/* If-conversion support.
- Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+ Free Software Foundation, Inc.
This file is part of GCC.
#define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
#endif
-#define NULL_EDGE ((edge) NULL)
#define NULL_BLOCK ((basic_block) NULL)
/* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
/* Forward references. */
static int count_bb_insns (basic_block);
-static int total_bb_rtx_cost (basic_block);
+static bool cheap_bb_rtx_cost_p (basic_block, int);
static rtx first_active_insn (basic_block);
static rtx last_active_insn (basic_block, int);
static basic_block block_fallthru (basic_block);
basic_block, int);
static void noce_emit_move_insn (rtx, rtx);
static rtx block_has_only_trap (basic_block);
-static void mark_loop_exit_edges (void);
\f
-/* Sets EDGE_LOOP_EXIT flag for all loop exits. */
-static void
-mark_loop_exit_edges (void)
-{
- struct loops loops;
- basic_block bb;
- edge e;
-
- flow_loops_find (&loops, LOOP_TREE);
- free_dominance_info (CDI_DOMINATORS);
-
- if (loops.num > 1)
- {
- FOR_EACH_BB (bb)
- {
- edge_iterator ei;
- FOR_EACH_EDGE (e, ei, bb->succs)
- {
- if (find_common_loop (bb->loop_father, e->dest->loop_father)
- != bb->loop_father)
- e->flags |= EDGE_LOOP_EXIT;
- else
- e->flags &= ~EDGE_LOOP_EXIT;
- }
- }
- }
-
- flow_loops_free (&loops);
-}
-
/* Count the number of non-jump active insns in BB. */
static int
return count;
}
-/* Count the total insn_rtx_cost of non-jump active insns in BB.
- This function returns -1, if the cost of any instruction could
- not be estimated. */
+/* Determine whether the total insn_rtx_cost on non-jump insns in
+ basic block BB is less than MAX_COST. This function returns
+ false if the cost of any instruction could not be estimated. */
-static int
-total_bb_rtx_cost (basic_block bb)
+static bool
+cheap_bb_rtx_cost_p (basic_block bb, int max_cost)
{
int count = 0;
rtx insn = BB_HEAD (bb);
{
int cost = insn_rtx_cost (PATTERN (insn));
if (cost == 0)
- return -1;
+ return false;
+
+ /* If this instruction is the load or set of a "stack" register,
+ such as a floating point register on x87, then the cost of
+ speculatively executing this instruction needs to include
+ the additional cost of popping this register off of the
+ register stack. */
+#ifdef STACK_REGS
+ {
+ rtx set = single_set (insn);
+ if (set && STACK_REG_P (SET_DEST (set)))
+ cost += COSTS_N_INSNS (1);
+ }
+#endif
+
count += cost;
+ if (count >= max_cost)
+ return false;
}
else if (CALL_P (insn))
- return -1;
+ return false;
if (insn == BB_END (bb))
break;
insn = NEXT_INSN (insn);
}
- return count;
+ return true;
}
/* Return the first non-jump active insn in the basic block. */
if (NOTE_P (insn))
goto insn_done;
- if (!NONJUMP_INSN_P (insn) && !CALL_P (insn))
- abort ();
+ gcc_assert(NONJUMP_INSN_P (insn) || CALL_P (insn));
/* Remove USE insns that get in the way. */
if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
static void
noce_emit_move_insn (rtx x, rtx y)
{
- enum machine_mode outmode, inmode;
+ enum machine_mode outmode;
rtx outer, inner;
int bitpos;
outer = XEXP (x, 0);
inner = XEXP (outer, 0);
outmode = GET_MODE (outer);
- inmode = GET_MODE (inner);
bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y);
}
rtx a = if_info->a;
rtx b = if_info->b;
rtx x = if_info->x;
+ rtx orig_a, orig_b;
rtx insn_a, insn_b;
rtx tmp, target;
int is_mem = 0;
start_sequence ();
+ orig_a = a;
+ orig_b = b;
+
/* If either operand is complex, load it into a register first.
The best way to do this is to copy the original insn. In this
way we preserve any clobbers etc that the insn may have had.
}
if (! general_operand (b, GET_MODE (b)))
{
- rtx set;
+ rtx set, last;
if (no_new_pseudos)
goto end_seq_and_fail;
if (is_mem)
{
tmp = gen_reg_rtx (GET_MODE (b));
- tmp = emit_insn (gen_rtx_SET (VOIDmode,
- tmp,
- b));
+ tmp = gen_rtx_SET (VOIDmode, tmp, b);
}
else if (! insn_b)
goto end_seq_and_fail;
tmp = copy_rtx (insn_b);
set = single_set (tmp);
SET_DEST (set) = b;
- tmp = emit_insn (PATTERN (tmp));
+ tmp = PATTERN (tmp);
+ }
+
+ /* If insn to set up A clobbers any registers B depends on, try to
+ swap insn that sets up A with the one that sets up B. If even
+ that doesn't help, punt. */
+ last = get_last_insn ();
+ if (last && modified_in_p (orig_b, last))
+ {
+ tmp = emit_insn_before (tmp, get_insns ());
+ if (modified_in_p (orig_a, tmp))
+ goto end_seq_and_fail;
}
+ else
+ tmp = emit_insn (tmp);
+
if (recog_memoized (tmp) < 0)
goto end_seq_and_fail;
}
/* The outgoing edge for the current COMBO block should already
be correct. Verify this. */
if (EDGE_COUNT (combo_bb->succs) == 0)
- {
- if (find_reg_note (last, REG_NORETURN, NULL))
- ;
- else if (NONJUMP_INSN_P (last)
- && GET_CODE (PATTERN (last)) == TRAP_IF
- && TRAP_CONDITION (PATTERN (last)) == const_true_rtx)
- ;
- else
- abort ();
- }
+ gcc_assert (find_reg_note (last, REG_NORETURN, NULL)
+ || (NONJUMP_INSN_P (last)
+ && GET_CODE (PATTERN (last)) == TRAP_IF
+ && (TRAP_CONDITION (PATTERN (last))
+ == const_true_rtx)));
+ else
/* There should still be something at the end of the THEN or ELSE
blocks taking us to our final destination. */
- else if (JUMP_P (last))
- ;
- else if (EDGE_SUCC (combo_bb, 0)->dest == EXIT_BLOCK_PTR
- && CALL_P (last)
- && SIBLING_CALL_P (last))
- ;
- else if ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
- && can_throw_internal (last))
- ;
- else
- abort ();
+ gcc_assert (JUMP_P (last)
+ || (EDGE_SUCC (combo_bb, 0)->dest == EXIT_BLOCK_PTR
+ && CALL_P (last)
+ && SIBLING_CALL_P (last))
+ || ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
+ && can_throw_internal (last)));
}
/* The JOIN block may have had quite a number of other predecessors too.
have only one remaining edge from our if-then-else diamond. If there
is more than one remaining edge, it must come from elsewhere. There
may be zero incoming edges if the THEN block didn't actually join
- back up (as with a call to abort). */
+ back up (as with a call to a non-return function). */
else if (EDGE_COUNT (join_bb->preds) < 2
&& join_bb != EXIT_BLOCK_PTR)
{
/* The outgoing edge for the current COMBO block should already
be correct. Verify this. */
- if (EDGE_COUNT (combo_bb->succs) > 1
- || EDGE_SUCC (combo_bb, 0)->dest != join_bb)
- abort ();
+ gcc_assert (single_succ_p (combo_bb)
+ && single_succ (combo_bb) == join_bb);
/* Remove the jump and cruft from the end of the COMBO block. */
if (join_bb != EXIT_BLOCK_PTR)
- tidy_fallthru_edge (EDGE_SUCC (combo_bb, 0));
+ tidy_fallthru_edge (single_succ_edge (combo_bb));
}
num_updated_if_blocks++;
were && tests (which jump to the else block) or || tests (which jump to
the then block). */
if (HAVE_conditional_execution && reload_completed
- && EDGE_COUNT (test_bb->preds) == 1
- && EDGE_PRED (test_bb, 0)->flags == EDGE_FALLTHRU)
+ && single_pred_p (test_bb)
+ && single_pred_edge (test_bb)->flags == EDGE_FALLTHRU)
{
- basic_block bb = EDGE_PRED (test_bb, 0)->src;
+ basic_block bb = single_pred (test_bb);
basic_block target_bb;
int max_insns = MAX_CONDITIONAL_EXECUTE;
int n_insns;
total_insns += n_insns;
blocks++;
- if (EDGE_COUNT (bb->preds) != 1)
+ if (!single_pred_p (bb))
break;
- bb = EDGE_PRED (bb, 0)->src;
+ bb = single_pred (bb);
n_insns = block_jumps_and_fallthru_p (bb, target_bb);
}
while (n_insns >= 0 && (total_insns + n_insns) <= max_insns);
/* The THEN block of an IF-THEN combo must have zero or one successors. */
if (EDGE_COUNT (then_bb->succs) > 0
- && (EDGE_COUNT (then_bb->succs) > 1
- || (EDGE_SUCC (then_bb, 0)->flags & EDGE_COMPLEX)
+ && (!single_succ_p (then_bb)
+ || (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
|| (flow2_completed && tablejump_p (BB_END (then_bb), NULL, NULL))))
return FALSE;
code processing. ??? we should fix this in the future. */
if (EDGE_COUNT (then_bb->succs) == 0)
{
- if (EDGE_COUNT (else_bb->preds) == 1)
+ if (single_pred_p (else_bb))
{
rtx last_insn = BB_END (then_bb);
/* If the THEN block's successor is the other edge out of the TEST block,
then we have an IF-THEN combo without an ELSE. */
- else if (EDGE_SUCC (then_bb, 0)->dest == else_bb)
+ else if (single_succ (then_bb) == else_bb)
{
join_bb = else_bb;
else_bb = NULL_BLOCK;
/* If the THEN and ELSE block meet in a subsequent block, and the ELSE
has exactly one predecessor and one successor, and the outgoing edge
is not complex, then we have an IF-THEN-ELSE combo. */
- else if (EDGE_COUNT (else_bb->succs) == 1
- && EDGE_SUCC (then_bb, 0)->dest == EDGE_SUCC (else_bb, 0)->dest
- && EDGE_COUNT (else_bb->preds) == 1
- && ! (EDGE_SUCC (else_bb, 0)->flags & EDGE_COMPLEX)
+ else if (single_succ_p (else_bb)
+ && single_succ (then_bb) == single_succ (else_bb)
+ && single_pred_p (else_bb)
+ && ! (single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
&& ! (flow2_completed && tablejump_p (BB_END (else_bb), NULL, NULL)))
- join_bb = EDGE_SUCC (else_bb, 0)->dest;
+ join_bb = single_succ (else_bb);
/* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
else
we checked the FALLTHRU flag, those are already adjacent to the last IF
block. */
/* ??? As an enhancement, move the ELSE block. Have to deal with
- BLOCK notes, if by no other means than aborting the merge if they
+ BLOCK notes, if by no other means than backing out the merge if they
exist. Sticky enough I don't want to think about it now. */
next = then_bb;
if (else_bb && (next = next->next_bb) != else_bb)
{
basic_block then_bb = then_edge->dest;
basic_block else_bb = else_edge->dest, new_bb;
- int then_bb_index, bb_cost;
+ int then_bb_index;
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
partition boundaries). See the comments at the top of
bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
- if (flag_reorder_blocks_and_partition
- && ((BB_END (then_bb)
- && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
- || (BB_END (else_bb)
- && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
- NULL_RTX))))
+ if ((BB_END (then_bb)
+ && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (test_bb)
+ && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (else_bb)
+ && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
+ NULL_RTX)))
return FALSE;
/* THEN has one successor. */
- if (EDGE_COUNT (then_bb->succs) != 1)
+ if (!single_succ_p (then_bb))
return FALSE;
/* THEN does not fall through, but is not strange either. */
- if (EDGE_SUCC (then_bb, 0)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
+ if (single_succ_edge (then_bb)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
return FALSE;
/* THEN has one predecessor. */
- if (EDGE_COUNT (then_bb->preds) != 1)
+ if (!single_pred_p (then_bb))
return FALSE;
/* THEN must do something. */
test_bb->index, then_bb->index);
/* THEN is small. */
- bb_cost = total_bb_rtx_cost (then_bb);
- if (bb_cost < 0 || bb_cost >= COSTS_N_INSNS (BRANCH_COST))
+ if (! cheap_bb_rtx_cost_p (then_bb, COSTS_N_INSNS (BRANCH_COST)))
return FALSE;
/* Registers set are dead, or are predicable. */
if (! dead_or_predicable (test_bb, then_bb, else_bb,
- EDGE_SUCC (then_bb, 0)->dest, 1))
+ single_succ (then_bb), 1))
return FALSE;
/* Conversion went ok, including moving the insns and fixing up the
else_bb->global_live_at_start,
then_bb->global_live_at_end);
- new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb), else_bb);
+
+ /* We can avoid creating a new basic block if then_bb is immediately
+ followed by else_bb, i.e. deleting then_bb allows test_bb to fall
+ thru to else_bb. */
+
+ if (then_bb->next_bb == else_bb
+ && then_bb->prev_bb == test_bb
+ && else_bb != EXIT_BLOCK_PTR)
+ {
+ redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
+ new_bb = 0;
+ }
+ else
+ new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
+ else_bb);
+
then_bb_index = then_bb->index;
delete_basic_block (then_bb);
basic_block then_bb = then_edge->dest;
basic_block else_bb = else_edge->dest;
edge else_succ;
- int bb_cost;
rtx note;
/* If we are partitioning hot/cold basic blocks, we don't want to
partition boundaries). See the comments at the top of
bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
- if (flag_reorder_blocks_and_partition
- && ((BB_END (then_bb)
- && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
- || (BB_END (else_bb)
- && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
- NULL_RTX))))
+ if ((BB_END (then_bb)
+ && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (test_bb)
+ && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
+ || (BB_END (else_bb)
+ && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
+ NULL_RTX)))
return FALSE;
/* ELSE has one successor. */
- if (EDGE_COUNT (else_bb->succs) != 1)
+ if (!single_succ_p (else_bb))
return FALSE;
else
- else_succ = EDGE_SUCC (else_bb, 0);
+ else_succ = single_succ_edge (else_bb);
/* ELSE outgoing edge is not complex. */
if (else_succ->flags & EDGE_COMPLEX)
return FALSE;
/* ELSE has one predecessor. */
- if (EDGE_COUNT (else_bb->preds) != 1)
+ if (!single_pred_p (else_bb))
return FALSE;
/* THEN is not EXIT. */
test_bb->index, else_bb->index);
/* ELSE is small. */
- bb_cost = total_bb_rtx_cost (else_bb);
- if (bb_cost < 0 || bb_cost >= COSTS_N_INSNS (BRANCH_COST))
+ if (! cheap_bb_rtx_cost_p (else_bb, COSTS_N_INSNS (BRANCH_COST)))
return FALSE;
/* Registers set are dead, or are predicable. */
that any registers modified are dead at the branch site. */
rtx insn, cond, prev;
- regset_head merge_set_head, tmp_head, test_live_head, test_set_head;
regset merge_set, tmp, test_live, test_set;
struct propagate_block_info *pbi;
unsigned i, fail = 0;
TEST_SET = set of registers set between EARLIEST and the
end of the block. */
- tmp = INITIALIZE_REG_SET (tmp_head);
- merge_set = INITIALIZE_REG_SET (merge_set_head);
- test_live = INITIALIZE_REG_SET (test_live_head);
- test_set = INITIALIZE_REG_SET (test_set_head);
+ tmp = ALLOC_REG_SET (®_obstack);
+ merge_set = ALLOC_REG_SET (®_obstack);
+ test_live = ALLOC_REG_SET (®_obstack);
+ test_set = ALLOC_REG_SET (®_obstack);
/* ??? bb->local_set is only valid during calculate_global_regs_live,
so we must recompute usage for MERGE_BB. Not so bad, I suppose,
if (other_bb != new_dest)
{
- if (old_dest)
- LABEL_NUSES (old_dest) -= 1;
- if (new_label)
- LABEL_NUSES (new_label) += 1;
- JUMP_LABEL (jump) = new_label;
- if (reversep)
- invert_br_probabilities (jump);
+ redirect_jump_2 (jump, old_dest, new_label, -1, reversep);
redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
if (reversep)
if ((! targetm.cannot_modify_jumps_p ())
&& (!flag_reorder_blocks_and_partition || !no_new_pseudos
|| !targetm.have_named_sections))
- mark_loop_exit_edges ();
+ {
+ struct loops loops;
+
+ flow_loops_find (&loops);
+ mark_loop_exit_edges (&loops);
+ flow_loops_free (&loops);
+ free_dominance_info (CDI_DOMINATORS);
+ }
/* Compute postdominators if we think we'll use them. */
if (HAVE_conditional_execution || life_data_ok)
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