diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
@@ -202,6 +202,8 @@
                              unsigned AS,
                              Instruction *I = nullptr) const override;
 
+  bool isLegalAddImmediate(int64_t Imm) const override;
+
   bool hasAndNotCompare(SDValue Y) const override;
 
   bool convertSelectOfConstantsToMath(EVT VT) const override { return true; }
diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -3243,6 +3243,10 @@
   return true;
 }
 
+bool LoongArchTargetLowering::isLegalAddImmediate(int64_t Imm) const {
+  return isInt<12>(Imm);
+}
+
 bool LoongArchTargetLowering::hasAndNotCompare(SDValue Y) const {
   // TODO: Support vectors.
   if (Y.getValueType().isVector())
diff --git a/llvm/test/CodeGen/LoongArch/lsr-legaladdimm.ll b/llvm/test/CodeGen/LoongArch/lsr-legaladdimm.ll
--- a/llvm/test/CodeGen/LoongArch/lsr-legaladdimm.ll
+++ b/llvm/test/CodeGen/LoongArch/lsr-legaladdimm.ll
@@ -4,8 +4,7 @@
 define i32 @lsr_addimm(i32 %x, i32 %y) {
 ; CHECK-LABEL: lsr_addimm:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    ori $a2, $zero, 4095
-; CHECK-NEXT:    add.d $a0, $a0, $a2
+; CHECK-NEXT:    addi.d $a0, $a0, -1
 ; CHECK-NEXT:    bstrpick.d $a1, $a1, 31, 20
 ; CHECK-NEXT:    and $a0, $a1, $a0
 ; CHECK-NEXT:    ret