diff options
Diffstat (limited to 'gcc-4.9/gcc/tree-ssa-threadupdate.c')
-rw-r--r-- | gcc-4.9/gcc/tree-ssa-threadupdate.c | 40 |
1 files changed, 34 insertions, 6 deletions
diff --git a/gcc-4.9/gcc/tree-ssa-threadupdate.c b/gcc-4.9/gcc/tree-ssa-threadupdate.c index d1b289ffa..3c7df9add 100644 --- a/gcc-4.9/gcc/tree-ssa-threadupdate.c +++ b/gcc-4.9/gcc/tree-ssa-threadupdate.c @@ -1772,6 +1772,21 @@ duplicate_seme_region (edge entry, edge exit, return true; } +/* Return true when PATH is a valid jump-thread path. */ + +static bool +valid_jump_thread_path (vec<jump_thread_edge *> *path) +{ + unsigned len = path->length (); + + /* Check that the path is connected. */ + for (unsigned int j = 0; j < len - 1; j++) + if ((*path)[j]->e->dest != (*path)[j+1]->e->src) + return false; + + return true; +} + /* Walk through all blocks and thread incoming edges to the appropriate outgoing edge for each edge pair recorded in THREADED_EDGES. @@ -1807,12 +1822,25 @@ thread_through_all_blocks (bool may_peel_loop_headers) vec<jump_thread_edge *> *path = paths[i]; edge entry = (*path)[0]->e; - if ((*path)[0]->type != EDGE_FSM_THREAD - /* Do not jump-thread twice from the same block. */ - || bitmap_bit_p (threaded_blocks, entry->src->index)) { - i++; - continue; - } + /* Only code-generate FSM jump-threads in this loop. */ + if ((*path)[0]->type != EDGE_FSM_THREAD) + { + i++; + continue; + } + + /* Do not jump-thread twice from the same block. */ + if (bitmap_bit_p (threaded_blocks, entry->src->index) + /* Verify that the jump thread path is still valid: a + previous jump-thread may have changed the CFG, and + invalidated the current path. */ + || !valid_jump_thread_path (path)) + { + /* Remove invalid FSM jump-thread paths. */ + delete_jump_thread_path (path); + paths.unordered_remove (i); + continue; + } unsigned len = path->length (); edge exit = (*path)[len - 1]->e; |