diff options
Diffstat (limited to 'gcc/tree-ssa-threadupdate.c')
| -rw-r--r-- | gcc/tree-ssa-threadupdate.c | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c index e791269..737a6a2 100644 --- a/gcc/tree-ssa-threadupdate.c +++ b/gcc/tree-ssa-threadupdate.c @@ -1244,7 +1244,7 @@ mark_threaded_blocks (bitmap threaded_blocks) When this occurs ignore the jump thread request with the joiner block. It's totally subsumed by the simpler jump thread request. - This results in less block copying, simpler CFGs. More improtantly, + This results in less block copying, simpler CFGs. More importantly, when we duplicate the joiner block, B, in this case we will create a new threading opportunity that we wouldn't be able to optimize until the next jump threading iteration. @@ -1263,20 +1263,30 @@ mark_threaded_blocks (bitmap threaded_blocks) } } - - /* Now iterate again, converting cases where we threaded through - a joiner block, but ignoring those where we have already - threaded through the joiner block. */ + /* Now iterate again, converting cases where we want to thread + through a joiner block, but only if no other edge on the path + already has a jump thread attached to it. */ for (i = 0; i < paths.length (); i++) { vec<jump_thread_edge *> *path = paths[i]; - if ((*path)[1]->type == EDGE_COPY_SRC_JOINER_BLOCK - && (*path)[0]->e->aux == NULL) + + if ((*path)[1]->type == EDGE_COPY_SRC_JOINER_BLOCK) { - edge e = (*path)[0]->e; - e->aux = path; - bitmap_set_bit (tmp, e->dest->index); + unsigned int j; + + for (j = 0; j < path->length (); j++) + if ((*path)[j]->e->aux != NULL) + break; + + /* If we iterated through the entire path without exiting the loop, + then we are good to go, attach the path to the starting edge. */ + if (j == path->length ()) + { + edge e = (*path)[0]->e; + e->aux = path; + bitmap_set_bit (tmp, e->dest->index); + } } } |