diff options
Diffstat (limited to 'gcc/tree-ssa-copy.c')
| -rw-r--r-- | gcc/tree-ssa-copy.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/gcc/tree-ssa-copy.c b/gcc/tree-ssa-copy.c index 4b8d0b9660b..5ee51e0ab58 100644 --- a/gcc/tree-ssa-copy.c +++ b/gcc/tree-ssa-copy.c @@ -749,6 +749,7 @@ init_copy_prop (void) { gimple_stmt_iterator si; int depth = bb->loop_depth; + bool loop_exit_p = false; for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) { @@ -786,6 +787,18 @@ init_copy_prop (void) cached_last_copy_of[SSA_NAME_VERSION (def)] = def; } + /* In loop-closed SSA form do not copy-propagate through + PHI nodes in blocks with a loop exit edge predecessor. */ + if (current_loops + && loops_state_satisfies_p (LOOP_CLOSED_SSA)) + { + edge_iterator ei; + edge e; + FOR_EACH_EDGE (e, ei, bb->preds) + if (loop_exit_edge_p (e->src->loop_father, e)) + loop_exit_p = true; + } + for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) { gimple phi = gsi_stmt (si); @@ -793,12 +806,7 @@ init_copy_prop (void) def = gimple_phi_result (phi); if (!is_gimple_reg (def) - /* In loop-closed SSA form do not copy-propagate through - PHI nodes. Technically this is only needed for loop - exit PHIs, but this is difficult to query. */ - || (current_loops - && gimple_phi_num_args (phi) == 1 - && loops_state_satisfies_p (LOOP_CLOSED_SSA))) + || loop_exit_p) prop_set_simulate_again (phi, false); else prop_set_simulate_again (phi, true); |