From 97258480438db77e52f4b3947fa2c075b09d3fe1 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Tue, 31 Jan 2023 15:45:43 +0100 Subject: [PATCH] middle-end/108500 - replace recursive domtree DFS traversal The following replaces the recursive DFS traversal of the dominator tree in assign_dfs_numbers with a tree traversal using the fact that we have recorded parents. Bootstrapped and tested on x86_64-unknown-linux-gnu. This makes r13-5325 somewhat obsolete, though not computing the DFS numbers at all is beneficial in the cases where we perform immediate CFG manipulations. OK for trunk and later branch(es)? Thanks, Richard. PR middle-end/108500 * dominance.cc (assign_dfs_numbers): Replace recursive DFS with tree traversal algorithm. --- gcc/dominance.cc | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/gcc/dominance.cc b/gcc/dominance.cc index 099b8fd3f24b..34fabe40c189 100644 --- a/gcc/dominance.cc +++ b/gcc/dominance.cc @@ -639,18 +639,25 @@ dom_info::calc_idoms () static void assign_dfs_numbers (struct et_node *node, int *num) { - struct et_node *son; - - node->dfs_num_in = (*num)++; - - if (node->son) + et_node *n = node; + while (1) { - assign_dfs_numbers (node->son, num); - for (son = node->son->right; son != node->son; son = son->right) - assign_dfs_numbers (son, num); + n->dfs_num_in = (*num)++; + if (n->son) + n = n->son; + else + { + while (!n->right || n->right == n->father->son) + { + n->dfs_num_out = (*num)++; + if (n == node) + return; + n = n->father; + } + n->dfs_num_out = (*num)++; + n = n->right; + } } - - node->dfs_num_out = (*num)++; } /* Compute the data necessary for fast resolving of dominator queries in a -- 2.47.2