Fix spurious valgrind errors in irred loop verification
Commit Message
The sbitmap bitmap_{set,clear}_bit changes trigger spurious
uninit value use reportings from valgrind since we now
read the old value before setting/clearing a bit so
verify_loop_structures optimization to not clear the sbitmap is reported.
Fixed by using a temporary BB flag which should also be more
efficient in terms of cache re-use.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2021-11-08 Richard Biener <rguenther@suse.de>
* cfgloop.c (verify_loop_structure): Use a temporary BB flag
instead of an sbitmap to cache irreducible state.
---
gcc/cfgloop.c | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)
@@ -1567,19 +1567,17 @@ verify_loop_structure (void)
/* Check irreducible loops. */
if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
{
- auto_edge_flag saved_irr_mask (cfun);
- /* Record old info. */
- auto_sbitmap irreds (last_basic_block_for_fn (cfun));
+ auto_edge_flag saved_edge_irr (cfun);
+ auto_bb_flag saved_bb_irr (cfun);
+ /* Save old info. */
FOR_EACH_BB_FN (bb, cfun)
{
edge_iterator ei;
if (bb->flags & BB_IRREDUCIBLE_LOOP)
- bitmap_set_bit (irreds, bb->index);
- else
- bitmap_clear_bit (irreds, bb->index);
+ bb->flags |= saved_bb_irr;
FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags & EDGE_IRREDUCIBLE_LOOP)
- e->flags |= saved_irr_mask;
+ e->flags |= saved_edge_irr;
}
/* Recount it. */
@@ -1591,34 +1589,35 @@ verify_loop_structure (void)
edge_iterator ei;
if ((bb->flags & BB_IRREDUCIBLE_LOOP)
- && !bitmap_bit_p (irreds, bb->index))
+ && !(bb->flags & saved_bb_irr))
{
error ("basic block %d should be marked irreducible", bb->index);
err = 1;
}
else if (!(bb->flags & BB_IRREDUCIBLE_LOOP)
- && bitmap_bit_p (irreds, bb->index))
+ && (bb->flags & saved_bb_irr))
{
error ("basic block %d should not be marked irreducible", bb->index);
err = 1;
}
+ bb->flags &= ~saved_bb_irr;
FOR_EACH_EDGE (e, ei, bb->succs)
{
if ((e->flags & EDGE_IRREDUCIBLE_LOOP)
- && !(e->flags & saved_irr_mask))
+ && !(e->flags & saved_edge_irr))
{
error ("edge from %d to %d should be marked irreducible",
e->src->index, e->dest->index);
err = 1;
}
else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP)
- && (e->flags & saved_irr_mask))
+ && (e->flags & saved_edge_irr))
{
error ("edge from %d to %d should not be marked irreducible",
e->src->index, e->dest->index);
err = 1;
}
- e->flags &= ~saved_irr_mask;
+ e->flags &= ~saved_edge_irr;
}
}
}