diff options
Diffstat (limited to 'gcc/tree-ssa-threadedge.cc')
| -rw-r--r-- | gcc/tree-ssa-threadedge.cc | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/gcc/tree-ssa-threadedge.cc b/gcc/tree-ssa-threadedge.cc index 7f82639..0aa2aa8 100644 --- a/gcc/tree-ssa-threadedge.cc +++ b/gcc/tree-ssa-threadedge.cc @@ -786,13 +786,17 @@ propagate_threaded_block_debug_into (basic_block dest, basic_block src) bool jump_threader::thread_around_empty_blocks (vec<jump_thread_edge *> *path, edge taken_edge, - bitmap visited) + bitmap visited, unsigned &limit) { basic_block bb = taken_edge->dest; gimple_stmt_iterator gsi; gimple *stmt; tree cond; + if (limit == 0) + return false; + --limit; + /* The key property of these blocks is that they need not be duplicated when threading. Thus they cannot have visible side effects such as PHI nodes. */ @@ -830,7 +834,8 @@ jump_threader::thread_around_empty_blocks (vec<jump_thread_edge *> *path, m_registry->push_edge (path, taken_edge, EDGE_NO_COPY_SRC_BLOCK); m_state->append_path (taken_edge->dest); bitmap_set_bit (visited, taken_edge->dest->index); - return thread_around_empty_blocks (path, taken_edge, visited); + return thread_around_empty_blocks (path, taken_edge, visited, + limit); } } @@ -872,7 +877,7 @@ jump_threader::thread_around_empty_blocks (vec<jump_thread_edge *> *path, m_registry->push_edge (path, taken_edge, EDGE_NO_COPY_SRC_BLOCK); m_state->append_path (taken_edge->dest); - thread_around_empty_blocks (path, taken_edge, visited); + thread_around_empty_blocks (path, taken_edge, visited, limit); return true; } @@ -899,8 +904,13 @@ jump_threader::thread_around_empty_blocks (vec<jump_thread_edge *> *path, int jump_threader::thread_through_normal_block (vec<jump_thread_edge *> *path, - edge e, bitmap visited) + edge e, bitmap visited, + unsigned &limit) { + if (limit == 0) + return 0; + limit--; + m_state->register_equivs_edge (e); /* PHIs create temporary equivalences. @@ -989,7 +999,7 @@ jump_threader::thread_through_normal_block (vec<jump_thread_edge *> *path, visited. This may be overly conservative. */ bitmap_set_bit (visited, dest->index); bitmap_set_bit (visited, e->dest->index); - thread_around_empty_blocks (path, taken_edge, visited); + thread_around_empty_blocks (path, taken_edge, visited, limit); return 1; } } @@ -1075,9 +1085,12 @@ jump_threader::thread_across_edge (edge e) bitmap_set_bit (visited, e->src->index); bitmap_set_bit (visited, e->dest->index); + /* Limit search space. */ + unsigned limit = param_max_jump_thread_paths; + int threaded = 0; if ((e->flags & EDGE_DFS_BACK) == 0) - threaded = thread_through_normal_block (path, e, visited); + threaded = thread_through_normal_block (path, e, visited, limit); if (threaded > 0) { @@ -1148,11 +1161,12 @@ jump_threader::thread_across_edge (edge e) m_registry->push_edge (path, e, EDGE_START_JUMP_THREAD); m_registry->push_edge (path, taken_edge, EDGE_COPY_SRC_JOINER_BLOCK); - found = thread_around_empty_blocks (path, taken_edge, visited); + found = thread_around_empty_blocks (path, taken_edge, visited, limit); if (!found) found = thread_through_normal_block (path, - path->last ()->e, visited) > 0; + path->last ()->e, visited, + limit) > 0; /* If we were able to thread through a successor of E->dest, then record the jump threading opportunity. */ |