diff --git a/tools/cc.py b/tools/cc.py
index 8c18f8c..50047cc 100644
--- a/tools/cc.py
+++ b/tools/cc.py
@@ -1107,11 +1107,17 @@ class CcInterp(lark.visitors.Interpreter):
         self._synth(op)
         self.cur_fun.regs.drop_temps()
         begin_vars = self.cur_fun.regs.snap()
+        valid_vars_set = set(begin_vars[0].items())
         self.visit(tree.children[1])
+        valid_vars_set &= set(self.cur_fun.regs.snap()[0].items())
         if has_else:
             self.cur_fun.regs.restore(begin_vars)
             self.cur_fun.ops.append(op.synth_else)
             self.visit(tree.children[2])
+            valid_vars_set &= set(self.cur_fun.regs.snap()[0].items())
+        valid_vars = dict(valid_vars_set)
+        valid_snap = (valid_vars, {r: begin_vars[1][r] for r in valid_vars.values()})
+        self.cur_fun.regs.restore(valid_snap)
         self.cur_fun.ops.append(op.synth_endif)
 
     def _restore_vars(self, begin_vars):