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}
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}
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/* Free all EDGE_INFO structures associated with edges in the CFG.
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/* Free all EDGE_INFO structures associated with edges in the CFG.
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If a particular edge can be threaded, copy the redirection
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If a particular edge can be threaded, copy the redirection
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target from the EDGE_INFO structure into the edge's AUX field
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target from the EDGE_INFO structure into the edge's AUX field
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as required by code to update the CFG and SSA graph for
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as required by code to update the CFG and SSA graph for
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jump threading. */
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jump threading. */
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static void
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static void
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free_all_edge_infos (void)
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free_all_edge_infos (void)
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{
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{
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basic_block bb;
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basic_block bb;
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edge_iterator ei;
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edge_iterator ei;
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edge e;
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edge e;
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FOR_EACH_BB (bb)
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FOR_EACH_BB (bb)
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{
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{
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FOR_EACH_EDGE (e, ei, bb->preds)
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FOR_EACH_EDGE (e, ei, bb->preds)
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{
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{
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struct edge_info *edge_info = (struct edge_info *) e->aux;
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struct edge_info *edge_info = (struct edge_info *) e->aux;
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if (edge_info)
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if (edge_info)
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{
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{
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if (edge_info->cond_equivalences)
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if (edge_info->cond_equivalences)
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free (edge_info->cond_equivalences);
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free (edge_info->cond_equivalences);
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free (edge_info);
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free (edge_info);
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e->aux = NULL;
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e->aux = NULL;
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}
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}
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}
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}
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}
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}
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}
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}
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/* Jump threading, redundancy elimination and const/copy propagation.
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/* Jump threading, redundancy elimination and const/copy propagation.
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This pass may expose new symbols that need to be renamed into SSA. For
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This pass may expose new symbols that need to be renamed into SSA. For
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every new symbol exposed, its corresponding bit will be set in
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every new symbol exposed, its corresponding bit will be set in
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VARS_TO_RENAME. */
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VARS_TO_RENAME. */
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static unsigned int
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static unsigned int
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tree_ssa_dominator_optimize (void)
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tree_ssa_dominator_optimize (void)
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{
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{
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struct dom_walk_data walk_data;
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struct dom_walk_data walk_data;
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unsigned int i;
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unsigned int i;
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struct loops loops_info;
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struct loops loops_info;
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memset (&opt_stats, 0, sizeof (opt_stats));
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memset (&opt_stats, 0, sizeof (opt_stats));
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/* Create our hash tables. */
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/* Create our hash tables. */
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avail_exprs = htab_create (1024, real_avail_expr_hash, avail_expr_eq, free);
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avail_exprs = htab_create (1024, real_avail_expr_hash, avail_expr_eq, free);
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avail_exprs_stack = VEC_alloc (tree, heap, 20);
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avail_exprs_stack = VEC_alloc (tree, heap, 20);
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const_and_copies_stack = VEC_alloc (tree, heap, 20);
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const_and_copies_stack = VEC_alloc (tree, heap, 20);
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stmts_to_rescan = VEC_alloc (tree, heap, 20);
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stmts_to_rescan = VEC_alloc (tree, heap, 20);
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need_eh_cleanup = BITMAP_ALLOC (NULL);
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need_eh_cleanup = BITMAP_ALLOC (NULL);
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/* Setup callbacks for the generic dominator tree walker. */
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/* Setup callbacks for the generic dominator tree walker. */
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walk_data.walk_stmts_backward = false;
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walk_data.walk_stmts_backward = false;
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walk_data.dom_direction = CDI_DOMINATORS;
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walk_data.dom_direction = CDI_DOMINATORS;
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walk_data.initialize_block_local_data = NULL;
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walk_data.initialize_block_local_data = NULL;
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walk_data.before_dom_children_before_stmts = dom_opt_initialize_block;
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walk_data.before_dom_children_before_stmts = dom_opt_initialize_block;
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walk_data.before_dom_children_walk_stmts = optimize_stmt;
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walk_data.before_dom_children_walk_stmts = optimize_stmt;
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walk_data.before_dom_children_after_stmts = propagate_to_outgoing_edges;
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walk_data.before_dom_children_after_stmts = propagate_to_outgoing_edges;
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walk_data.after_dom_children_before_stmts = NULL;
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walk_data.after_dom_children_before_stmts = NULL;
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walk_data.after_dom_children_walk_stmts = NULL;
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walk_data.after_dom_children_walk_stmts = NULL;
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walk_data.after_dom_children_after_stmts = dom_opt_finalize_block;
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walk_data.after_dom_children_after_stmts = dom_opt_finalize_block;
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/* Right now we only attach a dummy COND_EXPR to the global data pointer.
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/* Right now we only attach a dummy COND_EXPR to the global data pointer.
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When we attach more stuff we'll need to fill this out with a real
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When we attach more stuff we'll need to fill this out with a real
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structure. */
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structure. */
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walk_data.global_data = NULL;
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walk_data.global_data = NULL;
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walk_data.block_local_data_size = 0;
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walk_data.block_local_data_size = 0;
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walk_data.interesting_blocks = NULL;
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walk_data.interesting_blocks = NULL;
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/* Now initialize the dominator walker. */
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/* Now initialize the dominator walker. */
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init_walk_dominator_tree (&walk_data);
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init_walk_dominator_tree (&walk_data);
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calculate_dominance_info (CDI_DOMINATORS);
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calculate_dominance_info (CDI_DOMINATORS);
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/* We need to know which edges exit loops so that we can
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/* We need to know which edges exit loops so that we can
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aggressively thread through loop headers to an exit
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aggressively thread through loop headers to an exit
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edge. */
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edge. */
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flow_loops_find (&loops_info);
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flow_loops_find (&loops_info);
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mark_loop_exit_edges (&loops_info);
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mark_loop_exit_edges (&loops_info);
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flow_loops_free (&loops_info);
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flow_loops_free (&loops_info);
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/* Clean up the CFG so that any forwarder blocks created by loop
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/* Clean up the CFG so that any forwarder blocks created by loop
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canonicalization are removed. */
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canonicalization are removed. */
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cleanup_tree_cfg ();
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cleanup_tree_cfg ();
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calculate_dominance_info (CDI_DOMINATORS);
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calculate_dominance_info (CDI_DOMINATORS);
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/* We need accurate information regarding back edges in the CFG
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/* We need accurate information regarding back edges in the CFG
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for jump threading. */
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for jump threading. */
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mark_dfs_back_edges ();
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mark_dfs_back_edges ();
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/* Recursively walk the dominator tree optimizing statements. */
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/* Recursively walk the dominator tree optimizing statements. */
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walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
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walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
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|
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{
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{
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block_stmt_iterator bsi;
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block_stmt_iterator bsi;
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basic_block bb;
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basic_block bb;
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FOR_EACH_BB (bb)
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FOR_EACH_BB (bb)
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{
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{
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for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
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for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
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update_stmt_if_modified (bsi_stmt (bsi));
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update_stmt_if_modified (bsi_stmt (bsi));
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}
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}
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}
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}
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/* If we exposed any new variables, go ahead and put them into
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/* If we exposed any new variables, go ahead and put them into
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SSA form now, before we handle jump threading. This simplifies
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SSA form now, before we handle jump threading. This simplifies
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interactions between rewriting of _DECL nodes into SSA form
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interactions between rewriting of _DECL nodes into SSA form
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and rewriting SSA_NAME nodes into SSA form after block
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and rewriting SSA_NAME nodes into SSA form after block
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duplication and CFG manipulation. */
|
duplication and CFG manipulation. */
|
update_ssa (TODO_update_ssa);
|
update_ssa (TODO_update_ssa);
|
|
|
free_all_edge_infos ();
|
free_all_edge_infos ();
|
|
|
/* Thread jumps, creating duplicate blocks as needed. */
|
/* Thread jumps, creating duplicate blocks as needed. */
|
cfg_altered |= thread_through_all_blocks ();
|
cfg_altered |= thread_through_all_blocks ();
|
|
|
/* Removal of statements may make some EH edges dead. Purge
|
/* Removal of statements may make some EH edges dead. Purge
|
such edges from the CFG as needed. */
|
such edges from the CFG as needed. */
|
if (!bitmap_empty_p (need_eh_cleanup))
|
if (!bitmap_empty_p (need_eh_cleanup))
|
{
|
{
|
cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup);
|
cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup);
|
bitmap_zero (need_eh_cleanup);
|
bitmap_zero (need_eh_cleanup);
|
}
|
}
|
|
|
if (cfg_altered)
|
if (cfg_altered)
|
free_dominance_info (CDI_DOMINATORS);
|
free_dominance_info (CDI_DOMINATORS);
|
|
|
/* Finally, remove everything except invariants in SSA_NAME_VALUE.
|
/* Finally, remove everything except invariants in SSA_NAME_VALUE.
|
|
|
Long term we will be able to let everything in SSA_NAME_VALUE
|
Long term we will be able to let everything in SSA_NAME_VALUE
|
persist. However, for now, we know this is the safe thing to do. */
|
persist. However, for now, we know this is the safe thing to do. */
|
for (i = 0; i < num_ssa_names; i++)
|
for (i = 0; i < num_ssa_names; i++)
|
{
|
{
|
tree name = ssa_name (i);
|
tree name = ssa_name (i);
|
tree value;
|
tree value;
|
|
|
if (!name)
|
if (!name)
|
continue;
|
continue;
|
|
|
value = SSA_NAME_VALUE (name);
|
value = SSA_NAME_VALUE (name);
|
if (value && !is_gimple_min_invariant (value))
|
if (value && !is_gimple_min_invariant (value))
|
SSA_NAME_VALUE (name) = NULL;
|
SSA_NAME_VALUE (name) = NULL;
|
}
|
}
|
|
|
/* Debugging dumps. */
|
/* Debugging dumps. */
|
if (dump_file && (dump_flags & TDF_STATS))
|
if (dump_file && (dump_flags & TDF_STATS))
|
dump_dominator_optimization_stats (dump_file);
|
dump_dominator_optimization_stats (dump_file);
|
|
|
/* Delete our main hashtable. */
|
/* Delete our main hashtable. */
|
htab_delete (avail_exprs);
|
htab_delete (avail_exprs);
|
|
|
/* And finalize the dominator walker. */
|
/* And finalize the dominator walker. */
|
fini_walk_dominator_tree (&walk_data);
|
fini_walk_dominator_tree (&walk_data);
|
|
|
/* Free asserted bitmaps and stacks. */
|
/* Free asserted bitmaps and stacks. */
|
BITMAP_FREE (need_eh_cleanup);
|
BITMAP_FREE (need_eh_cleanup);
|
|
|
VEC_free (tree, heap, avail_exprs_stack);
|
VEC_free (tree, heap, avail_exprs_stack);
|
VEC_free (tree, heap, const_and_copies_stack);
|
VEC_free (tree, heap, const_and_copies_stack);
|
VEC_free (tree, heap, stmts_to_rescan);
|
VEC_free (tree, heap, stmts_to_rescan);
|
return 0;
|
return 0;
|
}
|
}
|
|
|
static bool
|
static bool
|
gate_dominator (void)
|
gate_dominator (void)
|
{
|
{
|
return flag_tree_dom != 0;
|
return flag_tree_dom != 0;
|
}
|
}
|
|
|
struct tree_opt_pass pass_dominator =
|
struct tree_opt_pass pass_dominator =
|
{
|
{
|
"dom", /* name */
|
"dom", /* name */
|
gate_dominator, /* gate */
|
gate_dominator, /* gate */
|
tree_ssa_dominator_optimize, /* execute */
|
tree_ssa_dominator_optimize, /* execute */
|
NULL, /* sub */
|
NULL, /* sub */
|
NULL, /* next */
|
NULL, /* next */
|
0, /* static_pass_number */
|
0, /* static_pass_number */
|
TV_TREE_SSA_DOMINATOR_OPTS, /* tv_id */
|
TV_TREE_SSA_DOMINATOR_OPTS, /* tv_id */
|
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
|
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
|
0, /* properties_provided */
|
0, /* properties_provided */
|
PROP_smt_usage, /* properties_destroyed */
|
PROP_smt_usage, /* properties_destroyed */
|
0, /* todo_flags_start */
|
0, /* todo_flags_start */
|
TODO_dump_func
|
TODO_dump_func
|
| TODO_update_ssa
|
| TODO_update_ssa
|
| TODO_cleanup_cfg
|
| TODO_cleanup_cfg
|
| TODO_verify_ssa
|
| TODO_verify_ssa
|
| TODO_update_smt_usage, /* todo_flags_finish */
|
| TODO_update_smt_usage, /* todo_flags_finish */
|
0 /* letter */
|
0 /* letter */
|
};
|
};
|
|
|
|
|
/* Given a stmt CONDSTMT containing a COND_EXPR, canonicalize the
|
/* Given a stmt CONDSTMT containing a COND_EXPR, canonicalize the
|
COND_EXPR into a canonical form. */
|
COND_EXPR into a canonical form. */
|
|
|
static void
|
static void
|
canonicalize_comparison (tree condstmt)
|
canonicalize_comparison (tree condstmt)
|
{
|
{
|
tree cond = COND_EXPR_COND (condstmt);
|
tree cond = COND_EXPR_COND (condstmt);
|
tree op0;
|
tree op0;
|
tree op1;
|
tree op1;
|
enum tree_code code = TREE_CODE (cond);
|
enum tree_code code = TREE_CODE (cond);
|
|
|
if (!COMPARISON_CLASS_P (cond))
|
if (!COMPARISON_CLASS_P (cond))
|
return;
|
return;
|
|
|
op0 = TREE_OPERAND (cond, 0);
|
op0 = TREE_OPERAND (cond, 0);
|
op1 = TREE_OPERAND (cond, 1);
|
op1 = TREE_OPERAND (cond, 1);
|
|
|
/* If it would be profitable to swap the operands, then do so to
|
/* If it would be profitable to swap the operands, then do so to
|
canonicalize the statement, enabling better optimization.
|
canonicalize the statement, enabling better optimization.
|
|
|
By placing canonicalization of such expressions here we
|
By placing canonicalization of such expressions here we
|
transparently keep statements in canonical form, even
|
transparently keep statements in canonical form, even
|
when the statement is modified. */
|
when the statement is modified. */
|
if (tree_swap_operands_p (op0, op1, false))
|
if (tree_swap_operands_p (op0, op1, false))
|
{
|
{
|
/* For relationals we need to swap the operands
|
/* For relationals we need to swap the operands
|
and change the code. */
|
and change the code. */
|
if (code == LT_EXPR
|
if (code == LT_EXPR
|
|| code == GT_EXPR
|
|| code == GT_EXPR
|
|| code == LE_EXPR
|
|| code == LE_EXPR
|
|| code == GE_EXPR)
|
|| code == GE_EXPR)
|
{
|
{
|
TREE_SET_CODE (cond, swap_tree_comparison (code));
|
TREE_SET_CODE (cond, swap_tree_comparison (code));
|
swap_tree_operands (condstmt,
|
swap_tree_operands (condstmt,
|
&TREE_OPERAND (cond, 0),
|
&TREE_OPERAND (cond, 0),
|
&TREE_OPERAND (cond, 1));
|
&TREE_OPERAND (cond, 1));
|
/* If one operand was in the operand cache, but the other is
|
/* If one operand was in the operand cache, but the other is
|
not, because it is a constant, this is a case that the
|
not, because it is a constant, this is a case that the
|
internal updating code of swap_tree_operands can't handle
|
internal updating code of swap_tree_operands can't handle
|
properly. */
|
properly. */
|
if (TREE_CODE_CLASS (TREE_CODE (op0))
|
if (TREE_CODE_CLASS (TREE_CODE (op0))
|
!= TREE_CODE_CLASS (TREE_CODE (op1)))
|
!= TREE_CODE_CLASS (TREE_CODE (op1)))
|
update_stmt (condstmt);
|
update_stmt (condstmt);
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* Initialize local stacks for this optimizer and record equivalences
|
/* Initialize local stacks for this optimizer and record equivalences
|
upon entry to BB. Equivalences can come from the edge traversed to
|
upon entry to BB. Equivalences can come from the edge traversed to
|
reach BB or they may come from PHI nodes at the start of BB. */
|
reach BB or they may come from PHI nodes at the start of BB. */
|
|
|
static void
|
static void
|
dom_opt_initialize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
|
dom_opt_initialize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
|
basic_block bb)
|
basic_block bb)
|
{
|
{
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
fprintf (dump_file, "\n\nOptimizing block #%d\n\n", bb->index);
|
fprintf (dump_file, "\n\nOptimizing block #%d\n\n", bb->index);
|
|
|
/* Push a marker on the stacks of local information so that we know how
|
/* Push a marker on the stacks of local information so that we know how
|
far to unwind when we finalize this block. */
|
far to unwind when we finalize this block. */
|
VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
|
|
|
record_equivalences_from_incoming_edge (bb);
|
record_equivalences_from_incoming_edge (bb);
|
|
|
/* PHI nodes can create equivalences too. */
|
/* PHI nodes can create equivalences too. */
|
record_equivalences_from_phis (bb);
|
record_equivalences_from_phis (bb);
|
}
|
}
|
|
|
/* Given an expression EXPR (a relational expression or a statement),
|
/* Given an expression EXPR (a relational expression or a statement),
|
initialize the hash table element pointed to by ELEMENT. */
|
initialize the hash table element pointed to by ELEMENT. */
|
|
|
static void
|
static void
|
initialize_hash_element (tree expr, tree lhs, struct expr_hash_elt *element)
|
initialize_hash_element (tree expr, tree lhs, struct expr_hash_elt *element)
|
{
|
{
|
/* Hash table elements may be based on conditional expressions or statements.
|
/* Hash table elements may be based on conditional expressions or statements.
|
|
|
For the former case, we have no annotation and we want to hash the
|
For the former case, we have no annotation and we want to hash the
|
conditional expression. In the latter case we have an annotation and
|
conditional expression. In the latter case we have an annotation and
|
we want to record the expression the statement evaluates. */
|
we want to record the expression the statement evaluates. */
|
if (COMPARISON_CLASS_P (expr) || TREE_CODE (expr) == TRUTH_NOT_EXPR)
|
if (COMPARISON_CLASS_P (expr) || TREE_CODE (expr) == TRUTH_NOT_EXPR)
|
{
|
{
|
element->stmt = NULL;
|
element->stmt = NULL;
|
element->rhs = expr;
|
element->rhs = expr;
|
}
|
}
|
else if (TREE_CODE (expr) == COND_EXPR)
|
else if (TREE_CODE (expr) == COND_EXPR)
|
{
|
{
|
element->stmt = expr;
|
element->stmt = expr;
|
element->rhs = COND_EXPR_COND (expr);
|
element->rhs = COND_EXPR_COND (expr);
|
}
|
}
|
else if (TREE_CODE (expr) == SWITCH_EXPR)
|
else if (TREE_CODE (expr) == SWITCH_EXPR)
|
{
|
{
|
element->stmt = expr;
|
element->stmt = expr;
|
element->rhs = SWITCH_COND (expr);
|
element->rhs = SWITCH_COND (expr);
|
}
|
}
|
else if (TREE_CODE (expr) == RETURN_EXPR && TREE_OPERAND (expr, 0))
|
else if (TREE_CODE (expr) == RETURN_EXPR && TREE_OPERAND (expr, 0))
|
{
|
{
|
element->stmt = expr;
|
element->stmt = expr;
|
element->rhs = TREE_OPERAND (TREE_OPERAND (expr, 0), 1);
|
element->rhs = TREE_OPERAND (TREE_OPERAND (expr, 0), 1);
|
}
|
}
|
else if (TREE_CODE (expr) == GOTO_EXPR)
|
else if (TREE_CODE (expr) == GOTO_EXPR)
|
{
|
{
|
element->stmt = expr;
|
element->stmt = expr;
|
element->rhs = GOTO_DESTINATION (expr);
|
element->rhs = GOTO_DESTINATION (expr);
|
}
|
}
|
else
|
else
|
{
|
{
|
element->stmt = expr;
|
element->stmt = expr;
|
element->rhs = TREE_OPERAND (expr, 1);
|
element->rhs = TREE_OPERAND (expr, 1);
|
}
|
}
|
|
|
element->lhs = lhs;
|
element->lhs = lhs;
|
element->hash = avail_expr_hash (element);
|
element->hash = avail_expr_hash (element);
|
}
|
}
|
|
|
/* Remove all the expressions in LOCALS from TABLE, stopping when there are
|
/* Remove all the expressions in LOCALS from TABLE, stopping when there are
|
LIMIT entries left in LOCALs. */
|
LIMIT entries left in LOCALs. */
|
|
|
static void
|
static void
|
remove_local_expressions_from_table (void)
|
remove_local_expressions_from_table (void)
|
{
|
{
|
/* Remove all the expressions made available in this block. */
|
/* Remove all the expressions made available in this block. */
|
while (VEC_length (tree, avail_exprs_stack) > 0)
|
while (VEC_length (tree, avail_exprs_stack) > 0)
|
{
|
{
|
struct expr_hash_elt element;
|
struct expr_hash_elt element;
|
tree expr = VEC_pop (tree, avail_exprs_stack);
|
tree expr = VEC_pop (tree, avail_exprs_stack);
|
|
|
if (expr == NULL_TREE)
|
if (expr == NULL_TREE)
|
break;
|
break;
|
|
|
initialize_hash_element (expr, NULL, &element);
|
initialize_hash_element (expr, NULL, &element);
|
htab_remove_elt_with_hash (avail_exprs, &element, element.hash);
|
htab_remove_elt_with_hash (avail_exprs, &element, element.hash);
|
}
|
}
|
}
|
}
|
|
|
/* Use the source/dest pairs in CONST_AND_COPIES_STACK to restore
|
/* Use the source/dest pairs in CONST_AND_COPIES_STACK to restore
|
CONST_AND_COPIES to its original state, stopping when we hit a
|
CONST_AND_COPIES to its original state, stopping when we hit a
|
NULL marker. */
|
NULL marker. */
|
|
|
static void
|
static void
|
restore_vars_to_original_value (void)
|
restore_vars_to_original_value (void)
|
{
|
{
|
while (VEC_length (tree, const_and_copies_stack) > 0)
|
while (VEC_length (tree, const_and_copies_stack) > 0)
|
{
|
{
|
tree prev_value, dest;
|
tree prev_value, dest;
|
|
|
dest = VEC_pop (tree, const_and_copies_stack);
|
dest = VEC_pop (tree, const_and_copies_stack);
|
|
|
if (dest == NULL)
|
if (dest == NULL)
|
break;
|
break;
|
|
|
prev_value = VEC_pop (tree, const_and_copies_stack);
|
prev_value = VEC_pop (tree, const_and_copies_stack);
|
SSA_NAME_VALUE (dest) = prev_value;
|
SSA_NAME_VALUE (dest) = prev_value;
|
}
|
}
|
}
|
}
|
|
|
/* A trivial wrapper so that we can present the generic jump
|
/* A trivial wrapper so that we can present the generic jump
|
threading code with a simple API for simplifying statements. */
|
threading code with a simple API for simplifying statements. */
|
static tree
|
static tree
|
simplify_stmt_for_jump_threading (tree stmt, tree within_stmt ATTRIBUTE_UNUSED)
|
simplify_stmt_for_jump_threading (tree stmt, tree within_stmt ATTRIBUTE_UNUSED)
|
{
|
{
|
return lookup_avail_expr (stmt, false);
|
return lookup_avail_expr (stmt, false);
|
}
|
}
|
|
|
/* Wrapper for common code to attempt to thread an edge. For example,
|
/* Wrapper for common code to attempt to thread an edge. For example,
|
it handles lazily building the dummy condition and the bookkeeping
|
it handles lazily building the dummy condition and the bookkeeping
|
when jump threading is successful. */
|
when jump threading is successful. */
|
|
|
static void
|
static void
|
dom_thread_across_edge (struct dom_walk_data *walk_data, edge e)
|
dom_thread_across_edge (struct dom_walk_data *walk_data, edge e)
|
{
|
{
|
/* If we don't already have a dummy condition, build it now. */
|
/* If we don't already have a dummy condition, build it now. */
|
if (! walk_data->global_data)
|
if (! walk_data->global_data)
|
{
|
{
|
tree dummy_cond = build2 (NE_EXPR, boolean_type_node,
|
tree dummy_cond = build2 (NE_EXPR, boolean_type_node,
|
integer_zero_node, integer_zero_node);
|
integer_zero_node, integer_zero_node);
|
dummy_cond = build3 (COND_EXPR, void_type_node, dummy_cond, NULL, NULL);
|
dummy_cond = build3 (COND_EXPR, void_type_node, dummy_cond, NULL, NULL);
|
walk_data->global_data = dummy_cond;
|
walk_data->global_data = dummy_cond;
|
}
|
}
|
|
|
thread_across_edge (walk_data->global_data, e, false,
|
thread_across_edge (walk_data->global_data, e, false,
|
&const_and_copies_stack,
|
&const_and_copies_stack,
|
simplify_stmt_for_jump_threading);
|
simplify_stmt_for_jump_threading);
|
}
|
}
|
|
|
/* We have finished processing the dominator children of BB, perform
|
/* We have finished processing the dominator children of BB, perform
|
any finalization actions in preparation for leaving this node in
|
any finalization actions in preparation for leaving this node in
|
the dominator tree. */
|
the dominator tree. */
|
|
|
static void
|
static void
|
dom_opt_finalize_block (struct dom_walk_data *walk_data, basic_block bb)
|
dom_opt_finalize_block (struct dom_walk_data *walk_data, basic_block bb)
|
{
|
{
|
tree last;
|
tree last;
|
|
|
|
|
/* If we have an outgoing edge to a block with multiple incoming and
|
/* If we have an outgoing edge to a block with multiple incoming and
|
outgoing edges, then we may be able to thread the edge. ie, we
|
outgoing edges, then we may be able to thread the edge. ie, we
|
may be able to statically determine which of the outgoing edges
|
may be able to statically determine which of the outgoing edges
|
will be traversed when the incoming edge from BB is traversed. */
|
will be traversed when the incoming edge from BB is traversed. */
|
if (single_succ_p (bb)
|
if (single_succ_p (bb)
|
&& (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0
|
&& (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0
|
&& potentially_threadable_block (single_succ (bb)))
|
&& potentially_threadable_block (single_succ (bb)))
|
{
|
{
|
dom_thread_across_edge (walk_data, single_succ_edge (bb));
|
dom_thread_across_edge (walk_data, single_succ_edge (bb));
|
}
|
}
|
else if ((last = last_stmt (bb))
|
else if ((last = last_stmt (bb))
|
&& TREE_CODE (last) == COND_EXPR
|
&& TREE_CODE (last) == COND_EXPR
|
&& (COMPARISON_CLASS_P (COND_EXPR_COND (last))
|
&& (COMPARISON_CLASS_P (COND_EXPR_COND (last))
|
|| TREE_CODE (COND_EXPR_COND (last)) == SSA_NAME)
|
|| TREE_CODE (COND_EXPR_COND (last)) == SSA_NAME)
|
&& EDGE_COUNT (bb->succs) == 2
|
&& EDGE_COUNT (bb->succs) == 2
|
&& (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) == 0
|
&& (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) == 0
|
&& (EDGE_SUCC (bb, 1)->flags & EDGE_ABNORMAL) == 0)
|
&& (EDGE_SUCC (bb, 1)->flags & EDGE_ABNORMAL) == 0)
|
{
|
{
|
edge true_edge, false_edge;
|
edge true_edge, false_edge;
|
|
|
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
|
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
|
|
|
/* Only try to thread the edge if it reaches a target block with
|
/* Only try to thread the edge if it reaches a target block with
|
more than one predecessor and more than one successor. */
|
more than one predecessor and more than one successor. */
|
if (potentially_threadable_block (true_edge->dest))
|
if (potentially_threadable_block (true_edge->dest))
|
{
|
{
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
unsigned int i;
|
unsigned int i;
|
|
|
/* Push a marker onto the available expression stack so that we
|
/* Push a marker onto the available expression stack so that we
|
unwind any expressions related to the TRUE arm before processing
|
unwind any expressions related to the TRUE arm before processing
|
the false arm below. */
|
the false arm below. */
|
VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
|
|
|
edge_info = (struct edge_info *) true_edge->aux;
|
edge_info = (struct edge_info *) true_edge->aux;
|
|
|
/* If we have info associated with this edge, record it into
|
/* If we have info associated with this edge, record it into
|
our equivalency tables. */
|
our equivalency tables. */
|
if (edge_info)
|
if (edge_info)
|
{
|
{
|
tree *cond_equivalences = edge_info->cond_equivalences;
|
tree *cond_equivalences = edge_info->cond_equivalences;
|
tree lhs = edge_info->lhs;
|
tree lhs = edge_info->lhs;
|
tree rhs = edge_info->rhs;
|
tree rhs = edge_info->rhs;
|
|
|
/* If we have a simple NAME = VALUE equivalency record it. */
|
/* If we have a simple NAME = VALUE equivalency record it. */
|
if (lhs && TREE_CODE (lhs) == SSA_NAME)
|
if (lhs && TREE_CODE (lhs) == SSA_NAME)
|
record_const_or_copy (lhs, rhs);
|
record_const_or_copy (lhs, rhs);
|
|
|
/* If we have 0 = COND or 1 = COND equivalences, record them
|
/* If we have 0 = COND or 1 = COND equivalences, record them
|
into our expression hash tables. */
|
into our expression hash tables. */
|
if (cond_equivalences)
|
if (cond_equivalences)
|
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
|
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
|
{
|
{
|
tree expr = cond_equivalences[i];
|
tree expr = cond_equivalences[i];
|
tree value = cond_equivalences[i + 1];
|
tree value = cond_equivalences[i + 1];
|
|
|
record_cond (expr, value);
|
record_cond (expr, value);
|
}
|
}
|
}
|
}
|
|
|
dom_thread_across_edge (walk_data, true_edge);
|
dom_thread_across_edge (walk_data, true_edge);
|
|
|
/* And restore the various tables to their state before
|
/* And restore the various tables to their state before
|
we threaded this edge. */
|
we threaded this edge. */
|
remove_local_expressions_from_table ();
|
remove_local_expressions_from_table ();
|
}
|
}
|
|
|
/* Similarly for the ELSE arm. */
|
/* Similarly for the ELSE arm. */
|
if (potentially_threadable_block (false_edge->dest))
|
if (potentially_threadable_block (false_edge->dest))
|
{
|
{
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
unsigned int i;
|
unsigned int i;
|
|
|
VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
|
VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
|
edge_info = (struct edge_info *) false_edge->aux;
|
edge_info = (struct edge_info *) false_edge->aux;
|
|
|
/* If we have info associated with this edge, record it into
|
/* If we have info associated with this edge, record it into
|
our equivalency tables. */
|
our equivalency tables. */
|
if (edge_info)
|
if (edge_info)
|
{
|
{
|
tree *cond_equivalences = edge_info->cond_equivalences;
|
tree *cond_equivalences = edge_info->cond_equivalences;
|
tree lhs = edge_info->lhs;
|
tree lhs = edge_info->lhs;
|
tree rhs = edge_info->rhs;
|
tree rhs = edge_info->rhs;
|
|
|
/* If we have a simple NAME = VALUE equivalency record it. */
|
/* If we have a simple NAME = VALUE equivalency record it. */
|
if (lhs && TREE_CODE (lhs) == SSA_NAME)
|
if (lhs && TREE_CODE (lhs) == SSA_NAME)
|
record_const_or_copy (lhs, rhs);
|
record_const_or_copy (lhs, rhs);
|
|
|
/* If we have 0 = COND or 1 = COND equivalences, record them
|
/* If we have 0 = COND or 1 = COND equivalences, record them
|
into our expression hash tables. */
|
into our expression hash tables. */
|
if (cond_equivalences)
|
if (cond_equivalences)
|
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
|
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
|
{
|
{
|
tree expr = cond_equivalences[i];
|
tree expr = cond_equivalences[i];
|
tree value = cond_equivalences[i + 1];
|
tree value = cond_equivalences[i + 1];
|
|
|
record_cond (expr, value);
|
record_cond (expr, value);
|
}
|
}
|
}
|
}
|
|
|
/* Now thread the edge. */
|
/* Now thread the edge. */
|
dom_thread_across_edge (walk_data, false_edge);
|
dom_thread_across_edge (walk_data, false_edge);
|
|
|
/* No need to remove local expressions from our tables
|
/* No need to remove local expressions from our tables
|
or restore vars to their original value as that will
|
or restore vars to their original value as that will
|
be done immediately below. */
|
be done immediately below. */
|
}
|
}
|
}
|
}
|
|
|
remove_local_expressions_from_table ();
|
remove_local_expressions_from_table ();
|
restore_vars_to_original_value ();
|
restore_vars_to_original_value ();
|
|
|
/* If we queued any statements to rescan in this block, then
|
/* If we queued any statements to rescan in this block, then
|
go ahead and rescan them now. */
|
go ahead and rescan them now. */
|
while (VEC_length (tree, stmts_to_rescan) > 0)
|
while (VEC_length (tree, stmts_to_rescan) > 0)
|
{
|
{
|
tree stmt = VEC_last (tree, stmts_to_rescan);
|
tree stmt = VEC_last (tree, stmts_to_rescan);
|
basic_block stmt_bb = bb_for_stmt (stmt);
|
basic_block stmt_bb = bb_for_stmt (stmt);
|
|
|
if (stmt_bb != bb)
|
if (stmt_bb != bb)
|
break;
|
break;
|
|
|
VEC_pop (tree, stmts_to_rescan);
|
VEC_pop (tree, stmts_to_rescan);
|
mark_new_vars_to_rename (stmt);
|
mark_new_vars_to_rename (stmt);
|
}
|
}
|
}
|
}
|
|
|
/* PHI nodes can create equivalences too.
|
/* PHI nodes can create equivalences too.
|
|
|
Ignoring any alternatives which are the same as the result, if
|
Ignoring any alternatives which are the same as the result, if
|
all the alternatives are equal, then the PHI node creates an
|
all the alternatives are equal, then the PHI node creates an
|
equivalence. */
|
equivalence. */
|
|
|
static void
|
static void
|
record_equivalences_from_phis (basic_block bb)
|
record_equivalences_from_phis (basic_block bb)
|
{
|
{
|
tree phi;
|
tree phi;
|
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
{
|
{
|
tree lhs = PHI_RESULT (phi);
|
tree lhs = PHI_RESULT (phi);
|
tree rhs = NULL;
|
tree rhs = NULL;
|
int i;
|
int i;
|
|
|
for (i = 0; i < PHI_NUM_ARGS (phi); i++)
|
for (i = 0; i < PHI_NUM_ARGS (phi); i++)
|
{
|
{
|
tree t = PHI_ARG_DEF (phi, i);
|
tree t = PHI_ARG_DEF (phi, i);
|
|
|
/* Ignore alternatives which are the same as our LHS. Since
|
/* Ignore alternatives which are the same as our LHS. Since
|
LHS is a PHI_RESULT, it is known to be a SSA_NAME, so we
|
LHS is a PHI_RESULT, it is known to be a SSA_NAME, so we
|
can simply compare pointers. */
|
can simply compare pointers. */
|
if (lhs == t)
|
if (lhs == t)
|
continue;
|
continue;
|
|
|
/* If we have not processed an alternative yet, then set
|
/* If we have not processed an alternative yet, then set
|
RHS to this alternative. */
|
RHS to this alternative. */
|
if (rhs == NULL)
|
if (rhs == NULL)
|
rhs = t;
|
rhs = t;
|
/* If we have processed an alternative (stored in RHS), then
|
/* If we have processed an alternative (stored in RHS), then
|
see if it is equal to this one. If it isn't, then stop
|
see if it is equal to this one. If it isn't, then stop
|
the search. */
|
the search. */
|
else if (! operand_equal_for_phi_arg_p (rhs, t))
|
else if (! operand_equal_for_phi_arg_p (rhs, t))
|
break;
|
break;
|
}
|
}
|
|
|
/* If we had no interesting alternatives, then all the RHS alternatives
|
/* If we had no interesting alternatives, then all the RHS alternatives
|
must have been the same as LHS. */
|
must have been the same as LHS. */
|
if (!rhs)
|
if (!rhs)
|
rhs = lhs;
|
rhs = lhs;
|
|
|
/* If we managed to iterate through each PHI alternative without
|
/* If we managed to iterate through each PHI alternative without
|
breaking out of the loop, then we have a PHI which may create
|
breaking out of the loop, then we have a PHI which may create
|
a useful equivalence. We do not need to record unwind data for
|
a useful equivalence. We do not need to record unwind data for
|
this, since this is a true assignment and not an equivalence
|
this, since this is a true assignment and not an equivalence
|
inferred from a comparison. All uses of this ssa name are dominated
|
inferred from a comparison. All uses of this ssa name are dominated
|
by this assignment, so unwinding just costs time and space. */
|
by this assignment, so unwinding just costs time and space. */
|
if (i == PHI_NUM_ARGS (phi)
|
if (i == PHI_NUM_ARGS (phi)
|
&& may_propagate_copy (lhs, rhs))
|
&& may_propagate_copy (lhs, rhs))
|
SSA_NAME_VALUE (lhs) = rhs;
|
SSA_NAME_VALUE (lhs) = rhs;
|
}
|
}
|
}
|
}
|
|
|
/* Ignoring loop backedges, if BB has precisely one incoming edge then
|
/* Ignoring loop backedges, if BB has precisely one incoming edge then
|
return that edge. Otherwise return NULL. */
|
return that edge. Otherwise return NULL. */
|
static edge
|
static edge
|
single_incoming_edge_ignoring_loop_edges (basic_block bb)
|
single_incoming_edge_ignoring_loop_edges (basic_block bb)
|
{
|
{
|
edge retval = NULL;
|
edge retval = NULL;
|
edge e;
|
edge e;
|
edge_iterator ei;
|
edge_iterator ei;
|
|
|
FOR_EACH_EDGE (e, ei, bb->preds)
|
FOR_EACH_EDGE (e, ei, bb->preds)
|
{
|
{
|
/* A loop back edge can be identified by the destination of
|
/* A loop back edge can be identified by the destination of
|
the edge dominating the source of the edge. */
|
the edge dominating the source of the edge. */
|
if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest))
|
if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest))
|
continue;
|
continue;
|
|
|
/* If we have already seen a non-loop edge, then we must have
|
/* If we have already seen a non-loop edge, then we must have
|
multiple incoming non-loop edges and thus we return NULL. */
|
multiple incoming non-loop edges and thus we return NULL. */
|
if (retval)
|
if (retval)
|
return NULL;
|
return NULL;
|
|
|
/* This is the first non-loop incoming edge we have found. Record
|
/* This is the first non-loop incoming edge we have found. Record
|
it. */
|
it. */
|
retval = e;
|
retval = e;
|
}
|
}
|
|
|
return retval;
|
return retval;
|
}
|
}
|
|
|
/* Record any equivalences created by the incoming edge to BB. If BB
|
/* Record any equivalences created by the incoming edge to BB. If BB
|
has more than one incoming edge, then no equivalence is created. */
|
has more than one incoming edge, then no equivalence is created. */
|
|
|
static void
|
static void
|
record_equivalences_from_incoming_edge (basic_block bb)
|
record_equivalences_from_incoming_edge (basic_block bb)
|
{
|
{
|
edge e;
|
edge e;
|
basic_block parent;
|
basic_block parent;
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
|
|
/* If our parent block ended with a control statement, then we may be
|
/* If our parent block ended with a control statement, then we may be
|
able to record some equivalences based on which outgoing edge from
|
able to record some equivalences based on which outgoing edge from
|
the parent was followed. */
|
the parent was followed. */
|
parent = get_immediate_dominator (CDI_DOMINATORS, bb);
|
parent = get_immediate_dominator (CDI_DOMINATORS, bb);
|
|
|
e = single_incoming_edge_ignoring_loop_edges (bb);
|
e = single_incoming_edge_ignoring_loop_edges (bb);
|
|
|
/* If we had a single incoming edge from our parent block, then enter
|
/* If we had a single incoming edge from our parent block, then enter
|
any data associated with the edge into our tables. */
|
any data associated with the edge into our tables. */
|
if (e && e->src == parent)
|
if (e && e->src == parent)
|
{
|
{
|
unsigned int i;
|
unsigned int i;
|
|
|
edge_info = (struct edge_info *) e->aux;
|
edge_info = (struct edge_info *) e->aux;
|
|
|
if (edge_info)
|
if (edge_info)
|
{
|
{
|
tree lhs = edge_info->lhs;
|
tree lhs = edge_info->lhs;
|
tree rhs = edge_info->rhs;
|
tree rhs = edge_info->rhs;
|
tree *cond_equivalences = edge_info->cond_equivalences;
|
tree *cond_equivalences = edge_info->cond_equivalences;
|
|
|
if (lhs)
|
if (lhs)
|
record_equality (lhs, rhs);
|
record_equality (lhs, rhs);
|
|
|
if (cond_equivalences)
|
if (cond_equivalences)
|
{
|
{
|
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
|
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
|
{
|
{
|
tree expr = cond_equivalences[i];
|
tree expr = cond_equivalences[i];
|
tree value = cond_equivalences[i + 1];
|
tree value = cond_equivalences[i + 1];
|
|
|
record_cond (expr, value);
|
record_cond (expr, value);
|
}
|
}
|
}
|
}
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* Dump SSA statistics on FILE. */
|
/* Dump SSA statistics on FILE. */
|
|
|
void
|
void
|
dump_dominator_optimization_stats (FILE *file)
|
dump_dominator_optimization_stats (FILE *file)
|
{
|
{
|
long n_exprs;
|
long n_exprs;
|
|
|
fprintf (file, "Total number of statements: %6ld\n\n",
|
fprintf (file, "Total number of statements: %6ld\n\n",
|
opt_stats.num_stmts);
|
opt_stats.num_stmts);
|
fprintf (file, "Exprs considered for dominator optimizations: %6ld\n",
|
fprintf (file, "Exprs considered for dominator optimizations: %6ld\n",
|
opt_stats.num_exprs_considered);
|
opt_stats.num_exprs_considered);
|
|
|
n_exprs = opt_stats.num_exprs_considered;
|
n_exprs = opt_stats.num_exprs_considered;
|
if (n_exprs == 0)
|
if (n_exprs == 0)
|
n_exprs = 1;
|
n_exprs = 1;
|
|
|
fprintf (file, " Redundant expressions eliminated: %6ld (%.0f%%)\n",
|
fprintf (file, " Redundant expressions eliminated: %6ld (%.0f%%)\n",
|
opt_stats.num_re, PERCENT (opt_stats.num_re,
|
opt_stats.num_re, PERCENT (opt_stats.num_re,
|
n_exprs));
|
n_exprs));
|
fprintf (file, " Constants propagated: %6ld\n",
|
fprintf (file, " Constants propagated: %6ld\n",
|
opt_stats.num_const_prop);
|
opt_stats.num_const_prop);
|
fprintf (file, " Copies propagated: %6ld\n",
|
fprintf (file, " Copies propagated: %6ld\n",
|
opt_stats.num_copy_prop);
|
opt_stats.num_copy_prop);
|
|
|
fprintf (file, "\nHash table statistics:\n");
|
fprintf (file, "\nHash table statistics:\n");
|
|
|
fprintf (file, " avail_exprs: ");
|
fprintf (file, " avail_exprs: ");
|
htab_statistics (file, avail_exprs);
|
htab_statistics (file, avail_exprs);
|
}
|
}
|
|
|
|
|
/* Dump SSA statistics on stderr. */
|
/* Dump SSA statistics on stderr. */
|
|
|
void
|
void
|
debug_dominator_optimization_stats (void)
|
debug_dominator_optimization_stats (void)
|
{
|
{
|
dump_dominator_optimization_stats (stderr);
|
dump_dominator_optimization_stats (stderr);
|
}
|
}
|
|
|
|
|
/* Dump statistics for the hash table HTAB. */
|
/* Dump statistics for the hash table HTAB. */
|
|
|
static void
|
static void
|
htab_statistics (FILE *file, htab_t htab)
|
htab_statistics (FILE *file, htab_t htab)
|
{
|
{
|
fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n",
|
fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n",
|
(long) htab_size (htab),
|
(long) htab_size (htab),
|
(long) htab_elements (htab),
|
(long) htab_elements (htab),
|
htab_collisions (htab));
|
htab_collisions (htab));
|
}
|
}
|
|
|
/* Enter a statement into the true/false expression hash table indicating
|
/* Enter a statement into the true/false expression hash table indicating
|
that the condition COND has the value VALUE. */
|
that the condition COND has the value VALUE. */
|
|
|
static void
|
static void
|
record_cond (tree cond, tree value)
|
record_cond (tree cond, tree value)
|
{
|
{
|
struct expr_hash_elt *element = XCNEW (struct expr_hash_elt);
|
struct expr_hash_elt *element = XCNEW (struct expr_hash_elt);
|
void **slot;
|
void **slot;
|
|
|
initialize_hash_element (cond, value, element);
|
initialize_hash_element (cond, value, element);
|
|
|
slot = htab_find_slot_with_hash (avail_exprs, (void *)element,
|
slot = htab_find_slot_with_hash (avail_exprs, (void *)element,
|
element->hash, INSERT);
|
element->hash, INSERT);
|
if (*slot == NULL)
|
if (*slot == NULL)
|
{
|
{
|
*slot = (void *) element;
|
*slot = (void *) element;
|
VEC_safe_push (tree, heap, avail_exprs_stack, cond);
|
VEC_safe_push (tree, heap, avail_exprs_stack, cond);
|
}
|
}
|
else
|
else
|
free (element);
|
free (element);
|
}
|
}
|
|
|
/* Build a new conditional using NEW_CODE, OP0 and OP1 and store
|
/* Build a new conditional using NEW_CODE, OP0 and OP1 and store
|
the new conditional into *p, then store a boolean_true_node
|
the new conditional into *p, then store a boolean_true_node
|
into *(p + 1). */
|
into *(p + 1). */
|
|
|
static void
|
static void
|
build_and_record_new_cond (enum tree_code new_code, tree op0, tree op1, tree *p)
|
build_and_record_new_cond (enum tree_code new_code, tree op0, tree op1, tree *p)
|
{
|
{
|
*p = build2 (new_code, boolean_type_node, op0, op1);
|
*p = build2 (new_code, boolean_type_node, op0, op1);
|
p++;
|
p++;
|
*p = boolean_true_node;
|
*p = boolean_true_node;
|
}
|
}
|
|
|
/* Record that COND is true and INVERTED is false into the edge information
|
/* Record that COND is true and INVERTED is false into the edge information
|
structure. Also record that any conditions dominated by COND are true
|
structure. Also record that any conditions dominated by COND are true
|
as well.
|
as well.
|
|
|
For example, if a < b is true, then a <= b must also be true. */
|
For example, if a < b is true, then a <= b must also be true. */
|
|
|
static void
|
static void
|
record_conditions (struct edge_info *edge_info, tree cond, tree inverted)
|
record_conditions (struct edge_info *edge_info, tree cond, tree inverted)
|
{
|
{
|
tree op0, op1;
|
tree op0, op1;
|
|
|
if (!COMPARISON_CLASS_P (cond))
|
if (!COMPARISON_CLASS_P (cond))
|
return;
|
return;
|
|
|
op0 = TREE_OPERAND (cond, 0);
|
op0 = TREE_OPERAND (cond, 0);
|
op1 = TREE_OPERAND (cond, 1);
|
op1 = TREE_OPERAND (cond, 1);
|
|
|
switch (TREE_CODE (cond))
|
switch (TREE_CODE (cond))
|
{
|
{
|
case LT_EXPR:
|
case LT_EXPR:
|
case GT_EXPR:
|
case GT_EXPR:
|
if (FLOAT_TYPE_P (TREE_TYPE (op0)))
|
if (FLOAT_TYPE_P (TREE_TYPE (op0)))
|
{
|
{
|
edge_info->max_cond_equivalences = 12;
|
edge_info->max_cond_equivalences = 12;
|
edge_info->cond_equivalences = XNEWVEC (tree, 12);
|
edge_info->cond_equivalences = XNEWVEC (tree, 12);
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
&edge_info->cond_equivalences[8]);
|
&edge_info->cond_equivalences[8]);
|
build_and_record_new_cond (LTGT_EXPR, op0, op1,
|
build_and_record_new_cond (LTGT_EXPR, op0, op1,
|
&edge_info->cond_equivalences[10]);
|
&edge_info->cond_equivalences[10]);
|
}
|
}
|
else
|
else
|
{
|
{
|
edge_info->max_cond_equivalences = 8;
|
edge_info->max_cond_equivalences = 8;
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
}
|
}
|
|
|
build_and_record_new_cond ((TREE_CODE (cond) == LT_EXPR
|
build_and_record_new_cond ((TREE_CODE (cond) == LT_EXPR
|
? LE_EXPR : GE_EXPR),
|
? LE_EXPR : GE_EXPR),
|
op0, op1, &edge_info->cond_equivalences[4]);
|
op0, op1, &edge_info->cond_equivalences[4]);
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[6]);
|
&edge_info->cond_equivalences[6]);
|
break;
|
break;
|
|
|
case GE_EXPR:
|
case GE_EXPR:
|
case LE_EXPR:
|
case LE_EXPR:
|
if (FLOAT_TYPE_P (TREE_TYPE (op0)))
|
if (FLOAT_TYPE_P (TREE_TYPE (op0)))
|
{
|
{
|
edge_info->max_cond_equivalences = 6;
|
edge_info->max_cond_equivalences = 6;
|
edge_info->cond_equivalences = XNEWVEC (tree, 6);
|
edge_info->cond_equivalences = XNEWVEC (tree, 6);
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
&edge_info->cond_equivalences[4]);
|
&edge_info->cond_equivalences[4]);
|
}
|
}
|
else
|
else
|
{
|
{
|
edge_info->max_cond_equivalences = 4;
|
edge_info->max_cond_equivalences = 4;
|
edge_info->cond_equivalences = XNEWVEC (tree, 4);
|
edge_info->cond_equivalences = XNEWVEC (tree, 4);
|
}
|
}
|
break;
|
break;
|
|
|
case EQ_EXPR:
|
case EQ_EXPR:
|
if (FLOAT_TYPE_P (TREE_TYPE (op0)))
|
if (FLOAT_TYPE_P (TREE_TYPE (op0)))
|
{
|
{
|
edge_info->max_cond_equivalences = 10;
|
edge_info->max_cond_equivalences = 10;
|
edge_info->cond_equivalences = XNEWVEC (tree, 10);
|
edge_info->cond_equivalences = XNEWVEC (tree, 10);
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
&edge_info->cond_equivalences[8]);
|
&edge_info->cond_equivalences[8]);
|
}
|
}
|
else
|
else
|
{
|
{
|
edge_info->max_cond_equivalences = 8;
|
edge_info->max_cond_equivalences = 8;
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
}
|
}
|
build_and_record_new_cond (LE_EXPR, op0, op1,
|
build_and_record_new_cond (LE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[4]);
|
&edge_info->cond_equivalences[4]);
|
build_and_record_new_cond (GE_EXPR, op0, op1,
|
build_and_record_new_cond (GE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[6]);
|
&edge_info->cond_equivalences[6]);
|
break;
|
break;
|
|
|
case UNORDERED_EXPR:
|
case UNORDERED_EXPR:
|
edge_info->max_cond_equivalences = 16;
|
edge_info->max_cond_equivalences = 16;
|
edge_info->cond_equivalences = XNEWVEC (tree, 16);
|
edge_info->cond_equivalences = XNEWVEC (tree, 16);
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[4]);
|
&edge_info->cond_equivalences[4]);
|
build_and_record_new_cond (UNLE_EXPR, op0, op1,
|
build_and_record_new_cond (UNLE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[6]);
|
&edge_info->cond_equivalences[6]);
|
build_and_record_new_cond (UNGE_EXPR, op0, op1,
|
build_and_record_new_cond (UNGE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[8]);
|
&edge_info->cond_equivalences[8]);
|
build_and_record_new_cond (UNEQ_EXPR, op0, op1,
|
build_and_record_new_cond (UNEQ_EXPR, op0, op1,
|
&edge_info->cond_equivalences[10]);
|
&edge_info->cond_equivalences[10]);
|
build_and_record_new_cond (UNLT_EXPR, op0, op1,
|
build_and_record_new_cond (UNLT_EXPR, op0, op1,
|
&edge_info->cond_equivalences[12]);
|
&edge_info->cond_equivalences[12]);
|
build_and_record_new_cond (UNGT_EXPR, op0, op1,
|
build_and_record_new_cond (UNGT_EXPR, op0, op1,
|
&edge_info->cond_equivalences[14]);
|
&edge_info->cond_equivalences[14]);
|
break;
|
break;
|
|
|
case UNLT_EXPR:
|
case UNLT_EXPR:
|
case UNGT_EXPR:
|
case UNGT_EXPR:
|
edge_info->max_cond_equivalences = 8;
|
edge_info->max_cond_equivalences = 8;
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
build_and_record_new_cond ((TREE_CODE (cond) == UNLT_EXPR
|
build_and_record_new_cond ((TREE_CODE (cond) == UNLT_EXPR
|
? UNLE_EXPR : UNGE_EXPR),
|
? UNLE_EXPR : UNGE_EXPR),
|
op0, op1, &edge_info->cond_equivalences[4]);
|
op0, op1, &edge_info->cond_equivalences[4]);
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[6]);
|
&edge_info->cond_equivalences[6]);
|
break;
|
break;
|
|
|
case UNEQ_EXPR:
|
case UNEQ_EXPR:
|
edge_info->max_cond_equivalences = 8;
|
edge_info->max_cond_equivalences = 8;
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
build_and_record_new_cond (UNLE_EXPR, op0, op1,
|
build_and_record_new_cond (UNLE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[4]);
|
&edge_info->cond_equivalences[4]);
|
build_and_record_new_cond (UNGE_EXPR, op0, op1,
|
build_and_record_new_cond (UNGE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[6]);
|
&edge_info->cond_equivalences[6]);
|
break;
|
break;
|
|
|
case LTGT_EXPR:
|
case LTGT_EXPR:
|
edge_info->max_cond_equivalences = 8;
|
edge_info->max_cond_equivalences = 8;
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
edge_info->cond_equivalences = XNEWVEC (tree, 8);
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
build_and_record_new_cond (NE_EXPR, op0, op1,
|
&edge_info->cond_equivalences[4]);
|
&edge_info->cond_equivalences[4]);
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
|
&edge_info->cond_equivalences[6]);
|
&edge_info->cond_equivalences[6]);
|
break;
|
break;
|
|
|
default:
|
default:
|
edge_info->max_cond_equivalences = 4;
|
edge_info->max_cond_equivalences = 4;
|
edge_info->cond_equivalences = XNEWVEC (tree, 4);
|
edge_info->cond_equivalences = XNEWVEC (tree, 4);
|
break;
|
break;
|
}
|
}
|
|
|
/* Now store the original true and false conditions into the first
|
/* Now store the original true and false conditions into the first
|
two slots. */
|
two slots. */
|
edge_info->cond_equivalences[0] = cond;
|
edge_info->cond_equivalences[0] = cond;
|
edge_info->cond_equivalences[1] = boolean_true_node;
|
edge_info->cond_equivalences[1] = boolean_true_node;
|
edge_info->cond_equivalences[2] = inverted;
|
edge_info->cond_equivalences[2] = inverted;
|
edge_info->cond_equivalences[3] = boolean_false_node;
|
edge_info->cond_equivalences[3] = boolean_false_node;
|
}
|
}
|
|
|
/* A helper function for record_const_or_copy and record_equality.
|
/* A helper function for record_const_or_copy and record_equality.
|
Do the work of recording the value and undo info. */
|
Do the work of recording the value and undo info. */
|
|
|
static void
|
static void
|
record_const_or_copy_1 (tree x, tree y, tree prev_x)
|
record_const_or_copy_1 (tree x, tree y, tree prev_x)
|
{
|
{
|
SSA_NAME_VALUE (x) = y;
|
SSA_NAME_VALUE (x) = y;
|
|
|
VEC_reserve (tree, heap, const_and_copies_stack, 2);
|
VEC_reserve (tree, heap, const_and_copies_stack, 2);
|
VEC_quick_push (tree, const_and_copies_stack, prev_x);
|
VEC_quick_push (tree, const_and_copies_stack, prev_x);
|
VEC_quick_push (tree, const_and_copies_stack, x);
|
VEC_quick_push (tree, const_and_copies_stack, x);
|
}
|
}
|
|
|
|
|
/* Return the loop depth of the basic block of the defining statement of X.
|
/* Return the loop depth of the basic block of the defining statement of X.
|
This number should not be treated as absolutely correct because the loop
|
This number should not be treated as absolutely correct because the loop
|
information may not be completely up-to-date when dom runs. However, it
|
information may not be completely up-to-date when dom runs. However, it
|
will be relatively correct, and as more passes are taught to keep loop info
|
will be relatively correct, and as more passes are taught to keep loop info
|
up to date, the result will become more and more accurate. */
|
up to date, the result will become more and more accurate. */
|
|
|
int
|
int
|
loop_depth_of_name (tree x)
|
loop_depth_of_name (tree x)
|
{
|
{
|
tree defstmt;
|
tree defstmt;
|
basic_block defbb;
|
basic_block defbb;
|
|
|
/* If it's not an SSA_NAME, we have no clue where the definition is. */
|
/* If it's not an SSA_NAME, we have no clue where the definition is. */
|
if (TREE_CODE (x) != SSA_NAME)
|
if (TREE_CODE (x) != SSA_NAME)
|
return 0;
|
return 0;
|
|
|
/* Otherwise return the loop depth of the defining statement's bb.
|
/* Otherwise return the loop depth of the defining statement's bb.
|
Note that there may not actually be a bb for this statement, if the
|
Note that there may not actually be a bb for this statement, if the
|
ssa_name is live on entry. */
|
ssa_name is live on entry. */
|
defstmt = SSA_NAME_DEF_STMT (x);
|
defstmt = SSA_NAME_DEF_STMT (x);
|
defbb = bb_for_stmt (defstmt);
|
defbb = bb_for_stmt (defstmt);
|
if (!defbb)
|
if (!defbb)
|
return 0;
|
return 0;
|
|
|
return defbb->loop_depth;
|
return defbb->loop_depth;
|
}
|
}
|
|
|
|
|
/* Record that X is equal to Y in const_and_copies. Record undo
|
/* Record that X is equal to Y in const_and_copies. Record undo
|
information in the block-local vector. */
|
information in the block-local vector. */
|
|
|
static void
|
static void
|
record_const_or_copy (tree x, tree y)
|
record_const_or_copy (tree x, tree y)
|
{
|
{
|
tree prev_x = SSA_NAME_VALUE (x);
|
tree prev_x = SSA_NAME_VALUE (x);
|
|
|
if (TREE_CODE (y) == SSA_NAME)
|
if (TREE_CODE (y) == SSA_NAME)
|
{
|
{
|
tree tmp = SSA_NAME_VALUE (y);
|
tree tmp = SSA_NAME_VALUE (y);
|
if (tmp)
|
if (tmp)
|
y = tmp;
|
y = tmp;
|
}
|
}
|
|
|
record_const_or_copy_1 (x, y, prev_x);
|
record_const_or_copy_1 (x, y, prev_x);
|
}
|
}
|
|
|
/* Similarly, but assume that X and Y are the two operands of an EQ_EXPR.
|
/* Similarly, but assume that X and Y are the two operands of an EQ_EXPR.
|
This constrains the cases in which we may treat this as assignment. */
|
This constrains the cases in which we may treat this as assignment. */
|
|
|
static void
|
static void
|
record_equality (tree x, tree y)
|
record_equality (tree x, tree y)
|
{
|
{
|
tree prev_x = NULL, prev_y = NULL;
|
tree prev_x = NULL, prev_y = NULL;
|
|
|
if (TREE_CODE (x) == SSA_NAME)
|
if (TREE_CODE (x) == SSA_NAME)
|
prev_x = SSA_NAME_VALUE (x);
|
prev_x = SSA_NAME_VALUE (x);
|
if (TREE_CODE (y) == SSA_NAME)
|
if (TREE_CODE (y) == SSA_NAME)
|
prev_y = SSA_NAME_VALUE (y);
|
prev_y = SSA_NAME_VALUE (y);
|
|
|
/* If one of the previous values is invariant, or invariant in more loops
|
/* If one of the previous values is invariant, or invariant in more loops
|
(by depth), then use that.
|
(by depth), then use that.
|
Otherwise it doesn't matter which value we choose, just so
|
Otherwise it doesn't matter which value we choose, just so
|
long as we canonicalize on one value. */
|
long as we canonicalize on one value. */
|
if (TREE_INVARIANT (y))
|
if (TREE_INVARIANT (y))
|
;
|
;
|
else if (TREE_INVARIANT (x) || (loop_depth_of_name (x) <= loop_depth_of_name (y)))
|
else if (TREE_INVARIANT (x) || (loop_depth_of_name (x) <= loop_depth_of_name (y)))
|
prev_x = x, x = y, y = prev_x, prev_x = prev_y;
|
prev_x = x, x = y, y = prev_x, prev_x = prev_y;
|
else if (prev_x && TREE_INVARIANT (prev_x))
|
else if (prev_x && TREE_INVARIANT (prev_x))
|
x = y, y = prev_x, prev_x = prev_y;
|
x = y, y = prev_x, prev_x = prev_y;
|
else if (prev_y && TREE_CODE (prev_y) != VALUE_HANDLE)
|
else if (prev_y && TREE_CODE (prev_y) != VALUE_HANDLE)
|
y = prev_y;
|
y = prev_y;
|
|
|
/* After the swapping, we must have one SSA_NAME. */
|
/* After the swapping, we must have one SSA_NAME. */
|
if (TREE_CODE (x) != SSA_NAME)
|
if (TREE_CODE (x) != SSA_NAME)
|
return;
|
return;
|
|
|
/* For IEEE, -0.0 == 0.0, so we don't necessarily know the sign of a
|
/* For IEEE, -0.0 == 0.0, so we don't necessarily know the sign of a
|
variable compared against zero. If we're honoring signed zeros,
|
variable compared against zero. If we're honoring signed zeros,
|
then we cannot record this value unless we know that the value is
|
then we cannot record this value unless we know that the value is
|
nonzero. */
|
nonzero. */
|
if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (x)))
|
if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (x)))
|
&& (TREE_CODE (y) != REAL_CST
|
&& (TREE_CODE (y) != REAL_CST
|
|| REAL_VALUES_EQUAL (dconst0, TREE_REAL_CST (y))))
|
|| REAL_VALUES_EQUAL (dconst0, TREE_REAL_CST (y))))
|
return;
|
return;
|
|
|
record_const_or_copy_1 (x, y, prev_x);
|
record_const_or_copy_1 (x, y, prev_x);
|
}
|
}
|
|
|
/* Returns true when STMT is a simple iv increment. It detects the
|
/* Returns true when STMT is a simple iv increment. It detects the
|
following situation:
|
following situation:
|
|
|
i_1 = phi (..., i_2)
|
i_1 = phi (..., i_2)
|
i_2 = i_1 +/- ... */
|
i_2 = i_1 +/- ... */
|
|
|
static bool
|
static bool
|
simple_iv_increment_p (tree stmt)
|
simple_iv_increment_p (tree stmt)
|
{
|
{
|
tree lhs, rhs, preinc, phi;
|
tree lhs, rhs, preinc, phi;
|
unsigned i;
|
unsigned i;
|
|
|
if (TREE_CODE (stmt) != MODIFY_EXPR)
|
if (TREE_CODE (stmt) != MODIFY_EXPR)
|
return false;
|
return false;
|
|
|
lhs = TREE_OPERAND (stmt, 0);
|
lhs = TREE_OPERAND (stmt, 0);
|
if (TREE_CODE (lhs) != SSA_NAME)
|
if (TREE_CODE (lhs) != SSA_NAME)
|
return false;
|
return false;
|
|
|
rhs = TREE_OPERAND (stmt, 1);
|
rhs = TREE_OPERAND (stmt, 1);
|
|
|
if (TREE_CODE (rhs) != PLUS_EXPR
|
if (TREE_CODE (rhs) != PLUS_EXPR
|
&& TREE_CODE (rhs) != MINUS_EXPR)
|
&& TREE_CODE (rhs) != MINUS_EXPR)
|
return false;
|
return false;
|
|
|
preinc = TREE_OPERAND (rhs, 0);
|
preinc = TREE_OPERAND (rhs, 0);
|
if (TREE_CODE (preinc) != SSA_NAME)
|
if (TREE_CODE (preinc) != SSA_NAME)
|
return false;
|
return false;
|
|
|
phi = SSA_NAME_DEF_STMT (preinc);
|
phi = SSA_NAME_DEF_STMT (preinc);
|
if (TREE_CODE (phi) != PHI_NODE)
|
if (TREE_CODE (phi) != PHI_NODE)
|
return false;
|
return false;
|
|
|
for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
|
for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
|
if (PHI_ARG_DEF (phi, i) == lhs)
|
if (PHI_ARG_DEF (phi, i) == lhs)
|
return true;
|
return true;
|
|
|
return false;
|
return false;
|
}
|
}
|
|
|
/* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
|
/* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
|
known value for that SSA_NAME (or NULL if no value is known).
|
known value for that SSA_NAME (or NULL if no value is known).
|
|
|
Propagate values from CONST_AND_COPIES into the PHI nodes of the
|
Propagate values from CONST_AND_COPIES into the PHI nodes of the
|
successors of BB. */
|
successors of BB. */
|
|
|
static void
|
static void
|
cprop_into_successor_phis (basic_block bb)
|
cprop_into_successor_phis (basic_block bb)
|
{
|
{
|
edge e;
|
edge e;
|
edge_iterator ei;
|
edge_iterator ei;
|
|
|
FOR_EACH_EDGE (e, ei, bb->succs)
|
FOR_EACH_EDGE (e, ei, bb->succs)
|
{
|
{
|
tree phi;
|
tree phi;
|
int indx;
|
int indx;
|
|
|
/* If this is an abnormal edge, then we do not want to copy propagate
|
/* If this is an abnormal edge, then we do not want to copy propagate
|
into the PHI alternative associated with this edge. */
|
into the PHI alternative associated with this edge. */
|
if (e->flags & EDGE_ABNORMAL)
|
if (e->flags & EDGE_ABNORMAL)
|
continue;
|
continue;
|
|
|
phi = phi_nodes (e->dest);
|
phi = phi_nodes (e->dest);
|
if (! phi)
|
if (! phi)
|
continue;
|
continue;
|
|
|
indx = e->dest_idx;
|
indx = e->dest_idx;
|
for ( ; phi; phi = PHI_CHAIN (phi))
|
for ( ; phi; phi = PHI_CHAIN (phi))
|
{
|
{
|
tree new;
|
tree new;
|
use_operand_p orig_p;
|
use_operand_p orig_p;
|
tree orig;
|
tree orig;
|
|
|
/* The alternative may be associated with a constant, so verify
|
/* The alternative may be associated with a constant, so verify
|
it is an SSA_NAME before doing anything with it. */
|
it is an SSA_NAME before doing anything with it. */
|
orig_p = PHI_ARG_DEF_PTR (phi, indx);
|
orig_p = PHI_ARG_DEF_PTR (phi, indx);
|
orig = USE_FROM_PTR (orig_p);
|
orig = USE_FROM_PTR (orig_p);
|
if (TREE_CODE (orig) != SSA_NAME)
|
if (TREE_CODE (orig) != SSA_NAME)
|
continue;
|
continue;
|
|
|
/* If we have *ORIG_P in our constant/copy table, then replace
|
/* If we have *ORIG_P in our constant/copy table, then replace
|
ORIG_P with its value in our constant/copy table. */
|
ORIG_P with its value in our constant/copy table. */
|
new = SSA_NAME_VALUE (orig);
|
new = SSA_NAME_VALUE (orig);
|
if (new
|
if (new
|
&& new != orig
|
&& new != orig
|
&& (TREE_CODE (new) == SSA_NAME
|
&& (TREE_CODE (new) == SSA_NAME
|
|| is_gimple_min_invariant (new))
|
|| is_gimple_min_invariant (new))
|
&& may_propagate_copy (orig, new))
|
&& may_propagate_copy (orig, new))
|
propagate_value (orig_p, new);
|
propagate_value (orig_p, new);
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* We have finished optimizing BB, record any information implied by
|
/* We have finished optimizing BB, record any information implied by
|
taking a specific outgoing edge from BB. */
|
taking a specific outgoing edge from BB. */
|
|
|
static void
|
static void
|
record_edge_info (basic_block bb)
|
record_edge_info (basic_block bb)
|
{
|
{
|
block_stmt_iterator bsi = bsi_last (bb);
|
block_stmt_iterator bsi = bsi_last (bb);
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
|
|
if (! bsi_end_p (bsi))
|
if (! bsi_end_p (bsi))
|
{
|
{
|
tree stmt = bsi_stmt (bsi);
|
tree stmt = bsi_stmt (bsi);
|
|
|
if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
|
if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
|
{
|
{
|
tree cond = SWITCH_COND (stmt);
|
tree cond = SWITCH_COND (stmt);
|
|
|
if (TREE_CODE (cond) == SSA_NAME)
|
if (TREE_CODE (cond) == SSA_NAME)
|
{
|
{
|
tree labels = SWITCH_LABELS (stmt);
|
tree labels = SWITCH_LABELS (stmt);
|
int i, n_labels = TREE_VEC_LENGTH (labels);
|
int i, n_labels = TREE_VEC_LENGTH (labels);
|
tree *info = XCNEWVEC (tree, last_basic_block);
|
tree *info = XCNEWVEC (tree, last_basic_block);
|
edge e;
|
edge e;
|
edge_iterator ei;
|
edge_iterator ei;
|
|
|
for (i = 0; i < n_labels; i++)
|
for (i = 0; i < n_labels; i++)
|
{
|
{
|
tree label = TREE_VEC_ELT (labels, i);
|
tree label = TREE_VEC_ELT (labels, i);
|
basic_block target_bb = label_to_block (CASE_LABEL (label));
|
basic_block target_bb = label_to_block (CASE_LABEL (label));
|
|
|
if (CASE_HIGH (label)
|
if (CASE_HIGH (label)
|
|| !CASE_LOW (label)
|
|| !CASE_LOW (label)
|
|| info[target_bb->index])
|
|| info[target_bb->index])
|
info[target_bb->index] = error_mark_node;
|
info[target_bb->index] = error_mark_node;
|
else
|
else
|
info[target_bb->index] = label;
|
info[target_bb->index] = label;
|
}
|
}
|
|
|
FOR_EACH_EDGE (e, ei, bb->succs)
|
FOR_EACH_EDGE (e, ei, bb->succs)
|
{
|
{
|
basic_block target_bb = e->dest;
|
basic_block target_bb = e->dest;
|
tree node = info[target_bb->index];
|
tree node = info[target_bb->index];
|
|
|
if (node != NULL && node != error_mark_node)
|
if (node != NULL && node != error_mark_node)
|
{
|
{
|
tree x = fold_convert (TREE_TYPE (cond), CASE_LOW (node));
|
tree x = fold_convert (TREE_TYPE (cond), CASE_LOW (node));
|
edge_info = allocate_edge_info (e);
|
edge_info = allocate_edge_info (e);
|
edge_info->lhs = cond;
|
edge_info->lhs = cond;
|
edge_info->rhs = x;
|
edge_info->rhs = x;
|
}
|
}
|
}
|
}
|
free (info);
|
free (info);
|
}
|
}
|
}
|
}
|
|
|
/* A COND_EXPR may create equivalences too. */
|
/* A COND_EXPR may create equivalences too. */
|
if (stmt && TREE_CODE (stmt) == COND_EXPR)
|
if (stmt && TREE_CODE (stmt) == COND_EXPR)
|
{
|
{
|
tree cond = COND_EXPR_COND (stmt);
|
tree cond = COND_EXPR_COND (stmt);
|
edge true_edge;
|
edge true_edge;
|
edge false_edge;
|
edge false_edge;
|
|
|
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
|
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
|
|
|
/* If the conditional is a single variable 'X', record 'X = 1'
|
/* If the conditional is a single variable 'X', record 'X = 1'
|
for the true edge and 'X = 0' on the false edge. */
|
for the true edge and 'X = 0' on the false edge. */
|
if (SSA_VAR_P (cond))
|
if (SSA_VAR_P (cond))
|
{
|
{
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
|
|
edge_info = allocate_edge_info (true_edge);
|
edge_info = allocate_edge_info (true_edge);
|
edge_info->lhs = cond;
|
edge_info->lhs = cond;
|
edge_info->rhs = constant_boolean_node (1, TREE_TYPE (cond));
|
edge_info->rhs = constant_boolean_node (1, TREE_TYPE (cond));
|
|
|
edge_info = allocate_edge_info (false_edge);
|
edge_info = allocate_edge_info (false_edge);
|
edge_info->lhs = cond;
|
edge_info->lhs = cond;
|
edge_info->rhs = constant_boolean_node (0, TREE_TYPE (cond));
|
edge_info->rhs = constant_boolean_node (0, TREE_TYPE (cond));
|
}
|
}
|
/* Equality tests may create one or two equivalences. */
|
/* Equality tests may create one or two equivalences. */
|
else if (COMPARISON_CLASS_P (cond))
|
else if (COMPARISON_CLASS_P (cond))
|
{
|
{
|
tree op0 = TREE_OPERAND (cond, 0);
|
tree op0 = TREE_OPERAND (cond, 0);
|
tree op1 = TREE_OPERAND (cond, 1);
|
tree op1 = TREE_OPERAND (cond, 1);
|
|
|
/* Special case comparing booleans against a constant as we
|
/* Special case comparing booleans against a constant as we
|
know the value of OP0 on both arms of the branch. i.e., we
|
know the value of OP0 on both arms of the branch. i.e., we
|
can record an equivalence for OP0 rather than COND. */
|
can record an equivalence for OP0 rather than COND. */
|
if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
|
if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
|
&& TREE_CODE (op0) == SSA_NAME
|
&& TREE_CODE (op0) == SSA_NAME
|
&& TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE
|
&& TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE
|
&& is_gimple_min_invariant (op1))
|
&& is_gimple_min_invariant (op1))
|
{
|
{
|
if (TREE_CODE (cond) == EQ_EXPR)
|
if (TREE_CODE (cond) == EQ_EXPR)
|
{
|
{
|
edge_info = allocate_edge_info (true_edge);
|
edge_info = allocate_edge_info (true_edge);
|
edge_info->lhs = op0;
|
edge_info->lhs = op0;
|
edge_info->rhs = (integer_zerop (op1)
|
edge_info->rhs = (integer_zerop (op1)
|
? boolean_false_node
|
? boolean_false_node
|
: boolean_true_node);
|
: boolean_true_node);
|
|
|
edge_info = allocate_edge_info (false_edge);
|
edge_info = allocate_edge_info (false_edge);
|
edge_info->lhs = op0;
|
edge_info->lhs = op0;
|
edge_info->rhs = (integer_zerop (op1)
|
edge_info->rhs = (integer_zerop (op1)
|
? boolean_true_node
|
? boolean_true_node
|
: boolean_false_node);
|
: boolean_false_node);
|
}
|
}
|
else
|
else
|
{
|
{
|
edge_info = allocate_edge_info (true_edge);
|
edge_info = allocate_edge_info (true_edge);
|
edge_info->lhs = op0;
|
edge_info->lhs = op0;
|
edge_info->rhs = (integer_zerop (op1)
|
edge_info->rhs = (integer_zerop (op1)
|
? boolean_true_node
|
? boolean_true_node
|
: boolean_false_node);
|
: boolean_false_node);
|
|
|
edge_info = allocate_edge_info (false_edge);
|
edge_info = allocate_edge_info (false_edge);
|
edge_info->lhs = op0;
|
edge_info->lhs = op0;
|
edge_info->rhs = (integer_zerop (op1)
|
edge_info->rhs = (integer_zerop (op1)
|
? boolean_false_node
|
? boolean_false_node
|
: boolean_true_node);
|
: boolean_true_node);
|
}
|
}
|
}
|
}
|
|
|
else if (is_gimple_min_invariant (op0)
|
else if (is_gimple_min_invariant (op0)
|
&& (TREE_CODE (op1) == SSA_NAME
|
&& (TREE_CODE (op1) == SSA_NAME
|
|| is_gimple_min_invariant (op1)))
|
|| is_gimple_min_invariant (op1)))
|
{
|
{
|
tree inverted = invert_truthvalue (cond);
|
tree inverted = invert_truthvalue (cond);
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
|
|
edge_info = allocate_edge_info (true_edge);
|
edge_info = allocate_edge_info (true_edge);
|
record_conditions (edge_info, cond, inverted);
|
record_conditions (edge_info, cond, inverted);
|
|
|
if (TREE_CODE (cond) == EQ_EXPR)
|
if (TREE_CODE (cond) == EQ_EXPR)
|
{
|
{
|
edge_info->lhs = op1;
|
edge_info->lhs = op1;
|
edge_info->rhs = op0;
|
edge_info->rhs = op0;
|
}
|
}
|
|
|
edge_info = allocate_edge_info (false_edge);
|
edge_info = allocate_edge_info (false_edge);
|
record_conditions (edge_info, inverted, cond);
|
record_conditions (edge_info, inverted, cond);
|
|
|
if (TREE_CODE (cond) == NE_EXPR)
|
if (TREE_CODE (cond) == NE_EXPR)
|
{
|
{
|
edge_info->lhs = op1;
|
edge_info->lhs = op1;
|
edge_info->rhs = op0;
|
edge_info->rhs = op0;
|
}
|
}
|
}
|
}
|
|
|
else if (TREE_CODE (op0) == SSA_NAME
|
else if (TREE_CODE (op0) == SSA_NAME
|
&& (is_gimple_min_invariant (op1)
|
&& (is_gimple_min_invariant (op1)
|
|| TREE_CODE (op1) == SSA_NAME))
|
|| TREE_CODE (op1) == SSA_NAME))
|
{
|
{
|
tree inverted = invert_truthvalue (cond);
|
tree inverted = invert_truthvalue (cond);
|
struct edge_info *edge_info;
|
struct edge_info *edge_info;
|
|
|
edge_info = allocate_edge_info (true_edge);
|
edge_info = allocate_edge_info (true_edge);
|
record_conditions (edge_info, cond, inverted);
|
record_conditions (edge_info, cond, inverted);
|
|
|
if (TREE_CODE (cond) == EQ_EXPR)
|
if (TREE_CODE (cond) == EQ_EXPR)
|
{
|
{
|
edge_info->lhs = op0;
|
edge_info->lhs = op0;
|
edge_info->rhs = op1;
|
edge_info->rhs = op1;
|
}
|
}
|
|
|
edge_info = allocate_edge_info (false_edge);
|
edge_info = allocate_edge_info (false_edge);
|
record_conditions (edge_info, inverted, cond);
|
record_conditions (edge_info, inverted, cond);
|
|
|
if (TREE_CODE (cond) == NE_EXPR)
|
if (TREE_CODE (cond) == NE_EXPR)
|
{
|
{
|
edge_info->lhs = op0;
|
edge_info->lhs = op0;
|
edge_info->rhs = op1;
|
edge_info->rhs = op1;
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* ??? TRUTH_NOT_EXPR can create an equivalence too. */
|
/* ??? TRUTH_NOT_EXPR can create an equivalence too. */
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* Propagate information from BB to its outgoing edges.
|
/* Propagate information from BB to its outgoing edges.
|
|
|
This can include equivalency information implied by control statements
|
This can include equivalency information implied by control statements
|
at the end of BB and const/copy propagation into PHIs in BB's
|
at the end of BB and const/copy propagation into PHIs in BB's
|
successor blocks. */
|
successor blocks. */
|
|
|
static void
|
static void
|
propagate_to_outgoing_edges (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
|
propagate_to_outgoing_edges (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
|
basic_block bb)
|
basic_block bb)
|
{
|
{
|
record_edge_info (bb);
|
record_edge_info (bb);
|
cprop_into_successor_phis (bb);
|
cprop_into_successor_phis (bb);
|
}
|
}
|
|
|
/* Search for redundant computations in STMT. If any are found, then
|
/* Search for redundant computations in STMT. If any are found, then
|
replace them with the variable holding the result of the computation.
|
replace them with the variable holding the result of the computation.
|
|
|
If safe, record this expression into the available expression hash
|
If safe, record this expression into the available expression hash
|
table. */
|
table. */
|
|
|
static bool
|
static bool
|
eliminate_redundant_computations (tree stmt)
|
eliminate_redundant_computations (tree stmt)
|
{
|
{
|
tree *expr_p, def = NULL_TREE;
|
tree *expr_p, def = NULL_TREE;
|
bool insert = true;
|
bool insert = true;
|
tree cached_lhs;
|
tree cached_lhs;
|
bool retval = false;
|
bool retval = false;
|
bool modify_expr_p = false;
|
bool modify_expr_p = false;
|
|
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
def = TREE_OPERAND (stmt, 0);
|
def = TREE_OPERAND (stmt, 0);
|
|
|
/* Certain expressions on the RHS can be optimized away, but can not
|
/* Certain expressions on the RHS can be optimized away, but can not
|
themselves be entered into the hash tables. */
|
themselves be entered into the hash tables. */
|
if (! def
|
if (! def
|
|| TREE_CODE (def) != SSA_NAME
|
|| TREE_CODE (def) != SSA_NAME
|
|| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
|
|| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
|
|| !ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF)
|
|| !ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF)
|
/* Do not record equivalences for increments of ivs. This would create
|
/* Do not record equivalences for increments of ivs. This would create
|
overlapping live ranges for a very questionable gain. */
|
overlapping live ranges for a very questionable gain. */
|
|| simple_iv_increment_p (stmt))
|
|| simple_iv_increment_p (stmt))
|
insert = false;
|
insert = false;
|
|
|
/* Check if the expression has been computed before. */
|
/* Check if the expression has been computed before. */
|
cached_lhs = lookup_avail_expr (stmt, insert);
|
cached_lhs = lookup_avail_expr (stmt, insert);
|
|
|
opt_stats.num_exprs_considered++;
|
opt_stats.num_exprs_considered++;
|
|
|
/* Get a pointer to the expression we are trying to optimize. */
|
/* Get a pointer to the expression we are trying to optimize. */
|
if (TREE_CODE (stmt) == COND_EXPR)
|
if (TREE_CODE (stmt) == COND_EXPR)
|
expr_p = &COND_EXPR_COND (stmt);
|
expr_p = &COND_EXPR_COND (stmt);
|
else if (TREE_CODE (stmt) == SWITCH_EXPR)
|
else if (TREE_CODE (stmt) == SWITCH_EXPR)
|
expr_p = &SWITCH_COND (stmt);
|
expr_p = &SWITCH_COND (stmt);
|
else if (TREE_CODE (stmt) == RETURN_EXPR && TREE_OPERAND (stmt, 0))
|
else if (TREE_CODE (stmt) == RETURN_EXPR && TREE_OPERAND (stmt, 0))
|
{
|
{
|
expr_p = &TREE_OPERAND (TREE_OPERAND (stmt, 0), 1);
|
expr_p = &TREE_OPERAND (TREE_OPERAND (stmt, 0), 1);
|
modify_expr_p = true;
|
modify_expr_p = true;
|
}
|
}
|
else
|
else
|
{
|
{
|
expr_p = &TREE_OPERAND (stmt, 1);
|
expr_p = &TREE_OPERAND (stmt, 1);
|
modify_expr_p = true;
|
modify_expr_p = true;
|
}
|
}
|
|
|
/* It is safe to ignore types here since we have already done
|
/* It is safe to ignore types here since we have already done
|
type checking in the hashing and equality routines. In fact
|
type checking in the hashing and equality routines. In fact
|
type checking here merely gets in the way of constant
|
type checking here merely gets in the way of constant
|
propagation. Also, make sure that it is safe to propagate
|
propagation. Also, make sure that it is safe to propagate
|
CACHED_LHS into *EXPR_P. */
|
CACHED_LHS into *EXPR_P. */
|
if (cached_lhs
|
if (cached_lhs
|
&& ((TREE_CODE (cached_lhs) != SSA_NAME
|
&& ((TREE_CODE (cached_lhs) != SSA_NAME
|
&& (modify_expr_p
|
&& (modify_expr_p
|
|| tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p),
|
|| tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p),
|
TREE_TYPE (cached_lhs))))
|
TREE_TYPE (cached_lhs))))
|
|| may_propagate_copy (*expr_p, cached_lhs)))
|
|| may_propagate_copy (*expr_p, cached_lhs)))
|
{
|
{
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Replaced redundant expr '");
|
fprintf (dump_file, " Replaced redundant expr '");
|
print_generic_expr (dump_file, *expr_p, dump_flags);
|
print_generic_expr (dump_file, *expr_p, dump_flags);
|
fprintf (dump_file, "' with '");
|
fprintf (dump_file, "' with '");
|
print_generic_expr (dump_file, cached_lhs, dump_flags);
|
print_generic_expr (dump_file, cached_lhs, dump_flags);
|
fprintf (dump_file, "'\n");
|
fprintf (dump_file, "'\n");
|
}
|
}
|
|
|
opt_stats.num_re++;
|
opt_stats.num_re++;
|
|
|
#if defined ENABLE_CHECKING
|
#if defined ENABLE_CHECKING
|
gcc_assert (TREE_CODE (cached_lhs) == SSA_NAME
|
gcc_assert (TREE_CODE (cached_lhs) == SSA_NAME
|
|| is_gimple_min_invariant (cached_lhs));
|
|| is_gimple_min_invariant (cached_lhs));
|
#endif
|
#endif
|
|
|
if (TREE_CODE (cached_lhs) == ADDR_EXPR
|
if (TREE_CODE (cached_lhs) == ADDR_EXPR
|
|| (POINTER_TYPE_P (TREE_TYPE (*expr_p))
|
|| (POINTER_TYPE_P (TREE_TYPE (*expr_p))
|
&& is_gimple_min_invariant (cached_lhs)))
|
&& is_gimple_min_invariant (cached_lhs)))
|
retval = true;
|
retval = true;
|
|
|
if (modify_expr_p
|
if (modify_expr_p
|
&& !tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p),
|
&& !tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p),
|
TREE_TYPE (cached_lhs)))
|
TREE_TYPE (cached_lhs)))
|
cached_lhs = fold_convert (TREE_TYPE (*expr_p), cached_lhs);
|
cached_lhs = fold_convert (TREE_TYPE (*expr_p), cached_lhs);
|
|
|
propagate_tree_value (expr_p, cached_lhs);
|
propagate_tree_value (expr_p, cached_lhs);
|
mark_stmt_modified (stmt);
|
mark_stmt_modified (stmt);
|
}
|
}
|
return retval;
|
return retval;
|
}
|
}
|
|
|
/* STMT, a MODIFY_EXPR, may create certain equivalences, in either
|
/* STMT, a MODIFY_EXPR, may create certain equivalences, in either
|
the available expressions table or the const_and_copies table.
|
the available expressions table or the const_and_copies table.
|
Detect and record those equivalences. */
|
Detect and record those equivalences. */
|
|
|
static void
|
static void
|
record_equivalences_from_stmt (tree stmt,
|
record_equivalences_from_stmt (tree stmt,
|
int may_optimize_p,
|
int may_optimize_p,
|
stmt_ann_t ann)
|
stmt_ann_t ann)
|
{
|
{
|
tree lhs = TREE_OPERAND (stmt, 0);
|
tree lhs = TREE_OPERAND (stmt, 0);
|
enum tree_code lhs_code = TREE_CODE (lhs);
|
enum tree_code lhs_code = TREE_CODE (lhs);
|
|
|
if (lhs_code == SSA_NAME)
|
if (lhs_code == SSA_NAME)
|
{
|
{
|
tree rhs = TREE_OPERAND (stmt, 1);
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
|
/* Strip away any useless type conversions. */
|
/* Strip away any useless type conversions. */
|
STRIP_USELESS_TYPE_CONVERSION (rhs);
|
STRIP_USELESS_TYPE_CONVERSION (rhs);
|
|
|
/* If the RHS of the assignment is a constant or another variable that
|
/* If the RHS of the assignment is a constant or another variable that
|
may be propagated, register it in the CONST_AND_COPIES table. We
|
may be propagated, register it in the CONST_AND_COPIES table. We
|
do not need to record unwind data for this, since this is a true
|
do not need to record unwind data for this, since this is a true
|
assignment and not an equivalence inferred from a comparison. All
|
assignment and not an equivalence inferred from a comparison. All
|
uses of this ssa name are dominated by this assignment, so unwinding
|
uses of this ssa name are dominated by this assignment, so unwinding
|
just costs time and space. */
|
just costs time and space. */
|
if (may_optimize_p
|
if (may_optimize_p
|
&& (TREE_CODE (rhs) == SSA_NAME
|
&& (TREE_CODE (rhs) == SSA_NAME
|
|| is_gimple_min_invariant (rhs)))
|
|| is_gimple_min_invariant (rhs)))
|
SSA_NAME_VALUE (lhs) = rhs;
|
SSA_NAME_VALUE (lhs) = rhs;
|
}
|
}
|
|
|
/* A memory store, even an aliased store, creates a useful
|
/* A memory store, even an aliased store, creates a useful
|
equivalence. By exchanging the LHS and RHS, creating suitable
|
equivalence. By exchanging the LHS and RHS, creating suitable
|
vops and recording the result in the available expression table,
|
vops and recording the result in the available expression table,
|
we may be able to expose more redundant loads. */
|
we may be able to expose more redundant loads. */
|
if (!ann->has_volatile_ops
|
if (!ann->has_volatile_ops
|
&& (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME
|
&& (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME
|
|| is_gimple_min_invariant (TREE_OPERAND (stmt, 1)))
|
|| is_gimple_min_invariant (TREE_OPERAND (stmt, 1)))
|
&& !is_gimple_reg (lhs))
|
&& !is_gimple_reg (lhs))
|
{
|
{
|
tree rhs = TREE_OPERAND (stmt, 1);
|
tree rhs = TREE_OPERAND (stmt, 1);
|
tree new;
|
tree new;
|
|
|
/* FIXME: If the LHS of the assignment is a bitfield and the RHS
|
/* FIXME: If the LHS of the assignment is a bitfield and the RHS
|
is a constant, we need to adjust the constant to fit into the
|
is a constant, we need to adjust the constant to fit into the
|
type of the LHS. If the LHS is a bitfield and the RHS is not
|
type of the LHS. If the LHS is a bitfield and the RHS is not
|
a constant, then we can not record any equivalences for this
|
a constant, then we can not record any equivalences for this
|
statement since we would need to represent the widening or
|
statement since we would need to represent the widening or
|
narrowing of RHS. This fixes gcc.c-torture/execute/921016-1.c
|
narrowing of RHS. This fixes gcc.c-torture/execute/921016-1.c
|
and should not be necessary if GCC represented bitfields
|
and should not be necessary if GCC represented bitfields
|
properly. */
|
properly. */
|
if (lhs_code == COMPONENT_REF
|
if (lhs_code == COMPONENT_REF
|
&& DECL_BIT_FIELD (TREE_OPERAND (lhs, 1)))
|
&& DECL_BIT_FIELD (TREE_OPERAND (lhs, 1)))
|
{
|
{
|
if (TREE_CONSTANT (rhs))
|
if (TREE_CONSTANT (rhs))
|
rhs = widen_bitfield (rhs, TREE_OPERAND (lhs, 1), lhs);
|
rhs = widen_bitfield (rhs, TREE_OPERAND (lhs, 1), lhs);
|
else
|
else
|
rhs = NULL;
|
rhs = NULL;
|
|
|
/* If the value overflowed, then we can not use this equivalence. */
|
/* If the value overflowed, then we can not use this equivalence. */
|
if (rhs && ! is_gimple_min_invariant (rhs))
|
if (rhs && ! is_gimple_min_invariant (rhs))
|
rhs = NULL;
|
rhs = NULL;
|
}
|
}
|
|
|
if (rhs)
|
if (rhs)
|
{
|
{
|
/* Build a new statement with the RHS and LHS exchanged. */
|
/* Build a new statement with the RHS and LHS exchanged. */
|
new = build2 (MODIFY_EXPR, TREE_TYPE (stmt), rhs, lhs);
|
new = build2 (MODIFY_EXPR, TREE_TYPE (stmt), rhs, lhs);
|
|
|
create_ssa_artficial_load_stmt (new, stmt);
|
create_ssa_artficial_load_stmt (new, stmt);
|
|
|
/* Finally enter the statement into the available expression
|
/* Finally enter the statement into the available expression
|
table. */
|
table. */
|
lookup_avail_expr (new, true);
|
lookup_avail_expr (new, true);
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* Replace *OP_P in STMT with any known equivalent value for *OP_P from
|
/* Replace *OP_P in STMT with any known equivalent value for *OP_P from
|
CONST_AND_COPIES. */
|
CONST_AND_COPIES. */
|
|
|
static bool
|
static bool
|
cprop_operand (tree stmt, use_operand_p op_p)
|
cprop_operand (tree stmt, use_operand_p op_p)
|
{
|
{
|
bool may_have_exposed_new_symbols = false;
|
bool may_have_exposed_new_symbols = false;
|
tree val;
|
tree val;
|
tree op = USE_FROM_PTR (op_p);
|
tree op = USE_FROM_PTR (op_p);
|
|
|
/* If the operand has a known constant value or it is known to be a
|
/* If the operand has a known constant value or it is known to be a
|
copy of some other variable, use the value or copy stored in
|
copy of some other variable, use the value or copy stored in
|
CONST_AND_COPIES. */
|
CONST_AND_COPIES. */
|
val = SSA_NAME_VALUE (op);
|
val = SSA_NAME_VALUE (op);
|
if (val && val != op && TREE_CODE (val) != VALUE_HANDLE)
|
if (val && val != op && TREE_CODE (val) != VALUE_HANDLE)
|
{
|
{
|
tree op_type, val_type;
|
tree op_type, val_type;
|
|
|
/* Do not change the base variable in the virtual operand
|
/* Do not change the base variable in the virtual operand
|
tables. That would make it impossible to reconstruct
|
tables. That would make it impossible to reconstruct
|
the renamed virtual operand if we later modify this
|
the renamed virtual operand if we later modify this
|
statement. Also only allow the new value to be an SSA_NAME
|
statement. Also only allow the new value to be an SSA_NAME
|
for propagation into virtual operands. */
|
for propagation into virtual operands. */
|
if (!is_gimple_reg (op)
|
if (!is_gimple_reg (op)
|
&& (TREE_CODE (val) != SSA_NAME
|
&& (TREE_CODE (val) != SSA_NAME
|
|| is_gimple_reg (val)
|
|| is_gimple_reg (val)
|
|| get_virtual_var (val) != get_virtual_var (op)))
|
|| get_virtual_var (val) != get_virtual_var (op)))
|
return false;
|
return false;
|
|
|
/* Do not replace hard register operands in asm statements. */
|
/* Do not replace hard register operands in asm statements. */
|
if (TREE_CODE (stmt) == ASM_EXPR
|
if (TREE_CODE (stmt) == ASM_EXPR
|
&& !may_propagate_copy_into_asm (op))
|
&& !may_propagate_copy_into_asm (op))
|
return false;
|
return false;
|
|
|
/* Get the toplevel type of each operand. */
|
/* Get the toplevel type of each operand. */
|
op_type = TREE_TYPE (op);
|
op_type = TREE_TYPE (op);
|
val_type = TREE_TYPE (val);
|
val_type = TREE_TYPE (val);
|
|
|
/* While both types are pointers, get the type of the object
|
/* While both types are pointers, get the type of the object
|
pointed to. */
|
pointed to. */
|
while (POINTER_TYPE_P (op_type) && POINTER_TYPE_P (val_type))
|
while (POINTER_TYPE_P (op_type) && POINTER_TYPE_P (val_type))
|
{
|
{
|
op_type = TREE_TYPE (op_type);
|
op_type = TREE_TYPE (op_type);
|
val_type = TREE_TYPE (val_type);
|
val_type = TREE_TYPE (val_type);
|
}
|
}
|
|
|
/* Make sure underlying types match before propagating a constant by
|
/* Make sure underlying types match before propagating a constant by
|
converting the constant to the proper type. Note that convert may
|
converting the constant to the proper type. Note that convert may
|
return a non-gimple expression, in which case we ignore this
|
return a non-gimple expression, in which case we ignore this
|
propagation opportunity. */
|
propagation opportunity. */
|
if (TREE_CODE (val) != SSA_NAME)
|
if (TREE_CODE (val) != SSA_NAME)
|
{
|
{
|
if (!lang_hooks.types_compatible_p (op_type, val_type))
|
if (!lang_hooks.types_compatible_p (op_type, val_type))
|
{
|
{
|
val = fold_convert (TREE_TYPE (op), val);
|
val = fold_convert (TREE_TYPE (op), val);
|
if (!is_gimple_min_invariant (val))
|
if (!is_gimple_min_invariant (val))
|
return false;
|
return false;
|
}
|
}
|
}
|
}
|
|
|
/* Certain operands are not allowed to be copy propagated due
|
/* Certain operands are not allowed to be copy propagated due
|
to their interaction with exception handling and some GCC
|
to their interaction with exception handling and some GCC
|
extensions. */
|
extensions. */
|
else if (!may_propagate_copy (op, val))
|
else if (!may_propagate_copy (op, val))
|
return false;
|
return false;
|
|
|
/* Do not propagate copies if the propagated value is at a deeper loop
|
/* Do not propagate copies if the propagated value is at a deeper loop
|
depth than the propagatee. Otherwise, this may move loop variant
|
depth than the propagatee. Otherwise, this may move loop variant
|
variables outside of their loops and prevent coalescing
|
variables outside of their loops and prevent coalescing
|
opportunities. If the value was loop invariant, it will be hoisted
|
opportunities. If the value was loop invariant, it will be hoisted
|
by LICM and exposed for copy propagation. */
|
by LICM and exposed for copy propagation. */
|
if (loop_depth_of_name (val) > loop_depth_of_name (op))
|
if (loop_depth_of_name (val) > loop_depth_of_name (op))
|
return false;
|
return false;
|
|
|
/* Dump details. */
|
/* Dump details. */
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Replaced '");
|
fprintf (dump_file, " Replaced '");
|
print_generic_expr (dump_file, op, dump_flags);
|
print_generic_expr (dump_file, op, dump_flags);
|
fprintf (dump_file, "' with %s '",
|
fprintf (dump_file, "' with %s '",
|
(TREE_CODE (val) != SSA_NAME ? "constant" : "variable"));
|
(TREE_CODE (val) != SSA_NAME ? "constant" : "variable"));
|
print_generic_expr (dump_file, val, dump_flags);
|
print_generic_expr (dump_file, val, dump_flags);
|
fprintf (dump_file, "'\n");
|
fprintf (dump_file, "'\n");
|
}
|
}
|
|
|
/* If VAL is an ADDR_EXPR or a constant of pointer type, note
|
/* If VAL is an ADDR_EXPR or a constant of pointer type, note
|
that we may have exposed a new symbol for SSA renaming. */
|
that we may have exposed a new symbol for SSA renaming. */
|
if (TREE_CODE (val) == ADDR_EXPR
|
if (TREE_CODE (val) == ADDR_EXPR
|
|| (POINTER_TYPE_P (TREE_TYPE (op))
|
|| (POINTER_TYPE_P (TREE_TYPE (op))
|
&& is_gimple_min_invariant (val)))
|
&& is_gimple_min_invariant (val)))
|
may_have_exposed_new_symbols = true;
|
may_have_exposed_new_symbols = true;
|
|
|
if (TREE_CODE (val) != SSA_NAME)
|
if (TREE_CODE (val) != SSA_NAME)
|
opt_stats.num_const_prop++;
|
opt_stats.num_const_prop++;
|
else
|
else
|
opt_stats.num_copy_prop++;
|
opt_stats.num_copy_prop++;
|
|
|
propagate_value (op_p, val);
|
propagate_value (op_p, val);
|
|
|
/* And note that we modified this statement. This is now
|
/* And note that we modified this statement. This is now
|
safe, even if we changed virtual operands since we will
|
safe, even if we changed virtual operands since we will
|
rescan the statement and rewrite its operands again. */
|
rescan the statement and rewrite its operands again. */
|
mark_stmt_modified (stmt);
|
mark_stmt_modified (stmt);
|
}
|
}
|
return may_have_exposed_new_symbols;
|
return may_have_exposed_new_symbols;
|
}
|
}
|
|
|
/* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
|
/* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
|
known value for that SSA_NAME (or NULL if no value is known).
|
known value for that SSA_NAME (or NULL if no value is known).
|
|
|
Propagate values from CONST_AND_COPIES into the uses, vuses and
|
Propagate values from CONST_AND_COPIES into the uses, vuses and
|
v_may_def_ops of STMT. */
|
v_may_def_ops of STMT. */
|
|
|
static bool
|
static bool
|
cprop_into_stmt (tree stmt)
|
cprop_into_stmt (tree stmt)
|
{
|
{
|
bool may_have_exposed_new_symbols = false;
|
bool may_have_exposed_new_symbols = false;
|
use_operand_p op_p;
|
use_operand_p op_p;
|
ssa_op_iter iter;
|
ssa_op_iter iter;
|
|
|
FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_ALL_USES)
|
FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_ALL_USES)
|
{
|
{
|
if (TREE_CODE (USE_FROM_PTR (op_p)) == SSA_NAME)
|
if (TREE_CODE (USE_FROM_PTR (op_p)) == SSA_NAME)
|
may_have_exposed_new_symbols |= cprop_operand (stmt, op_p);
|
may_have_exposed_new_symbols |= cprop_operand (stmt, op_p);
|
}
|
}
|
|
|
return may_have_exposed_new_symbols;
|
return may_have_exposed_new_symbols;
|
}
|
}
|
|
|
|
|
/* Optimize the statement pointed to by iterator SI.
|
/* Optimize the statement pointed to by iterator SI.
|
|
|
We try to perform some simplistic global redundancy elimination and
|
We try to perform some simplistic global redundancy elimination and
|
constant propagation:
|
constant propagation:
|
|
|
1- To detect global redundancy, we keep track of expressions that have
|
1- To detect global redundancy, we keep track of expressions that have
|
been computed in this block and its dominators. If we find that the
|
been computed in this block and its dominators. If we find that the
|
same expression is computed more than once, we eliminate repeated
|
same expression is computed more than once, we eliminate repeated
|
computations by using the target of the first one.
|
computations by using the target of the first one.
|
|
|
2- Constant values and copy assignments. This is used to do very
|
2- Constant values and copy assignments. This is used to do very
|
simplistic constant and copy propagation. When a constant or copy
|
simplistic constant and copy propagation. When a constant or copy
|
assignment is found, we map the value on the RHS of the assignment to
|
assignment is found, we map the value on the RHS of the assignment to
|
the variable in the LHS in the CONST_AND_COPIES table. */
|
the variable in the LHS in the CONST_AND_COPIES table. */
|
|
|
static void
|
static void
|
optimize_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
|
optimize_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
|
basic_block bb, block_stmt_iterator si)
|
basic_block bb, block_stmt_iterator si)
|
{
|
{
|
stmt_ann_t ann;
|
stmt_ann_t ann;
|
tree stmt, old_stmt;
|
tree stmt, old_stmt;
|
bool may_optimize_p;
|
bool may_optimize_p;
|
bool may_have_exposed_new_symbols = false;
|
bool may_have_exposed_new_symbols = false;
|
|
|
old_stmt = stmt = bsi_stmt (si);
|
old_stmt = stmt = bsi_stmt (si);
|
|
|
if (TREE_CODE (stmt) == COND_EXPR)
|
if (TREE_CODE (stmt) == COND_EXPR)
|
canonicalize_comparison (stmt);
|
canonicalize_comparison (stmt);
|
|
|
update_stmt_if_modified (stmt);
|
update_stmt_if_modified (stmt);
|
ann = stmt_ann (stmt);
|
ann = stmt_ann (stmt);
|
opt_stats.num_stmts++;
|
opt_stats.num_stmts++;
|
may_have_exposed_new_symbols = false;
|
may_have_exposed_new_symbols = false;
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, "Optimizing statement ");
|
fprintf (dump_file, "Optimizing statement ");
|
print_generic_stmt (dump_file, stmt, TDF_SLIM);
|
print_generic_stmt (dump_file, stmt, TDF_SLIM);
|
}
|
}
|
|
|
/* Const/copy propagate into USES, VUSES and the RHS of V_MAY_DEFs. */
|
/* Const/copy propagate into USES, VUSES and the RHS of V_MAY_DEFs. */
|
may_have_exposed_new_symbols = cprop_into_stmt (stmt);
|
may_have_exposed_new_symbols = cprop_into_stmt (stmt);
|
|
|
/* If the statement has been modified with constant replacements,
|
/* If the statement has been modified with constant replacements,
|
fold its RHS before checking for redundant computations. */
|
fold its RHS before checking for redundant computations. */
|
if (ann->modified)
|
if (ann->modified)
|
{
|
{
|
tree rhs;
|
tree rhs;
|
|
|
/* Try to fold the statement making sure that STMT is kept
|
/* Try to fold the statement making sure that STMT is kept
|
up to date. */
|
up to date. */
|
if (fold_stmt (bsi_stmt_ptr (si)))
|
if (fold_stmt (bsi_stmt_ptr (si)))
|
{
|
{
|
stmt = bsi_stmt (si);
|
stmt = bsi_stmt (si);
|
ann = stmt_ann (stmt);
|
ann = stmt_ann (stmt);
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Folded to: ");
|
fprintf (dump_file, " Folded to: ");
|
print_generic_stmt (dump_file, stmt, TDF_SLIM);
|
print_generic_stmt (dump_file, stmt, TDF_SLIM);
|
}
|
}
|
}
|
}
|
|
|
rhs = get_rhs (stmt);
|
rhs = get_rhs (stmt);
|
if (rhs && TREE_CODE (rhs) == ADDR_EXPR)
|
if (rhs && TREE_CODE (rhs) == ADDR_EXPR)
|
recompute_tree_invariant_for_addr_expr (rhs);
|
recompute_tree_invariant_for_addr_expr (rhs);
|
|
|
/* Constant/copy propagation above may change the set of
|
/* Constant/copy propagation above may change the set of
|
virtual operands associated with this statement. Folding
|
virtual operands associated with this statement. Folding
|
may remove the need for some virtual operands.
|
may remove the need for some virtual operands.
|
|
|
Indicate we will need to rescan and rewrite the statement. */
|
Indicate we will need to rescan and rewrite the statement. */
|
may_have_exposed_new_symbols = true;
|
may_have_exposed_new_symbols = true;
|
}
|
}
|
|
|
/* Check for redundant computations. Do this optimization only
|
/* Check for redundant computations. Do this optimization only
|
for assignments that have no volatile ops and conditionals. */
|
for assignments that have no volatile ops and conditionals. */
|
may_optimize_p = (!ann->has_volatile_ops
|
may_optimize_p = (!ann->has_volatile_ops
|
&& ((TREE_CODE (stmt) == RETURN_EXPR
|
&& ((TREE_CODE (stmt) == RETURN_EXPR
|
&& TREE_OPERAND (stmt, 0)
|
&& TREE_OPERAND (stmt, 0)
|
&& TREE_CODE (TREE_OPERAND (stmt, 0)) == MODIFY_EXPR
|
&& TREE_CODE (TREE_OPERAND (stmt, 0)) == MODIFY_EXPR
|
&& ! (TREE_SIDE_EFFECTS
|
&& ! (TREE_SIDE_EFFECTS
|
(TREE_OPERAND (TREE_OPERAND (stmt, 0), 1))))
|
(TREE_OPERAND (TREE_OPERAND (stmt, 0), 1))))
|
|| (TREE_CODE (stmt) == MODIFY_EXPR
|
|| (TREE_CODE (stmt) == MODIFY_EXPR
|
&& ! TREE_SIDE_EFFECTS (TREE_OPERAND (stmt, 1)))
|
&& ! TREE_SIDE_EFFECTS (TREE_OPERAND (stmt, 1)))
|
|| TREE_CODE (stmt) == COND_EXPR
|
|| TREE_CODE (stmt) == COND_EXPR
|
|| TREE_CODE (stmt) == SWITCH_EXPR));
|
|| TREE_CODE (stmt) == SWITCH_EXPR));
|
|
|
if (may_optimize_p)
|
if (may_optimize_p)
|
may_have_exposed_new_symbols |= eliminate_redundant_computations (stmt);
|
may_have_exposed_new_symbols |= eliminate_redundant_computations (stmt);
|
|
|
/* Record any additional equivalences created by this statement. */
|
/* Record any additional equivalences created by this statement. */
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
record_equivalences_from_stmt (stmt,
|
record_equivalences_from_stmt (stmt,
|
may_optimize_p,
|
may_optimize_p,
|
ann);
|
ann);
|
|
|
/* If STMT is a COND_EXPR and it was modified, then we may know
|
/* If STMT is a COND_EXPR and it was modified, then we may know
|
where it goes. If that is the case, then mark the CFG as altered.
|
where it goes. If that is the case, then mark the CFG as altered.
|
|
|
This will cause us to later call remove_unreachable_blocks and
|
This will cause us to later call remove_unreachable_blocks and
|
cleanup_tree_cfg when it is safe to do so. It is not safe to
|
cleanup_tree_cfg when it is safe to do so. It is not safe to
|
clean things up here since removal of edges and such can trigger
|
clean things up here since removal of edges and such can trigger
|
the removal of PHI nodes, which in turn can release SSA_NAMEs to
|
the removal of PHI nodes, which in turn can release SSA_NAMEs to
|
the manager.
|
the manager.
|
|
|
That's all fine and good, except that once SSA_NAMEs are released
|
That's all fine and good, except that once SSA_NAMEs are released
|
to the manager, we must not call create_ssa_name until all references
|
to the manager, we must not call create_ssa_name until all references
|
to released SSA_NAMEs have been eliminated.
|
to released SSA_NAMEs have been eliminated.
|
|
|
All references to the deleted SSA_NAMEs can not be eliminated until
|
All references to the deleted SSA_NAMEs can not be eliminated until
|
we remove unreachable blocks.
|
we remove unreachable blocks.
|
|
|
We can not remove unreachable blocks until after we have completed
|
We can not remove unreachable blocks until after we have completed
|
any queued jump threading.
|
any queued jump threading.
|
|
|
We can not complete any queued jump threads until we have taken
|
We can not complete any queued jump threads until we have taken
|
appropriate variables out of SSA form. Taking variables out of
|
appropriate variables out of SSA form. Taking variables out of
|
SSA form can call create_ssa_name and thus we lose.
|
SSA form can call create_ssa_name and thus we lose.
|
|
|
Ultimately I suspect we're going to need to change the interface
|
Ultimately I suspect we're going to need to change the interface
|
into the SSA_NAME manager. */
|
into the SSA_NAME manager. */
|
|
|
if (ann->modified)
|
if (ann->modified)
|
{
|
{
|
tree val = NULL;
|
tree val = NULL;
|
|
|
if (TREE_CODE (stmt) == COND_EXPR)
|
if (TREE_CODE (stmt) == COND_EXPR)
|
val = COND_EXPR_COND (stmt);
|
val = COND_EXPR_COND (stmt);
|
else if (TREE_CODE (stmt) == SWITCH_EXPR)
|
else if (TREE_CODE (stmt) == SWITCH_EXPR)
|
val = SWITCH_COND (stmt);
|
val = SWITCH_COND (stmt);
|
|
|
if (val && TREE_CODE (val) == INTEGER_CST && find_taken_edge (bb, val))
|
if (val && TREE_CODE (val) == INTEGER_CST && find_taken_edge (bb, val))
|
cfg_altered = true;
|
cfg_altered = true;
|
|
|
/* If we simplified a statement in such a way as to be shown that it
|
/* If we simplified a statement in such a way as to be shown that it
|
cannot trap, update the eh information and the cfg to match. */
|
cannot trap, update the eh information and the cfg to match. */
|
if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
|
if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
|
{
|
{
|
bitmap_set_bit (need_eh_cleanup, bb->index);
|
bitmap_set_bit (need_eh_cleanup, bb->index);
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
fprintf (dump_file, " Flagged to clear EH edges.\n");
|
fprintf (dump_file, " Flagged to clear EH edges.\n");
|
}
|
}
|
}
|
}
|
|
|
if (may_have_exposed_new_symbols)
|
if (may_have_exposed_new_symbols)
|
VEC_safe_push (tree, heap, stmts_to_rescan, bsi_stmt (si));
|
VEC_safe_push (tree, heap, stmts_to_rescan, bsi_stmt (si));
|
}
|
}
|
|
|
/* Search for an existing instance of STMT in the AVAIL_EXPRS table. If
|
/* Search for an existing instance of STMT in the AVAIL_EXPRS table. If
|
found, return its LHS. Otherwise insert STMT in the table and return
|
found, return its LHS. Otherwise insert STMT in the table and return
|
NULL_TREE.
|
NULL_TREE.
|
|
|
Also, when an expression is first inserted in the AVAIL_EXPRS table, it
|
Also, when an expression is first inserted in the AVAIL_EXPRS table, it
|
is also added to the stack pointed to by BLOCK_AVAIL_EXPRS_P, so that they
|
is also added to the stack pointed to by BLOCK_AVAIL_EXPRS_P, so that they
|
can be removed when we finish processing this block and its children.
|
can be removed when we finish processing this block and its children.
|
|
|
NOTE: This function assumes that STMT is a MODIFY_EXPR node that
|
NOTE: This function assumes that STMT is a MODIFY_EXPR node that
|
contains no CALL_EXPR on its RHS and makes no volatile nor
|
contains no CALL_EXPR on its RHS and makes no volatile nor
|
aliased references. */
|
aliased references. */
|
|
|
static tree
|
static tree
|
lookup_avail_expr (tree stmt, bool insert)
|
lookup_avail_expr (tree stmt, bool insert)
|
{
|
{
|
void **slot;
|
void **slot;
|
tree lhs;
|
tree lhs;
|
tree temp;
|
tree temp;
|
struct expr_hash_elt *element = XNEW (struct expr_hash_elt);
|
struct expr_hash_elt *element = XNEW (struct expr_hash_elt);
|
|
|
lhs = TREE_CODE (stmt) == MODIFY_EXPR ? TREE_OPERAND (stmt, 0) : NULL;
|
lhs = TREE_CODE (stmt) == MODIFY_EXPR ? TREE_OPERAND (stmt, 0) : NULL;
|
|
|
initialize_hash_element (stmt, lhs, element);
|
initialize_hash_element (stmt, lhs, element);
|
|
|
/* Don't bother remembering constant assignments and copy operations.
|
/* Don't bother remembering constant assignments and copy operations.
|
Constants and copy operations are handled by the constant/copy propagator
|
Constants and copy operations are handled by the constant/copy propagator
|
in optimize_stmt. */
|
in optimize_stmt. */
|
if (TREE_CODE (element->rhs) == SSA_NAME
|
if (TREE_CODE (element->rhs) == SSA_NAME
|
|| is_gimple_min_invariant (element->rhs))
|
|| is_gimple_min_invariant (element->rhs))
|
{
|
{
|
free (element);
|
free (element);
|
return NULL_TREE;
|
return NULL_TREE;
|
}
|
}
|
|
|
/* Finally try to find the expression in the main expression hash table. */
|
/* Finally try to find the expression in the main expression hash table. */
|
slot = htab_find_slot_with_hash (avail_exprs, element, element->hash,
|
slot = htab_find_slot_with_hash (avail_exprs, element, element->hash,
|
(insert ? INSERT : NO_INSERT));
|
(insert ? INSERT : NO_INSERT));
|
if (slot == NULL)
|
if (slot == NULL)
|
{
|
{
|
free (element);
|
free (element);
|
return NULL_TREE;
|
return NULL_TREE;
|
}
|
}
|
|
|
if (*slot == NULL)
|
if (*slot == NULL)
|
{
|
{
|
*slot = (void *) element;
|
*slot = (void *) element;
|
VEC_safe_push (tree, heap, avail_exprs_stack,
|
VEC_safe_push (tree, heap, avail_exprs_stack,
|
stmt ? stmt : element->rhs);
|
stmt ? stmt : element->rhs);
|
return NULL_TREE;
|
return NULL_TREE;
|
}
|
}
|
|
|
/* Extract the LHS of the assignment so that it can be used as the current
|
/* Extract the LHS of the assignment so that it can be used as the current
|
definition of another variable. */
|
definition of another variable. */
|
lhs = ((struct expr_hash_elt *)*slot)->lhs;
|
lhs = ((struct expr_hash_elt *)*slot)->lhs;
|
|
|
/* See if the LHS appears in the CONST_AND_COPIES table. If it does, then
|
/* See if the LHS appears in the CONST_AND_COPIES table. If it does, then
|
use the value from the const_and_copies table. */
|
use the value from the const_and_copies table. */
|
if (TREE_CODE (lhs) == SSA_NAME)
|
if (TREE_CODE (lhs) == SSA_NAME)
|
{
|
{
|
temp = SSA_NAME_VALUE (lhs);
|
temp = SSA_NAME_VALUE (lhs);
|
if (temp && TREE_CODE (temp) != VALUE_HANDLE)
|
if (temp && TREE_CODE (temp) != VALUE_HANDLE)
|
lhs = temp;
|
lhs = temp;
|
}
|
}
|
|
|
free (element);
|
free (element);
|
return lhs;
|
return lhs;
|
}
|
}
|
|
|
/* Hashing and equality functions for AVAIL_EXPRS. The table stores
|
/* Hashing and equality functions for AVAIL_EXPRS. The table stores
|
MODIFY_EXPR statements. We compute a value number for expressions using
|
MODIFY_EXPR statements. We compute a value number for expressions using
|
the code of the expression and the SSA numbers of its operands. */
|
the code of the expression and the SSA numbers of its operands. */
|
|
|
static hashval_t
|
static hashval_t
|
avail_expr_hash (const void *p)
|
avail_expr_hash (const void *p)
|
{
|
{
|
tree stmt = ((struct expr_hash_elt *)p)->stmt;
|
tree stmt = ((struct expr_hash_elt *)p)->stmt;
|
tree rhs = ((struct expr_hash_elt *)p)->rhs;
|
tree rhs = ((struct expr_hash_elt *)p)->rhs;
|
tree vuse;
|
tree vuse;
|
ssa_op_iter iter;
|
ssa_op_iter iter;
|
hashval_t val = 0;
|
hashval_t val = 0;
|
|
|
/* iterative_hash_expr knows how to deal with any expression and
|
/* iterative_hash_expr knows how to deal with any expression and
|
deals with commutative operators as well, so just use it instead
|
deals with commutative operators as well, so just use it instead
|
of duplicating such complexities here. */
|
of duplicating such complexities here. */
|
val = iterative_hash_expr (rhs, val);
|
val = iterative_hash_expr (rhs, val);
|
|
|
/* If the hash table entry is not associated with a statement, then we
|
/* If the hash table entry is not associated with a statement, then we
|
can just hash the expression and not worry about virtual operands
|
can just hash the expression and not worry about virtual operands
|
and such. */
|
and such. */
|
if (!stmt || !stmt_ann (stmt))
|
if (!stmt || !stmt_ann (stmt))
|
return val;
|
return val;
|
|
|
/* Add the SSA version numbers of every vuse operand. This is important
|
/* Add the SSA version numbers of every vuse operand. This is important
|
because compound variables like arrays are not renamed in the
|
because compound variables like arrays are not renamed in the
|
operands. Rather, the rename is done on the virtual variable
|
operands. Rather, the rename is done on the virtual variable
|
representing all the elements of the array. */
|
representing all the elements of the array. */
|
FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE)
|
FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE)
|
val = iterative_hash_expr (vuse, val);
|
val = iterative_hash_expr (vuse, val);
|
|
|
return val;
|
return val;
|
}
|
}
|
|
|
static hashval_t
|
static hashval_t
|
real_avail_expr_hash (const void *p)
|
real_avail_expr_hash (const void *p)
|
{
|
{
|
return ((const struct expr_hash_elt *)p)->hash;
|
return ((const struct expr_hash_elt *)p)->hash;
|
}
|
}
|
|
|
static int
|
static int
|
avail_expr_eq (const void *p1, const void *p2)
|
avail_expr_eq (const void *p1, const void *p2)
|
{
|
{
|
tree stmt1 = ((struct expr_hash_elt *)p1)->stmt;
|
tree stmt1 = ((struct expr_hash_elt *)p1)->stmt;
|
tree rhs1 = ((struct expr_hash_elt *)p1)->rhs;
|
tree rhs1 = ((struct expr_hash_elt *)p1)->rhs;
|
tree stmt2 = ((struct expr_hash_elt *)p2)->stmt;
|
tree stmt2 = ((struct expr_hash_elt *)p2)->stmt;
|
tree rhs2 = ((struct expr_hash_elt *)p2)->rhs;
|
tree rhs2 = ((struct expr_hash_elt *)p2)->rhs;
|
|
|
/* If they are the same physical expression, return true. */
|
/* If they are the same physical expression, return true. */
|
if (rhs1 == rhs2 && stmt1 == stmt2)
|
if (rhs1 == rhs2 && stmt1 == stmt2)
|
return true;
|
return true;
|
|
|
/* If their codes are not equal, then quit now. */
|
/* If their codes are not equal, then quit now. */
|
if (TREE_CODE (rhs1) != TREE_CODE (rhs2))
|
if (TREE_CODE (rhs1) != TREE_CODE (rhs2))
|
return false;
|
return false;
|
|
|
/* In case of a collision, both RHS have to be identical and have the
|
/* In case of a collision, both RHS have to be identical and have the
|
same VUSE operands. */
|
same VUSE operands. */
|
if ((TREE_TYPE (rhs1) == TREE_TYPE (rhs2)
|
if ((TREE_TYPE (rhs1) == TREE_TYPE (rhs2)
|
|| lang_hooks.types_compatible_p (TREE_TYPE (rhs1), TREE_TYPE (rhs2)))
|
|| lang_hooks.types_compatible_p (TREE_TYPE (rhs1), TREE_TYPE (rhs2)))
|
&& operand_equal_p (rhs1, rhs2, OEP_PURE_SAME))
|
&& operand_equal_p (rhs1, rhs2, OEP_PURE_SAME))
|
{
|
{
|
bool ret = compare_ssa_operands_equal (stmt1, stmt2, SSA_OP_VUSE);
|
bool ret = compare_ssa_operands_equal (stmt1, stmt2, SSA_OP_VUSE);
|
gcc_assert (!ret || ((struct expr_hash_elt *)p1)->hash
|
gcc_assert (!ret || ((struct expr_hash_elt *)p1)->hash
|
== ((struct expr_hash_elt *)p2)->hash);
|
== ((struct expr_hash_elt *)p2)->hash);
|
return ret;
|
return ret;
|
}
|
}
|
|
|
return false;
|
return false;
|
}
|
}
|
|
|
/* PHI-ONLY copy and constant propagation. This pass is meant to clean
|
/* PHI-ONLY copy and constant propagation. This pass is meant to clean
|
up degenerate PHIs created by or exposed by jump threading. */
|
up degenerate PHIs created by or exposed by jump threading. */
|
|
|
/* Given PHI, return its RHS if the PHI is a degenerate, otherwise return
|
/* Given PHI, return its RHS if the PHI is a degenerate, otherwise return
|
NULL. */
|
NULL. */
|
|
|
static tree
|
static tree
|
degenerate_phi_result (tree phi)
|
degenerate_phi_result (tree phi)
|
{
|
{
|
tree lhs = PHI_RESULT (phi);
|
tree lhs = PHI_RESULT (phi);
|
tree val = NULL;
|
tree val = NULL;
|
int i;
|
int i;
|
|
|
/* Ignoring arguments which are the same as LHS, if all the remaining
|
/* Ignoring arguments which are the same as LHS, if all the remaining
|
arguments are the same, then the PHI is a degenerate and has the
|
arguments are the same, then the PHI is a degenerate and has the
|
value of that common argument. */
|
value of that common argument. */
|
for (i = 0; i < PHI_NUM_ARGS (phi); i++)
|
for (i = 0; i < PHI_NUM_ARGS (phi); i++)
|
{
|
{
|
tree arg = PHI_ARG_DEF (phi, i);
|
tree arg = PHI_ARG_DEF (phi, i);
|
|
|
if (arg == lhs)
|
if (arg == lhs)
|
continue;
|
continue;
|
else if (!val)
|
else if (!val)
|
val = arg;
|
val = arg;
|
else if (!operand_equal_p (arg, val, 0))
|
else if (!operand_equal_p (arg, val, 0))
|
break;
|
break;
|
}
|
}
|
return (i == PHI_NUM_ARGS (phi) ? val : NULL);
|
return (i == PHI_NUM_ARGS (phi) ? val : NULL);
|
}
|
}
|
|
|
/* Given a tree node T, which is either a PHI_NODE or MODIFY_EXPR,
|
/* Given a tree node T, which is either a PHI_NODE or MODIFY_EXPR,
|
remove it from the IL. */
|
remove it from the IL. */
|
|
|
static void
|
static void
|
remove_stmt_or_phi (tree t)
|
remove_stmt_or_phi (tree t)
|
{
|
{
|
if (TREE_CODE (t) == PHI_NODE)
|
if (TREE_CODE (t) == PHI_NODE)
|
remove_phi_node (t, NULL);
|
remove_phi_node (t, NULL);
|
else
|
else
|
{
|
{
|
block_stmt_iterator bsi = bsi_for_stmt (t);
|
block_stmt_iterator bsi = bsi_for_stmt (t);
|
bsi_remove (&bsi, true);
|
bsi_remove (&bsi, true);
|
}
|
}
|
}
|
}
|
|
|
/* Given a tree node T, which is either a PHI_NODE or MODIFY_EXPR,
|
/* Given a tree node T, which is either a PHI_NODE or MODIFY_EXPR,
|
return the "rhs" of the node, in the case of a non-degenerate
|
return the "rhs" of the node, in the case of a non-degenerate
|
PHI, NULL is returned. */
|
PHI, NULL is returned. */
|
|
|
static tree
|
static tree
|
get_rhs_or_phi_arg (tree t)
|
get_rhs_or_phi_arg (tree t)
|
{
|
{
|
if (TREE_CODE (t) == PHI_NODE)
|
if (TREE_CODE (t) == PHI_NODE)
|
return degenerate_phi_result (t);
|
return degenerate_phi_result (t);
|
else if (TREE_CODE (t) == MODIFY_EXPR)
|
else if (TREE_CODE (t) == MODIFY_EXPR)
|
return TREE_OPERAND (t, 1);
|
return TREE_OPERAND (t, 1);
|
gcc_unreachable ();
|
gcc_unreachable ();
|
}
|
}
|
|
|
|
|
/* Given a tree node T, which is either a PHI_NODE or a MODIFY_EXPR,
|
/* Given a tree node T, which is either a PHI_NODE or a MODIFY_EXPR,
|
return the "lhs" of the node. */
|
return the "lhs" of the node. */
|
|
|
static tree
|
static tree
|
get_lhs_or_phi_result (tree t)
|
get_lhs_or_phi_result (tree t)
|
{
|
{
|
if (TREE_CODE (t) == PHI_NODE)
|
if (TREE_CODE (t) == PHI_NODE)
|
return PHI_RESULT (t);
|
return PHI_RESULT (t);
|
else if (TREE_CODE (t) == MODIFY_EXPR)
|
else if (TREE_CODE (t) == MODIFY_EXPR)
|
return TREE_OPERAND (t, 0);
|
return TREE_OPERAND (t, 0);
|
gcc_unreachable ();
|
gcc_unreachable ();
|
}
|
}
|
|
|
/* Propagate RHS into all uses of LHS (when possible).
|
/* Propagate RHS into all uses of LHS (when possible).
|
|
|
RHS and LHS are derived from STMT, which is passed in solely so
|
RHS and LHS are derived from STMT, which is passed in solely so
|
that we can remove it if propagation is successful.
|
that we can remove it if propagation is successful.
|
|
|
When propagating into a PHI node or into a statement which turns
|
When propagating into a PHI node or into a statement which turns
|
into a trivial copy or constant initialization, set the
|
into a trivial copy or constant initialization, set the
|
appropriate bit in INTERESTING_NAMEs so that we will visit those
|
appropriate bit in INTERESTING_NAMEs so that we will visit those
|
nodes as well in an effort to pick up secondary optimization
|
nodes as well in an effort to pick up secondary optimization
|
opportunities. */
|
opportunities. */
|
|
|
static void
|
static void
|
propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
|
propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
|
{
|
{
|
/* First verify that propagation is valid and isn't going to move a
|
/* First verify that propagation is valid and isn't going to move a
|
loop variant variable outside its loop. */
|
loop variant variable outside its loop. */
|
if (! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)
|
if (! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)
|
&& (TREE_CODE (rhs) != SSA_NAME
|
&& (TREE_CODE (rhs) != SSA_NAME
|
|| ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs))
|
|| ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs))
|
&& may_propagate_copy (lhs, rhs)
|
&& may_propagate_copy (lhs, rhs)
|
&& loop_depth_of_name (lhs) >= loop_depth_of_name (rhs))
|
&& loop_depth_of_name (lhs) >= loop_depth_of_name (rhs))
|
{
|
{
|
use_operand_p use_p;
|
use_operand_p use_p;
|
imm_use_iterator iter;
|
imm_use_iterator iter;
|
tree use_stmt;
|
tree use_stmt;
|
bool all = true;
|
bool all = true;
|
|
|
/* Dump details. */
|
/* Dump details. */
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Replacing '");
|
fprintf (dump_file, " Replacing '");
|
print_generic_expr (dump_file, lhs, dump_flags);
|
print_generic_expr (dump_file, lhs, dump_flags);
|
fprintf (dump_file, "' with %s '",
|
fprintf (dump_file, "' with %s '",
|
(TREE_CODE (rhs) != SSA_NAME ? "constant" : "variable"));
|
(TREE_CODE (rhs) != SSA_NAME ? "constant" : "variable"));
|
print_generic_expr (dump_file, rhs, dump_flags);
|
print_generic_expr (dump_file, rhs, dump_flags);
|
fprintf (dump_file, "'\n");
|
fprintf (dump_file, "'\n");
|
}
|
}
|
|
|
/* Walk over every use of LHS and try to replace the use with RHS.
|
/* Walk over every use of LHS and try to replace the use with RHS.
|
At this point the only reason why such a propagation would not
|
At this point the only reason why such a propagation would not
|
be successful would be if the use occurs in an ASM_EXPR. */
|
be successful would be if the use occurs in an ASM_EXPR. */
|
FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
|
FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
|
{
|
{
|
|
|
/* It's not always safe to propagate into an ASM_EXPR. */
|
/* It's not always safe to propagate into an ASM_EXPR. */
|
if (TREE_CODE (use_stmt) == ASM_EXPR
|
if (TREE_CODE (use_stmt) == ASM_EXPR
|
&& ! may_propagate_copy_into_asm (lhs))
|
&& ! may_propagate_copy_into_asm (lhs))
|
{
|
{
|
all = false;
|
all = false;
|
continue;
|
continue;
|
}
|
}
|
|
|
/* Dump details. */
|
/* Dump details. */
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Original statement:");
|
fprintf (dump_file, " Original statement:");
|
print_generic_expr (dump_file, use_stmt, dump_flags);
|
print_generic_expr (dump_file, use_stmt, dump_flags);
|
fprintf (dump_file, "\n");
|
fprintf (dump_file, "\n");
|
}
|
}
|
|
|
/* Propagate the RHS into this use of the LHS. */
|
/* Propagate the RHS into this use of the LHS. */
|
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
|
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
|
propagate_value (use_p, rhs);
|
propagate_value (use_p, rhs);
|
|
|
/* Special cases to avoid useless calls into the folding
|
/* Special cases to avoid useless calls into the folding
|
routines, operand scanning, etc.
|
routines, operand scanning, etc.
|
|
|
First, propagation into a PHI may cause the PHI to become
|
First, propagation into a PHI may cause the PHI to become
|
a degenerate, so mark the PHI as interesting. No other
|
a degenerate, so mark the PHI as interesting. No other
|
actions are necessary.
|
actions are necessary.
|
|
|
Second, if we're propagating a virtual operand and the
|
Second, if we're propagating a virtual operand and the
|
propagation does not change the underlying _DECL node for
|
propagation does not change the underlying _DECL node for
|
the virtual operand, then no further actions are necessary. */
|
the virtual operand, then no further actions are necessary. */
|
if (TREE_CODE (use_stmt) == PHI_NODE
|
if (TREE_CODE (use_stmt) == PHI_NODE
|
|| (! is_gimple_reg (lhs)
|
|| (! is_gimple_reg (lhs)
|
&& TREE_CODE (rhs) == SSA_NAME
|
&& TREE_CODE (rhs) == SSA_NAME
|
&& SSA_NAME_VAR (lhs) == SSA_NAME_VAR (rhs)))
|
&& SSA_NAME_VAR (lhs) == SSA_NAME_VAR (rhs)))
|
{
|
{
|
/* Dump details. */
|
/* Dump details. */
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Updated statement:");
|
fprintf (dump_file, " Updated statement:");
|
print_generic_expr (dump_file, use_stmt, dump_flags);
|
print_generic_expr (dump_file, use_stmt, dump_flags);
|
fprintf (dump_file, "\n");
|
fprintf (dump_file, "\n");
|
}
|
}
|
|
|
/* Propagation into a PHI may expose new degenerate PHIs,
|
/* Propagation into a PHI may expose new degenerate PHIs,
|
so mark the result of the PHI as interesting. */
|
so mark the result of the PHI as interesting. */
|
if (TREE_CODE (use_stmt) == PHI_NODE)
|
if (TREE_CODE (use_stmt) == PHI_NODE)
|
{
|
{
|
tree result = get_lhs_or_phi_result (use_stmt);
|
tree result = get_lhs_or_phi_result (use_stmt);
|
bitmap_set_bit (interesting_names, SSA_NAME_VERSION (result));
|
bitmap_set_bit (interesting_names, SSA_NAME_VERSION (result));
|
}
|
}
|
continue;
|
continue;
|
}
|
}
|
|
|
/* From this point onward we are propagating into a
|
/* From this point onward we are propagating into a
|
real statement. Folding may (or may not) be possible,
|
real statement. Folding may (or may not) be possible,
|
we may expose new operands, expose dead EH edges,
|
we may expose new operands, expose dead EH edges,
|
etc. */
|
etc. */
|
fold_stmt_inplace (use_stmt);
|
fold_stmt_inplace (use_stmt);
|
|
|
/* Sometimes propagation can expose new operands to the
|
/* Sometimes propagation can expose new operands to the
|
renamer. Note this will call update_stmt at the
|
renamer. Note this will call update_stmt at the
|
appropriate time. */
|
appropriate time. */
|
mark_new_vars_to_rename (use_stmt);
|
mark_new_vars_to_rename (use_stmt);
|
|
|
/* Dump details. */
|
/* Dump details. */
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
{
|
{
|
fprintf (dump_file, " Updated statement:");
|
fprintf (dump_file, " Updated statement:");
|
print_generic_expr (dump_file, use_stmt, dump_flags);
|
print_generic_expr (dump_file, use_stmt, dump_flags);
|
fprintf (dump_file, "\n");
|
fprintf (dump_file, "\n");
|
}
|
}
|
|
|
/* If we replaced a variable index with a constant, then
|
/* If we replaced a variable index with a constant, then
|
we would need to update the invariant flag for ADDR_EXPRs. */
|
we would need to update the invariant flag for ADDR_EXPRs. */
|
if (TREE_CODE (use_stmt) == MODIFY_EXPR
|
if (TREE_CODE (use_stmt) == MODIFY_EXPR
|
&& TREE_CODE (TREE_OPERAND (use_stmt, 1)) == ADDR_EXPR)
|
&& TREE_CODE (TREE_OPERAND (use_stmt, 1)) == ADDR_EXPR)
|
recompute_tree_invariant_for_addr_expr (TREE_OPERAND (use_stmt, 1));
|
recompute_tree_invariant_for_addr_expr (TREE_OPERAND (use_stmt, 1));
|
|
|
/* If we cleaned up EH information from the statement,
|
/* If we cleaned up EH information from the statement,
|
mark its containing block as needing EH cleanups. */
|
mark its containing block as needing EH cleanups. */
|
if (maybe_clean_or_replace_eh_stmt (use_stmt, use_stmt))
|
if (maybe_clean_or_replace_eh_stmt (use_stmt, use_stmt))
|
{
|
{
|
bitmap_set_bit (need_eh_cleanup, bb_for_stmt (use_stmt)->index);
|
bitmap_set_bit (need_eh_cleanup, bb_for_stmt (use_stmt)->index);
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
fprintf (dump_file, " Flagged to clear EH edges.\n");
|
fprintf (dump_file, " Flagged to clear EH edges.\n");
|
}
|
}
|
|
|
/* Propagation may expose new trivial copy/constant propagation
|
/* Propagation may expose new trivial copy/constant propagation
|
opportunities. */
|
opportunities. */
|
if (TREE_CODE (use_stmt) == MODIFY_EXPR
|
if (TREE_CODE (use_stmt) == MODIFY_EXPR
|
&& TREE_CODE (TREE_OPERAND (use_stmt, 0)) == SSA_NAME
|
&& TREE_CODE (TREE_OPERAND (use_stmt, 0)) == SSA_NAME
|
&& (TREE_CODE (TREE_OPERAND (use_stmt, 1)) == SSA_NAME
|
&& (TREE_CODE (TREE_OPERAND (use_stmt, 1)) == SSA_NAME
|
|| is_gimple_min_invariant (TREE_OPERAND (use_stmt, 1))))
|
|| is_gimple_min_invariant (TREE_OPERAND (use_stmt, 1))))
|
{
|
{
|
tree result = get_lhs_or_phi_result (use_stmt);
|
tree result = get_lhs_or_phi_result (use_stmt);
|
bitmap_set_bit (interesting_names, SSA_NAME_VERSION (result));
|
bitmap_set_bit (interesting_names, SSA_NAME_VERSION (result));
|
}
|
}
|
|
|
/* Propagation into these nodes may make certain edges in
|
/* Propagation into these nodes may make certain edges in
|
the CFG unexecutable. We want to identify them as PHI nodes
|
the CFG unexecutable. We want to identify them as PHI nodes
|
at the destination of those unexecutable edges may become
|
at the destination of those unexecutable edges may become
|
degenerates. */
|
degenerates. */
|
else if (TREE_CODE (use_stmt) == COND_EXPR
|
else if (TREE_CODE (use_stmt) == COND_EXPR
|
|| TREE_CODE (use_stmt) == SWITCH_EXPR
|
|| TREE_CODE (use_stmt) == SWITCH_EXPR
|
|| TREE_CODE (use_stmt) == GOTO_EXPR)
|
|| TREE_CODE (use_stmt) == GOTO_EXPR)
|
{
|
{
|
tree val;
|
tree val;
|
|
|
if (TREE_CODE (use_stmt) == COND_EXPR)
|
if (TREE_CODE (use_stmt) == COND_EXPR)
|
val = COND_EXPR_COND (use_stmt);
|
val = COND_EXPR_COND (use_stmt);
|
else if (TREE_CODE (use_stmt) == SWITCH_EXPR)
|
else if (TREE_CODE (use_stmt) == SWITCH_EXPR)
|
val = SWITCH_COND (use_stmt);
|
val = SWITCH_COND (use_stmt);
|
else
|
else
|
val = GOTO_DESTINATION (use_stmt);
|
val = GOTO_DESTINATION (use_stmt);
|
|
|
if (is_gimple_min_invariant (val))
|
if (is_gimple_min_invariant (val))
|
{
|
{
|
basic_block bb = bb_for_stmt (use_stmt);
|
basic_block bb = bb_for_stmt (use_stmt);
|
edge te = find_taken_edge (bb, val);
|
edge te = find_taken_edge (bb, val);
|
edge_iterator ei;
|
edge_iterator ei;
|
edge e;
|
edge e;
|
block_stmt_iterator bsi;
|
block_stmt_iterator bsi;
|
|
|
/* Remove all outgoing edges except TE. */
|
/* Remove all outgoing edges except TE. */
|
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei));)
|
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei));)
|
{
|
{
|
if (e != te)
|
if (e != te)
|
{
|
{
|
tree phi;
|
tree phi;
|
|
|
/* Mark all the PHI nodes at the destination of
|
/* Mark all the PHI nodes at the destination of
|
the unexecutable edge as interesting. */
|
the unexecutable edge as interesting. */
|
for (phi = phi_nodes (e->dest);
|
for (phi = phi_nodes (e->dest);
|
phi;
|
phi;
|
phi = PHI_CHAIN (phi))
|
phi = PHI_CHAIN (phi))
|
{
|
{
|
tree result = PHI_RESULT (phi);
|
tree result = PHI_RESULT (phi);
|
int version = SSA_NAME_VERSION (result);
|
int version = SSA_NAME_VERSION (result);
|
|
|
bitmap_set_bit (interesting_names, version);
|
bitmap_set_bit (interesting_names, version);
|
}
|
}
|
|
|
te->probability += e->probability;
|
te->probability += e->probability;
|
|
|
te->count += e->count;
|
te->count += e->count;
|
remove_edge (e);
|
remove_edge (e);
|
cfg_altered = 1;
|
cfg_altered = 1;
|
}
|
}
|
else
|
else
|
ei_next (&ei);
|
ei_next (&ei);
|
}
|
}
|
|
|
bsi = bsi_last (bb_for_stmt (use_stmt));
|
bsi = bsi_last (bb_for_stmt (use_stmt));
|
bsi_remove (&bsi, true);
|
bsi_remove (&bsi, true);
|
|
|
/* And fixup the flags on the single remaining edge. */
|
/* And fixup the flags on the single remaining edge. */
|
te->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
|
te->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
|
te->flags &= ~EDGE_ABNORMAL;
|
te->flags &= ~EDGE_ABNORMAL;
|
te->flags |= EDGE_FALLTHRU;
|
te->flags |= EDGE_FALLTHRU;
|
if (te->probability > REG_BR_PROB_BASE)
|
if (te->probability > REG_BR_PROB_BASE)
|
te->probability = REG_BR_PROB_BASE;
|
te->probability = REG_BR_PROB_BASE;
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* Ensure there is nothing else to do. */
|
/* Ensure there is nothing else to do. */
|
gcc_assert (!all || has_zero_uses (lhs));
|
gcc_assert (!all || has_zero_uses (lhs));
|
|
|
/* If we were able to propagate away all uses of LHS, then
|
/* If we were able to propagate away all uses of LHS, then
|
we can remove STMT. */
|
we can remove STMT. */
|
if (all)
|
if (all)
|
remove_stmt_or_phi (stmt);
|
remove_stmt_or_phi (stmt);
|
}
|
}
|
}
|
}
|
|
|
/* T is either a PHI node (potentially a degenerate PHI node) or
|
/* T is either a PHI node (potentially a degenerate PHI node) or
|
a statement that is a trivial copy or constant initialization.
|
a statement that is a trivial copy or constant initialization.
|
|
|
Attempt to eliminate T by propagating its RHS into all uses of
|
Attempt to eliminate T by propagating its RHS into all uses of
|
its LHS. This may in turn set new bits in INTERESTING_NAMES
|
its LHS. This may in turn set new bits in INTERESTING_NAMES
|
for nodes we want to revisit later.
|
for nodes we want to revisit later.
|
|
|
All exit paths should clear INTERESTING_NAMES for the result
|
All exit paths should clear INTERESTING_NAMES for the result
|
of T. */
|
of T. */
|
|
|
static void
|
static void
|
eliminate_const_or_copy (tree t, bitmap interesting_names)
|
eliminate_const_or_copy (tree t, bitmap interesting_names)
|
{
|
{
|
tree lhs = get_lhs_or_phi_result (t);
|
tree lhs = get_lhs_or_phi_result (t);
|
tree rhs;
|
tree rhs;
|
int version = SSA_NAME_VERSION (lhs);
|
int version = SSA_NAME_VERSION (lhs);
|
|
|
/* If the LHS of this statement or PHI has no uses, then we can
|
/* If the LHS of this statement or PHI has no uses, then we can
|
just eliminate it. This can occur if, for example, the PHI
|
just eliminate it. This can occur if, for example, the PHI
|
was created by block duplication due to threading and its only
|
was created by block duplication due to threading and its only
|
use was in the conditional at the end of the block which was
|
use was in the conditional at the end of the block which was
|
deleted. */
|
deleted. */
|
if (has_zero_uses (lhs))
|
if (has_zero_uses (lhs))
|
{
|
{
|
bitmap_clear_bit (interesting_names, version);
|
bitmap_clear_bit (interesting_names, version);
|
remove_stmt_or_phi (t);
|
remove_stmt_or_phi (t);
|
return;
|
return;
|
}
|
}
|
|
|
/* Get the RHS of the assignment or PHI node if the PHI is a
|
/* Get the RHS of the assignment or PHI node if the PHI is a
|
degenerate. */
|
degenerate. */
|
rhs = get_rhs_or_phi_arg (t);
|
rhs = get_rhs_or_phi_arg (t);
|
if (!rhs)
|
if (!rhs)
|
{
|
{
|
bitmap_clear_bit (interesting_names, version);
|
bitmap_clear_bit (interesting_names, version);
|
return;
|
return;
|
}
|
}
|
|
|
propagate_rhs_into_lhs (t, lhs, rhs, interesting_names);
|
propagate_rhs_into_lhs (t, lhs, rhs, interesting_names);
|
|
|
/* Note that T may well have been deleted by now, so do
|
/* Note that T may well have been deleted by now, so do
|
not access it, instead use the saved version # to clear
|
not access it, instead use the saved version # to clear
|
T's entry in the worklist. */
|
T's entry in the worklist. */
|
bitmap_clear_bit (interesting_names, version);
|
bitmap_clear_bit (interesting_names, version);
|
}
|
}
|
|
|
/* The first phase in degenerate PHI elimination.
|
/* The first phase in degenerate PHI elimination.
|
|
|
Eliminate the degenerate PHIs in BB, then recurse on the
|
Eliminate the degenerate PHIs in BB, then recurse on the
|
dominator children of BB. */
|
dominator children of BB. */
|
|
|
static void
|
static void
|
eliminate_degenerate_phis_1 (basic_block bb, bitmap interesting_names)
|
eliminate_degenerate_phis_1 (basic_block bb, bitmap interesting_names)
|
{
|
{
|
tree phi, next;
|
tree phi, next;
|
basic_block son;
|
basic_block son;
|
|
|
for (phi = phi_nodes (bb); phi; phi = next)
|
for (phi = phi_nodes (bb); phi; phi = next)
|
{
|
{
|
next = PHI_CHAIN (phi);
|
next = PHI_CHAIN (phi);
|
eliminate_const_or_copy (phi, interesting_names);
|
eliminate_const_or_copy (phi, interesting_names);
|
}
|
}
|
|
|
/* Recurse into the dominator children of BB. */
|
/* Recurse into the dominator children of BB. */
|
for (son = first_dom_son (CDI_DOMINATORS, bb);
|
for (son = first_dom_son (CDI_DOMINATORS, bb);
|
son;
|
son;
|
son = next_dom_son (CDI_DOMINATORS, son))
|
son = next_dom_son (CDI_DOMINATORS, son))
|
eliminate_degenerate_phis_1 (son, interesting_names);
|
eliminate_degenerate_phis_1 (son, interesting_names);
|
}
|
}
|
|
|
|
|
/* A very simple pass to eliminate degenerate PHI nodes from the
|
/* A very simple pass to eliminate degenerate PHI nodes from the
|
IL. This is meant to be fast enough to be able to be run several
|
IL. This is meant to be fast enough to be able to be run several
|
times in the optimization pipeline.
|
times in the optimization pipeline.
|
|
|
Certain optimizations, particularly those which duplicate blocks
|
Certain optimizations, particularly those which duplicate blocks
|
or remove edges from the CFG can create or expose PHIs which are
|
or remove edges from the CFG can create or expose PHIs which are
|
trivial copies or constant initializations.
|
trivial copies or constant initializations.
|
|
|
While we could pick up these optimizations in DOM or with the
|
While we could pick up these optimizations in DOM or with the
|
combination of copy-prop and CCP, those solutions are far too
|
combination of copy-prop and CCP, those solutions are far too
|
heavy-weight for our needs.
|
heavy-weight for our needs.
|
|
|
This implementation has two phases so that we can efficiently
|
This implementation has two phases so that we can efficiently
|
eliminate the first order degenerate PHIs and second order
|
eliminate the first order degenerate PHIs and second order
|
degenerate PHIs.
|
degenerate PHIs.
|
|
|
The first phase performs a dominator walk to identify and eliminate
|
The first phase performs a dominator walk to identify and eliminate
|
the vast majority of the degenerate PHIs. When a degenerate PHI
|
the vast majority of the degenerate PHIs. When a degenerate PHI
|
is identified and eliminated any affected statements or PHIs
|
is identified and eliminated any affected statements or PHIs
|
are put on a worklist.
|
are put on a worklist.
|
|
|
The second phase eliminates degenerate PHIs and trivial copies
|
The second phase eliminates degenerate PHIs and trivial copies
|
or constant initializations using the worklist. This is how we
|
or constant initializations using the worklist. This is how we
|
pick up the secondary optimization opportunities with minimal
|
pick up the secondary optimization opportunities with minimal
|
cost. */
|
cost. */
|
|
|
static unsigned int
|
static unsigned int
|
eliminate_degenerate_phis (void)
|
eliminate_degenerate_phis (void)
|
{
|
{
|
bitmap interesting_names;
|
bitmap interesting_names;
|
bitmap interesting_names1;
|
bitmap interesting_names1;
|
|
|
/* Bitmap of blocks which need EH information updated. We can not
|
/* Bitmap of blocks which need EH information updated. We can not
|
update it on-the-fly as doing so invalidates the dominator tree. */
|
update it on-the-fly as doing so invalidates the dominator tree. */
|
need_eh_cleanup = BITMAP_ALLOC (NULL);
|
need_eh_cleanup = BITMAP_ALLOC (NULL);
|
|
|
/* INTERESTING_NAMES is effectively our worklist, indexed by
|
/* INTERESTING_NAMES is effectively our worklist, indexed by
|
SSA_NAME_VERSION.
|
SSA_NAME_VERSION.
|
|
|
A set bit indicates that the statement or PHI node which
|
A set bit indicates that the statement or PHI node which
|
defines the SSA_NAME should be (re)examined to determine if
|
defines the SSA_NAME should be (re)examined to determine if
|
it has become a degenerate PHI or trivial const/copy propagation
|
it has become a degenerate PHI or trivial const/copy propagation
|
opportunity.
|
opportunity.
|
|
|
Experiments have show we generally get better compilation
|
Experiments have show we generally get better compilation
|
time behavior with bitmaps rather than sbitmaps. */
|
time behavior with bitmaps rather than sbitmaps. */
|
interesting_names = BITMAP_ALLOC (NULL);
|
interesting_names = BITMAP_ALLOC (NULL);
|
interesting_names1 = BITMAP_ALLOC (NULL);
|
interesting_names1 = BITMAP_ALLOC (NULL);
|
|
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/* First phase. Eliminate degenerate PHIs via a dominator
|
/* First phase. Eliminate degenerate PHIs via a dominator
|
walk of the CFG.
|
walk of the CFG.
|
|
|
Experiments have indicated that we generally get better
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Experiments have indicated that we generally get better
|
compile-time behavior by visiting blocks in the first
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compile-time behavior by visiting blocks in the first
|
phase in dominator order. Presumably this is because walking
|
phase in dominator order. Presumably this is because walking
|
in dominator order leaves fewer PHIs for later examination
|
in dominator order leaves fewer PHIs for later examination
|
by the worklist phase. */
|
by the worklist phase. */
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calculate_dominance_info (CDI_DOMINATORS);
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calculate_dominance_info (CDI_DOMINATORS);
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eliminate_degenerate_phis_1 (ENTRY_BLOCK_PTR, interesting_names);
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eliminate_degenerate_phis_1 (ENTRY_BLOCK_PTR, interesting_names);
|
|
|
/* Second phase. Eliminate second order degenerate PHIs as well
|
/* Second phase. Eliminate second order degenerate PHIs as well
|
as trivial copies or constant initializations identified by
|
as trivial copies or constant initializations identified by
|
the first phase or this phase. Basically we keep iterating
|
the first phase or this phase. Basically we keep iterating
|
until our set of INTERESTING_NAMEs is empty. */
|
until our set of INTERESTING_NAMEs is empty. */
|
while (!bitmap_empty_p (interesting_names))
|
while (!bitmap_empty_p (interesting_names))
|
{
|
{
|
unsigned int i;
|
unsigned int i;
|
bitmap_iterator bi;
|
bitmap_iterator bi;
|
|
|
/* EXECUTE_IF_SET_IN_BITMAP does not like its bitmap
|
/* EXECUTE_IF_SET_IN_BITMAP does not like its bitmap
|
changed during the loop. Copy it to another bitmap and
|
changed during the loop. Copy it to another bitmap and
|
use that. */
|
use that. */
|
bitmap_copy (interesting_names1, interesting_names);
|
bitmap_copy (interesting_names1, interesting_names);
|
|
|
EXECUTE_IF_SET_IN_BITMAP (interesting_names1, 0, i, bi)
|
EXECUTE_IF_SET_IN_BITMAP (interesting_names1, 0, i, bi)
|
{
|
{
|
tree name = ssa_name (i);
|
tree name = ssa_name (i);
|
|
|
/* Ignore SSA_NAMEs that have been released because
|
/* Ignore SSA_NAMEs that have been released because
|
their defining statement was deleted (unreachable). */
|
their defining statement was deleted (unreachable). */
|
if (name)
|
if (name)
|
eliminate_const_or_copy (SSA_NAME_DEF_STMT (ssa_name (i)),
|
eliminate_const_or_copy (SSA_NAME_DEF_STMT (ssa_name (i)),
|
interesting_names);
|
interesting_names);
|
}
|
}
|
}
|
}
|
|
|
/* Propagation of const and copies may make some EH edges dead. Purge
|
/* Propagation of const and copies may make some EH edges dead. Purge
|
such edges from the CFG as needed. */
|
such edges from the CFG as needed. */
|
if (!bitmap_empty_p (need_eh_cleanup))
|
if (!bitmap_empty_p (need_eh_cleanup))
|
{
|
{
|
cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup);
|
cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup);
|
BITMAP_FREE (need_eh_cleanup);
|
BITMAP_FREE (need_eh_cleanup);
|
}
|
}
|
|
|
BITMAP_FREE (interesting_names);
|
BITMAP_FREE (interesting_names);
|
BITMAP_FREE (interesting_names1);
|
BITMAP_FREE (interesting_names1);
|
if (cfg_altered)
|
if (cfg_altered)
|
free_dominance_info (CDI_DOMINATORS);
|
free_dominance_info (CDI_DOMINATORS);
|
return 0;
|
return 0;
|
}
|
}
|
|
|
struct tree_opt_pass pass_phi_only_cprop =
|
struct tree_opt_pass pass_phi_only_cprop =
|
{
|
{
|
"phicprop", /* name */
|
"phicprop", /* name */
|
gate_dominator, /* gate */
|
gate_dominator, /* gate */
|
eliminate_degenerate_phis, /* execute */
|
eliminate_degenerate_phis, /* execute */
|
NULL, /* sub */
|
NULL, /* sub */
|
NULL, /* next */
|
NULL, /* next */
|
0, /* static_pass_number */
|
0, /* static_pass_number */
|
TV_TREE_PHI_CPROP, /* tv_id */
|
TV_TREE_PHI_CPROP, /* tv_id */
|
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
|
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
|
0, /* properties_provided */
|
0, /* properties_provided */
|
PROP_smt_usage, /* properties_destroyed */
|
PROP_smt_usage, /* properties_destroyed */
|
0, /* todo_flags_start */
|
0, /* todo_flags_start */
|
TODO_cleanup_cfg | TODO_dump_func
|
TODO_cleanup_cfg | TODO_dump_func
|
| TODO_ggc_collect | TODO_verify_ssa
|
| TODO_ggc_collect | TODO_verify_ssa
|
| TODO_verify_stmts | TODO_update_smt_usage
|
| TODO_verify_stmts | TODO_update_smt_usage
|
| TODO_update_ssa, /* todo_flags_finish */
|
| TODO_update_ssa, /* todo_flags_finish */
|
0 /* letter */
|
0 /* letter */
|
};
|
};
|
|
|
