diff options
Diffstat (limited to 'gcc/tree-ssa-dce.c')
| -rw-r--r-- | gcc/tree-ssa-dce.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c index f37430d..4f72d82 100644 --- a/gcc/tree-ssa-dce.c +++ b/gcc/tree-ssa-dce.c @@ -93,6 +93,10 @@ static sbitmap last_stmt_necessary; on the Ith edge. */ bitmap *control_dependence_map; +/* Vector indicating that a basic block has already had all the edges + processed that it is control dependent on. */ +sbitmap visited_control_parents; + /* Execute CODE for each edge (given number EDGE_NUMBER within the CODE) for which the block with index N is control dependent. */ #define EXECUTE_IF_CONTROL_DEPENDENT(N, EDGE_NUMBER, CODE) \ @@ -482,11 +486,6 @@ find_obviously_necessary_stmts (struct edge_list *el) NECESSARY (stmt) = 0; mark_stmt_if_obviously_necessary (stmt, el != NULL); } - - /* Mark this basic block as `not visited'. A block will be marked - visited when the edges that it is control dependent on have been - marked. */ - bb->flags &= ~BB_VISITED; } if (el) @@ -565,9 +564,10 @@ propagate_necessity (struct edge_list *el) containing `i' is control dependent on, but only if we haven't already done so. */ basic_block bb = bb_for_stmt (i); - if (! (bb->flags & BB_VISITED)) + if (bb != ENTRY_BLOCK_PTR + && ! TEST_BIT (visited_control_parents, bb->index)) { - bb->flags |= BB_VISITED; + SET_BIT (visited_control_parents, bb->index); mark_control_dependent_edges_necessary (bb, el); } } @@ -593,9 +593,10 @@ propagate_necessity (struct edge_list *el) for (k = 0; k < PHI_NUM_ARGS (i); k++) { basic_block arg_bb = PHI_ARG_EDGE (i, k)->src; - if (! (arg_bb->flags & BB_VISITED)) + if (arg_bb != ENTRY_BLOCK_PTR + && ! TEST_BIT (visited_control_parents, arg_bb->index)) { - arg_bb->flags |= BB_VISITED; + SET_BIT (visited_control_parents, arg_bb->index); mark_control_dependent_edges_necessary (arg_bb, el); } } @@ -903,6 +904,7 @@ tree_dce_done (bool aggressive) BITMAP_XFREE (control_dependence_map[i]); free (control_dependence_map); + sbitmap_free (visited_control_parents); sbitmap_free (last_stmt_necessary); } @@ -939,6 +941,9 @@ perform_tree_ssa_dce (bool aggressive) find_all_control_dependences (el); timevar_pop (TV_CONTROL_DEPENDENCES); + visited_control_parents = sbitmap_alloc (last_basic_block); + sbitmap_zero (visited_control_parents); + mark_dfs_back_edges (); } |