diff options
Diffstat (limited to 'gcc/tree-ssa-phiprop.cc')
| -rw-r--r-- | gcc/tree-ssa-phiprop.cc | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/gcc/tree-ssa-phiprop.cc b/gcc/tree-ssa-phiprop.cc index 21a349a..b01ef44 100644 --- a/gcc/tree-ssa-phiprop.cc +++ b/gcc/tree-ssa-phiprop.cc @@ -340,6 +340,9 @@ propagate_with_phi (basic_block bb, gphi *phi, struct phiprop_d *phivn, gimple *def_stmt; tree vuse; + if (!dom_info_available_p (cfun, CDI_POST_DOMINATORS)) + calculate_dominance_info (CDI_POST_DOMINATORS); + /* Only replace loads in blocks that post-dominate the PHI node. That makes sure we don't end up speculating loads. */ if (!dominated_by_p (CDI_POST_DOMINATORS, @@ -399,14 +402,18 @@ propagate_with_phi (basic_block bb, gphi *phi, struct phiprop_d *phivn, there are no statements that could read from memory aliasing the lhs in between the start of bb and use_stmt. As we require use_stmt to have a VDEF above, loads after - use_stmt will use a different virtual SSA_NAME. */ + use_stmt will use a different virtual SSA_NAME. When + we reach an edge inserted load the constraints we place + on processing guarantees that program order is preserved + so we can avoid checking those. */ FOR_EACH_IMM_USE_FAST (vuse_p, vui, vuse) { vuse_stmt = USE_STMT (vuse_p); if (vuse_stmt == use_stmt) continue; - if (!dominated_by_p (CDI_DOMINATORS, - gimple_bb (vuse_stmt), bb)) + if (!gimple_bb (vuse_stmt) + || !dominated_by_p (CDI_DOMINATORS, + gimple_bb (vuse_stmt), bb)) continue; if (ref_maybe_used_by_stmt_p (vuse_stmt, gimple_assign_lhs (use_stmt))) @@ -481,7 +488,7 @@ const pass_data pass_data_phiprop = 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ - TODO_update_ssa, /* todo_flags_finish */ + 0, /* todo_flags_finish */ }; class pass_phiprop : public gimple_opt_pass @@ -509,7 +516,6 @@ pass_phiprop::execute (function *fun) size_t n; calculate_dominance_info (CDI_DOMINATORS); - calculate_dominance_info (CDI_POST_DOMINATORS); n = num_ssa_names; phivn = XCNEWVEC (struct phiprop_d, n); @@ -535,7 +541,7 @@ pass_phiprop::execute (function *fun) free_dominance_info (CDI_POST_DOMINATORS); - return 0; + return did_something ? TODO_update_ssa_only_virtuals : 0; } } // anon namespace |