if (NOTE_INSN_BASIC_BLOCK_P (i1) && NOTE_INSN_BASIC_BLOCK_P (i2))
return true;
- p1 = PATTERN (i1);
+ p1 = PATTERN (i1);
p2 = PATTERN (i2);
if (GET_CODE (p1) != GET_CODE (p2))
while (true)
{
/* Ignore notes. */
- while (!INSN_P (i1) && i1 != BB_HEAD (bb1))
+ while (!NONDEBUG_INSN_P (i1) && i1 != BB_HEAD (bb1))
i1 = PREV_INSN (i1);
- while (!INSN_P (i2) && i2 != BB_HEAD (bb2))
+ while (!NONDEBUG_INSN_P (i2) && i2 != BB_HEAD (bb2))
i2 = PREV_INSN (i2);
if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2))
Two, it keeps line number notes as matched as may be. */
if (ninsns)
{
- while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1)))
+ while (last1 != BB_HEAD (bb1) && !NONDEBUG_INSN_P (PREV_INSN (last1)))
last1 = PREV_INSN (last1);
if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
last1 = PREV_INSN (last1);
- while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2)))
+ while (last2 != BB_HEAD (bb2) && !NONDEBUG_INSN_P (PREV_INSN (last2)))
last2 = PREV_INSN (last2);
if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
/* Skip possible basic block header. */
if (LABEL_P (newpos2))
newpos2 = NEXT_INSN (newpos2);
+ while (DEBUG_INSN_P (newpos2))
+ newpos2 = NEXT_INSN (newpos2);
if (NOTE_P (newpos2))
newpos2 = NEXT_INSN (newpos2);
+ while (DEBUG_INSN_P (newpos2))
+ newpos2 = NEXT_INSN (newpos2);
}
if (dump_file)
/* Skip possible basic block header. */
if (LABEL_P (newpos1))
newpos1 = NEXT_INSN (newpos1);
+
+ while (DEBUG_INSN_P (newpos1))
+ newpos1 = NEXT_INSN (newpos1);
+
if (NOTE_INSN_BASIC_BLOCK_P (newpos1))
newpos1 = NEXT_INSN (newpos1);
+ while (DEBUG_INSN_P (newpos1))
+ newpos1 = NEXT_INSN (newpos1);
+
redirect_from = split_block (src1, PREV_INSN (newpos1))->src;
to_remove = single_succ (redirect_from);
return changed;
}
+/* Return true if BB contains just bb note, or bb note followed
+ by only DEBUG_INSNs. */
+
+static bool
+trivially_empty_bb_p (basic_block bb)
+{
+ rtx insn = BB_END (bb);
+
+ while (1)
+ {
+ if (insn == BB_HEAD (bb))
+ return true;
+ if (!DEBUG_INSN_P (insn))
+ return false;
+ insn = PREV_INSN (insn);
+ }
+}
+
/* Do simple CFG optimizations - basic block merging, simplifying of jump
instructions etc. Return nonzero if changes were made. */
/* Delete trivially dead basic blocks. This is either
blocks with no predecessors, or empty blocks with no
- successors. Empty blocks may result from expanding
+ successors. However if the empty block with no
+ successors is the successor of the ENTRY_BLOCK, it is
+ kept. This ensures that the ENTRY_BLOCK will have a
+ successor which is a precondition for many RTL
+ passes. Empty blocks may result from expanding
__builtin_unreachable (). */
if (EDGE_COUNT (b->preds) == 0
- || (EDGE_COUNT (b->succs) == 0 && BB_HEAD (b) == BB_END (b)))
+ || (EDGE_COUNT (b->succs) == 0
+ && trivially_empty_bb_p (b)
+ && single_succ_edge (ENTRY_BLOCK_PTR)->dest != b))
{
c = b->prev_bb;
- if (dump_file)
- fprintf (dump_file, "Deleting block %i.\n",
- b->index);
-
delete_basic_block (b);
if (!(mode & CLEANUP_CFGLAYOUT))
changed = true;
delete_basic_block (b);
changed = true;
b = c;
+ continue;
}
if (single_succ_p (b)
delete_unreachable_blocks (void)
{
bool changed = false;
- basic_block b, next_bb;
+ basic_block b, prev_bb;
find_unreachable_blocks ();
- /* Delete all unreachable basic blocks. */
-
- for (b = ENTRY_BLOCK_PTR->next_bb; b != EXIT_BLOCK_PTR; b = next_bb)
+ /* When we're in GIMPLE mode and there may be debug insns, we should
+ delete blocks in reverse dominator order, so as to get a chance
+ to substitute all released DEFs into debug stmts. If we don't
+ have dominators information, walking blocks backward gets us a
+ better chance of retaining most debug information than
+ otherwise. */
+ if (MAY_HAVE_DEBUG_STMTS && current_ir_type () == IR_GIMPLE
+ && dom_info_available_p (CDI_DOMINATORS))
{
- next_bb = b->next_bb;
+ for (b = EXIT_BLOCK_PTR->prev_bb; b != ENTRY_BLOCK_PTR; b = prev_bb)
+ {
+ prev_bb = b->prev_bb;
- if (!(b->flags & BB_REACHABLE))
+ if (!(b->flags & BB_REACHABLE))
+ {
+ /* Speed up the removal of blocks that don't dominate
+ others. Walking backwards, this should be the common
+ case. */
+ if (!first_dom_son (CDI_DOMINATORS, b))
+ delete_basic_block (b);
+ else
+ {
+ VEC (basic_block, heap) *h
+ = get_all_dominated_blocks (CDI_DOMINATORS, b);
+
+ while (VEC_length (basic_block, h))
+ {
+ b = VEC_pop (basic_block, h);
+
+ prev_bb = b->prev_bb;
+
+ gcc_assert (!(b->flags & BB_REACHABLE));
+
+ delete_basic_block (b);
+ }
+
+ VEC_free (basic_block, heap, h);
+ }
+
+ changed = true;
+ }
+ }
+ }
+ else
+ {
+ for (b = EXIT_BLOCK_PTR->prev_bb; b != ENTRY_BLOCK_PTR; b = prev_bb)
{
- delete_basic_block (b);
- changed = true;
+ prev_bb = b->prev_bb;
+
+ if (!(b->flags & BB_REACHABLE))
+ {
+ delete_basic_block (b);
+ changed = true;
+ }
}
}
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