/* Induction variable canonicalization.
- Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2007, 2008 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
+Free Software Foundation; either version 3, or (at your option) any
later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
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, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* This pass detects the loops that iterate a constant number of times,
adds a canonical induction variable (step -1, tested against 0)
create_canonical_iv (struct loop *loop, edge exit, tree niter)
{
edge in;
- tree cond, type, var;
- block_stmt_iterator incr_at;
+ tree type, var;
+ gimple cond;
+ gimple_stmt_iterator incr_at;
enum tree_code cmp;
if (dump_file && (dump_flags & TDF_DETAILS))
niter = fold_build2 (PLUS_EXPR, type,
niter,
build_int_cst (type, 1));
- incr_at = bsi_last (in->src);
+ incr_at = gsi_last_bb (in->src);
create_iv (niter,
- fold_convert (type, integer_minus_one_node),
+ build_int_cst (type, -1),
NULL_TREE, loop,
&incr_at, false, NULL, &var);
cmp = (exit->flags & EDGE_TRUE_VALUE) ? EQ_EXPR : NE_EXPR;
- COND_EXPR_COND (cond) = build2 (cmp, boolean_type_node,
- var,
- build_int_cst (type, 0));
+ gimple_cond_set_code (cond, cmp);
+ gimple_cond_set_lhs (cond, var);
+ gimple_cond_set_rhs (cond, build_int_cst (type, 0));
update_stmt (cond);
}
-/* Computes an estimated number of insns in LOOP. */
+/* Computes an estimated number of insns in LOOP, weighted by WEIGHTS. */
unsigned
-tree_num_loop_insns (struct loop *loop)
+tree_num_loop_insns (struct loop *loop, eni_weights *weights)
{
basic_block *body = get_loop_body (loop);
- block_stmt_iterator bsi;
+ gimple_stmt_iterator gsi;
unsigned size = 1, i;
for (i = 0; i < loop->num_nodes; i++)
- for (bsi = bsi_start (body[i]); !bsi_end_p (bsi); bsi_next (&bsi))
- size += estimate_num_insns (bsi_stmt (bsi));
+ for (gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi); gsi_next (&gsi))
+ size += estimate_num_insns (gsi_stmt (gsi), weights);
free (body);
return size;
return unr_insns;
}
-/* Tries to unroll LOOP completely, i.e. NITER times. LOOPS is the
- loop tree. UL determines which loops we are allowed to unroll.
+/* Tries to unroll LOOP completely, i.e. NITER times.
+ UL determines which loops we are allowed to unroll.
EXIT is the exit of the loop that should be eliminated. */
static bool
-try_unroll_loop_completely (struct loops *loops ATTRIBUTE_UNUSED,
- struct loop *loop,
+try_unroll_loop_completely (struct loop *loop,
edge exit, tree niter,
enum unroll_level ul)
{
unsigned HOST_WIDE_INT n_unroll, ninsns, max_unroll, unr_insns;
- tree old_cond, cond, dont_exit, do_exit;
+ gimple cond;
if (loop->inner)
return false;
if (ul == UL_SINGLE_ITER)
return false;
- ninsns = tree_num_loop_insns (loop);
+ ninsns = tree_num_loop_insns (loop, &eni_size_weights);
- if (n_unroll * ninsns
- > (unsigned) PARAM_VALUE (PARAM_MAX_COMPLETELY_PEELED_INSNS))
- return false;
+ unr_insns = estimated_unrolled_size (ninsns, n_unroll);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, " Loop size: %d\n", (int) ninsns);
+ fprintf (dump_file, " Estimated size after unrolling: %d\n",
+ (int) unr_insns);
+ }
- if (ul == UL_NO_GROWTH)
+ if (unr_insns > ninsns
+ && (unr_insns
+ > (unsigned) PARAM_VALUE (PARAM_MAX_COMPLETELY_PEELED_INSNS)))
{
- unr_insns = estimated_unrolled_size (ninsns, n_unroll);
-
if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, " Loop size: %d\n", (int) ninsns);
- fprintf (dump_file, " Estimated size after unrolling: %d\n",
- (int) unr_insns);
- }
-
- if (unr_insns > ninsns)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Not unrolling loop %d:\n", loop->num);
- return false;
- }
+ fprintf (dump_file, "Not unrolling loop %d "
+ "(--param max-completely-peeled-insns limit reached).\n",
+ loop->num);
+ return false;
}
- }
- if (exit->flags & EDGE_TRUE_VALUE)
- {
- dont_exit = boolean_false_node;
- do_exit = boolean_true_node;
- }
- else
- {
- dont_exit = boolean_true_node;
- do_exit = boolean_false_node;
+ if (ul == UL_NO_GROWTH
+ && unr_insns > ninsns)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Not unrolling loop %d.\n", loop->num);
+ return false;
+ }
}
- cond = last_stmt (exit->src);
-
+
if (n_unroll)
{
sbitmap wont_exit;
- edge *edges_to_remove = xmalloc (sizeof (edge *) * n_unroll);
- unsigned int n_to_remove = 0;
+ edge e;
+ unsigned i;
+ VEC (edge, heap) *to_remove = NULL;
- old_cond = COND_EXPR_COND (cond);
- COND_EXPR_COND (cond) = dont_exit;
- update_stmt (cond);
initialize_original_copy_tables ();
-
wont_exit = sbitmap_alloc (n_unroll + 1);
sbitmap_ones (wont_exit);
RESET_BIT (wont_exit, 0);
- if (!tree_duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
- loops, n_unroll, wont_exit,
- exit, edges_to_remove,
- &n_to_remove,
- DLTHE_FLAG_UPDATE_FREQ
- | DLTHE_FLAG_COMPLETTE_PEEL))
+ if (!gimple_duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
+ n_unroll, wont_exit,
+ exit, &to_remove,
+ DLTHE_FLAG_UPDATE_FREQ
+ | DLTHE_FLAG_COMPLETTE_PEEL))
{
- COND_EXPR_COND (cond) = old_cond;
- update_stmt (cond);
free_original_copy_tables ();
free (wont_exit);
- free (edges_to_remove);
return false;
}
+
+ for (i = 0; VEC_iterate (edge, to_remove, i, e); i++)
+ {
+ bool ok = remove_path (e);
+ gcc_assert (ok);
+ }
+
+ VEC_free (edge, heap, to_remove);
free (wont_exit);
- free (edges_to_remove);
free_original_copy_tables ();
}
-
- COND_EXPR_COND (cond) = do_exit;
- update_stmt (cond);
+ cond = last_stmt (exit->src);
+ if (exit->flags & EDGE_TRUE_VALUE)
+ gimple_cond_make_true (cond);
+ else
+ gimple_cond_make_false (cond);
+ update_stmt (cond);
update_ssa (TODO_update_ssa);
if (dump_file && (dump_flags & TDF_DETAILS))
return true;
}
-/* Adds a canonical induction variable to LOOP if suitable. LOOPS is the loops
- tree. CREATE_IV is true if we may create a new iv. UL determines what
+/* Adds a canonical induction variable to LOOP if suitable.
+ CREATE_IV is true if we may create a new iv. UL determines
which loops we are allowed to completely unroll. If TRY_EVAL is true, we try
to determine the number of iterations of a loop by direct evaluation.
Returns true if cfg is changed. */
static bool
-canonicalize_loop_induction_variables (struct loops *loops, struct loop *loop,
+canonicalize_loop_induction_variables (struct loop *loop,
bool create_iv, enum unroll_level ul,
bool try_eval)
{
edge exit = NULL;
tree niter;
- niter = number_of_iterations_in_loop (loop);
+ niter = number_of_latch_executions (loop);
if (TREE_CODE (niter) == INTEGER_CST)
{
- exit = loop->single_exit;
+ exit = single_exit (loop);
if (!just_once_each_iteration_p (loop, exit->src))
return false;
-
- /* The result of number_of_iterations_in_loop is by one higher than
- we expect (i.e. it returns number of executions of the exit
- condition, not of the loop latch edge). */
- niter = fold_build2 (MINUS_EXPR, TREE_TYPE (niter), niter,
- build_int_cst (TREE_TYPE (niter), 1));
}
else
{
/* If the loop has more than one exit, try checking all of them
for # of iterations determinable through scev. */
- if (!loop->single_exit)
+ if (!single_exit (loop))
niter = find_loop_niter (loop, &exit);
/* Finally if everything else fails, try brute force evaluation. */
fprintf (dump_file, " times.\n");
}
- if (try_unroll_loop_completely (loops, loop, exit, niter, ul))
+ if (try_unroll_loop_completely (loop, exit, niter, ul))
return true;
if (create_iv)
}
/* The main entry point of the pass. Adds canonical induction variables
- to the suitable LOOPS. */
+ to the suitable loops. */
-void
-canonicalize_induction_variables (struct loops *loops)
+unsigned int
+canonicalize_induction_variables (void)
{
- unsigned i;
+ loop_iterator li;
struct loop *loop;
bool changed = false;
- for (i = 1; i < loops->num; i++)
+ FOR_EACH_LOOP (li, loop, 0)
{
- loop = loops->parray[i];
-
- if (loop)
- changed |= canonicalize_loop_induction_variables (loops, loop,
- true, UL_SINGLE_ITER,
- true);
+ changed |= canonicalize_loop_induction_variables (loop,
+ true, UL_SINGLE_ITER,
+ true);
}
/* Clean up the information about numbers of iterations, since brute force
scev_reset ();
if (changed)
- cleanup_tree_cfg_loop ();
+ return TODO_cleanup_cfg;
+ return 0;
}
/* Unroll LOOPS completely if they iterate just few times. Unless
MAY_INCREASE_SIZE is true, perform the unrolling only if the
size of the code does not increase. */
-void
-tree_unroll_loops_completely (struct loops *loops, bool may_increase_size)
+unsigned int
+tree_unroll_loops_completely (bool may_increase_size, bool unroll_outer)
{
- unsigned i;
+ loop_iterator li;
struct loop *loop;
- bool changed = false;
+ bool changed;
enum unroll_level ul;
- for (i = 1; i < loops->num; i++)
+ do
{
- loop = loops->parray[i];
+ changed = false;
- if (!loop)
- continue;
+ FOR_EACH_LOOP (li, loop, LI_ONLY_INNERMOST)
+ {
+ if (may_increase_size && optimize_loop_for_speed_p (loop)
+ /* Unroll outermost loops only if asked to do so or they do
+ not cause code growth. */
+ && (unroll_outer
+ || loop_outer (loop_outer (loop))))
+ ul = UL_ALL;
+ else
+ ul = UL_NO_GROWTH;
+ changed |= canonicalize_loop_induction_variables
+ (loop, false, ul, !flag_tree_loop_ivcanon);
+ }
- if (may_increase_size && maybe_hot_bb_p (loop->header))
- ul = UL_ALL;
- else
- ul = UL_NO_GROWTH;
- changed |= canonicalize_loop_induction_variables (loops, loop,
- false, ul,
- !flag_tree_loop_ivcanon);
+ if (changed)
+ {
+ /* This will take care of removing completely unrolled loops
+ from the loop structures so we can continue unrolling now
+ innermost loops. */
+ if (cleanup_tree_cfg ())
+ update_ssa (TODO_update_ssa_only_virtuals);
+
+ /* Clean up the information about numbers of iterations, since
+ complete unrolling might have invalidated it. */
+ scev_reset ();
+ }
}
+ while (changed);
- /* Clean up the information about numbers of iterations, since complete
- unrolling might have invalidated it. */
- scev_reset ();
-
- if (changed)
- cleanup_tree_cfg_loop ();
+ return 0;
}
/* Checks whether LOOP is empty. */
{
edge exit;
struct tree_niter_desc niter;
- tree phi, def;
basic_block *body;
- block_stmt_iterator bsi;
+ gimple_stmt_iterator gsi;
unsigned i;
- tree stmt;
/* If the loop has multiple exits, it is too hard for us to handle.
Similarly, if the exit is not dominating, we cannot determine
return false;
/* Values of all loop exit phi nodes must be invariants. */
- for (phi = phi_nodes (exit->dest); phi; phi = PHI_CHAIN (phi))
+ for (gsi = gsi_start(phi_nodes (exit->dest)); !gsi_end_p (gsi); gsi_next (&gsi))
{
+ gimple phi = gsi_stmt (gsi);
+ tree def;
+
if (!is_gimple_reg (PHI_RESULT (phi)))
continue;
return false;
}
- for (bsi = bsi_start (body[i]); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi); gsi_next (&gsi))
{
- stmt = bsi_stmt (bsi);
+ gimple stmt = gsi_stmt (gsi);
+
if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS)
- || stmt_ann (stmt)->has_volatile_ops)
+ || gimple_has_volatile_ops (stmt))
{
free (body);
return false;
/* Also, asm statements and calls may have side effects and we
cannot change the number of times they are executed. */
- switch (TREE_CODE (stmt))
+ switch (gimple_code (stmt))
{
- case RETURN_EXPR:
- case MODIFY_EXPR:
- stmt = get_call_expr_in (stmt);
- if (!stmt)
- break;
-
- case CALL_EXPR:
- if (TREE_SIDE_EFFECTS (stmt))
+ case GIMPLE_CALL:
+ if (gimple_has_side_effects (stmt))
{
free (body);
return false;
}
break;
- case ASM_EXPR:
+ case GIMPLE_ASM:
/* We cannot remove volatile assembler. */
- if (ASM_VOLATILE_P (stmt))
+ if (gimple_asm_volatile_p (stmt))
{
free (body);
return false;
static void
remove_empty_loop (struct loop *loop)
{
- edge exit = single_dom_exit (loop);
- tree cond_stmt = last_stmt (exit->src);
- tree do_exit;
+ edge exit = single_dom_exit (loop), non_exit;
+ gimple cond_stmt = last_stmt (exit->src);
+ basic_block *body;
+ unsigned n_before, freq_in, freq_h;
+ gcov_type exit_count = exit->count;
+
+ if (dump_file)
+ fprintf (dump_file, "Removing empty loop %d\n", loop->num);
+
+ non_exit = EDGE_SUCC (exit->src, 0);
+ if (non_exit == exit)
+ non_exit = EDGE_SUCC (exit->src, 1);
if (exit->flags & EDGE_TRUE_VALUE)
- do_exit = boolean_true_node;
+ gimple_cond_make_true (cond_stmt);
else
- do_exit = boolean_false_node;
-
- COND_EXPR_COND (cond_stmt) = do_exit;
+ gimple_cond_make_false (cond_stmt);
update_stmt (cond_stmt);
+
+ /* Let us set the probabilities of the edges coming from the exit block. */
+ exit->probability = REG_BR_PROB_BASE;
+ non_exit->probability = 0;
+ non_exit->count = 0;
+
+ /* Update frequencies and counts. Everything before
+ the exit needs to be scaled FREQ_IN/FREQ_H times,
+ where FREQ_IN is the frequency of the entry edge
+ and FREQ_H is the frequency of the loop header.
+ Everything after the exit has zero frequency. */
+ freq_h = loop->header->frequency;
+ freq_in = EDGE_FREQUENCY (loop_preheader_edge (loop));
+ if (freq_h != 0)
+ {
+ body = get_loop_body_in_dom_order (loop);
+ for (n_before = 1; n_before <= loop->num_nodes; n_before++)
+ if (body[n_before - 1] == exit->src)
+ break;
+ scale_bbs_frequencies_int (body, n_before, freq_in, freq_h);
+ scale_bbs_frequencies_int (body + n_before, loop->num_nodes - n_before,
+ 0, 1);
+ free (body);
+ }
+
+ /* Number of executions of exit is not changed, thus we need to restore
+ the original value. */
+ exit->count = exit_count;
}
/* Removes LOOP if it is empty. Returns true if LOOP is removed. CHANGED
return true;
}
-/* Remove the empty LOOPS. */
+/* Remove the empty loops. */
-void
-remove_empty_loops (struct loops *loops)
+unsigned int
+remove_empty_loops (void)
{
bool changed = false;
struct loop *loop;
- for (loop = loops->tree_root->inner; loop; loop = loop->next)
+ for (loop = current_loops->tree_root->inner; loop; loop = loop->next)
try_remove_empty_loop (loop, &changed);
if (changed)
{
scev_reset ();
- cleanup_tree_cfg_loop ();
+ return TODO_cleanup_cfg;
}
+ return 0;
}
+
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