822 lines
23 KiB
C
822 lines
23 KiB
C
/* High-level loop manipulation functions.
|
|
Copyright (C) 2004 Free Software Foundation, Inc.
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU General Public License as published by the
|
|
Free Software Foundation; either version 2, or (at your option) any
|
|
later version.
|
|
|
|
GCC is distributed in the hope that it will be useful, but WITHOUT
|
|
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with GCC; see the file COPYING. If not, write to the Free
|
|
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
|
|
02111-1307, USA. */
|
|
|
|
#include "config.h"
|
|
#include "system.h"
|
|
#include "coretypes.h"
|
|
#include "tm.h"
|
|
#include "tree.h"
|
|
#include "rtl.h"
|
|
#include "tm_p.h"
|
|
#include "hard-reg-set.h"
|
|
#include "basic-block.h"
|
|
#include "output.h"
|
|
#include "diagnostic.h"
|
|
#include "tree-flow.h"
|
|
#include "tree-dump.h"
|
|
#include "timevar.h"
|
|
#include "cfgloop.h"
|
|
#include "tree-pass.h"
|
|
#include "cfglayout.h"
|
|
#include "tree-scalar-evolution.h"
|
|
|
|
/* Creates an induction variable with value BASE + STEP * iteration in LOOP.
|
|
It is expected that neither BASE nor STEP are shared with other expressions
|
|
(unless the sharing rules allow this). Use VAR as a base var_decl for it
|
|
(if NULL, a new temporary will be created). The increment will occur at
|
|
INCR_POS (after it if AFTER is true, before it otherwise). The ssa versions
|
|
of the variable before and after increment will be stored in VAR_BEFORE and
|
|
VAR_AFTER (unless they are NULL). */
|
|
|
|
void
|
|
create_iv (tree base, tree step, tree var, struct loop *loop,
|
|
block_stmt_iterator *incr_pos, bool after,
|
|
tree *var_before, tree *var_after)
|
|
{
|
|
tree stmt, initial, step1, stmts;
|
|
tree vb, va;
|
|
enum tree_code incr_op = PLUS_EXPR;
|
|
|
|
if (!var)
|
|
{
|
|
var = create_tmp_var (TREE_TYPE (base), "ivtmp");
|
|
add_referenced_tmp_var (var);
|
|
}
|
|
|
|
vb = make_ssa_name (var, NULL_TREE);
|
|
if (var_before)
|
|
*var_before = vb;
|
|
va = make_ssa_name (var, NULL_TREE);
|
|
if (var_after)
|
|
*var_after = va;
|
|
|
|
/* For easier readability of the created code, produce MINUS_EXPRs
|
|
when suitable. */
|
|
if (TREE_CODE (step) == INTEGER_CST)
|
|
{
|
|
if (TYPE_UNSIGNED (TREE_TYPE (step)))
|
|
{
|
|
step1 = fold (build1 (NEGATE_EXPR, TREE_TYPE (step), step));
|
|
if (tree_int_cst_lt (step1, step))
|
|
{
|
|
incr_op = MINUS_EXPR;
|
|
step = step1;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (!tree_expr_nonnegative_p (step)
|
|
&& may_negate_without_overflow_p (step))
|
|
{
|
|
incr_op = MINUS_EXPR;
|
|
step = fold (build1 (NEGATE_EXPR, TREE_TYPE (step), step));
|
|
}
|
|
}
|
|
}
|
|
|
|
stmt = build2 (MODIFY_EXPR, void_type_node, va,
|
|
build2 (incr_op, TREE_TYPE (base),
|
|
vb, step));
|
|
SSA_NAME_DEF_STMT (va) = stmt;
|
|
if (after)
|
|
bsi_insert_after (incr_pos, stmt, BSI_NEW_STMT);
|
|
else
|
|
bsi_insert_before (incr_pos, stmt, BSI_NEW_STMT);
|
|
|
|
initial = force_gimple_operand (base, &stmts, true, var);
|
|
if (stmts)
|
|
{
|
|
edge pe = loop_preheader_edge (loop);
|
|
|
|
bsi_insert_on_edge_immediate_loop (pe, stmts);
|
|
}
|
|
|
|
stmt = create_phi_node (vb, loop->header);
|
|
SSA_NAME_DEF_STMT (vb) = stmt;
|
|
add_phi_arg (&stmt, initial, loop_preheader_edge (loop));
|
|
add_phi_arg (&stmt, va, loop_latch_edge (loop));
|
|
}
|
|
|
|
/* Add exit phis for the USE on EXIT. */
|
|
|
|
static void
|
|
add_exit_phis_edge (basic_block exit, tree use)
|
|
{
|
|
tree phi, def_stmt = SSA_NAME_DEF_STMT (use);
|
|
basic_block def_bb = bb_for_stmt (def_stmt);
|
|
struct loop *def_loop;
|
|
edge e;
|
|
edge_iterator ei;
|
|
|
|
/* Check that some of the edges entering the EXIT block exits a loop in
|
|
that USE is defined. */
|
|
FOR_EACH_EDGE (e, ei, exit->preds)
|
|
{
|
|
def_loop = find_common_loop (def_bb->loop_father, e->src->loop_father);
|
|
if (!flow_bb_inside_loop_p (def_loop, e->dest))
|
|
break;
|
|
}
|
|
|
|
if (!e)
|
|
return;
|
|
|
|
phi = create_phi_node (use, exit);
|
|
|
|
FOR_EACH_EDGE (e, ei, exit->preds)
|
|
add_phi_arg (&phi, use, e);
|
|
|
|
SSA_NAME_DEF_STMT (use) = def_stmt;
|
|
}
|
|
|
|
/* Add exit phis for VAR that is used in LIVEIN.
|
|
Exits of the loops are stored in EXITS. */
|
|
|
|
static void
|
|
add_exit_phis_var (tree var, bitmap livein, bitmap exits)
|
|
{
|
|
bitmap def;
|
|
unsigned index;
|
|
basic_block def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (var));
|
|
bitmap_iterator bi;
|
|
|
|
bitmap_clear_bit (livein, def_bb->index);
|
|
|
|
def = BITMAP_XMALLOC ();
|
|
bitmap_set_bit (def, def_bb->index);
|
|
compute_global_livein (livein, def);
|
|
BITMAP_XFREE (def);
|
|
|
|
EXECUTE_IF_AND_IN_BITMAP (exits, livein, 0, index, bi)
|
|
{
|
|
add_exit_phis_edge (BASIC_BLOCK (index), var);
|
|
}
|
|
}
|
|
|
|
/* Add exit phis for the names marked in NAMES_TO_RENAME.
|
|
Exits of the loops are stored in EXITS. Sets of blocks where the ssa
|
|
names are used are stored in USE_BLOCKS. */
|
|
|
|
static void
|
|
add_exit_phis (bitmap names_to_rename, bitmap *use_blocks, bitmap loop_exits)
|
|
{
|
|
unsigned i;
|
|
bitmap_iterator bi;
|
|
|
|
EXECUTE_IF_SET_IN_BITMAP (names_to_rename, 0, i, bi)
|
|
{
|
|
add_exit_phis_var (ssa_name (i), use_blocks[i], loop_exits);
|
|
}
|
|
}
|
|
|
|
/* Returns a bitmap of all loop exit edge targets. */
|
|
|
|
static bitmap
|
|
get_loops_exits (void)
|
|
{
|
|
bitmap exits = BITMAP_XMALLOC ();
|
|
basic_block bb;
|
|
edge e;
|
|
edge_iterator ei;
|
|
|
|
FOR_EACH_BB (bb)
|
|
{
|
|
FOR_EACH_EDGE (e, ei, bb->preds)
|
|
if (e->src != ENTRY_BLOCK_PTR
|
|
&& !flow_bb_inside_loop_p (e->src->loop_father, bb))
|
|
{
|
|
bitmap_set_bit (exits, bb->index);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return exits;
|
|
}
|
|
|
|
/* For USE in BB, if it is used outside of the loop it is defined in,
|
|
mark it for rewrite. Record basic block BB where it is used
|
|
to USE_BLOCKS. */
|
|
|
|
static void
|
|
find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks)
|
|
{
|
|
unsigned ver;
|
|
basic_block def_bb;
|
|
struct loop *def_loop;
|
|
|
|
if (TREE_CODE (use) != SSA_NAME)
|
|
return;
|
|
|
|
ver = SSA_NAME_VERSION (use);
|
|
def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (use));
|
|
if (!def_bb)
|
|
return;
|
|
def_loop = def_bb->loop_father;
|
|
|
|
/* If the definition is not inside loop, it is not interesting. */
|
|
if (!def_loop->outer)
|
|
return;
|
|
|
|
if (!use_blocks[ver])
|
|
use_blocks[ver] = BITMAP_XMALLOC ();
|
|
bitmap_set_bit (use_blocks[ver], bb->index);
|
|
|
|
if (!flow_bb_inside_loop_p (def_loop, bb))
|
|
mark_for_rewrite (use);
|
|
}
|
|
|
|
/* For uses in STMT, mark names that are used outside of the loop they are
|
|
defined to rewrite. Record the set of blocks in that the ssa
|
|
names are defined to USE_BLOCKS. */
|
|
|
|
static void
|
|
find_uses_to_rename_stmt (tree stmt, bitmap *use_blocks)
|
|
{
|
|
ssa_op_iter iter;
|
|
tree var;
|
|
basic_block bb = bb_for_stmt (stmt);
|
|
|
|
get_stmt_operands (stmt);
|
|
|
|
FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES | SSA_OP_ALL_KILLS)
|
|
find_uses_to_rename_use (bb, var, use_blocks);
|
|
}
|
|
|
|
/* Marks names that are used outside of the loop they are defined in
|
|
for rewrite. Records the set of blocks in that the ssa
|
|
names are defined to USE_BLOCKS. */
|
|
|
|
static void
|
|
find_uses_to_rename (bitmap *use_blocks)
|
|
{
|
|
basic_block bb;
|
|
block_stmt_iterator bsi;
|
|
tree phi;
|
|
unsigned i;
|
|
|
|
FOR_EACH_BB (bb)
|
|
{
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
|
for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
|
|
find_uses_to_rename_use (PHI_ARG_EDGE (phi, i)->src,
|
|
PHI_ARG_DEF (phi, i), use_blocks);
|
|
|
|
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
|
|
find_uses_to_rename_stmt (bsi_stmt (bsi), use_blocks);
|
|
}
|
|
}
|
|
|
|
/* Rewrites the program into a loop closed ssa form -- i.e. inserts extra
|
|
phi nodes to ensure that no variable is used outside the loop it is
|
|
defined in.
|
|
|
|
This strengthening of the basic ssa form has several advantages:
|
|
|
|
1) Updating it during unrolling/peeling/versioning is trivial, since
|
|
we do not need to care about the uses outside of the loop.
|
|
2) The behavior of all uses of an induction variable is the same.
|
|
Without this, you need to distinguish the case when the variable
|
|
is used outside of the loop it is defined in, for example
|
|
|
|
for (i = 0; i < 100; i++)
|
|
{
|
|
for (j = 0; j < 100; j++)
|
|
{
|
|
k = i + j;
|
|
use1 (k);
|
|
}
|
|
use2 (k);
|
|
}
|
|
|
|
Looking from the outer loop with the normal SSA form, the first use of k
|
|
is not well-behaved, while the second one is an induction variable with
|
|
base 99 and step 1. */
|
|
|
|
void
|
|
rewrite_into_loop_closed_ssa (void)
|
|
{
|
|
bitmap loop_exits = get_loops_exits ();
|
|
bitmap *use_blocks;
|
|
unsigned i;
|
|
bitmap names_to_rename;
|
|
|
|
gcc_assert (!any_marked_for_rewrite_p ());
|
|
|
|
use_blocks = xcalloc (num_ssa_names, sizeof (bitmap));
|
|
|
|
/* Find the uses outside loops. */
|
|
find_uses_to_rename (use_blocks);
|
|
|
|
/* Add the phi nodes on exits of the loops for the names we need to
|
|
rewrite. */
|
|
names_to_rename = marked_ssa_names ();
|
|
add_exit_phis (names_to_rename, use_blocks, loop_exits);
|
|
|
|
for (i = 0; i < num_ssa_names; i++)
|
|
BITMAP_XFREE (use_blocks[i]);
|
|
free (use_blocks);
|
|
BITMAP_XFREE (loop_exits);
|
|
BITMAP_XFREE (names_to_rename);
|
|
|
|
/* Do the rewriting. */
|
|
rewrite_ssa_into_ssa ();
|
|
}
|
|
|
|
/* Check invariants of the loop closed ssa form for the USE in BB. */
|
|
|
|
static void
|
|
check_loop_closed_ssa_use (basic_block bb, tree use)
|
|
{
|
|
tree def;
|
|
basic_block def_bb;
|
|
|
|
if (TREE_CODE (use) != SSA_NAME)
|
|
return;
|
|
|
|
def = SSA_NAME_DEF_STMT (use);
|
|
def_bb = bb_for_stmt (def);
|
|
gcc_assert (!def_bb
|
|
|| flow_bb_inside_loop_p (def_bb->loop_father, bb));
|
|
}
|
|
|
|
/* Checks invariants of loop closed ssa form in statement STMT in BB. */
|
|
|
|
static void
|
|
check_loop_closed_ssa_stmt (basic_block bb, tree stmt)
|
|
{
|
|
ssa_op_iter iter;
|
|
tree var;
|
|
|
|
get_stmt_operands (stmt);
|
|
|
|
FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES)
|
|
check_loop_closed_ssa_use (bb, var);
|
|
}
|
|
|
|
/* Checks that invariants of the loop closed ssa form are preserved. */
|
|
|
|
void
|
|
verify_loop_closed_ssa (void)
|
|
{
|
|
basic_block bb;
|
|
block_stmt_iterator bsi;
|
|
tree phi;
|
|
unsigned i;
|
|
|
|
verify_ssa ();
|
|
|
|
FOR_EACH_BB (bb)
|
|
{
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
|
for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
|
|
check_loop_closed_ssa_use (PHI_ARG_EDGE (phi, i)->src,
|
|
PHI_ARG_DEF (phi, i));
|
|
|
|
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
|
|
check_loop_closed_ssa_stmt (bb, bsi_stmt (bsi));
|
|
}
|
|
}
|
|
|
|
/* Split loop exit edge EXIT. The things are a bit complicated by a need to
|
|
preserve the loop closed ssa form. */
|
|
|
|
void
|
|
split_loop_exit_edge (edge exit)
|
|
{
|
|
basic_block dest = exit->dest;
|
|
basic_block bb = loop_split_edge_with (exit, NULL);
|
|
tree phi, new_phi, new_name, name;
|
|
use_operand_p op_p;
|
|
|
|
for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
|
|
{
|
|
op_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, EDGE_SUCC (bb, 0));
|
|
|
|
name = USE_FROM_PTR (op_p);
|
|
|
|
/* If the argument of the phi node is a constant, we do not need
|
|
to keep it inside loop. */
|
|
if (TREE_CODE (name) != SSA_NAME)
|
|
continue;
|
|
|
|
/* Otherwise create an auxiliary phi node that will copy the value
|
|
of the ssa name out of the loop. */
|
|
new_name = duplicate_ssa_name (name, NULL);
|
|
new_phi = create_phi_node (new_name, bb);
|
|
SSA_NAME_DEF_STMT (new_name) = new_phi;
|
|
add_phi_arg (&new_phi, name, exit);
|
|
SET_USE (op_p, new_name);
|
|
}
|
|
}
|
|
|
|
/* Insert statement STMT to the edge E and update the loop structures.
|
|
Returns the newly created block (if any). */
|
|
|
|
basic_block
|
|
bsi_insert_on_edge_immediate_loop (edge e, tree stmt)
|
|
{
|
|
basic_block src, dest, new_bb;
|
|
struct loop *loop_c;
|
|
|
|
src = e->src;
|
|
dest = e->dest;
|
|
|
|
loop_c = find_common_loop (src->loop_father, dest->loop_father);
|
|
|
|
new_bb = bsi_insert_on_edge_immediate (e, stmt);
|
|
|
|
if (!new_bb)
|
|
return NULL;
|
|
|
|
add_bb_to_loop (new_bb, loop_c);
|
|
if (dest->loop_father->latch == src)
|
|
dest->loop_father->latch = new_bb;
|
|
|
|
return new_bb;
|
|
}
|
|
|
|
/* Returns the basic block in that statements should be emitted for induction
|
|
variables incremented at the end of the LOOP. */
|
|
|
|
basic_block
|
|
ip_end_pos (struct loop *loop)
|
|
{
|
|
return loop->latch;
|
|
}
|
|
|
|
/* Returns the basic block in that statements should be emitted for induction
|
|
variables incremented just before exit condition of a LOOP. */
|
|
|
|
basic_block
|
|
ip_normal_pos (struct loop *loop)
|
|
{
|
|
tree last;
|
|
basic_block bb;
|
|
edge exit;
|
|
|
|
if (EDGE_COUNT (loop->latch->preds) > 1)
|
|
return NULL;
|
|
|
|
bb = EDGE_PRED (loop->latch, 0)->src;
|
|
last = last_stmt (bb);
|
|
if (TREE_CODE (last) != COND_EXPR)
|
|
return NULL;
|
|
|
|
exit = EDGE_SUCC (bb, 0);
|
|
if (exit->dest == loop->latch)
|
|
exit = EDGE_SUCC (bb, 1);
|
|
|
|
if (flow_bb_inside_loop_p (loop, exit->dest))
|
|
return NULL;
|
|
|
|
return bb;
|
|
}
|
|
|
|
/* Stores the standard position for induction variable increment in LOOP
|
|
(just before the exit condition if it is available and latch block is empty,
|
|
end of the latch block otherwise) to BSI. INSERT_AFTER is set to true if
|
|
the increment should be inserted after *BSI. */
|
|
|
|
void
|
|
standard_iv_increment_position (struct loop *loop, block_stmt_iterator *bsi,
|
|
bool *insert_after)
|
|
{
|
|
basic_block bb = ip_normal_pos (loop), latch = ip_end_pos (loop);
|
|
tree last = last_stmt (latch);
|
|
|
|
if (!bb
|
|
|| (last && TREE_CODE (last) != LABEL_EXPR))
|
|
{
|
|
*bsi = bsi_last (latch);
|
|
*insert_after = true;
|
|
}
|
|
else
|
|
{
|
|
*bsi = bsi_last (bb);
|
|
*insert_after = false;
|
|
}
|
|
}
|
|
|
|
/* Copies phi node arguments for duplicated blocks. The index of the first
|
|
duplicated block is FIRST_NEW_BLOCK. */
|
|
|
|
static void
|
|
copy_phi_node_args (unsigned first_new_block)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = first_new_block; i < (unsigned) last_basic_block; i++)
|
|
BASIC_BLOCK (i)->rbi->duplicated = 1;
|
|
|
|
for (i = first_new_block; i < (unsigned) last_basic_block; i++)
|
|
add_phi_args_after_copy_bb (BASIC_BLOCK (i));
|
|
|
|
for (i = first_new_block; i < (unsigned) last_basic_block; i++)
|
|
BASIC_BLOCK (i)->rbi->duplicated = 0;
|
|
}
|
|
|
|
/* Renames variables in the area copied by tree_duplicate_loop_to_header_edge.
|
|
FIRST_NEW_BLOCK is the first block in the copied area. DEFINITIONS is
|
|
a bitmap of all ssa names defined inside the loop. */
|
|
|
|
static void
|
|
rename_variables (unsigned first_new_block, bitmap definitions)
|
|
{
|
|
unsigned i, copy_number = 0;
|
|
basic_block bb;
|
|
htab_t ssa_name_map = NULL;
|
|
|
|
for (i = first_new_block; i < (unsigned) last_basic_block; i++)
|
|
{
|
|
bb = BASIC_BLOCK (i);
|
|
|
|
/* We assume that first come all blocks from the first copy, then all
|
|
blocks from the second copy, etc. */
|
|
if (copy_number != (unsigned) bb->rbi->copy_number)
|
|
{
|
|
allocate_ssa_names (definitions, &ssa_name_map);
|
|
copy_number = bb->rbi->copy_number;
|
|
}
|
|
|
|
rewrite_to_new_ssa_names_bb (bb, ssa_name_map);
|
|
}
|
|
|
|
htab_delete (ssa_name_map);
|
|
}
|
|
|
|
/* Sets SSA_NAME_DEF_STMT for results of all phi nodes in BB. */
|
|
|
|
static void
|
|
set_phi_def_stmts (basic_block bb)
|
|
{
|
|
tree phi;
|
|
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
|
SSA_NAME_DEF_STMT (PHI_RESULT (phi)) = phi;
|
|
}
|
|
|
|
/* The same as cfgloopmanip.c:duplicate_loop_to_header_edge, but also updates
|
|
ssa. In order to achieve this, only loops whose exits all lead to the same
|
|
location are handled.
|
|
|
|
FIXME: we create some degenerate phi nodes that could be avoided by copy
|
|
propagating them instead. Unfortunately this is not completely
|
|
straightforward due to problems with constant folding. */
|
|
|
|
bool
|
|
tree_duplicate_loop_to_header_edge (struct loop *loop, edge e,
|
|
struct loops *loops,
|
|
unsigned int ndupl, sbitmap wont_exit,
|
|
edge orig, edge *to_remove,
|
|
unsigned int *n_to_remove, int flags)
|
|
{
|
|
unsigned first_new_block;
|
|
basic_block bb;
|
|
unsigned i;
|
|
bitmap definitions;
|
|
|
|
if (!(loops->state & LOOPS_HAVE_SIMPLE_LATCHES))
|
|
return false;
|
|
if (!(loops->state & LOOPS_HAVE_PREHEADERS))
|
|
return false;
|
|
|
|
#ifdef ENABLE_CHECKING
|
|
verify_loop_closed_ssa ();
|
|
#endif
|
|
|
|
gcc_assert (!any_marked_for_rewrite_p ());
|
|
|
|
first_new_block = last_basic_block;
|
|
if (!duplicate_loop_to_header_edge (loop, e, loops, ndupl, wont_exit,
|
|
orig, to_remove, n_to_remove, flags))
|
|
return false;
|
|
|
|
/* Readd the removed phi args for e. */
|
|
flush_pending_stmts (e);
|
|
|
|
/* Copy the phi node arguments. */
|
|
copy_phi_node_args (first_new_block);
|
|
|
|
/* Rename the variables. */
|
|
definitions = marked_ssa_names ();
|
|
rename_variables (first_new_block, definitions);
|
|
unmark_all_for_rewrite ();
|
|
BITMAP_XFREE (definitions);
|
|
|
|
/* For some time we have the identical ssa names as results in multiple phi
|
|
nodes. When phi node is resized, it sets SSA_NAME_DEF_STMT of its result
|
|
to the new copy. This means that we cannot easily ensure that the ssa
|
|
names defined in those phis are pointing to the right one -- so just
|
|
recompute SSA_NAME_DEF_STMT for them. */
|
|
|
|
for (i = first_new_block; i < (unsigned) last_basic_block; i++)
|
|
{
|
|
bb = BASIC_BLOCK (i);
|
|
set_phi_def_stmts (bb);
|
|
if (bb->rbi->copy_number == 1)
|
|
set_phi_def_stmts (bb->rbi->original);
|
|
}
|
|
|
|
scev_reset ();
|
|
#ifdef ENABLE_CHECKING
|
|
verify_loop_closed_ssa ();
|
|
#endif
|
|
|
|
return true;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------
|
|
Loop versioning
|
|
---------------------------------------------------------------------------*/
|
|
|
|
/* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
|
|
of 'first'. Both of them are dominated by 'new_head' basic block. When
|
|
'new_head' was created by 'second's incoming edge it received phi arguments
|
|
on the edge by split_edge(). Later, additional edge 'e' was created to
|
|
connect 'new_head' and 'first'. Now this routine adds phi args on this
|
|
additional edge 'e' that new_head to second edge received as part of edge
|
|
splitting.
|
|
*/
|
|
|
|
static void
|
|
lv_adjust_loop_header_phi (basic_block first, basic_block second,
|
|
basic_block new_head, edge e)
|
|
{
|
|
tree phi1, phi2;
|
|
|
|
/* Browse all 'second' basic block phi nodes and add phi args to
|
|
edge 'e' for 'first' head. PHI args are always in correct order. */
|
|
|
|
for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
|
|
phi2 && phi1;
|
|
phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
|
|
{
|
|
int i;
|
|
for (i = 0; i < PHI_NUM_ARGS (phi2); i++)
|
|
{
|
|
if (PHI_ARG_EDGE (phi2, i)->src == new_head)
|
|
{
|
|
tree def = PHI_ARG_DEF (phi2, i);
|
|
add_phi_arg (&phi1, def, e);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Adjust entry edge for lv.
|
|
|
|
e is an incoming edge.
|
|
|
|
--- edge e ---- > [second_head]
|
|
|
|
Split it and insert new conditional expression and adjust edges.
|
|
|
|
--- edge e ---> [cond expr] ---> [first_head]
|
|
|
|
|
+---------> [second_head]
|
|
|
|
*/
|
|
|
|
static basic_block
|
|
lv_adjust_loop_entry_edge (basic_block first_head,
|
|
basic_block second_head,
|
|
edge e,
|
|
tree cond_expr)
|
|
{
|
|
block_stmt_iterator bsi;
|
|
basic_block new_head = NULL;
|
|
tree goto1 = NULL_TREE;
|
|
tree goto2 = NULL_TREE;
|
|
tree new_cond_expr = NULL_TREE;
|
|
edge e0, e1;
|
|
|
|
gcc_assert (e->dest == second_head);
|
|
|
|
/* Split edge 'e'. This will create a new basic block, where we can
|
|
insert conditional expr. */
|
|
new_head = split_edge (e);
|
|
|
|
/* Build new conditional expr */
|
|
goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
|
|
goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
|
|
new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
|
|
|
|
/* Add new cond. in new head. */
|
|
bsi = bsi_start (new_head);
|
|
bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
|
|
|
|
/* Adjust edges appropriately to connect new head with first head
|
|
as well as second head. */
|
|
e0 = EDGE_SUCC (new_head, 0);
|
|
e0->flags &= ~EDGE_FALLTHRU;
|
|
e0->flags |= EDGE_FALSE_VALUE;
|
|
e1 = make_edge (new_head, first_head, EDGE_TRUE_VALUE);
|
|
set_immediate_dominator (CDI_DOMINATORS, first_head, new_head);
|
|
set_immediate_dominator (CDI_DOMINATORS, second_head, new_head);
|
|
|
|
/* Adjust loop header phi nodes. */
|
|
lv_adjust_loop_header_phi (first_head, second_head, new_head, e1);
|
|
|
|
return new_head;
|
|
}
|
|
|
|
/* Main entry point for Loop Versioning transformation.
|
|
|
|
This transformation given a condition and a loop, creates
|
|
-if (condition) { loop_copy1 } else { loop_copy2 },
|
|
where loop_copy1 is the loop transformed in one way, and loop_copy2
|
|
is the loop transformed in another way (or unchanged). 'condition'
|
|
may be a run time test for things that were not resolved by static
|
|
analysis (overlapping ranges (anti-aliasing), alignment, etc.). */
|
|
|
|
struct loop *
|
|
tree_ssa_loop_version (struct loops *loops, struct loop * loop,
|
|
tree cond_expr, basic_block *condition_bb)
|
|
{
|
|
edge entry, latch_edge, exit, true_edge, false_edge;
|
|
basic_block first_head, second_head;
|
|
int irred_flag;
|
|
struct loop *nloop;
|
|
|
|
/* CHECKME: Loop versioning does not handle nested loop at this point. */
|
|
if (loop->inner)
|
|
return NULL;
|
|
|
|
/* Record entry and latch edges for the loop */
|
|
entry = loop_preheader_edge (loop);
|
|
|
|
/* Note down head of loop as first_head. */
|
|
first_head = entry->dest;
|
|
|
|
/* Duplicate loop. */
|
|
irred_flag = entry->flags & EDGE_IRREDUCIBLE_LOOP;
|
|
entry->flags &= ~EDGE_IRREDUCIBLE_LOOP;
|
|
if (!tree_duplicate_loop_to_header_edge (loop, entry, loops, 1,
|
|
NULL, NULL, NULL, NULL, 0))
|
|
{
|
|
entry->flags |= irred_flag;
|
|
return NULL;
|
|
}
|
|
|
|
/* After duplication entry edge now points to new loop head block.
|
|
Note down new head as second_head. */
|
|
second_head = entry->dest;
|
|
|
|
/* Split loop entry edge and insert new block with cond expr. */
|
|
*condition_bb = lv_adjust_loop_entry_edge (first_head, second_head, entry,
|
|
cond_expr);
|
|
|
|
latch_edge = EDGE_SUCC (loop->latch->rbi->copy, 0);
|
|
|
|
extract_true_false_edges_from_block (*condition_bb, &true_edge, &false_edge);
|
|
nloop = loopify (loops,
|
|
latch_edge,
|
|
EDGE_PRED (loop->header->rbi->copy, 0),
|
|
*condition_bb, true_edge, false_edge,
|
|
false /* Do not redirect all edges. */);
|
|
|
|
exit = loop->single_exit;
|
|
if (exit)
|
|
nloop->single_exit = find_edge (exit->src->rbi->copy, exit->dest);
|
|
|
|
/* loopify redirected latch_edge. Update its PENDING_STMTS. */
|
|
flush_pending_stmts (latch_edge);
|
|
|
|
/* loopify redirected condition_bb's succ edge. Update its PENDING_STMTS. */
|
|
extract_true_false_edges_from_block (*condition_bb, &true_edge, &false_edge);
|
|
flush_pending_stmts (false_edge);
|
|
|
|
/* Adjust irreducible flag. */
|
|
if (irred_flag)
|
|
{
|
|
(*condition_bb)->flags |= BB_IRREDUCIBLE_LOOP;
|
|
loop_preheader_edge (loop)->flags |= EDGE_IRREDUCIBLE_LOOP;
|
|
loop_preheader_edge (nloop)->flags |= EDGE_IRREDUCIBLE_LOOP;
|
|
EDGE_PRED ((*condition_bb), 0)->flags |= EDGE_IRREDUCIBLE_LOOP;
|
|
}
|
|
|
|
/* At this point condition_bb is loop predheader with two successors,
|
|
first_head and second_head. Make sure that loop predheader has only
|
|
one successor. */
|
|
loop_split_edge_with (loop_preheader_edge (loop), NULL);
|
|
loop_split_edge_with (loop_preheader_edge (nloop), NULL);
|
|
|
|
return nloop;
|
|
}
|