Only ignore SC stores when the load is SC

Author: cbeuw

src/weak_memory.rs

@@ -182,10 +182,15 @@ impl<'mir, 'tcx: 'mir> StoreBuffer {
                 true
             })
             .filter(|&store_elem| {
-                // Skip over all but the last SC store
-                let include = !(store_elem.is_seqcst && found_sc);
-                found_sc |= store_elem.is_seqcst;
-                include
+                if is_seqcst {
+                    // An SC load needs to ignore all but last store maked SC (stores not marked SC are not
+                    // affected)
+                    let include = !(store_elem.is_seqcst && found_sc);
+                    found_sc |= store_elem.is_seqcst;
+                    include
+                } else {
+                    true
+                }
             });
 
         candidates.choose(rng)