diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2878,6 +2878,50 @@
   return convertFromScalableVector(VT, Res, DAG, Subtarget);
 }
 
+// Lower the following shuffle to vslidedown.
+// t49: v8i8 = extract_subvector t13, Constant:i64<0>
+// t109: v8i8 = extract_subvector t12, Constant:i64<8>
+// t108: v8i8 = vector_shuffle<1,2,3,4,5,6,7,8> t49, t106
+static SDValue lowerVECTOR_SHUFFLEAsVSlidedown(const SDLoc &DL, MVT VT,
+                                               SDValue V1, SDValue V2,
+                                               ArrayRef<int> Mask,
+                                               const RISCVSubtarget &Subtarget,
+                                               SelectionDAG &DAG) {
+  // Both input must be extracts.
+  if (V1.getOpcode() != ISD::EXTRACT_SUBVECTOR ||
+      V2.getOpcode() != ISD::EXTRACT_SUBVECTOR)
+    return SDValue();
+
+  // Extracting from the same source.
+  SDValue Src = V1.getOperand(0);
+  if (Src != V2.getOperand(0))
+    return SDValue();
+
+  // V1 and V2 are continuous.
+  if (V1.getConstantOperandVal(1) +
+          V1.getSimpleValueType().getVectorNumElements() !=
+      V2.getConstantOperandVal(1))
+    return SDValue();
+
+  // Mask is also continuous.
+  for (unsigned i = 1; i != Mask.size(); ++i)
+    if (Mask[i - 1] + 1 != Mask[i])
+      return SDValue();
+
+  MVT XLenVT = Subtarget.getXLenVT();
+  MVT SrcVT = Src.getSimpleValueType();
+  MVT ContainerVT = getContainerForFixedLengthVector(DAG, SrcVT, Subtarget);
+  auto [TrueMask, VL] = getDefaultVLOps(SrcVT, ContainerVT, DL, DAG, Subtarget);
+  SDValue Slidedown = DAG.getNode(
+      RISCVISD::VSLIDEDOWN_VL, DL, ContainerVT, DAG.getUNDEF(ContainerVT),
+      convertToScalableVector(ContainerVT, Src, DAG, Subtarget),
+      DAG.getConstant(Mask[0], DL, XLenVT), TrueMask, VL);
+  return DAG.getNode(
+      ISD::EXTRACT_SUBVECTOR, DL, VT,
+      convertFromScalableVector(SrcVT, Slidedown, DAG, Subtarget),
+      DAG.getConstant(0, DL, XLenVT));
+}
+
 static SDValue lowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG,
                                    const RISCVSubtarget &Subtarget) {
   SDValue V1 = Op.getOperand(0);
@@ -2969,6 +3013,10 @@
 
   ArrayRef<int> Mask = SVN->getMask();
 
+  if (SDValue V =
+          lowerVECTOR_SHUFFLEAsVSlidedown(DL, VT, V1, V2, Mask, Subtarget, DAG))
+    return V;
+
   // Lower rotations to a SLIDEDOWN and a SLIDEUP. One of the source vectors may
   // be undef which can be handled with a single SLIDEDOWN/UP.
   int LoSrc, HiSrc;
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-shuffles.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-shuffles.ll
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-shuffles.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-shuffles.ll
@@ -226,6 +226,39 @@
   ret <4 x double> %s
 }
 
+define <4 x half> @shuffle_v8f16_to_vslidedown_1(<8 x half> %x) {
+; CHECK-LABEL: shuffle_v8f16_to_vslidedown_1:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; CHECK-NEXT:    vslidedown.vi v8, v8, 1
+; CHECK-NEXT:    ret
+entry:
+  %s = shufflevector <8 x half> %x, <8 x half> poison, <4 x i32> <i32 1, i32 2, i32 3, i32 4>
+  ret <4 x half> %s
+}
+
+define <4 x half> @shuffle_v8f16_to_vslidedown_3(<8 x half> %x) {
+; CHECK-LABEL: shuffle_v8f16_to_vslidedown_3:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; CHECK-NEXT:    vslidedown.vi v8, v8, 3
+; CHECK-NEXT:    ret
+entry:
+  %s = shufflevector <8 x half> %x, <8 x half> poison, <4 x i32> <i32 3, i32 4, i32 5, i32 6>
+  ret <4 x half> %s
+}
+
+define <2 x float> @shuffle_v4f32_to_vslidedown(<4 x float> %x) {
+; CHECK-LABEL: shuffle_v4f32_to_vslidedown:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 4, e32, m1, ta, ma
+; CHECK-NEXT:    vslidedown.vi v8, v8, 1
+; CHECK-NEXT:    ret
+entry:
+  %s = shufflevector <4 x float> %x, <4 x float> poison, <2 x i32> <i32 1, i32 2>
+  ret <2 x float> %s
+}
+
 define <4 x half> @slidedown_v4f16(<4 x half> %x) {
 ; CHECK-LABEL: slidedown_v4f16:
 ; CHECK:       # %bb.0:
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
@@ -292,6 +292,39 @@
   ret <8 x i64> %s
 }
 
+define <4 x i16> @shuffle_v8i16_to_vslidedown_1(<8 x i16> %x) {
+; CHECK-LABEL: shuffle_v8i16_to_vslidedown_1:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; CHECK-NEXT:    vslidedown.vi v8, v8, 1
+; CHECK-NEXT:    ret
+entry:
+  %s = shufflevector <8 x i16> %x, <8 x i16> poison, <4 x i32> <i32 1, i32 2, i32 3, i32 4>
+  ret <4 x i16> %s
+}
+
+define <4 x i16> @shuffle_v8i16_to_vslidedown_3(<8 x i16> %x) {
+; CHECK-LABEL: shuffle_v8i16_to_vslidedown_3:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; CHECK-NEXT:    vslidedown.vi v8, v8, 3
+; CHECK-NEXT:    ret
+entry:
+  %s = shufflevector <8 x i16> %x, <8 x i16> poison, <4 x i32> <i32 3, i32 4, i32 5, i32 6>
+  ret <4 x i16> %s
+}
+
+define <2 x i32> @shuffle_v4i32_to_vslidedown(<4 x i32> %x) {
+; CHECK-LABEL: shuffle_v4i32_to_vslidedown:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 4, e32, m1, ta, ma
+; CHECK-NEXT:    vslidedown.vi v8, v8, 1
+; CHECK-NEXT:    ret
+entry:
+  %s = shufflevector <4 x i32> %x, <4 x i32> poison, <2 x i32> <i32 1, i32 2>
+  ret <2 x i32> %s
+}
+
 define <4 x i8> @interleave_shuffles(<4 x i8> %x) {
 ; CHECK-LABEL: interleave_shuffles:
 ; CHECK:       # %bb.0: