static bool
nonpure_call_p (tree stmt)
{
tree call = get_call_expr_in (stmt);
if (!call)
return false;
return TREE_SIDE_EFFECTS (call) != 0;
}
static struct mem_ref_group *
gather_memory_references (struct loop *loop, bool *no_other_refs)
{
basic_block *body = get_loop_body_in_dom_order (loop);
basic_block bb;
unsigned i;
block_stmt_iterator bsi;
tree stmt, lhs, rhs, call;
struct mem_ref_group *refs = NULL;
*no_other_refs = true;
/* Scan the loop body in order, so that the former references precede the
later ones. */
for (i = 0; i < loop->num_nodes; i++)
{
bb = body[i];
if (bb->loop_father != loop)
continue;
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
stmt = bsi_stmt (bsi);
call = get_call_expr_in (stmt);
if (call && !(call_expr_flags (call) & ECF_CONST))
*no_other_refs = false;
if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
{
if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
*no_other_refs = false;
continue;
}
lhs = GIMPLE_STMT_OPERAND (stmt, 0);
rhs = GIMPLE_STMT_OPERAND (stmt, 1);
if (REFERENCE_CLASS_P (rhs))
*no_other_refs &= gather_memory_references_ref (loop, &refs,
rhs, false, stmt);
if (REFERENCE_CLASS_P (lhs))
*no_other_refs &= gather_memory_references_ref (loop, &refs,
lhs, true, stmt);
}
}
free (body);
return refs;
}
static bool
should_duplicate_loop_header_p (basic_block header, struct loop *loop,
int *limit)
{
block_stmt_iterator bsi;
tree last;
/* Do not copy one block more than once (we do not really want to do
loop peeling here). */
if (header->aux)
return false;
gcc_assert (EDGE_COUNT (header->succs) > 0);
if (EDGE_COUNT (header->succs) == 1)
return false;
if (flow_bb_inside_loop_p (loop, EDGE_SUCC (header, 0)->dest)
&& flow_bb_inside_loop_p (loop, EDGE_SUCC (header, 1)->dest))
return false;
/* If this is not the original loop header, we want it to have just
one predecessor in order to match the && pattern. */
if (header != loop->header && EDGE_COUNT (header->preds) >= 2)
return false;
last = last_stmt (header);
if (TREE_CODE (last) != COND_EXPR)
return false;
/* Approximately copy the conditions that used to be used in jump.c --
at most 20 insns and no calls. */
for (bsi = bsi_start (header); !bsi_end_p (bsi); bsi_next (&bsi))
{
last = bsi_stmt (bsi);
if (TREE_CODE (last) == LABEL_EXPR)
continue;
if (get_call_expr_in (last))
return false;
*limit -= estimate_num_insns (last);
if (*limit < 0)
return false;
}
return true;
}
enum move_pos
movement_possibility (tree stmt)
{
tree lhs, rhs;
if (flag_unswitch_loops
&& TREE_CODE (stmt) == COND_EXPR)
{
/* If we perform unswitching, force the operands of the invariant
condition to be moved out of the loop. */
return MOVE_POSSIBLE;
}
if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
return MOVE_IMPOSSIBLE;
if (stmt_ends_bb_p (stmt))
return MOVE_IMPOSSIBLE;
if (stmt_ann (stmt)->has_volatile_ops)
return MOVE_IMPOSSIBLE;
lhs = GIMPLE_STMT_OPERAND (stmt, 0);
if (TREE_CODE (lhs) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
return MOVE_IMPOSSIBLE;
rhs = GIMPLE_STMT_OPERAND (stmt, 1);
if (TREE_SIDE_EFFECTS (rhs)
|| tree_could_throw_p (rhs))
return MOVE_IMPOSSIBLE;
if (TREE_CODE (lhs) != SSA_NAME
|| tree_could_trap_p (rhs))
return MOVE_PRESERVE_EXECUTION;
if (get_call_expr_in (stmt))
{
/* While pure or const call is guaranteed to have no side effects, we
cannot move it arbitrarily. Consider code like
char *s = something ();
while (1)
{
if (s)
t = strlen (s);
else
t = 0;
}
Here the strlen call cannot be moved out of the loop, even though
s is invariant. In addition to possibly creating a call with
invalid arguments, moving out a function call that is not executed
may cause performance regressions in case the call is costly and
not executed at all. */
return MOVE_PRESERVE_EXECUTION;
}
return MOVE_POSSIBLE;
}
static basic_block
expand_gimple_basic_block (basic_block bb, FILE * dump_file)
{
block_stmt_iterator bsi = bsi_start (bb);
tree stmt = NULL;
rtx note, last;
edge e;
edge_iterator ei;
if (dump_file)
{
fprintf (dump_file,
"\n;; Generating RTL for tree basic block %d\n",
bb->index);
}
if (!bsi_end_p (bsi))
stmt = bsi_stmt (bsi);
if (stmt && TREE_CODE (stmt) == LABEL_EXPR)
{
last = get_last_insn ();
expand_expr_stmt (stmt);
/* Java emits line number notes in the top of labels.
??? Make this go away once line number notes are obsoleted. */
BB_HEAD (bb) = NEXT_INSN (last);
if (NOTE_P (BB_HEAD (bb)))
BB_HEAD (bb) = NEXT_INSN (BB_HEAD (bb));
bsi_next (&bsi);
note = emit_note_after (NOTE_INSN_BASIC_BLOCK, BB_HEAD (bb));
maybe_dump_rtl_for_tree_stmt (stmt, last);
}
else
note = BB_HEAD (bb) = emit_note (NOTE_INSN_BASIC_BLOCK);
NOTE_BASIC_BLOCK (note) = bb;
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
/* Clear EDGE_EXECUTABLE. This flag is never used in the backend. */
e->flags &= ~EDGE_EXECUTABLE;
/* At the moment not all abnormal edges match the RTL representation.
It is safe to remove them here as find_sub_basic_blocks will
rediscover them. In the future we should get this fixed properly. */
if (e->flags & EDGE_ABNORMAL)
remove_edge (e);
else
ei_next (&ei);
}
for (; !bsi_end_p (bsi); bsi_next (&bsi))
{
tree stmt = bsi_stmt (bsi);
basic_block new_bb;
if (!stmt)
continue;
/* Expand this statement, then evaluate the resulting RTL and
fixup the CFG accordingly. */
if (TREE_CODE (stmt) == COND_EXPR)
{
new_bb = expand_gimple_cond_expr (bb, stmt);
if (new_bb)
return new_bb;
}
else
{
tree call = get_call_expr_in (stmt);
if (call && CALL_EXPR_TAILCALL (call))
{
bool can_fallthru;
new_bb = expand_gimple_tailcall (bb, stmt, &can_fallthru);
if (new_bb)
{
if (can_fallthru)
bb = new_bb;
else
return new_bb;
}
}
else
{
last = get_last_insn ();
expand_expr_stmt (stmt);
maybe_dump_rtl_for_tree_stmt (stmt, last);
}
}
}
do_pending_stack_adjust ();
/* Find the block tail. The last insn in the block is the insn
before a barrier and/or table jump insn. */
last = get_last_insn ();
if (BARRIER_P (last))
last = PREV_INSN (last);
if (JUMP_TABLE_DATA_P (last))
last = PREV_INSN (PREV_INSN (last));
BB_END (bb) = last;
update_bb_for_insn (bb);
return bb;
}
