diff options
Diffstat (limited to 'gcc/tree-cfgcleanup.c')
| -rw-r--r-- | gcc/tree-cfgcleanup.c | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c index ab8a913..3fe0d3e 100644 --- a/gcc/tree-cfgcleanup.c +++ b/gcc/tree-cfgcleanup.c @@ -641,24 +641,25 @@ cleanup_tree_cfg_bb (basic_block bb) && remove_forwarder_block (bb)) return true; + /* If there is a merge opportunity with the predecessor + do nothing now but wait until we process the predecessor. + This happens when we visit BBs in a non-optimal order and + avoids quadratic behavior with adjusting stmts BB pointer. */ + if (single_pred_p (bb) + && can_merge_blocks_p (single_pred (bb), bb)) + /* But make sure we _do_ visit it. When we remove unreachable paths + ending in a backedge we fail to mark the destinations predecessors + as changed. */ + bitmap_set_bit (cfgcleanup_altered_bbs, single_pred (bb)->index); + /* Merging the blocks may create new opportunities for folding conditional branches (due to the elimination of single-valued PHI nodes). */ - if (single_succ_p (bb) - && can_merge_blocks_p (bb, single_succ (bb))) + else if (single_succ_p (bb) + && can_merge_blocks_p (bb, single_succ (bb))) { - /* If there is a merge opportunity with the predecessor - do nothing now but wait until we process the predecessor. - This happens when we visit BBs in a non-optimal order and - avoids quadratic behavior with adjusting stmts BB pointer. */ - if (single_pred_p (bb) - && can_merge_blocks_p (single_pred (bb), bb)) - ; - else - { - merge_blocks (bb, single_succ (bb)); - return true; - } + merge_blocks (bb, single_succ (bb)); + return true; } return false; |