/* If-conversion for vectorizer.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007 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.
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 propagate condition into destination basic blocks'
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-#include "errors.h"
#include "tree.h"
#include "c-common.h"
#include "flags.h"
#include "target.h"
/* local function prototypes */
-static void main_tree_if_conversion (void);
+static unsigned int main_tree_if_conversion (void);
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,
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_gimple_modify_stmt_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, edge,
+ 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_gimple_modify_stmt (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;
for vectorizer or not. If it is used for vectorizer, additional checks are
used. (Vectorization checks are not yet implemented). */
-bool
+static bool
tree_if_conversion (struct loop *loop, bool for_vectorizer)
{
basic_block bb;
block_stmt_iterator itr;
- tree cond;
unsigned int i;
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++)
{
+ tree cond;
+
bb = ifc_bbs [i];
/* Update condition using predicate list. */
/* 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
+ If T is a GIMPLE_MODIFY_STMT 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
case LABEL_EXPR:
break;
- case MODIFY_EXPR:
- /* 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
- 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;
+ case GIMPLE_MODIFY_STMT:
+ /* This GIMPLE_MODIFY_STMT 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 program. */
break;
case COND_EXPR:
break;
default:
- abort ();
- break;
+ gcc_unreachable ();
}
return 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 = TREE_OPERAND (stmt, 0);
- then_clause = TREE_OPERAND (stmt, 1);
- else_clause = TREE_OPERAND (stmt, 2);
+ c = COND_EXPR_COND (stmt);
- /* 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);
- }
+ extract_true_false_edges_from_block (bb_for_stmt (stmt),
+ &true_edge, &false_edge);
/* 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);
- }
+ /* If 'c' is true then TRUE_EDGE is taken. */
+ add_to_dst_predicate_list (loop, true_edge, 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, 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))
{
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.
+ GIMPLE_MODIFY_STMT is not if-convertible if,
- It is not movable.
- It could trap.
- LHS is not var decl.
- MODIFY_EXPR is part of block BB, which is inside loop LOOP.
+ GIMPLE_MODIFY_STMT is part of block BB, which is inside loop LOOP.
*/
static bool
-if_convertable_modify_expr_p (struct loop *loop, basic_block bb, tree m_expr)
+if_convertible_gimple_modify_stmt_p (struct loop *loop, basic_block bb,
+ tree m_expr)
{
+ tree lhs, rhs;
+
+ if (TREE_CODE (m_expr) != GIMPLE_MODIFY_STMT)
+ return false;
+
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)
+ lhs = GIMPLE_STMT_OPERAND (m_expr, 0);
+ rhs = GIMPLE_STMT_OPERAND (m_expr, 1);
+
+ /* Some of these constrains might be too conservative. */
+ if (stmt_ends_bb_p (m_expr) || stmt_ann (m_expr)->has_volatile_ops
+ || (TREE_CODE (lhs) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
+ || TREE_SIDE_EFFECTS (rhs))
{
if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "stmt is movable. Don't take risk\n");
+ fprintf (dump_file, "stmt not suitable for ifcvt\n");
return false;
}
/* See if it needs speculative loading or not. */
if (bb != loop->header
- && tree_could_trap_p (TREE_OPERAND (m_expr, 1)))
+ && tree_could_trap_p (GIMPLE_STMT_OPERAND (m_expr, 1)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "tree could trap...\n");
return false;
}
- if (TREE_CODE (TREE_OPERAND (m_expr, 1)) == CALL_EXPR)
+ if (TREE_CODE (GIMPLE_STMT_OPERAND (m_expr, 1)) == CALL_EXPR)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "CALL_EXPR \n");
return false;
}
- if (TREE_CODE (TREE_OPERAND (m_expr, 0)) != SSA_NAME
+ if (TREE_CODE (GIMPLE_STMT_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-convertable 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 GIMPLE_MODIFY_STMT
+ - 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:
+ case GIMPLE_MODIFY_STMT:
- if (!if_convertable_modify_expr_p (loop, bb, stmt))
+ if (!if_convertible_gimple_modify_stmt_p (loop, bb, stmt))
return false;
break;
- case GOTO_EXPR:
case COND_EXPR:
break;
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-convertable if,
+ 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.
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)
+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 adventurous and handle only normal edges. */
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags &
(EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_ABNORMAL | EDGE_IRREDUCIBLE_LOOP))
{
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
+ - 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)
return false;
}
- flow_loop_scan (loop, LOOP_ALL);
-
/* If only one block, no need for if-conversion. */
if (loop->num_nodes <= 2)
{
}
/* More than one loop exit is too much to handle. */
- if (loop->num_exits > 1)
+ if (!single_exit (loop))
{
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);
{
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))
+ phi = phi_nodes (bb);
+
+ /* Clear aux field of incoming edges to a bb with a phi node. */
+ if (phi)
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ e->aux = NULL;
+
+ /* Check statements. */
+ for (; 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
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, edge e,
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))
+ if (!flow_bb_inside_loop_p (loop, e->dest))
return NULL_TREE;
if (prev_cond == boolean_true_node || !prev_cond)
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);
+
+ /* Add the condition to aux field of the edge. In case edge
+ destination is a PHI node, this condition will be ANDed with
+ block predicate to construct complete condition. */
+ e->aux = cond;
+
/* 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);
+ new_cond = GIMPLE_STMT_OPERAND (tmp_stmt, 0);
}
- add_to_predicate_list (bb, new_cond);
+ add_to_predicate_list (e->dest, new_cond);
return new_cond;
}
-/* During if-conversion aux field from basic block is used to hold predicate
- list. Clean each basic block's predicate list for the given LOOP. */
+/* During if-conversion aux field from basic block structure is used to hold
+ predicate list. Clean each basic block's predicate list for the given LOOP.
+ Also clean aux field of successor edges, used to hold true and false
+ condition from conditional expression. */
static void
clean_predicate_lists (struct loop *loop)
{
+ basic_block *bb;
unsigned int i;
+ edge e;
+ edge_iterator ei;
+ bb = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
- ifc_bbs[i]->aux = NULL;
+ {
+ bb[i]->aux = NULL;
+ FOR_EACH_EDGE (e, ei, bb[i]->succs)
+ e->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;
- tree tmp_cond;
+ edge first_edge, second_edge;
+ tree tmp_cond, new_stmts;
+
+ gcc_assert (EDGE_COUNT (bb->preds) == 2);
+ first_edge = EDGE_PRED (bb, 0);
+ second_edge = EDGE_PRED (bb, 1);
+
+ /* Use condition based on following criteria:
+ 1)
+ S1: x = !c ? a : b;
- for (e = bb->pred; e; e = e->pred_next)
+ 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_edge->src)->aux;
+ if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR)
{
- if (p1 == NULL)
- p1 = e->src;
- else if (p2 == NULL)
- p2 = e->src;
- else
- /* More than two predecessors. This is not expected. */
- abort ();
+ edge tmp_edge;
+
+ tmp_edge = first_edge;
+ first_edge = second_edge;
+ second_edge = tmp_edge;
}
- /* Use condition that is not TRUTH_NOT_EXPR in conditional modify expr. */
- tmp_cond = p1->aux;
- if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR)
+ /* Check if FIRST_BB is loop header or not and make sure that
+ FIRST_BB does not dominate SECOND_BB. */
+ if (first_edge->src == loop->header
+ || dominated_by_p (CDI_DOMINATORS,
+ second_edge->src, first_edge->src))
{
- *cond = p2->aux;
- switch_args = true;
+ *cond = (second_edge->src)->aux;
+
+ /* If there is a condition on an incoming edge,
+ AND it with the incoming bb predicate. */
+ if (second_edge->aux)
+ *cond = build2 (TRUTH_AND_EXPR, boolean_type_node,
+ *cond, second_edge->aux);
+
+ if (TREE_CODE (*cond) == TRUTH_NOT_EXPR)
+ /* We can be smart here and choose inverted
+ condition without switching bbs. */
+ *cond = invert_truthvalue (*cond);
+ else
+ /* Select non loop header bb. */
+ first_edge = second_edge;
}
else
{
- *cond = p1->aux;
- switch_args = false;
+ /* FIRST_BB is not loop header */
+ *cond = (first_edge->src)->aux;
+
+ /* If there is a condition on an incoming edge,
+ AND it with the incoming bb predicate. */
+ if (first_edge->aux)
+ *cond = build2 (TRUTH_AND_EXPR, boolean_type_node,
+ *cond, first_edge->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. */
+ *cond = force_gimple_operand (*cond, &new_stmts, false, NULL_TREE);
+ if (new_stmts)
+ bsi_insert_before (bsi, new_stmts, BSI_SAME_STMT);
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);
- *cond = TREE_OPERAND (new_stmt, 0);
+ bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
+ *cond = GIMPLE_STMT_OPERAND (new_stmt, 0);
}
-#ifdef ENABLE_CHECKING
- if (*cond == NULL_TREE)
- abort ();
-#endif
+ gcc_assert (*cond);
- return switch_args;
+ return first_edge->src;
}
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,
- block_stmt_iterator *bsi)
+replace_phi_with_cond_gimple_modify_stmt (tree phi, tree cond,
+ basic_block true_bb,
+ block_stmt_iterator *bsi)
{
tree new_stmt;
basic_block bb;
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);
}
/* Build new RHS using selected condition and arguments. */
- rhs = build (COND_EXPR, TREE_TYPE (PHI_RESULT (phi)),
- unshare_expr (cond), unshare_expr (arg_0),
- unshare_expr (arg_1));
+ rhs = build3 (COND_EXPR, TREE_TYPE (PHI_RESULT (phi)),
+ unshare_expr (cond), unshare_expr (arg_0),
+ unshare_expr (arg_1));
/* Create new MODIFY expression using RHS. */
- new_stmt = build (MODIFY_EXPR, TREE_TYPE (PHI_RESULT (phi)),
- unshare_expr (PHI_RESULT (phi)), rhs);
+ new_stmt = build_gimple_modify_stmt (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))
{
{
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_gimple_modify_stmt (phi, cond, true_bb, &bsi);
release_phi_node (phi);
phi = next;
}
- bb_ann (bb)->phi_nodes = NULL;
+ set_phi_nodes (bb, NULL_TREE);
}
return;
}
/* Combine all basic block from the given LOOP into one or two super
- basic block. Replace PHI nodes with conditional modify expression. */
+ 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;
+ edge e;
+ edge_iterator ei;
/* Process phi nodes to prepare blocks for merge. */
process_phi_nodes (loop);
+ /* Merge basic blocks. First remove all the edges in the loop, except
+ for those from the exit block. */
exit_bb = NULL;
+ for (i = 0; i < orig_loop_num_nodes; i++)
+ {
+ bb = ifc_bbs[i];
+ if (bb_with_exit_edge_p (loop, bb))
+ {
+ exit_bb = bb;
+ break;
+ }
+ }
+ gcc_assert (exit_bb != loop->latch);
- /* Merge basic blocks */
- merge_target_bb = loop->header;
for (i = 1; i < orig_loop_num_nodes; i++)
{
- edge e;
- block_stmt_iterator bsi;
- tree_stmt_iterator last;
-
bb = ifc_bbs[i];
- if (bb == loop->latch)
- continue;
-
- if (!exit_bb && bb_with_exit_edge_p (bb))
- exit_bb = bb;
-
- if (bb == exit_bb)
+ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei));)
{
- edge new_e;
+ if (e->src == exit_bb)
+ ei_next (&ei);
+ else
+ remove_edge (e);
+ }
+ }
+ if (exit_bb != NULL)
+ {
+ if (exit_bb != loop->header)
+ {
/* Connect this node with loop header. */
- new_e = make_edge (ifc_bbs[0], bb, EDGE_FALLTHRU);
- set_immediate_dominator (CDI_DOMINATORS, bb, ifc_bbs[0]);
+ make_edge (loop->header, exit_bb, EDGE_FALLTHRU);
+ set_immediate_dominator (CDI_DOMINATORS, exit_bb, loop->header);
+ }
- 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);
- }
- }
- continue;
+ /* Redirect non-exit edges to loop->latch. */
+ FOR_EACH_EDGE (e, ei, exit_bb->succs)
+ {
+ if (!loop_exit_edge_p (loop, e))
+ redirect_edge_and_branch (e, loop->latch);
}
+ set_immediate_dominator (CDI_DOMINATORS, loop->latch, exit_bb);
+ }
+ else
+ {
+ /* If the loop does not have exit then reconnect header and latch. */
+ make_edge (loop->header, loop->latch, EDGE_FALLTHRU);
+ set_immediate_dominator (CDI_DOMINATORS, loop->latch, loop->header);
+ }
- /* 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);
+ merge_target_bb = loop->header;
+ for (i = 1; i < orig_loop_num_nodes; i++)
+ {
+ block_stmt_iterator bsi;
+ tree_stmt_iterator last;
+
+ bb = ifc_bbs[i];
+
+ if (bb == exit_bb || bb == loop->latch)
+ continue;
/* 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);
}
/* Update stmt list. */
- last = tsi_last (merge_target_bb->stmt_list);
- tsi_link_after (&last, bb->stmt_list, TSI_NEW_STMT);
- bb->stmt_list = NULL;
-
- /* Update dominator info. */
- if (dom_computed[CDI_DOMINATORS])
- delete_from_dominance_info (CDI_DOMINATORS, bb);
- if (dom_computed[CDI_POST_DOMINATORS])
- delete_from_dominance_info (CDI_POST_DOMINATORS, bb);
-
- /* Remove basic block. */
- remove_bb_from_loops (bb);
- expunge_block (bb);
+ last = tsi_last (bb_stmt_list (merge_target_bb));
+ tsi_link_after (&last, bb_stmt_list (bb), TSI_NEW_STMT);
+ set_bb_stmt_list (bb, NULL);
+
+ delete_basic_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
+ && exit_bb != loop->header
+ && can_merge_blocks_p (loop->header, 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 GIMPLE_MODIFY_STMT to assign EXP
to the new variable. */
static tree
/* Create new temporary variable. */
var = create_tmp_var (type, name);
- add_referenced_tmp_var (var);
+ add_referenced_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 = build_gimple_modify_stmt (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;
+ GIMPLE_STMT_OPERAND (stmt, 0) = new_name;
SSA_NAME_DEF_STMT (new_name) = stmt;
return 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;
unsigned int index = 0;
unsigned int visited_count = 0;
- if (!loop->num_nodes)
- abort ();
+ gcc_assert (loop->num_nodes);
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
- if (loop->latch == EXIT_BLOCK_PTR)
- abort ();
-
- 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);
}
}
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;
}
/* Tree if-conversion pass management. */
-static void
+static unsigned int
main_tree_if_conversion (void)
{
- unsigned i, loop_num;
+ loop_iterator li;
struct loop *loop;
- if (!current_loops)
- return;
+ if (number_of_loops () <= 1)
+ return 0;
- loop_num = current_loops->num;
- for (i = 0; i < loop_num; i++)
+ FOR_EACH_LOOP (li, loop, 0)
{
- loop = current_loops->parray[i];
- if (!loop)
- continue;
-
tree_if_conversion (loop, true);
}
-
+ return 0;
}
static bool
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 */
};
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