useless opt

src/backend/assign.rs

@@ -363,9 +363,11 @@ impl RegisterRewriter {
                     }
                 }
 
-                for reg in used_set {
-                    if let Some(inst) = self.load_from_stack(reg, sf) {
-                        insts.push(inst);
+                if analyser.flow().from_duplicate(&label).len() != 1 {
+                    for reg in used_set {
+                        if let Some(inst) = self.load_from_stack(reg, sf) {
+                            insts.push(inst);
+                        }
                     }
                 }
 

src/backend/dataflow.rs

@@ -227,6 +227,10 @@ impl LiveVariableAnalyser {
         }
     }
 
+    pub fn flow(&self) -> &GlobalFLowGraph {
+        &self.flow
+    }
+
     pub fn ins(&self, label: &Label) -> &HashSet<Register> {
         self.ins.get(label).unwrap()
     }