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.
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-#include "errors.h"
#include "tree.h"
#include "c-common.h"
#include "flags.h"
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, bool);
+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, basic_block, tree, tree,
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. */
/* Return true, iff STMT is if-convertible.
Statement is if-convertible if,
- It is if-convertible MODIFY_EXPR
- - IT is LABEL_EXPR, GOTO_EXPR or COND_EXPR.
+ - IT is LABEL_EXPR or COND_EXPR.
STMT is inside block BB, which is inside loop LOOP. */
static bool
return false;
break;
- case GOTO_EXPR:
case COND_EXPR:
break;
BB is inside loop LOOP. */
static bool
-if_convertible_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. */
unsigned int i;
edge e;
edge_iterator ei;
- bool exit_bb_seen = false;
+ basic_block exit_bb = NULL;
/* Handle only inner most loop. */
if (!loop || loop->inner)
{
bb = ifc_bbs[i];
- if (!if_convertible_bb_p (loop, bb, exit_bb_seen))
+ if (!if_convertible_bb_p (loop, bb, exit_bb))
return false;
/* Check statements. */
return false;
if (bb_with_exit_edge_p (loop, bb))
- exit_bb_seen = true;
+ 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;
basic_block bb, tree *cond,
block_stmt_iterator *bsi)
{
- edge e;
- basic_block p1 = NULL;
- basic_block p2 = NULL;
- basic_block true_bb = NULL;
+ basic_block first_bb = NULL;
+ basic_block second_bb = NULL;
tree tmp_cond;
- edge_iterator ei;
- FOR_EACH_EDGE (e, ei, bb->preds)
- {
- if (p1 == NULL)
- p1 = e->src;
- else
- {
- gcc_assert (!p2);
- p2 = e->src;
- }
- }
+ 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. */
+
+ /* Select condition that is not TRUTH_NOT_EXPR. */
+ tmp_cond = first_bb->aux;
if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR)
{
- /* If p2 is loop->header than its aux field does not have useful
- info. Instead use !(cond) where cond is p1's aux field. */
- if (p2 == loop->header)
- *cond = invert_truthvalue (unshare_expr (p1->aux));
- else
- *cond = p2->aux;
- true_bb = p2;
+ 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. */
+ if (first_bb == loop->header)
{
- /* If p1 is loop->header than its aux field does not have useful
- info. Instead use !(cond) where cond is p2's aux field. */
- if (p1 == loop->header)
- *cond = invert_truthvalue (unshare_expr (p2->aux));
+ 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
- *cond = p1->aux;
- true_bb = p1;
+ {
+ /* Select non loop header condition. */
+ first_bb = second_bb;
+ *cond = first_bb->aux;
+ }
}
+ 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
gcc_assert (*cond);
- return true_bb;
+ return first_bb;
}
/* 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);
-
+ /* Insert using iterator. */
bsi_insert_after (bsi, new_stmt, BSI_SAME_STMT);
bsi_next (bsi);
release_phi_node (phi);
phi = next;
}
- bb_ann (bb)->phi_nodes = NULL;
+ bb->phi_nodes = NULL;
}
return;
}
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func | TODO_verify_loops, /* todo_flags_finish */
+ TODO_dump_func | TODO_verify_loops | TODO_verify_stmts | TODO_verify_flow,
+ /* todo_flags_finish */
0 /* letter */
};