/* High-level loop manipulation functions.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
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
+ INCR_POS (after it if AFTER is true, before it otherwise). INCR_POS and
+ AFTER can be computed using standard_iv_increment_position. The ssa versions
of the variable before and after increment will be stored in VAR_BEFORE and
VAR_AFTER (unless they are NULL). */
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_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. */
phi = create_phi_node (use, exit);
FOR_EACH_EDGE (e, ei, exit->preds)
- add_phi_arg (&phi, use, e);
+ add_phi_arg (phi, use, e);
SSA_NAME_DEF_STMT (use) = def_stmt;
}
bitmap_clear_bit (livein, def_bb->index);
- def = BITMAP_XMALLOC ();
+ def = BITMAP_ALLOC (NULL);
bitmap_set_bit (def, def_bb->index);
compute_global_livein (livein, def);
- BITMAP_XFREE (def);
+ BITMAP_FREE (def);
EXECUTE_IF_AND_IN_BITMAP (exits, livein, 0, index, bi)
{
static bitmap
get_loops_exits (void)
{
- bitmap exits = BITMAP_XMALLOC ();
+ bitmap exits = BITMAP_ALLOC (NULL);
basic_block bb;
edge e;
edge_iterator ei;
return;
if (!use_blocks[ver])
- use_blocks[ver] = BITMAP_XMALLOC ();
+ use_blocks[ver] = BITMAP_ALLOC (NULL);
bitmap_set_bit (use_blocks[ver], bb->index);
if (!flow_bb_inside_loop_p (def_loop, bb))
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
+/* Marks names that are used in BB and 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)
+find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks)
{
- basic_block bb;
block_stmt_iterator bsi;
+ edge e;
+ edge_iterator ei;
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_EACH_EDGE (e, ei, bb->succs)
+ for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
+ find_uses_to_rename_use (bb, PHI_ARG_DEF_FROM_EDGE (phi, e),
+ use_blocks);
+
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ find_uses_to_rename_stmt (bsi_stmt (bsi), 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. If CHANGED_BBS is not NULL,
+ scan only blocks in this set. */
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
- find_uses_to_rename_stmt (bsi_stmt (bsi), use_blocks);
+static void
+find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks)
+{
+ basic_block bb;
+ unsigned index;
+ bitmap_iterator bi;
+
+ if (changed_bbs)
+ {
+ EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi)
+ {
+ find_uses_to_rename_bb (BASIC_BLOCK (index), use_blocks);
+ }
+ }
+ else
+ {
+ FOR_EACH_BB (bb)
+ {
+ find_uses_to_rename_bb (bb, use_blocks);
+ }
}
}
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. */
+ base 99 and step 1.
+
+ If CHANGED_BBS is not NULL, we look for uses outside loops only in
+ the basic blocks in this set. */
void
-rewrite_into_loop_closed_ssa (void)
+rewrite_into_loop_closed_ssa (bitmap changed_bbs)
{
bitmap loop_exits = get_loops_exits ();
bitmap *use_blocks;
use_blocks = xcalloc (num_ssa_names, sizeof (bitmap));
/* Find the uses outside loops. */
- find_uses_to_rename (use_blocks);
+ find_uses_to_rename (changed_bbs, use_blocks);
+
+ if (!any_marked_for_rewrite_p ())
+ {
+ free (use_blocks);
+ BITMAP_FREE (loop_exits);
+ return;
+ }
/* Add the phi nodes on exits of the loops for the names we need to
rewrite. */
add_exit_phis (names_to_rename, use_blocks, loop_exits);
for (i = 0; i < num_ssa_names; i++)
- BITMAP_XFREE (use_blocks[i]);
+ BITMAP_FREE (use_blocks[i]);
free (use_blocks);
- BITMAP_XFREE (loop_exits);
- BITMAP_XFREE (names_to_rename);
+ BITMAP_FREE (loop_exits);
+ BITMAP_FREE (names_to_rename);
/* Do the rewriting. */
rewrite_ssa_into_ssa ();
for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
{
- op_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, EDGE_SUCC (bb, 0));
+ op_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, single_succ_edge (bb));
name = USE_FROM_PTR (op_p);
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);
+ add_phi_arg (new_phi, name, exit);
SET_USE (op_p, new_name);
}
}
basic_block bb;
edge exit;
- if (EDGE_COUNT (loop->latch->preds) > 1)
+ if (!single_pred_p (loop->latch))
return NULL;
- bb = EDGE_PRED (loop->latch, 0)->src;
+ bb = single_pred (loop->latch);
last = last_stmt (bb);
if (TREE_CODE (last) != COND_EXPR)
return NULL;
definitions = marked_ssa_names ();
rename_variables (first_new_block, definitions);
unmark_all_for_rewrite ();
- BITMAP_XFREE (definitions);
+ BITMAP_FREE (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
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 = TREE_CHAIN (phi2), phi1 = TREE_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 a 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;
-}
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