diff options
Diffstat (limited to 'gcc/cfgcleanup.c')
| -rw-r--r-- | gcc/cfgcleanup.c | 98 |
1 files changed, 54 insertions, 44 deletions
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c index 08a334a0874..fcf6944d4bb 100644 --- a/gcc/cfgcleanup.c +++ b/gcc/cfgcleanup.c @@ -147,7 +147,7 @@ try_simplify_condjump (cbranch_block) unconditional jump. */ jump_block = cbranch_fallthru_edge->dest; if (jump_block->pred->pred_next - || jump_block->next_bb == EXIT_BLOCK_PTR + || jump_block->index == n_basic_blocks - 1 || !FORWARDER_BLOCK_P (jump_block)) return false; jump_dest_block = jump_block->succ->dest; @@ -439,7 +439,7 @@ try_forward_edges (mode, b) target = first = e->dest; counter = 0; - while (counter < num_basic_blocks) + while (counter < n_basic_blocks) { basic_block new_target = NULL; bool new_target_threaded = false; @@ -449,7 +449,7 @@ try_forward_edges (mode, b) { /* Bypass trivial infinite loops. */ if (target == target->succ->dest) - counter = num_basic_blocks; + counter = n_basic_blocks; new_target = target->succ->dest; } @@ -462,7 +462,7 @@ try_forward_edges (mode, b) { if (!threaded_edges) threaded_edges = xmalloc (sizeof (*threaded_edges) - * num_basic_blocks); + * n_basic_blocks); else { int i; @@ -474,7 +474,7 @@ try_forward_edges (mode, b) break; if (i < nthreaded_edges) { - counter = num_basic_blocks; + counter = n_basic_blocks; break; } } @@ -483,7 +483,7 @@ try_forward_edges (mode, b) if (t->dest == b) break; - if (nthreaded_edges >= num_basic_blocks) + if (nthreaded_edges >= n_basic_blocks) abort (); threaded_edges[nthreaded_edges++] = t; @@ -524,11 +524,11 @@ try_forward_edges (mode, b) threaded |= new_target_threaded; } - if (counter >= num_basic_blocks) + if (counter >= n_basic_blocks) { if (rtl_dump_file) fprintf (rtl_dump_file, "Infinite loop in BB %i.\n", - target->sindex); + target->index); } else if (target == first) ; /* We didn't do anything. */ @@ -552,7 +552,7 @@ try_forward_edges (mode, b) if (rtl_dump_file) fprintf (rtl_dump_file, "Forwarding edge %i->%i to %i failed.\n", - b->sindex, e->dest->sindex, target->sindex); + b->index, e->dest->index, target->index); continue; } @@ -688,6 +688,7 @@ merge_blocks_move_predecessor_nojumps (a, b) basic_block a, b; { rtx barrier; + int index; barrier = next_nonnote_insn (a->end); if (GET_CODE (barrier) != BARRIER) @@ -711,11 +712,16 @@ merge_blocks_move_predecessor_nojumps (a, b) if (rtl_dump_file) fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n", - a->sindex, b->sindex); + a->index, b->index); - /* Swap the records for the two blocks around. */ - unlink_block (a); - link_block (a, b->prev_bb); + /* Swap the records for the two blocks around. Although we are deleting B, + A is now where B was and we want to compact the BB array from where + A used to be. */ + BASIC_BLOCK (a->index) = b; + BASIC_BLOCK (b->index) = a; + index = a->index; + a->index = b->index; + b->index = index; /* Now blocks A and B are contiguous. Merge them. */ merge_blocks_nomove (a, b); @@ -770,7 +776,7 @@ merge_blocks_move_successor_nojumps (a, b) if (rtl_dump_file) fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n", - b->sindex, a->sindex); + b->index, a->index); /* Now blocks A and B are contiguous. Merge them. */ merge_blocks_nomove (a, b); @@ -797,7 +803,7 @@ merge_blocks (e, b, c, mode) /* If B has a fallthru edge to C, no need to move anything. */ if (e->flags & EDGE_FALLTHRU) { - int b_index = b->sindex, c_index = c->sindex; + int b_index = b->index, c_index = c->index; merge_blocks_nomove (b, c); update_forwarder_flag (b); @@ -1224,7 +1230,7 @@ outgoing_edges_match (mode, bb1, bb2) if (rtl_dump_file) fprintf (rtl_dump_file, "Outcomes of branch in bb %i and %i differs to much (%i %i)\n", - bb1->sindex, bb2->sindex, b1->probability, prob2); + bb1->index, bb2->index, b1->probability, prob2); return false; } @@ -1232,7 +1238,7 @@ outgoing_edges_match (mode, bb1, bb2) if (rtl_dump_file && match) fprintf (rtl_dump_file, "Conditionals in bb %i and %i match.\n", - bb1->sindex, bb2->sindex); + bb1->index, bb2->index); return match; } @@ -1365,14 +1371,14 @@ try_crossjump_to_edge (mode, e1, e2) { if (rtl_dump_file) fprintf (rtl_dump_file, "Splitting bb %i before %i insns\n", - src2->sindex, nmatch); + src2->index, nmatch); redirect_to = split_block (src2, PREV_INSN (newpos2))->dest; } if (rtl_dump_file) fprintf (rtl_dump_file, "Cross jumping from bb %i to bb %i; %i common insns\n", - src1->sindex, src2->sindex, nmatch); + src1->index, src2->index, nmatch); redirect_to->count += src1->count; redirect_to->frequency += src1->frequency; @@ -1533,7 +1539,6 @@ try_crossjump_bb (mode, bb) for (e2 = bb->pred; e2; e2 = nexte2) { - basic_block foll; nexte2 = e2->pred_next; if (e2 == e) @@ -1547,10 +1552,7 @@ try_crossjump_bb (mode, bb) checks of crossjump(A,B). In order to prevent redundant checks of crossjump(B,A), require that A be the block with the lowest index. */ - for (foll = e->src; foll && foll != e2->src; foll = foll->next_bb) - { - } - if (!foll) + if (e->src->index > e2->src->index) continue; if (try_crossjump_to_edge (mode, e, e2)) @@ -1572,16 +1574,16 @@ static bool try_optimize_cfg (mode) int mode; { + int i; bool changed_overall = false; bool changed; int iterations = 0; - basic_block bb, b; if (mode & CLEANUP_CROSSJUMP) add_noreturn_fake_exit_edges (); - FOR_ALL_BB (bb) - update_forwarder_flag (bb); + for (i = 0; i < n_basic_blocks; i++) + update_forwarder_flag (BASIC_BLOCK (i)); if (mode & CLEANUP_UPDATE_LIFE) clear_bb_flags (); @@ -1601,19 +1603,19 @@ try_optimize_cfg (mode) "\n\ntry_optimize_cfg iteration %i\n\n", iterations); - for (b = ENTRY_BLOCK_PTR->next_bb; b != EXIT_BLOCK_PTR;) + for (i = 0; i < n_basic_blocks;) { - basic_block c; + basic_block c, b = BASIC_BLOCK (i); edge s; bool changed_here = false; /* Delete trivially dead basic blocks. */ while (b->pred == NULL) { - c = b->prev_bb; + c = BASIC_BLOCK (b->index - 1); if (rtl_dump_file) fprintf (rtl_dump_file, "Deleting block %i.\n", - b->sindex); + b->index); flow_delete_block (b); changed = true; @@ -1646,7 +1648,7 @@ try_optimize_cfg (mode) delete_insn_chain (label, label); if (rtl_dump_file) fprintf (rtl_dump_file, "Deleted label in block %i.\n", - b->sindex); + b->index); } /* If we fall through an empty block, we can remove it. */ @@ -1657,14 +1659,14 @@ try_optimize_cfg (mode) /* Note that forwarder_block_p true ensures that there is a successor for this block. */ && (b->succ->flags & EDGE_FALLTHRU) - && num_basic_blocks > 1) + && n_basic_blocks > 1) { if (rtl_dump_file) fprintf (rtl_dump_file, "Deleting fallthru block %i.\n", - b->sindex); + b->index); - c = b->prev_bb == ENTRY_BLOCK_PTR ? b->next_bb : b->prev_bb; + c = BASIC_BLOCK (b->index ? b->index - 1 : 1); redirect_edge_succ_nodup (b->pred, b->succ->dest); flow_delete_block (b); changed = true; @@ -1716,7 +1718,7 @@ try_optimize_cfg (mode) /* Don't get confused by the index shift caused by deleting blocks. */ if (!changed_here) - b = b->next_bb; + i = b->index + 1; else changed = true; } @@ -1748,22 +1750,33 @@ try_optimize_cfg (mode) bool delete_unreachable_blocks () { + int i, j; bool changed = false; - basic_block b, next_bb; find_unreachable_blocks (); - /* Delete all unreachable basic blocks. */ + /* Delete all unreachable basic blocks. Do compaction concurrently, + as otherwise we can wind up with O(N^2) behaviour here when we + have oodles of dead code. */ - for (b = ENTRY_BLOCK_PTR->next_bb; b != EXIT_BLOCK_PTR; b = next_bb) + for (i = j = 0; i < n_basic_blocks; ++i) { - next_bb = b->next_bb; + basic_block b = BASIC_BLOCK (i); + if (!(b->flags & BB_REACHABLE)) { - flow_delete_block (b); + flow_delete_block_noexpunge (b); + expunge_block_nocompact (b); changed = true; } + else + { + BASIC_BLOCK (j) = b; + b->index = j++; + } } + n_basic_blocks = j; + basic_block_info->num_elements = j; if (changed) tidy_fallthru_edges (); @@ -1788,9 +1801,6 @@ cleanup_cfg (mode) && !reload_completed) delete_trivially_dead_insns (get_insns(), max_reg_num ()); } - - compact_blocks (); - while (try_optimize_cfg (mode)) { delete_unreachable_blocks (), changed = true; |