diff options
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/tree-cfg.c | 288 |
2 files changed, 152 insertions, 141 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 13d0ae467c8..d4e95c14179 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2004-10-19 Kazu Hirata <kazu@cs.umass.edu> + * tree-cfg.c (thread_jumps): Use a do-while loop instead of a + loop with goto. + +2004-10-19 Kazu Hirata <kazu@cs.umass.edu> + * expr.c (expand_assignment): Remove the last argument. Change the return type to void. * expr.h: Update the prototype of expand_assignment. diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c index 012ad706af7..0722df15ac3 100644 --- a/gcc/tree-cfg.c +++ b/gcc/tree-cfg.c @@ -3781,173 +3781,179 @@ thread_jumps (void) FOR_EACH_BB (bb) bb_ann (bb)->forwardable = tree_forwarder_block_p (bb); - restart: - rerun = false; - FOR_EACH_BB (bb) + do { - edge_iterator ei; - bool this_jump_threaded = false; - - /* Don't waste time on forwarders. */ - if (bb_ann (bb)->forwardable) - continue; - - /* Examine each of our block's successors to see if it is - forwardable. */ - for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) + rerun = false; + FOR_EACH_BB (bb) { - int freq; - gcov_type count; + edge_iterator ei; + bool this_jump_threaded = false; - /* If the edge is abnormal or its destination is not - forwardable, then there's nothing to do. */ - if ((e->flags & EDGE_ABNORMAL) - || !bb_ann (e->dest)->forwardable) - { - ei_next (&ei); - continue; - } + /* Don't waste time on forwarders. */ + if (bb_ann (bb)->forwardable) + continue; - count = e->count; - freq = EDGE_FREQUENCY (e); - - /* Now walk through as many forwarder blocks as possible to - find the ultimate destination we want to thread our jump - to. */ - last = EDGE_SUCC (e->dest, 0); - bb_ann (e->dest)->forwardable = 0; - for (dest = EDGE_SUCC (e->dest, 0)->dest; - bb_ann (dest)->forwardable; - last = EDGE_SUCC (dest, 0), - dest = EDGE_SUCC (dest, 0)->dest) - bb_ann (dest)->forwardable = 0; - - /* Reset the forwardable marks to 1. */ - for (tmp = e->dest; - tmp != dest; - tmp = EDGE_SUCC (tmp, 0)->dest) - bb_ann (tmp)->forwardable = 1; - - if (dest == e->dest) + /* Examine each of our block's successors to see if it is + forwardable. */ + for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) { - ei_next (&ei); - continue; - } + int freq; + gcov_type count; + + /* If the edge is abnormal or its destination is not + forwardable, then there's nothing to do. */ + if ((e->flags & EDGE_ABNORMAL) + || !bb_ann (e->dest)->forwardable) + { + ei_next (&ei); + continue; + } + + count = e->count; + freq = EDGE_FREQUENCY (e); + + /* Now walk through as many forwarder blocks as possible to + find the ultimate destination we want to thread our jump + to. */ + last = EDGE_SUCC (e->dest, 0); + bb_ann (e->dest)->forwardable = 0; + for (dest = EDGE_SUCC (e->dest, 0)->dest; + bb_ann (dest)->forwardable; + last = EDGE_SUCC (dest, 0), + dest = EDGE_SUCC (dest, 0)->dest) + bb_ann (dest)->forwardable = 0; + + /* Reset the forwardable marks to 1. */ + for (tmp = e->dest; + tmp != dest; + tmp = EDGE_SUCC (tmp, 0)->dest) + bb_ann (tmp)->forwardable = 1; + + if (dest == e->dest) + { + ei_next (&ei); + continue; + } - old = find_edge (bb, dest); - if (old) - { - /* If there already is an edge, check whether the values - in phi nodes differ. */ - if (!phi_alternatives_equal (dest, last, old)) + old = find_edge (bb, dest); + if (old) { - /* The previous block is forwarder. Redirect our jump - to that target instead since we know it has no PHI - nodes that will need updating. */ - dest = last->src; - - /* That might mean that no forwarding at all is possible. */ - if (dest == e->dest) + /* If there already is an edge, check whether the values + in phi nodes differ. */ + if (!phi_alternatives_equal (dest, last, old)) { - ei_next (&ei); - continue; + /* The previous block is forwarder. Redirect our jump + to that target instead since we know it has no PHI + nodes that will need updating. */ + dest = last->src; + + /* That might mean that no forwarding at all is + possible. */ + if (dest == e->dest) + { + ei_next (&ei); + continue; + } + + old = find_edge (bb, dest); } - - old = find_edge (bb, dest); } - } - /* Perform the redirection. */ - retval = this_jump_threaded = true; - old_dest = e->dest; - e = redirect_edge_and_branch (e, dest); + /* Perform the redirection. */ + retval = this_jump_threaded = true; + old_dest = e->dest; + e = redirect_edge_and_branch (e, dest); - /* Update the profile. */ - if (profile_status != PROFILE_ABSENT) - for (curr = old_dest; curr != dest; curr = EDGE_SUCC (curr, 0)->dest) - { - curr->frequency -= freq; - if (curr->frequency < 0) - curr->frequency = 0; - curr->count -= count; - if (curr->count < 0) - curr->count = 0; - EDGE_SUCC (curr, 0)->count -= count; - if (EDGE_SUCC (curr, 0)->count < 0) - EDGE_SUCC (curr, 0)->count = 0; - } + /* Update the profile. */ + if (profile_status != PROFILE_ABSENT) + for (curr = old_dest; + curr != dest; + curr = EDGE_SUCC (curr, 0)->dest) + { + curr->frequency -= freq; + if (curr->frequency < 0) + curr->frequency = 0; + curr->count -= count; + if (curr->count < 0) + curr->count = 0; + EDGE_SUCC (curr, 0)->count -= count; + if (EDGE_SUCC (curr, 0)->count < 0) + EDGE_SUCC (curr, 0)->count = 0; + } - if (!old) - { - /* Update PHI nodes. We know that the new argument should - have the same value as the argument associated with LAST. - Otherwise we would have changed our target block above. */ - for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) + if (!old) { - arg = phi_arg_from_edge (phi, last); - gcc_assert (arg >= 0); - add_phi_arg (&phi, PHI_ARG_DEF (phi, arg), e); + /* Update PHI nodes. We know that the new argument + should have the same value as the argument + associated with LAST. Otherwise we would have + changed our target block above. */ + for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) + { + arg = phi_arg_from_edge (phi, last); + gcc_assert (arg >= 0); + add_phi_arg (&phi, PHI_ARG_DEF (phi, arg), e); + } } - } - - /* Remove the unreachable blocks (observe that if all blocks - were reachable before, only those in the path we threaded - over and did not have any predecessor outside of the path - become unreachable). */ - for (; old_dest != dest; old_dest = tmp) - { - tmp = EDGE_SUCC (old_dest, 0)->dest; - - if (EDGE_COUNT (old_dest->preds) > 0) - break; - - delete_basic_block (old_dest); - } - - /* Update the dominators. */ - if (dom_info_available_p (CDI_DOMINATORS)) - { - /* If the dominator of the destination was in the path, set its - dominator to the start of the redirected edge. */ - if (get_immediate_dominator (CDI_DOMINATORS, old_dest) == NULL) - set_immediate_dominator (CDI_DOMINATORS, old_dest, bb); - - /* Now proceed like if we forwarded just over one edge at a time. - Algorithm for forwarding edge S --> A over edge A --> B then - is - - if (idom (B) == A - && !dominated_by (S, B)) - idom (B) = idom (A); - recount_idom (A); */ + /* Remove the unreachable blocks (observe that if all blocks + were reachable before, only those in the path we threaded + over and did not have any predecessor outside of the path + become unreachable). */ for (; old_dest != dest; old_dest = tmp) { tmp = EDGE_SUCC (old_dest, 0)->dest; - if (get_immediate_dominator (CDI_DOMINATORS, tmp) == old_dest - && !dominated_by_p (CDI_DOMINATORS, bb, tmp)) + if (EDGE_COUNT (old_dest->preds) > 0) + break; + + delete_basic_block (old_dest); + } + + /* Update the dominators. */ + if (dom_info_available_p (CDI_DOMINATORS)) + { + /* If the dominator of the destination was in the + path, set its dominator to the start of the + redirected edge. */ + if (get_immediate_dominator (CDI_DOMINATORS, old_dest) == NULL) + set_immediate_dominator (CDI_DOMINATORS, old_dest, bb); + + /* Now proceed like if we forwarded just over one + edge at a time. Algorithm for forwarding edge + S --> A over edge A --> B then is + + if (idom (B) == A + && !dominated_by (S, B)) + idom (B) = idom (A); + recount_idom (A); */ + + for (; old_dest != dest; old_dest = tmp) { - dom = get_immediate_dominator (CDI_DOMINATORS, old_dest); - set_immediate_dominator (CDI_DOMINATORS, tmp, dom); - } + tmp = EDGE_SUCC (old_dest, 0)->dest; + + if (get_immediate_dominator (CDI_DOMINATORS, tmp) == old_dest + && !dominated_by_p (CDI_DOMINATORS, bb, tmp)) + { + dom = get_immediate_dominator (CDI_DOMINATORS, old_dest); + set_immediate_dominator (CDI_DOMINATORS, tmp, dom); + } - dom = recount_dominator (CDI_DOMINATORS, old_dest); - set_immediate_dominator (CDI_DOMINATORS, old_dest, dom); + dom = recount_dominator (CDI_DOMINATORS, old_dest); + set_immediate_dominator (CDI_DOMINATORS, old_dest, dom); + } } } - } - /* If we succeeded in threading a jump at BB, update the - forwardable mark as BB may have become a new forwarder block. - This could happen if we have a useless "if" statement whose - two arms eventually merge without any intervening - statements. */ - if (this_jump_threaded && tree_forwarder_block_p (bb)) - bb_ann (bb)->forwardable = rerun = true; + /* If we succeeded in threading a jump at BB, update the + forwardable mark as BB may have become a new forwarder + block. This could happen if we have a useless "if" + statement whose two arms eventually merge without any + intervening statements. */ + if (this_jump_threaded && tree_forwarder_block_p (bb)) + bb_ann (bb)->forwardable = rerun = true; + } } - if (rerun) - goto restart; + while (rerun); return retval; } |