diff --git a/llvm/lib/Target/LoongArch/LoongArchFrameLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchFrameLowering.cpp
--- a/llvm/lib/Target/LoongArch/LoongArchFrameLowering.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchFrameLowering.cpp
@@ -291,18 +291,15 @@
   if (hasFP(MF)) {
     // Realign stack.
     if (RI->hasStackRealignment(MF)) {
-      unsigned ShiftAmount = Log2(MFI.getMaxAlign());
-      Register VR =
-          MF.getRegInfo().createVirtualRegister(&LoongArch::GPRRegClass);
+      unsigned MSB = Log2(MFI.getMaxAlign());
+      assert(MSB > 0 && "The stack realignment size is invalid!");
       BuildMI(MBB, MBBI, DL,
-              TII->get(IsLA64 ? LoongArch::SRLI_D : LoongArch::SRLI_W), VR)
+              TII->get(IsLA64 ? LoongArch::BSTRINS_D : LoongArch::BSTRINS_W),
+              SPReg)
           .addReg(SPReg)
-          .addImm(ShiftAmount)
-          .setMIFlag(MachineInstr::FrameSetup);
-      BuildMI(MBB, MBBI, DL,
-              TII->get(IsLA64 ? LoongArch::SLLI_D : LoongArch::SLLI_W), SPReg)
-          .addReg(VR)
-          .addImm(ShiftAmount)
+          .addReg(LoongArch::R0)
+          .addImm(MSB - 1)
+          .addImm(0)
           .setMIFlag(MachineInstr::FrameSetup);
       // FP will be used to restore the frame in the epilogue, so we need
       // another base register BP to record SP after re-alignment. SP will
diff --git a/llvm/test/CodeGen/LoongArch/stack-realignment-with-variable-sized-objects.ll b/llvm/test/CodeGen/LoongArch/stack-realignment-with-variable-sized-objects.ll
--- a/llvm/test/CodeGen/LoongArch/stack-realignment-with-variable-sized-objects.ll
+++ b/llvm/test/CodeGen/LoongArch/stack-realignment-with-variable-sized-objects.ll
@@ -19,8 +19,7 @@
 ; LA32-NEXT:    .cfi_offset 31, -12
 ; LA32-NEXT:    addi.w $fp, $sp, 64
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
-; LA32-NEXT:    srli.w $a1, $sp, 6
-; LA32-NEXT:    slli.w $sp, $a1, 6
+; LA32-NEXT:    bstrins.w $sp, $zero, 5, 0
 ; LA32-NEXT:    move $s8, $sp
 ; LA32-NEXT:    addi.w $a0, $a0, 15
 ; LA32-NEXT:    addi.w $a1, $zero, -16
@@ -48,8 +47,7 @@
 ; LA64-NEXT:    .cfi_offset 31, -24
 ; LA64-NEXT:    addi.d $fp, $sp, 64
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
-; LA64-NEXT:    srli.d $a1, $sp, 6
-; LA64-NEXT:    slli.d $sp, $a1, 6
+; LA64-NEXT:    bstrins.d $sp, $zero, 5, 0
 ; LA64-NEXT:    move $s8, $sp
 ; LA64-NEXT:    bstrpick.d $a0, $a0, 31, 0
 ; LA64-NEXT:    addi.d $a0, $a0, 15
diff --git a/llvm/test/CodeGen/LoongArch/stack-realignment.ll b/llvm/test/CodeGen/LoongArch/stack-realignment.ll
--- a/llvm/test/CodeGen/LoongArch/stack-realignment.ll
+++ b/llvm/test/CodeGen/LoongArch/stack-realignment.ll
@@ -17,8 +17,7 @@
 ; LA32-NEXT:    .cfi_offset 22, -8
 ; LA32-NEXT:    addi.w $fp, $sp, 32
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
-; LA32-NEXT:    srli.w $a0, $sp, 5
-; LA32-NEXT:    slli.w $sp, $a0, 5
+; LA32-NEXT:    bstrins.w $sp, $zero, 4, 0
 ; LA32-NEXT:    addi.w $a0, $sp, 0
 ; LA32-NEXT:    bl %plt(callee)
 ; LA32-NEXT:    addi.w $sp, $fp, -32
@@ -37,8 +36,7 @@
 ; LA64-NEXT:    .cfi_offset 22, -16
 ; LA64-NEXT:    addi.d $fp, $sp, 32
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
-; LA64-NEXT:    srli.d $a0, $sp, 5
-; LA64-NEXT:    slli.d $sp, $a0, 5
+; LA64-NEXT:    bstrins.d $sp, $zero, 4, 0
 ; LA64-NEXT:    addi.d $a0, $sp, 0
 ; LA64-NEXT:    bl %plt(callee)
 ; LA64-NEXT:    addi.d $sp, $fp, -32
@@ -91,8 +89,7 @@
 ; LA32-NEXT:    .cfi_offset 22, -8
 ; LA32-NEXT:    addi.w $fp, $sp, 64
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
-; LA32-NEXT:    srli.w $a0, $sp, 6
-; LA32-NEXT:    slli.w $sp, $a0, 6
+; LA32-NEXT:    bstrins.w $sp, $zero, 5, 0
 ; LA32-NEXT:    addi.w $a0, $sp, 0
 ; LA32-NEXT:    bl %plt(callee)
 ; LA32-NEXT:    addi.w $sp, $fp, -64
@@ -111,8 +108,7 @@
 ; LA64-NEXT:    .cfi_offset 22, -16
 ; LA64-NEXT:    addi.d $fp, $sp, 64
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
-; LA64-NEXT:    srli.d $a0, $sp, 6
-; LA64-NEXT:    slli.d $sp, $a0, 6
+; LA64-NEXT:    bstrins.d $sp, $zero, 5, 0
 ; LA64-NEXT:    addi.d $a0, $sp, 0
 ; LA64-NEXT:    bl %plt(callee)
 ; LA64-NEXT:    addi.d $sp, $fp, -64
@@ -165,8 +161,7 @@
 ; LA32-NEXT:    .cfi_offset 22, -8
 ; LA32-NEXT:    addi.w $fp, $sp, 128
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
-; LA32-NEXT:    srli.w $a0, $sp, 7
-; LA32-NEXT:    slli.w $sp, $a0, 7
+; LA32-NEXT:    bstrins.w $sp, $zero, 6, 0
 ; LA32-NEXT:    addi.w $a0, $sp, 0
 ; LA32-NEXT:    bl %plt(callee)
 ; LA32-NEXT:    addi.w $sp, $fp, -128
@@ -185,8 +180,7 @@
 ; LA64-NEXT:    .cfi_offset 22, -16
 ; LA64-NEXT:    addi.d $fp, $sp, 128
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
-; LA64-NEXT:    srli.d $a0, $sp, 7
-; LA64-NEXT:    slli.d $sp, $a0, 7
+; LA64-NEXT:    bstrins.d $sp, $zero, 6, 0
 ; LA64-NEXT:    addi.d $a0, $sp, 0
 ; LA64-NEXT:    bl %plt(callee)
 ; LA64-NEXT:    addi.d $sp, $fp, -128
@@ -239,8 +233,7 @@
 ; LA32-NEXT:    .cfi_offset 22, -8
 ; LA32-NEXT:    addi.w $fp, $sp, 256
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
-; LA32-NEXT:    srli.w $a0, $sp, 8
-; LA32-NEXT:    slli.w $sp, $a0, 8
+; LA32-NEXT:    bstrins.w $sp, $zero, 7, 0
 ; LA32-NEXT:    addi.w $a0, $sp, 0
 ; LA32-NEXT:    bl %plt(callee)
 ; LA32-NEXT:    addi.w $sp, $fp, -256
@@ -259,8 +252,7 @@
 ; LA64-NEXT:    .cfi_offset 22, -16
 ; LA64-NEXT:    addi.d $fp, $sp, 256
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
-; LA64-NEXT:    srli.d $a0, $sp, 8
-; LA64-NEXT:    slli.d $sp, $a0, 8
+; LA64-NEXT:    bstrins.d $sp, $zero, 7, 0
 ; LA64-NEXT:    addi.d $a0, $sp, 0
 ; LA64-NEXT:    bl %plt(callee)
 ; LA64-NEXT:    addi.d $sp, $fp, -256
@@ -313,8 +305,7 @@
 ; LA32-NEXT:    .cfi_offset 22, -8
 ; LA32-NEXT:    addi.w $fp, $sp, 1024
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
-; LA32-NEXT:    srli.w $a0, $sp, 9
-; LA32-NEXT:    slli.w $sp, $a0, 9
+; LA32-NEXT:    bstrins.w $sp, $zero, 8, 0
 ; LA32-NEXT:    addi.w $a0, $sp, 512
 ; LA32-NEXT:    bl %plt(callee)
 ; LA32-NEXT:    addi.w $sp, $fp, -1024
@@ -333,8 +324,7 @@
 ; LA64-NEXT:    .cfi_offset 22, -16
 ; LA64-NEXT:    addi.d $fp, $sp, 1024
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
-; LA64-NEXT:    srli.d $a0, $sp, 9
-; LA64-NEXT:    slli.d $sp, $a0, 9
+; LA64-NEXT:    bstrins.d $sp, $zero, 8, 0
 ; LA64-NEXT:    addi.d $a0, $sp, 512
 ; LA64-NEXT:    bl %plt(callee)
 ; LA64-NEXT:    addi.d $sp, $fp, -1024
@@ -388,8 +378,7 @@
 ; LA32-NEXT:    addi.w $fp, $sp, 2032
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
 ; LA32-NEXT:    addi.w $sp, $sp, -16
-; LA32-NEXT:    srli.w $a0, $sp, 10
-; LA32-NEXT:    slli.w $sp, $a0, 10
+; LA32-NEXT:    bstrins.w $sp, $zero, 9, 0
 ; LA32-NEXT:    addi.w $a0, $sp, 1024
 ; LA32-NEXT:    bl %plt(callee)
 ; LA32-NEXT:    addi.w $sp, $fp, -2048
@@ -410,8 +399,7 @@
 ; LA64-NEXT:    addi.d $fp, $sp, 2032
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
 ; LA64-NEXT:    addi.d $sp, $sp, -16
-; LA64-NEXT:    srli.d $a0, $sp, 10
-; LA64-NEXT:    slli.d $sp, $a0, 10
+; LA64-NEXT:    bstrins.d $sp, $zero, 9, 0
 ; LA64-NEXT:    addi.d $a0, $sp, 1024
 ; LA64-NEXT:    bl %plt(callee)
 ; LA64-NEXT:    addi.d $sp, $fp, -2048
@@ -467,8 +455,7 @@
 ; LA32-NEXT:    .cfi_def_cfa 22, 0
 ; LA32-NEXT:    addi.w $sp, $sp, -2048
 ; LA32-NEXT:    addi.w $sp, $sp, -16
-; LA32-NEXT:    srli.w $a0, $sp, 11
-; LA32-NEXT:    slli.w $sp, $a0, 11
+; LA32-NEXT:    bstrins.w $sp, $zero, 10, 0
 ; LA32-NEXT:    ori $a0, $zero, 2048
 ; LA32-NEXT:    add.w $a0, $sp, $a0
 ; LA32-NEXT:    bl %plt(callee)
@@ -493,8 +480,7 @@
 ; LA64-NEXT:    .cfi_def_cfa 22, 0
 ; LA64-NEXT:    addi.d $sp, $sp, -2048
 ; LA64-NEXT:    addi.d $sp, $sp, -16
-; LA64-NEXT:    srli.d $a0, $sp, 11
-; LA64-NEXT:    slli.d $sp, $a0, 11
+; LA64-NEXT:    bstrins.d $sp, $zero, 10, 0
 ; LA64-NEXT:    ori $a0, $zero, 2048
 ; LA64-NEXT:    add.d $a0, $sp, $a0
 ; LA64-NEXT:    bl %plt(callee)
@@ -554,8 +540,7 @@
 ; LA32-NEXT:    lu12i.w $a0, 1
 ; LA32-NEXT:    ori $a0, $a0, 2064
 ; LA32-NEXT:    sub.w $sp, $sp, $a0
-; LA32-NEXT:    srli.w $a0, $sp, 12
-; LA32-NEXT:    slli.w $sp, $a0, 12
+; LA32-NEXT:    bstrins.w $sp, $zero, 11, 0
 ; LA32-NEXT:    lu12i.w $a0, 1
 ; LA32-NEXT:    add.w $a0, $sp, $a0
 ; LA32-NEXT:    bl %plt(callee)
@@ -582,8 +567,7 @@
 ; LA64-NEXT:    lu12i.w $a0, 1
 ; LA64-NEXT:    ori $a0, $a0, 2064
 ; LA64-NEXT:    sub.d $sp, $sp, $a0
-; LA64-NEXT:    srli.d $a0, $sp, 12
-; LA64-NEXT:    slli.d $sp, $a0, 12
+; LA64-NEXT:    bstrins.d $sp, $zero, 11, 0
 ; LA64-NEXT:    lu12i.w $a0, 1
 ; LA64-NEXT:    add.d $a0, $sp, $a0
 ; LA64-NEXT:    bl %plt(callee)