diff --git a/src/mapleall/maple_be/src/cg/aarch64/aarch64_global.cpp b/src/mapleall/maple_be/src/cg/aarch64/aarch64_global.cpp
index 67e6b853d6e4f480d49bd398f21eafee81ebd636..704c4a2ea92e987f8438aba0e3ef8a8e032d698e 100644
--- a/src/mapleall/maple_be/src/cg/aarch64/aarch64_global.cpp
+++ b/src/mapleall/maple_be/src/cg/aarch64/aarch64_global.cpp
@@ -1198,15 +1198,17 @@ void ExtendShiftOptPattern::ReplaceUseInsn(Insn &use, Insn &def, uint32 amount)
 void ExtendShiftOptPattern::Optimize(Insn &insn) {
   if (shiftOp == BitShiftOperand::kLSL) {
     InsnSet preDef = cgFunc.GetRD()->FindDefForRegOpnd(*defInsn, kInsnSecondOpnd, false);
-    Insn *preDefInsn = *preDef.begin();
-    CHECK_FATAL((preDefInsn != nullptr), "defInsn is null!");
-    SelectExtenOp(*preDefInsn);
-    /* preDefInsn must be uxt/sxt */
-    if (extendOp != ExtendShiftOperand::kUndef) {
-      AArch64ImmOperand &immOpnd = static_cast<AArch64ImmOperand&>(defInsn->GetOperand(kInsnThirdOpnd));
-      /* do pattern2 */
-      ReplaceUseInsn(insn, *preDefInsn, immOpnd.GetValue());
-      return;
+    if (preDef.size() == 1) {
+      Insn *preDefInsn = *preDef.begin();
+      CHECK_FATAL((preDefInsn != nullptr), "defInsn is null!");
+      SelectExtenOp(*preDefInsn);
+      /* preDefInsn must be uxt/sxt */
+      if (extendOp != ExtendShiftOperand::kUndef) {
+        AArch64ImmOperand &immOpnd = static_cast<AArch64ImmOperand &>(defInsn->GetOperand(kInsnThirdOpnd));
+        /* do pattern2 */
+        ReplaceUseInsn(insn, *preDefInsn, immOpnd.GetValue());
+        return;
+      }
     }
   }
   /* reset shiftOp and extendOp */
@@ -1216,7 +1218,7 @@ void ExtendShiftOptPattern::Optimize(Insn &insn) {
     /* do pattern1 */
     ReplaceUseInsn(insn, *defInsn, 0);
   } else if (shiftOp != BitShiftOperand::kUndef) {
-    /* do pattern2 */
+    /* do pattern3 */
     AArch64ImmOperand &immOpnd = static_cast<AArch64ImmOperand&>(defInsn->GetOperand(kInsnThirdOpnd));
     ReplaceUseInsn(insn, *defInsn, immOpnd.GetValue());
   } else {
@@ -1282,4 +1284,4 @@ void ExtendShiftOptPattern::Run() {
     }
   }
 }
-}  /* namespace maplebe */
\ No newline at end of file
+}  /* namespace maplebe */