tree-ssa-dce.c (visited_control_parents): New sbitmap to replace BB_VISITED uses.
* tree-ssa-dce.c (visited_control_parents): New sbitmap to replace BB_VISITED uses. (find_obviously_necessary_stmts): Don't clear BB_VISITED. (propagate_necessity): Check the bitmap instead of BB_VISITED. (tree_dce_done): Free visited_control_parents. (perform_tree_ssa_dce): Allocate and clear it. * tree-ssa-pre.c (compute_antic_aux): Make non-recursive. (compute_antic): Iterate from here using a DFS. Use an sbitmap instead of BB_VISITED. From-SVN: r93654
This commit is contained in:
Steven Bosscher
Steven Bosscher
parent
103a83e0fa
commit
a28fee0388
3 changed files with 103 additions and 72 deletions
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@ -1,3 +1,15 @@
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2005-01-14 Steven Bosscher <stevenb@suse.de>
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* tree-ssa-dce.c (visited_control_parents): New sbitmap to
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replace BB_VISITED uses.
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(find_obviously_necessary_stmts): Don't clear BB_VISITED.
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(propagate_necessity): Check the bitmap instead of BB_VISITED.
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(tree_dce_done): Free visited_control_parents.
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(perform_tree_ssa_dce): Allocate and clear it.
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* tree-ssa-pre.c (compute_antic_aux): Make non-recursive.
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(compute_antic): Iterate from here using a DFS. Use an sbitmap
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instead of BB_VISITED.
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2005-01-14 Kazu Hirata <kazu@cs.umass.edu>
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* c-tree.h, coverage.h, langhooks-def.h, optabs.h, output.h,
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@ -93,6 +93,10 @@ static sbitmap last_stmt_necessary;
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on the Ith edge. */
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bitmap *control_dependence_map;
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/* Vector indicating that a basic block has already had all the edges
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processed that it is control dependent on. */
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sbitmap visited_control_parents;
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/* Execute CODE for each edge (given number EDGE_NUMBER within the CODE)
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for which the block with index N is control dependent. */
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#define EXECUTE_IF_CONTROL_DEPENDENT(N, EDGE_NUMBER, CODE) \
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@ -482,11 +486,6 @@ find_obviously_necessary_stmts (struct edge_list *el)
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NECESSARY (stmt) = 0;
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mark_stmt_if_obviously_necessary (stmt, el != NULL);
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}
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/* Mark this basic block as `not visited'. A block will be marked
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visited when the edges that it is control dependent on have been
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marked. */
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bb->flags &= ~BB_VISITED;
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}
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if (el)
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@ -565,9 +564,10 @@ propagate_necessity (struct edge_list *el)
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containing `i' is control dependent on, but only if we haven't
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already done so. */
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basic_block bb = bb_for_stmt (i);
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if (! (bb->flags & BB_VISITED))
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if (bb != ENTRY_BLOCK_PTR
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&& ! TEST_BIT (visited_control_parents, bb->index))
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{
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bb->flags |= BB_VISITED;
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SET_BIT (visited_control_parents, bb->index);
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mark_control_dependent_edges_necessary (bb, el);
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}
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}
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@ -593,9 +593,10 @@ propagate_necessity (struct edge_list *el)
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for (k = 0; k < PHI_NUM_ARGS (i); k++)
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{
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basic_block arg_bb = PHI_ARG_EDGE (i, k)->src;
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if (! (arg_bb->flags & BB_VISITED))
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if (arg_bb != ENTRY_BLOCK_PTR
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&& ! TEST_BIT (visited_control_parents, arg_bb->index))
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{
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arg_bb->flags |= BB_VISITED;
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SET_BIT (visited_control_parents, arg_bb->index);
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mark_control_dependent_edges_necessary (arg_bb, el);
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}
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}
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@ -903,6 +904,7 @@ tree_dce_done (bool aggressive)
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BITMAP_XFREE (control_dependence_map[i]);
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free (control_dependence_map);
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sbitmap_free (visited_control_parents);
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sbitmap_free (last_stmt_necessary);
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}
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@ -939,6 +941,9 @@ perform_tree_ssa_dce (bool aggressive)
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find_all_control_dependences (el);
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timevar_pop (TV_CONTROL_DEPENDENCES);
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visited_control_parents = sbitmap_alloc (last_basic_block);
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sbitmap_zero (visited_control_parents);
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mark_dfs_back_edges ();
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}
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@ -1113,52 +1113,32 @@ DEF_VEC_MALLOC_P (basic_block);
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ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
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Iterate until fixpointed.
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XXX: It would be nice to either write a set_clear, and use it for
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ANTIC_OUT, or to mark the antic_out set as deleted at the end
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of this routine, so that the pool can hand the same memory back out
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again for the next ANTIC_OUT. */
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static bool
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compute_antic_aux (basic_block block)
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compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
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{
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basic_block son;
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edge e;
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bool changed = false;
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value_set_t S, old, ANTIC_OUT;
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value_set_node_t node;
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ANTIC_OUT = S = NULL;
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/* If any edges from predecessors are abnormal, antic_in is empty, so
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punt. Remember that the block has an incoming abnormal edge by
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setting the BB_VISITED flag. */
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if (! (block->flags & BB_VISITED))
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{
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edge_iterator ei;
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FOR_EACH_EDGE (e, ei, block->preds)
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if (e->flags & EDGE_ABNORMAL)
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{
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block->flags |= BB_VISITED;
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break;
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}
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}
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if (block->flags & BB_VISITED)
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{
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S = NULL;
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goto visit_sons;
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}
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/* If any edges from predecessors are abnormal, antic_in is empty,
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so do nothing. */
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if (block_has_abnormal_pred_edge)
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goto maybe_dump_sets;
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old = set_new (false);
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set_copy (old, ANTIC_IN (block));
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ANTIC_OUT = set_new (true);
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/* If the block has no successors, ANTIC_OUT is empty, because it is
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the exit block. */
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if (EDGE_COUNT (block->succs) == 0);
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/* If the block has no successors, ANTIC_OUT is empty. */
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if (EDGE_COUNT (block->succs) == 0)
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;
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/* If we have one successor, we could have some phi nodes to
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translate through. */
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else if (EDGE_COUNT (block->succs) == 1)
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@ -1206,21 +1186,16 @@ compute_antic_aux (basic_block block)
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TMP_GEN (block),
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true);
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/* Then union in the ANTIC_OUT - TMP_GEN values, to get ANTIC_OUT U
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EXP_GEN - TMP_GEN */
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for (node = S->head;
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node;
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node = node->next)
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{
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value_insert_into_set (ANTIC_IN (block), node->expr);
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}
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clean (ANTIC_IN (block));
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/* Then union in the ANTIC_OUT - TMP_GEN values,
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to get ANTIC_OUT U EXP_GEN - TMP_GEN */
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for (node = S->head; node; node = node->next)
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value_insert_into_set (ANTIC_IN (block), node->expr);
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clean (ANTIC_IN (block));
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if (!set_equal (old, ANTIC_IN (block)))
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changed = true;
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visit_sons:
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maybe_dump_sets:
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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if (ANTIC_OUT)
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@ -1228,43 +1203,82 @@ compute_antic_aux (basic_block block)
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print_value_set (dump_file, ANTIC_IN (block), "ANTIC_IN", block->index);
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if (S)
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print_value_set (dump_file, S, "S", block->index);
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}
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for (son = first_dom_son (CDI_POST_DOMINATORS, block);
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son;
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son = next_dom_son (CDI_POST_DOMINATORS, son))
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{
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changed |= compute_antic_aux (son);
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}
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return changed;
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}
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/* Compute ANTIC sets. */
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/* Compute ANTIC sets. Iterates until fixpointed. */
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static void
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compute_antic (void)
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{
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bool changed = true;
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basic_block bb;
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bool changed= true;
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int num_iterations = 0;
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FOR_ALL_BB (bb)
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{
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ANTIC_IN (bb) = set_new (true);
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gcc_assert (!(bb->flags & BB_VISITED));
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}
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basic_block block, *worklist;
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size_t sp = 0;
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sbitmap has_abnormal_preds;
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/* If any predecessor edges are abnormal, we punt, so antic_in is empty.
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We pre-build the map of blocks with incoming abnormal edges here. */
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has_abnormal_preds = sbitmap_alloc (last_basic_block);
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sbitmap_zero (has_abnormal_preds);
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FOR_EACH_BB (block)
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{
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edge_iterator ei;
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edge e;
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FOR_EACH_EDGE (e, ei, block->preds)
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if (e->flags & EDGE_ABNORMAL)
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{
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SET_BIT (has_abnormal_preds, block->index);
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break;
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}
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/* While we are here, give empty ANTIC_IN sets to each block. */
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ANTIC_IN (block) = set_new (true);
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}
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/* At the exit block we anticipate nothing. */
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ANTIC_IN (EXIT_BLOCK_PTR) = set_new (true);
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/* Allocate the worklist. */
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worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
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/* Loop until fixpointed. */
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while (changed)
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{
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num_iterations++;
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basic_block son, bb;
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changed = false;
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changed = compute_antic_aux (EXIT_BLOCK_PTR);
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num_iterations++;
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/* Seed the algorithm by putting post-dominator children of
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the exit block in the worklist. */
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for (son = first_dom_son (CDI_POST_DOMINATORS, EXIT_BLOCK_PTR);
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son;
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son = next_dom_son (CDI_POST_DOMINATORS, son))
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worklist[sp++] = son;
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/* Now visit all blocks in a DFS of the post dominator tree. */
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while (sp)
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{
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bool bb_has_abnormal_pred;
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bb = worklist[--sp];
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bb_has_abnormal_pred = TEST_BIT (has_abnormal_preds, bb->index);
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changed |= compute_antic_aux (bb, bb_has_abnormal_pred);
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for (son = first_dom_son (CDI_POST_DOMINATORS, bb);
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son;
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son = next_dom_son (CDI_POST_DOMINATORS, son))
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worklist[sp++] = son;
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}
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}
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FOR_ALL_BB (bb)
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{
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bb->flags &= ~BB_VISITED;
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}
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if (num_iterations > 2 && dump_file && (dump_flags & TDF_STATS))
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free (worklist);
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sbitmap_free (has_abnormal_preds);
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if (dump_file && (dump_flags & TDF_STATS))
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fprintf (dump_file, "compute_antic required %d iterations\n", num_iterations);
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}
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