/* If-conversion for vectorizer.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005 Free Software Foundation, Inc.
Contributed by Devang Patel <dpatel@apple.com>
This file is part of GCC.
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. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
-/* This pass implements tree level if-conversion transformation of loops.
+/* This pass implements tree level if-conversion transformation of loops.
Initial goal is to help vectorizer vectorize loops with conditions.
A short description of if-conversion:
- o Decide if a loop is if-convertable or not.
+ o Decide if a loop is if-convertible or not.
o Walk all loop basic blocks in breadth first order (BFS order).
o Remove conditional statements (at the end of basic block)
- and propogate condition into destination basic blcoks'
+ and propagate condition into destination basic blocks'
predicate list.
o Replace modify expression with conditional modify expression
using current basic block's condition.
# i_23 = PHI <0(0), i_18(10)>;
<L0>:;
j_15 = A[i_23];
-
+
<L3>:;
iftmp.2_4 = j_15 > 41 ? 42 : 0;
A[i_23] = iftmp.2_4;
i_18 = i_23 + 1;
if (i_18 <= 15) goto <L19>; else goto <L18>;
-
+
<L19>:;
goto <bb 1> (<L0>);
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-#include "errors.h"
#include "tree.h"
#include "c-common.h"
#include "flags.h"
/* local function prototypes */
static void main_tree_if_conversion (void);
-static tree tree_if_convert_stmt (struct loop *loop, tree, tree,
+static tree tree_if_convert_stmt (struct loop *loop, tree, tree,
block_stmt_iterator *);
-static void tree_if_convert_cond_expr (struct loop *, tree, tree,
+static void tree_if_convert_cond_expr (struct loop *, tree, tree,
block_stmt_iterator *);
-static bool if_convertable_phi_p (struct loop *, basic_block, tree);
-static bool if_convertable_modify_expr_p (struct loop *, basic_block, tree);
-static bool if_convertable_stmt_p (struct loop *, basic_block, tree);
-static bool if_convertable_bb_p (struct loop *, basic_block, bool);
-static bool if_convertable_loop_p (struct loop *, bool);
+static bool if_convertible_phi_p (struct loop *, basic_block, tree);
+static bool if_convertible_modify_expr_p (struct loop *, basic_block, tree);
+static bool if_convertible_stmt_p (struct loop *, basic_block, tree);
+static bool if_convertible_bb_p (struct loop *, basic_block, basic_block);
+static bool if_convertible_loop_p (struct loop *, bool);
static void add_to_predicate_list (basic_block, tree);
-static tree add_to_dst_predicate_list (struct loop * loop, tree, tree, tree,
+static tree add_to_dst_predicate_list (struct loop * loop, basic_block, tree, tree,
block_stmt_iterator *);
static void clean_predicate_lists (struct loop *loop);
-static bool find_phi_replacement_condition (basic_block, tree *,
- block_stmt_iterator *);
-static void replace_phi_with_cond_modify_expr (tree, tree, bool,
+static basic_block find_phi_replacement_condition (struct loop *loop,
+ basic_block, tree *,
+ block_stmt_iterator *);
+static void replace_phi_with_cond_modify_expr (tree, tree, basic_block,
block_stmt_iterator *);
static void process_phi_nodes (struct loop *);
static void combine_blocks (struct loop *);
static tree ifc_temp_var (tree, tree);
static bool pred_blocks_visited_p (basic_block, bitmap *);
static basic_block * get_loop_body_in_if_conv_order (const struct loop *loop);
-static bool bb_with_exit_edge_p (basic_block);
+static bool bb_with_exit_edge_p (struct loop *, basic_block);
/* List of basic blocks in if-conversion-suitable order. */
static basic_block *ifc_bbs;
/* Main entry point.
Apply if-conversion to the LOOP. Return true if successful otherwise return
- false. If false is returned then loop remains unchanged.
+ false. If false is returned then loop remains unchanged.
FOR_VECTORIZER is a boolean flag. It indicates whether if-conversion is used
for vectorizer or not. If it is used for vectorizer, additional checks are
- used. (Vectorization checks are not yet imlemented). */
+ used. (Vectorization checks are not yet implemented). */
-bool
+static bool
tree_if_conversion (struct loop *loop, bool for_vectorizer)
{
basic_block bb;
ifc_bbs = NULL;
/* if-conversion is not appropriate for all loops. First, check if loop is
- if-convertable or not. */
- if (!if_convertable_loop_p (loop, for_vectorizer))
+ if-convertible or not. */
+ if (!if_convertible_loop_p (loop, for_vectorizer))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,"-------------------------\n");
ifc_bbs = NULL;
}
free_dominance_info (CDI_POST_DOMINATORS);
- free_df ();
return false;
}
cond = NULL_TREE;
-
+
/* Do actual work now. */
- for (i = 0; i < loop->num_nodes; i++)
+ for (i = 0; i < loop->num_nodes; i++)
{
bb = ifc_bbs [i];
cond = bb->aux;
/* Process all statements in this basic block.
- Remove conditional expresion, if any, and annotate
+ Remove conditional expression, if any, and annotate
destination basic block(s) appropriately. */
for (itr = bsi_start (bb); !bsi_end_p (itr); /* empty */)
{
bsi_next (&itr);
}
- /* If current bb has only one successor, then consider it as an
+ /* If current bb has only one successor, then consider it as an
unconditional goto. */
- if (bb->succ && !bb->succ->succ_next)
+ if (single_succ_p (bb))
{
- basic_block bb_n = bb->succ->dest;
+ basic_block bb_n = single_succ (bb);
if (cond != NULL_TREE)
add_to_predicate_list (bb_n, cond);
cond = NULL_TREE;
clean_predicate_lists (loop);
free (ifc_bbs);
ifc_bbs = NULL;
- free_df ();
return true;
}
-/* if-convert stmt T which is part of LOOP.
- If T is a MODIFY_EXPR than it is converted into conditional modify
- expression using COND. For conditional expressions, add condition in the
- destination basic block's predicate list and remove conditional
- expression itself. BSI is the iterator used to traverse statements of
+/* if-convert stmt T which is part of LOOP.
+ If T is a MODIFY_EXPR than it is converted into conditional modify
+ expression using COND. For conditional expressions, add condition in the
+ destination basic block's predicate list and remove conditional
+ expression itself. BSI is the iterator used to traverse statements of
loop. It is used here when it is required to delete current statement. */
static tree
-tree_if_convert_stmt (struct loop * loop, tree t, tree cond,
+tree_if_convert_stmt (struct loop * loop, tree t, tree cond,
block_stmt_iterator *bsi)
{
if (dump_file && (dump_flags & TDF_DETAILS))
/* This modify_expr is killing previous value of LHS. Appropriate value will
be selected by PHI node based on condition. It is possible that before
this transformation, PHI nodes was selecting default value and now it will
- use this new value. This is OK because it does not change validity the
+ use this new value. This is OK because it does not change validity the
program. */
break;
- case GOTO_EXPR:
- /* Unconditional goto */
- add_to_predicate_list (bb_for_stmt (TREE_OPERAND (t, 1)), cond);
- bsi_remove (bsi);
- cond = NULL_TREE;
- break;
-
case COND_EXPR:
/* Update destination blocks' predicate list and remove this
condition expression. */
tree_if_convert_cond_expr (loop, t, cond, bsi);
- cond = NULL_TREE;
- break;
-
- default:
- abort ();
+ cond = NULL_TREE;
break;
+
+ default:
+ gcc_unreachable ();
}
return cond;
}
/* STMT is COND_EXPR. Update two destination's predicate list.
Remove COND_EXPR, if it is not the loop exit condition. Otherwise
- update loop exit condition appropriatly. BSI is the iterator
+ update loop exit condition appropriately. BSI is the iterator
used to traverse statement list. STMT is part of loop LOOP. */
static void
-tree_if_convert_cond_expr (struct loop *loop, tree stmt, tree cond,
+tree_if_convert_cond_expr (struct loop *loop, tree stmt, tree cond,
block_stmt_iterator *bsi)
{
- tree then_clause, else_clause, c, new_cond;
- new_cond = NULL_TREE;
+ tree c, c2;
+ edge true_edge, false_edge;
-#ifdef ENABLE_CHECKING
- if (TREE_CODE (stmt) != COND_EXPR)
- abort ();
-#endif
+ gcc_assert (TREE_CODE (stmt) == COND_EXPR);
+
+ c = COND_EXPR_COND (stmt);
+
+ extract_true_false_edges_from_block (bb_for_stmt (stmt),
+ &true_edge, &false_edge);
- c = TREE_OPERAND (stmt, 0);
- then_clause = TREE_OPERAND (stmt, 1);
- else_clause = TREE_OPERAND (stmt, 2);
-
- /* Create temp. for condition. */
- if (!is_gimple_reg (c))
- {
- tree new_stmt;
- new_stmt = ifc_temp_var (TREE_TYPE (c), unshare_expr (c));
- bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
- c = TREE_OPERAND (new_stmt, 0);
- }
-
/* Add new condition into destination's predicate list. */
- if (then_clause)
- /* if 'c' is true then then_clause is reached. */
- new_cond = add_to_dst_predicate_list (loop, then_clause, cond, c, bsi);
-
- if (else_clause)
- {
- /* if 'c' is false then else_clause is reached. */
- tree c2 = build1 (TRUTH_NOT_EXPR,
- boolean_type_node,
- unshare_expr (c));
- add_to_dst_predicate_list (loop, else_clause, cond, c2, bsi);
- }
- /* Now this conditional statement is redundent. Remove it.
+ /* If 'c' is true then TRUE_EDGE is taken. */
+ add_to_dst_predicate_list (loop, true_edge->dest, cond,
+ unshare_expr (c), bsi);
+
+ /* If 'c' is false then FALSE_EDGE is taken. */
+ c2 = invert_truthvalue (unshare_expr (c));
+ add_to_dst_predicate_list (loop, false_edge->dest, cond, c2, bsi);
+
+ /* Now this conditional statement is redundant. Remove it.
But, do not remove exit condition! Update exit condition
using new condition. */
- if (!bb_with_exit_edge_p (bb_for_stmt (stmt)))
+ if (!bb_with_exit_edge_p (loop, bb_for_stmt (stmt)))
{
- bsi_remove (bsi);
+ bsi_remove (bsi, true);
cond = NULL_TREE;
}
- else if (new_cond != NULL_TREE)
- {
- TREE_OPERAND (stmt, 0) = new_cond;
- modify_stmt (stmt);
- }
return;
}
-/* Return true, iff PHI is if-convertable. PHI is part of loop LOOP
+/* Return true, iff PHI is if-convertible. PHI is part of loop LOOP
and it belongs to basic block BB.
- PHI is not if-convertable
+ PHI is not if-convertible
- if it has more than 2 arguments.
- Virtual PHI is immediately used in another PHI node. */
static bool
-if_convertable_phi_p (struct loop *loop, basic_block bb, tree phi)
+if_convertible_phi_p (struct loop *loop, basic_block bb, tree phi)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "-------------------------\n");
print_generic_stmt (dump_file, phi, TDF_SLIM);
}
-
+
if (bb != loop->header && PHI_NUM_ARGS (phi) != 2)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "More than two phi node args.\n");
return false;
}
-
+
if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
{
- int j;
- dataflow_t df = get_immediate_uses (phi);
- int num_uses = num_immediate_uses (df);
- for (j = 0; j < num_uses; j++)
+ imm_use_iterator imm_iter;
+ use_operand_p use_p;
+ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, PHI_RESULT (phi))
{
- tree use = immediate_use (df, j);
- if (TREE_CODE (use) == PHI_NODE)
+ if (TREE_CODE (USE_STMT (use_p)) == PHI_NODE)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Difficult to handle this virtual phi.\n");
return true;
}
-/* Return true, if M_EXPR is if-convertable.
- MODIFY_EXPR is not if-convertable if,
+/* Return true, if M_EXPR is if-convertible.
+ MODIFY_EXPR is not if-convertible if,
- It is not movable.
- It could trap.
- LHS is not var decl.
*/
static bool
-if_convertable_modify_expr_p (struct loop *loop, basic_block bb, tree m_expr)
+if_convertible_modify_expr_p (struct loop *loop, basic_block bb, tree m_expr)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "-------------------------\n");
print_generic_stmt (dump_file, m_expr, TDF_SLIM);
}
-
+
/* Be conservative and do not handle immovable expressions. */
if (movement_possibility (m_expr) == MOVE_IMPOSSIBLE)
{
}
/* See if it needs speculative loading or not. */
- if (bb != loop->header
+ if (bb != loop->header
&& tree_could_trap_p (TREE_OPERAND (m_expr, 1)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
if (TREE_CODE (TREE_OPERAND (m_expr, 0)) != SSA_NAME
&& bb != loop->header
- && !bb_with_exit_edge_p (bb))
+ && !bb_with_exit_edge_p (loop, bb))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
return true;
}
-/* Return true, iff STMT is if-convertable.
- Statement is if-convertable if,
- - It is if-converatable MODIFY_EXPR
- - IT is LABEL_EXPR, GOTO_EXPR or COND_EXPR.
+/* Return true, iff STMT is if-convertible.
+ Statement is if-convertible if,
+ - It is if-convertible MODIFY_EXPR
+ - IT is LABEL_EXPR or COND_EXPR.
STMT is inside block BB, which is inside loop LOOP. */
static bool
-if_convertable_stmt_p (struct loop *loop, basic_block bb, tree stmt)
+if_convertible_stmt_p (struct loop *loop, basic_block bb, tree stmt)
{
switch (TREE_CODE (stmt))
{
case LABEL_EXPR:
break;
-
+
case MODIFY_EXPR:
-
- if (!if_convertable_modify_expr_p (loop, bb, stmt))
+
+ if (!if_convertible_modify_expr_p (loop, bb, stmt))
return false;
break;
-
- case GOTO_EXPR:
+
case COND_EXPR:
break;
-
+
default:
/* Don't know what to do with 'em so don't do anything. */
if (dump_file && (dump_flags & TDF_DETAILS))
return true;
}
-/* Return true, iff BB is if-convertable.
+/* Return true, iff BB is if-convertible.
Note: This routine does _not_ check basic block statements and phis.
- Basic block is not if-converatable if,
- - Basic block is non-empty and it is after exit block (in BFS order).
+ Basic block is not if-convertible if,
+ - Basic block is non-empty and it is after exit block (in BFS order).
- Basic block is after exit block but before latch.
- - Basic block edge(s) is not normal.
+ - Basic block edge(s) is not normal.
EXIT_BB_SEEN is true if basic block with exit edge is already seen.
- BB is inside loop LOOP. */
+ BB is inside loop LOOP. */
-static bool
-if_convertable_bb_p (struct loop *loop, basic_block bb, bool exit_bb_seen)
+static bool
+if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb)
{
edge e;
+ edge_iterator ei;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "----------[%d]-------------\n", bb->index);
-
- if (exit_bb_seen)
+
+ if (exit_bb)
{
if (bb != loop->latch)
{
fprintf (dump_file, "non empty basic block after exit bb\n");
return false;
}
+ else if (bb == loop->latch
+ && bb != exit_bb
+ && !dominated_by_p (CDI_DOMINATORS, bb, exit_bb))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "latch is not dominated by exit_block\n");
+ return false;
+ }
}
-
- /* Be less adveturous and handle only normal edges. */
- for (e = bb->succ; e; e = e->succ_next)
- if (e->flags &
+
+ /* Be less adventurous and handle only normal edges. */
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (e->flags &
(EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_ABNORMAL | EDGE_IRREDUCIBLE_LOOP))
{
if (dump_file && (dump_flags & TDF_DETAILS))
return true;
}
-/* Return true, iff LOOP is if-convertable.
- LOOP is if-convertable if,
+/* Return true, iff LOOP is if-convertible.
+ LOOP is if-convertible if,
- It is innermost.
- It has two or more basic blocks.
- It has only one exit.
- - Loop header is not the exit edge.
- - If its basic blocks and phi nodes are if convertable. See above for
- more info.
+ - Loop header is not the exit edge.
+ - If its basic blocks and phi nodes are if convertible. See above for
+ more info.
FOR_VECTORIZER enables vectorizer specific checks. For example, support
for vector conditions, data dependency checks etc.. (Not implemented yet). */
static bool
-if_convertable_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED)
+if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED)
{
tree phi;
basic_block bb;
block_stmt_iterator itr;
unsigned int i;
edge e;
- bool exit_bb_seen = false;
+ edge_iterator ei;
+ basic_block exit_bb = NULL;
/* Handle only inner most loop. */
if (!loop || loop->inner)
fprintf (dump_file, "not inner most loop\n");
return false;
}
-
- flow_loop_scan (loop, LOOP_ALL);
/* If only one block, no need for if-conversion. */
if (loop->num_nodes <= 2)
{
if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "less thant 2 basic blocks\n");
+ fprintf (dump_file, "less than 2 basic blocks\n");
return false;
}
-
+
/* More than one loop exit is too much to handle. */
- if (loop->num_exits > 1)
+ if (!loop->single_exit)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "multiple exits\n");
/* If one of the loop header's edge is exit edge then do not apply
if-conversion. */
- for (e = loop->header->succ; e; e = e->succ_next)
- if ( e->flags & EDGE_LOOP_EXIT)
- return false;
-
- compute_immediate_uses (TDFA_USE_OPS|TDFA_USE_VOPS, NULL);
+ FOR_EACH_EDGE (e, ei, loop->header->succs)
+ {
+ if (loop_exit_edge_p (loop, e))
+ return false;
+ }
calculate_dominance_info (CDI_DOMINATORS);
calculate_dominance_info (CDI_POST_DOMINATORS);
free_dominance_info (CDI_POST_DOMINATORS);
return false;
}
-
+
for (i = 0; i < loop->num_nodes; i++)
{
bb = ifc_bbs[i];
- if (!if_convertable_bb_p (loop, bb, exit_bb_seen))
+ if (!if_convertible_bb_p (loop, bb, exit_bb))
return false;
/* Check statements. */
for (itr = bsi_start (bb); !bsi_end_p (itr); bsi_next (&itr))
- if (!if_convertable_stmt_p (loop, bb, bsi_stmt (itr)))
+ if (!if_convertible_stmt_p (loop, bb, bsi_stmt (itr)))
return false;
/* ??? Check data dependency for vectorizer. */
/* What about phi nodes ? */
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
- if (!if_convertable_phi_p (loop, bb, phi))
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ if (!if_convertible_phi_p (loop, bb, phi))
return false;
- if (bb_with_exit_edge_p (bb))
- exit_bb_seen = true;
+ if (bb_with_exit_edge_p (loop, bb))
+ exit_bb = bb;
}
/* OK. Did not find any potential issues so go ahead in if-convert
add_to_predicate_list (basic_block bb, tree new_cond)
{
tree cond = bb->aux;
-
+
if (cond)
- cond = fold (build (TRUTH_OR_EXPR, boolean_type_node,
- unshare_expr (cond), new_cond));
+ cond = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ unshare_expr (cond), new_cond);
else
cond = new_cond;
bb->aux = cond;
}
-/* Add condition COND into DST's predicate list. PREV_COND is
+/* Add condition COND into BB's predicate list. PREV_COND is
existing condition. */
static tree
-add_to_dst_predicate_list (struct loop * loop, tree dst,
+add_to_dst_predicate_list (struct loop * loop, basic_block bb,
tree prev_cond, tree cond,
block_stmt_iterator *bsi)
{
- basic_block bb;
tree new_cond = NULL_TREE;
-#ifdef ENABLE_CHECKING
- if (TREE_CODE (dst) != GOTO_EXPR)
- abort ();
-#endif
- bb = label_to_block (TREE_OPERAND (dst, 0));
if (!flow_bb_inside_loop_p (loop, bb))
return NULL_TREE;
new_cond = unshare_expr (cond);
else
{
- tree tmp_stmt;
+ tree tmp;
+ tree tmp_stmt = NULL_TREE;
+ tree tmp_stmts1 = NULL_TREE;
+ tree tmp_stmts2 = NULL_TREE;
+ prev_cond = force_gimple_operand (unshare_expr (prev_cond),
+ &tmp_stmts1, true, NULL);
+ if (tmp_stmts1)
+ bsi_insert_before (bsi, tmp_stmts1, BSI_SAME_STMT);
+
+ cond = force_gimple_operand (unshare_expr (cond),
+ &tmp_stmts2, true, NULL);
+ if (tmp_stmts2)
+ bsi_insert_before (bsi, tmp_stmts2, BSI_SAME_STMT);
+
/* new_cond == prev_cond AND cond */
- tree tmp = build (TRUTH_AND_EXPR, boolean_type_node,
- unshare_expr (prev_cond), cond);
+ tmp = build2 (TRUTH_AND_EXPR, boolean_type_node,
+ unshare_expr (prev_cond), cond);
tmp_stmt = ifc_temp_var (boolean_type_node, tmp);
bsi_insert_before (bsi, tmp_stmt, BSI_SAME_STMT);
new_cond = TREE_OPERAND (tmp_stmt, 0);
static void
clean_predicate_lists (struct loop *loop)
{
+ basic_block *bb;
unsigned int i;
-
+ bb = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
- ifc_bbs[i]->aux = NULL;
+ bb[i]->aux = NULL;
+
+ free (bb);
}
/* Basic block BB has two predecessors. Using predecessor's aux field, set
- appropriate condition COND for the PHI node replacement. Return true if
- phi arguments are condition is selected from second predecessor. */
+ appropriate condition COND for the PHI node replacement. Return true block
+ whose phi arguments are selected when cond is true. */
-static bool
-find_phi_replacement_condition (basic_block bb, tree *cond,
+static basic_block
+find_phi_replacement_condition (struct loop *loop,
+ basic_block bb, tree *cond,
block_stmt_iterator *bsi)
{
- edge e;
- basic_block p1 = NULL;
- basic_block p2 = NULL;
- bool switch_args = false;
+ basic_block first_bb = NULL;
+ basic_block second_bb = NULL;
tree tmp_cond;
- for (e = bb->pred; e; e = e->pred_next)
- {
- if (p1 == NULL)
- p1 = e->src;
- else if (p2 == NULL)
- p2 = e->src;
- else
- /* More than two predecessors. This is not expected. */
- abort ();
- }
+ gcc_assert (EDGE_COUNT (bb->preds) == 2);
+ first_bb = (EDGE_PRED (bb, 0))->src;
+ second_bb = (EDGE_PRED (bb, 1))->src;
- /* Use condition that is not TRUTH_NOT_EXPR in conditional modify expr. */
- tmp_cond = p1->aux;
+ /* Use condition based on following criteria:
+ 1)
+ S1: x = !c ? a : b;
+
+ S2: x = c ? b : a;
+
+ S2 is preferred over S1. Make 'b' first_bb and use its condition.
+
+ 2) Do not make loop header first_bb.
+
+ 3)
+ S1: x = !(c == d)? a : b;
+
+ S21: t1 = c == d;
+ S22: x = t1 ? b : a;
+
+ S3: x = (c == d) ? b : a;
+
+ S3 is preferred over S1 and S2*, Make 'b' first_bb and use
+ its condition.
+
+ 4) If pred B is dominated by pred A then use pred B's condition.
+ See PR23115. */
+
+ /* Select condition that is not TRUTH_NOT_EXPR. */
+ tmp_cond = first_bb->aux;
if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR)
{
- *cond = p2->aux;
- switch_args = true;
+ basic_block tmp_bb;
+ tmp_bb = first_bb;
+ first_bb = second_bb;
+ second_bb = tmp_bb;
}
- else
+
+ /* Check if FIRST_BB is loop header or not and make sure that
+ FIRST_BB does not dominate SECOND_BB. */
+ if (first_bb == loop->header
+ || dominated_by_p (CDI_DOMINATORS, second_bb, first_bb))
{
- *cond = p1->aux;
- switch_args = false;
+ tmp_cond = second_bb->aux;
+ if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR)
+ {
+ /* Select non loop header condition but do not switch basic blocks. */
+ *cond = invert_truthvalue (unshare_expr (tmp_cond));
+ }
+ else
+ {
+ /* Select non loop header condition. */
+ first_bb = second_bb;
+ *cond = first_bb->aux;
+ }
}
-
- /* Create temp. for the condition. Vectorizier prefers to have gimple
- value as condition. Various targets use different means to communicate
- condition in vector compare operation. Using gimple value allows compiler
+ else
+ /* FIRST_BB is not loop header */
+ *cond = first_bb->aux;
+
+ /* Create temp. for the condition. Vectorizer prefers to have gimple
+ value as condition. Various targets use different means to communicate
+ condition in vector compare operation. Using gimple value allows compiler
to emit vector compare and select RTL without exposing compare's result. */
if (!is_gimple_reg (*cond) && !is_gimple_condexpr (*cond))
{
tree new_stmt;
new_stmt = ifc_temp_var (TREE_TYPE (*cond), unshare_expr (*cond));
- bsi_insert_after (bsi, new_stmt, BSI_SAME_STMT);
- bsi_next (bsi);
+ bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
*cond = TREE_OPERAND (new_stmt, 0);
}
-#ifdef ENABLE_CHECKING
- if (*cond == NULL_TREE)
- abort ();
-#endif
+ gcc_assert (*cond);
- return switch_args;
+ return first_bb;
}
-/* Replace PHI node with conditional modify expr using COND.
- This routine does not handle PHI nodes with more than two arguments.
+/* Replace PHI node with conditional modify expr using COND.
+ This routine does not handle PHI nodes with more than two arguments.
For example,
S1: A = PHI <x1(1), x2(5)
is converted into,
S2: A = cond ? x1 : x2;
S2 is inserted at the top of basic block's statement list.
- PHI arguments are switched if SWITCH_ARGS is true.
+ When COND is true, phi arg from TRUE_BB is selected.
*/
static void
-replace_phi_with_cond_modify_expr (tree phi, tree cond, bool switch_args,
+replace_phi_with_cond_modify_expr (tree phi, tree cond, basic_block true_bb,
block_stmt_iterator *bsi)
{
tree new_stmt;
tree rhs;
tree arg_0, arg_1;
-#ifdef ENABLE_CHECKING
- if (TREE_CODE (phi) != PHI_NODE)
- abort ();
-
+ gcc_assert (TREE_CODE (phi) == PHI_NODE);
+
/* If this is not filtered earlier, then now it is too late. */
- if (PHI_NUM_ARGS (phi) != 2)
- abort ();
-#endif
+ gcc_assert (PHI_NUM_ARGS (phi) == 2);
/* Find basic block and initialize iterator. */
bb = bb_for_stmt (phi);
new_stmt = NULL_TREE;
arg_0 = NULL_TREE;
arg_1 = NULL_TREE;
-
+
/* Use condition that is not TRUTH_NOT_EXPR in conditional modify expr. */
- if (switch_args)
+ if (EDGE_PRED (bb, 1)->src == true_bb)
{
arg_0 = PHI_ARG_DEF (phi, 1);
arg_1 = PHI_ARG_DEF (phi, 0);
arg_1 = PHI_ARG_DEF (phi, 1);
}
- /* Build new RHS using selected condtion and arguments. */
- rhs = build (COND_EXPR, TREE_TYPE (PHI_RESULT (phi)),
- unshare_expr (cond), unshare_expr (arg_0),
- unshare_expr (arg_1));
+ /* Build new RHS using selected condition and arguments. */
+ rhs = build3 (COND_EXPR, TREE_TYPE (PHI_RESULT (phi)),
+ unshare_expr (cond), unshare_expr (arg_0),
+ unshare_expr (arg_1));
- /* Create new MODIFY expresstion using RHS. */
- new_stmt = build (MODIFY_EXPR, TREE_TYPE (PHI_RESULT (phi)),
- unshare_expr (PHI_RESULT (phi)), rhs);
+ /* Create new MODIFY expression using RHS. */
+ new_stmt = build2 (MODIFY_EXPR, TREE_TYPE (PHI_RESULT (phi)),
+ unshare_expr (PHI_RESULT (phi)), rhs);
/* Make new statement definition of the original phi result. */
SSA_NAME_DEF_STMT (PHI_RESULT (phi)) = new_stmt;
- /* Set basic block and insert using iterator. */
- set_bb_for_stmt (new_stmt, bb);
-
- bsi_insert_after (bsi, new_stmt, BSI_SAME_STMT);
- bsi_next (bsi);
-
- modify_stmt (new_stmt);
+ /* Insert using iterator. */
+ bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
+ update_stmt (new_stmt);
if (dump_file && (dump_flags & TDF_DETAILS))
{
}
}
-/* Process phi nodes for the given LOOP. Replace phi nodes with cond
+/* Process phi nodes for the given LOOP. Replace phi nodes with cond
modify expr. */
static void
{
tree phi, cond;
block_stmt_iterator bsi;
- bool switch_args = false;
+ basic_block true_bb = NULL;
bb = ifc_bbs[i];
-
- if (bb == loop->header || bb == loop->latch)
+
+ if (bb == loop->header)
continue;
phi = phi_nodes (bb);
- bsi = bsi_start (bb);
+ bsi = bsi_after_labels (bb);
/* BB has two predecessors. Using predecessor's aux field, set
appropriate condition for the PHI node replacement. */
if (phi)
- switch_args = find_phi_replacement_condition (bb, &cond, &bsi);
+ true_bb = find_phi_replacement_condition (loop, bb, &cond, &bsi);
while (phi)
{
- tree next = TREE_CHAIN (phi);
- replace_phi_with_cond_modify_expr (phi, cond, switch_args, &bsi);
+ tree next = PHI_CHAIN (phi);
+ replace_phi_with_cond_modify_expr (phi, cond, true_bb, &bsi);
release_phi_node (phi);
phi = next;
}
- bb_ann (bb)->phi_nodes = NULL;
+ bb->phi_nodes = NULL;
}
return;
}
-/* Combine all basic block from the given LOOP into one or two super
- basic block. Replace PHI nodes with conditional modify expression. */
+/* Combine all basic block from the given LOOP into one or two super
+ basic block. Replace PHI nodes with conditional modify expression. */
static void
combine_blocks (struct loop *loop)
basic_block bb, exit_bb, merge_target_bb;
unsigned int orig_loop_num_nodes = loop->num_nodes;
unsigned int i;
+ unsigned int n_exits;
+ get_loop_exit_edges (loop, &n_exits);
/* Process phi nodes to prepare blocks for merge. */
process_phi_nodes (loop);
bb = ifc_bbs[i];
- if (bb == loop->latch)
- continue;
-
- if (!exit_bb && bb_with_exit_edge_p (bb))
+ if (!exit_bb && bb_with_exit_edge_p (loop, bb))
exit_bb = bb;
if (bb == exit_bb)
{
- edge new_e;
+ edge_iterator ei;
/* Connect this node with loop header. */
- new_e = make_edge (ifc_bbs[0], bb, EDGE_FALLTHRU);
+ make_edge (ifc_bbs[0], bb, EDGE_FALLTHRU);
set_immediate_dominator (CDI_DOMINATORS, bb, ifc_bbs[0]);
if (exit_bb != loop->latch)
{
/* Redirect non-exit edge to loop->latch. */
- for (e = bb->succ; e; e = e->succ_next)
- if (!(e->flags & EDGE_LOOP_EXIT))
- {
- redirect_edge_and_branch (e, loop->latch);
- set_immediate_dominator (CDI_DOMINATORS, loop->latch, bb);
- }
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (!loop_exit_edge_p (loop, e))
+ {
+ redirect_edge_and_branch (e, loop->latch);
+ set_immediate_dominator (CDI_DOMINATORS, loop->latch, bb);
+ }
+ }
}
continue;
}
+ if (bb == loop->latch && empty_block_p (bb))
+ continue;
+
/* It is time to remove this basic block. First remove edges. */
- while (bb->succ != NULL)
- ssa_remove_edge (bb->succ);
- while (bb->pred != NULL)
- ssa_remove_edge (bb->pred);
+ while (EDGE_COUNT (bb->preds) > 0)
+ remove_edge (EDGE_PRED (bb, 0));
+
+ /* This is loop latch and loop does not have exit then do not
+ delete this basic block. Just remove its PREDS and reconnect
+ loop->header and loop->latch blocks. */
+ if (bb == loop->latch && n_exits == 0)
+ {
+ make_edge (loop->header, loop->latch, EDGE_FALLTHRU);
+ set_immediate_dominator (CDI_DOMINATORS, loop->latch, loop->header);
+ continue;
+ }
+
+ while (EDGE_COUNT (bb->succs) > 0)
+ remove_edge (EDGE_SUCC (bb, 0));
/* Remove labels and make stmts member of loop->header. */
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
- bsi_remove (&bsi);
+ bsi_remove (&bsi, true);
else
{
set_bb_for_stmt (bsi_stmt (bsi), merge_target_bb);
delete_from_dominance_info (CDI_DOMINATORS, bb);
if (dom_computed[CDI_POST_DOMINATORS])
delete_from_dominance_info (CDI_POST_DOMINATORS, bb);
-
+
/* Remove basic block. */
+ if (bb == loop->latch)
+ loop->latch = merge_target_bb;
remove_bb_from_loops (bb);
expunge_block (bb);
}
+
+ /* Now if possible, merge loop header and block with exit edge.
+ This reduces number of basic blocks to 2. Auto vectorizer addresses
+ loops with two nodes only. FIXME: Use cleanup_tree_cfg(). */
+ if (exit_bb
+ && loop->header != loop->latch
+ && exit_bb != loop->latch
+ && empty_block_p (loop->latch))
+ {
+ if (can_merge_blocks_p (loop->header, exit_bb))
+ {
+ remove_bb_from_loops (exit_bb);
+ merge_blocks (loop->header, exit_bb);
+ }
+ }
}
-/* Make new temp variable of type TYPE. Add MODIFY_EXPR to assign EXP
+/* Make new temp variable of type TYPE. Add MODIFY_EXPR to assign EXP
to the new variable. */
static tree
var = create_tmp_var (type, name);
add_referenced_tmp_var (var);
- /* Build new statement to assigne EXP to new variable. */
- stmt = build (MODIFY_EXPR, type, var, exp);
-
+ /* Build new statement to assign EXP to new variable. */
+ stmt = build2 (MODIFY_EXPR, type, var, exp);
+
/* Get SSA name for the new variable and set make new statement
- its definition statment. */
+ its definition statement. */
new_name = make_ssa_name (var, stmt);
TREE_OPERAND (stmt, 0) = new_name;
SSA_NAME_DEF_STMT (new_name) = stmt;
pred_blocks_visited_p (basic_block bb, bitmap *visited)
{
edge e;
- for (e = bb->pred; e; e = e->pred_next)
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->preds)
if (!bitmap_bit_p (*visited, e->src->index))
return false;
-
+
return true;
}
additional constraint. Select block in BFS block, if all
pred are already selected. */
-static basic_block *
+static basic_block *
get_loop_body_in_if_conv_order (const struct loop *loop)
{
basic_block *blocks, *blocks_in_bfs_order;
unsigned int index = 0;
unsigned int visited_count = 0;
- if (!loop->num_nodes)
- abort ();
-
- if (loop->latch == EXIT_BLOCK_PTR)
- abort ();
+ gcc_assert (loop->num_nodes);
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
- blocks = xcalloc (loop->num_nodes, sizeof (basic_block));
- visited = BITMAP_XMALLOC ();
+ blocks = XCNEWVEC (basic_block, loop->num_nodes);
+ visited = BITMAP_ALLOC (NULL);
blocks_in_bfs_order = get_loop_body_in_bfs_order (loop);
while (index < loop->num_nodes)
{
bb = blocks_in_bfs_order [index];
-
+
if (bb->flags & BB_IRREDUCIBLE_LOOP)
{
free (blocks_in_bfs_order);
}
}
free (blocks_in_bfs_order);
- BITMAP_XFREE (visited);
+ BITMAP_FREE (visited);
return blocks;
}
-/* Return true if one of the basic block BB edge is loop exit. */
+/* Return true if one of the basic block BB edge is exit of LOOP. */
static bool
-bb_with_exit_edge_p (basic_block bb)
+bb_with_exit_edge_p (struct loop *loop, basic_block bb)
{
edge e;
+ edge_iterator ei;
bool exit_edge_found = false;
- for (e = bb->succ; e && !exit_edge_found ; e = e->succ_next)
- if (e->flags & EDGE_LOOP_EXIT)
- exit_edge_found = true;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (loop_exit_edge_p (loop, e))
+ {
+ exit_edge_found = true;
+ break;
+ }
return exit_edge_found;
}
static bool
gate_tree_if_conversion (void)
{
- return true;
+ return flag_tree_vectorize != 0;
}
struct tree_opt_pass pass_if_conversion =
{
- "ifcvt", /* name */
- gate_tree_if_conversion, /* gate */
- main_tree_if_conversion, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- 0, /* tv_id */
- PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- TODO_dump_func, /* todo_flags_start */
- TODO_dump_func
- | TODO_verify_ssa
- | TODO_verify_stmts
- | TODO_verify_flow /* todo_flags_finish */
+ "ifcvt", /* name */
+ gate_tree_if_conversion, /* gate */
+ main_tree_if_conversion, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ 0, /* tv_id */
+ PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func | TODO_verify_loops | TODO_verify_stmts | TODO_verify_flow,
+ /* todo_flags_finish */
+ 0 /* letter */
};
-
OSDN Git Service
