/* If-conversion support.
- Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010,
+ 2011
Free Software Foundation, Inc.
This file is part of GCC.
static int cond_exec_find_if_block (ce_if_block_t *);
static int find_if_case_1 (basic_block, edge, edge);
static int find_if_case_2 (basic_block, edge, edge);
-static int find_memory (rtx *, void *);
static int dead_or_predicable (basic_block, basic_block, basic_block,
basic_block, int);
static void noce_emit_move_insn (rtx, rtx);
for (insn = start; ; insn = NEXT_INSN (insn))
{
+ /* dwarf2out can't cope with conditional prologues. */
+ if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_PROLOGUE_END)
+ return FALSE;
+
if (NOTE_P (insn) || DEBUG_INSN_P (insn))
goto insn_done;
/* Look for matching sequences at the head and tail of the two blocks,
and limit the range of insns to be converted if possible. */
n_matching = flow_find_cross_jump (then_bb, else_bb,
- &then_first_tail, &else_first_tail);
+ &then_first_tail, &else_first_tail,
+ NULL);
if (then_first_tail == BB_HEAD (then_bb))
then_start = then_end = NULL_RTX;
if (else_first_tail == BB_HEAD (else_bb))
return TRUE;
}
-/* A subroutine of dead_or_predicable called through for_each_rtx.
- Return 1 if a memory is found. */
-
-static int
-find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
-{
- return MEM_P (*px);
-}
-
/* Used by the code above to perform the actual rtl transformations.
Return TRUE if successful.
basic_block other_bb, basic_block new_dest, int reversep)
{
rtx head, end, jump, earliest = NULL_RTX, old_dest, new_label = NULL_RTX;
- bitmap merge_set = NULL, merge_set_noclobber = NULL;
+ bitmap merge_set = NULL;
/* Number of pending changes. */
int n_validated_changes = 0;
}
#endif
+ /* If we allocated new pseudos (e.g. in the conditional move
+ expander called from noce_emit_cmove), we must resize the
+ array first. */
+ if (max_regno < max_reg_num ())
+ max_regno = max_reg_num ();
+
/* Try the NCE path if the CE path did not result in any changes. */
if (n_validated_changes == 0)
{
+ rtx cond, insn;
+ regset live;
+ bool success;
+
/* In the non-conditional execution case, we have to verify that there
are no trapping operations, no calls, no references to memory, and
that any registers modified are dead at the branch site. */
- rtx insn, cond, prev;
- bitmap test_live, test_set;
- bool intersect = false;
-
- /* Check for no calls or trapping operations. */
- for (insn = head; ; insn = NEXT_INSN (insn))
- {
- if (CALL_P (insn))
- return FALSE;
- if (NONDEBUG_INSN_P (insn))
- {
- if (may_trap_p (PATTERN (insn)))
- return FALSE;
-
- /* ??? Even non-trapping memories such as stack frame
- references must be avoided. For stores, we collect
- no lifetime info; for reads, we'd have to assert
- true_dependence false against every store in the
- TEST range. */
- if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
- return FALSE;
- }
- if (insn == end)
- break;
- }
-
- if (! any_condjump_p (jump))
+ if (!any_condjump_p (jump))
return FALSE;
/* Find the extent of the conditional. */
cond = noce_get_condition (jump, &earliest, false);
- if (! cond)
+ if (!cond)
return FALSE;
- /* Collect:
- MERGE_SET = set of registers set in MERGE_BB
- MERGE_SET_NOCLOBBER = like MERGE_SET, but only includes registers
- that are really set, not just clobbered.
- TEST_LIVE = set of registers live at EARLIEST
- TEST_SET = set of registers set between EARLIEST and the
- end of the block. */
+ live = BITMAP_ALLOC (®_obstack);
+ simulate_backwards_to_point (merge_bb, live, end);
+ success = can_move_insns_across (head, end, earliest, jump,
+ merge_bb, live,
+ df_get_live_in (other_bb), NULL);
+ BITMAP_FREE (live);
+ if (!success)
+ return FALSE;
+ /* Collect the set of registers set in MERGE_BB. */
merge_set = BITMAP_ALLOC (®_obstack);
- merge_set_noclobber = BITMAP_ALLOC (®_obstack);
-
- /* If we allocated new pseudos (e.g. in the conditional move
- expander called from noce_emit_cmove), we must resize the
- array first. */
- if (max_regno < max_reg_num ())
- max_regno = max_reg_num ();
FOR_BB_INSNS (merge_bb, insn)
- {
- if (NONDEBUG_INSN_P (insn))
- {
- df_simulate_find_defs (insn, merge_set);
- df_simulate_find_noclobber_defs (insn, merge_set_noclobber);
- }
- }
-
- /* For small register class machines, don't lengthen lifetimes of
- hard registers before reload. */
- if (! reload_completed
- && targetm.small_register_classes_for_mode_p (VOIDmode))
- {
- unsigned i;
- bitmap_iterator bi;
-
- EXECUTE_IF_SET_IN_BITMAP (merge_set_noclobber, 0, i, bi)
- {
- if (i < FIRST_PSEUDO_REGISTER
- && ! fixed_regs[i]
- && ! global_regs[i])
- goto fail;
- }
- }
-
- /* For TEST, we're interested in a range of insns, not a whole block.
- Moreover, we're interested in the insns live from OTHER_BB. */
- test_live = BITMAP_ALLOC (®_obstack);
- test_set = BITMAP_ALLOC (®_obstack);
-
- /* The loop below takes the set of live registers
- after JUMP, and calculates the live set before EARLIEST. */
- bitmap_copy (test_live, df_get_live_in (other_bb));
- df_simulate_initialize_backwards (test_bb, test_live);
- for (insn = jump; ; insn = prev)
- {
- if (INSN_P (insn))
- {
- df_simulate_find_defs (insn, test_set);
- df_simulate_one_insn_backwards (test_bb, insn, test_live);
- }
- prev = PREV_INSN (insn);
- if (insn == earliest)
- break;
- }
-
- /* We can perform the transformation if
- MERGE_SET_NOCLOBBER & TEST_SET
- and
- MERGE_SET & TEST_LIVE
- and
- TEST_SET & DF_LIVE_IN (merge_bb)
- are empty. */
-
- if (bitmap_intersect_p (merge_set_noclobber, test_set)
- || bitmap_intersect_p (merge_set, test_live)
- || bitmap_intersect_p (test_set, df_get_live_in (merge_bb)))
- intersect = true;
-
- BITMAP_FREE (test_live);
- BITMAP_FREE (test_set);
-
- if (intersect)
- goto fail;
+ if (NONDEBUG_INSN_P (insn))
+ df_simulate_find_defs (insn, merge_set);
}
no_body:
remove_reg_equal_equiv_notes_for_regno (i);
BITMAP_FREE (merge_set);
- BITMAP_FREE (merge_set_noclobber);
}
reorder_insns (head, end, PREV_INSN (earliest));
cancel:
cancel_changes (0);
- fail:
+
if (merge_set)
- {
- BITMAP_FREE (merge_set);
- BITMAP_FREE (merge_set_noclobber);
- }
+ BITMAP_FREE (merge_set);
+
return FALSE;
}
\f
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