model: refactor build_reads_from_past

Just rearrange the logic a little, to prepare for some other additions.

diff --git a/model.cc b/model.cc
index fc86d5c7e9955d3b5e4ccd17cc25ccc5e2e38fa6..d6ebfe5abc9f4e60920f9b08bed0112746c3afce 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -2289,15 +2289,20 @@ void ModelChecker::build_reads_from_past(ModelAction *curr)
                                continue;
 
                        /* Don't consider more than one seq_cst write if we are a seq_cst read. */
-                       if (!curr->is_seqcst() || (!act->is_seqcst() && (last_sc_write == NULL || !act->happens_before(last_sc_write))) || act == last_sc_write) {
-                               if (!curr->get_sleep_flag() || curr->is_seqcst() || sleep_can_read_from(curr, act)) {
-                                       DEBUG("Adding action to may_read_from:\n");
-                                       if (DBG_ENABLED()) {
-                                               act->print();
-                                               curr->print();
-                                       }
-                                       curr->get_node()->add_read_from(act);
+                       bool allow_read = true;
+
+                       if (curr->is_seqcst() && (act->is_seqcst() || (last_sc_write != NULL && act->happens_before(last_sc_write))) && act != last_sc_write)
+                               allow_read = false;
+                       else if (curr->get_sleep_flag() && !curr->is_seqcst() && !sleep_can_read_from(curr, act))
+                               allow_read = false;
+
+                       if (allow_read) {
+                               DEBUG("Adding action to may_read_from:\n");
+                               if (DBG_ENABLED()) {
+                                       act->print();
+                                       curr->print();
                                }
+                               curr->get_node()->add_read_from(act);
                        }
 
                        /* Include at most one act per-thread that "happens before" curr */