diff --git a/src/mapleall/maple_be/src/cg/aarch64/aarch64_prop.cpp b/src/mapleall/maple_be/src/cg/aarch64/aarch64_prop.cpp
index cf65ddf8ef57df09e1be9577a9ed8f0ae51ee1f3..66f4ebe36c94129e8719299404b1dd15f9410e8a 100644
--- a/src/mapleall/maple_be/src/cg/aarch64/aarch64_prop.cpp
+++ b/src/mapleall/maple_be/src/cg/aarch64/aarch64_prop.cpp
@@ -2508,6 +2508,9 @@ bool A64PregCopyPattern::CheckPhiCaseCondition(Insn &defInsn) {
       return false;
     }
   }
+  if (differIdx == -1) {
+    return false;
+  }
   return true;
 }