diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -571,6 +571,13 @@
   /// implicitly truncated to it.
   SPLAT_VECTOR,
 
+  /// SPLAT_VECTOR_PARTS(Hi, Lo) - Returns a vector with the scalar
+  /// values Lo and Hi joined together and then duplicated in all lanes. This
+  /// represents a SPLAT_VECTOR that has had its scalar operand expanded. The
+  /// total width of the scalars must cover the element width. This allows
+  /// representing a 64-bit splat on a target with 32-bit integers.
+  SPLAT_VECTOR_PARTS,
+
   /// MULHU/MULHS - Multiply high - Multiply two integers of type iN,
   /// producing an unsigned/signed value of type i[2*N], then return the top
   /// part.
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -4192,6 +4192,7 @@
   case ISD::EXTRACT_ELEMENT:   Res = ExpandOp_EXTRACT_ELEMENT(N); break;
   case ISD::INSERT_VECTOR_ELT: Res = ExpandOp_INSERT_VECTOR_ELT(N); break;
   case ISD::SCALAR_TO_VECTOR:  Res = ExpandOp_SCALAR_TO_VECTOR(N); break;
+  case ISD::SPLAT_VECTOR:      Res = ExpandIntOp_SPLAT_VECTOR(N); break;
   case ISD::SELECT_CC:         Res = ExpandIntOp_SELECT_CC(N); break;
   case ISD::SETCC:             Res = ExpandIntOp_SETCC(N); break;
   case ISD::SETCCCARRY:        Res = ExpandIntOp_SETCCCARRY(N); break;
@@ -4447,6 +4448,14 @@
                      LowCmp.getValue(1), Cond);
 }
 
+SDValue DAGTypeLegalizer::ExpandIntOp_SPLAT_VECTOR(SDNode *N) {
+  // Split the operand and replace with SPLAT_VECTOR_PARTS.
+  SDValue Lo, Hi;
+  GetExpandedInteger(N->getOperand(0), Lo, Hi);
+  return DAG.getNode(ISD::SPLAT_VECTOR_PARTS, SDLoc(N), N->getValueType(0), Lo,
+                     Hi);
+}
+
 SDValue DAGTypeLegalizer::ExpandIntOp_Shift(SDNode *N) {
   // The value being shifted is legal, but the shift amount is too big.
   // It follows that either the result of the shift is undefined, or the
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -480,6 +480,7 @@
   SDValue ExpandIntOp_UINT_TO_FP(SDNode *N);
   SDValue ExpandIntOp_RETURNADDR(SDNode *N);
   SDValue ExpandIntOp_ATOMIC_STORE(SDNode *N);
+  SDValue ExpandIntOp_SPLAT_VECTOR(SDNode *N);
 
   void IntegerExpandSetCCOperands(SDValue &NewLHS, SDValue &NewRHS,
                                   ISD::CondCode &CCCode, const SDLoc &dl);
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1372,6 +1372,22 @@
     const APInt &NewVal = Elt->getValue();
     EVT ViaEltVT = TLI->getTypeToTransformTo(*getContext(), EltVT);
     unsigned ViaEltSizeInBits = ViaEltVT.getSizeInBits();
+
+    // For scalable vectors, try to use a SPLAT_VECTOR_PARTS node.
+    if (VT.isScalableVector()) {
+      assert(EltVT.getSizeInBits() % ViaEltSizeInBits == 0 &&
+             "Can only handle an even split!");
+      unsigned Parts = EltVT.getSizeInBits() / ViaEltSizeInBits;
+      assert(Parts == 2 && "Can't handle more than 2 parts yet!");
+
+      SDValue Lo =
+          getConstant(NewVal.trunc(ViaEltSizeInBits), DL, ViaEltVT, isT, isO);
+      SDValue Hi =
+          getConstant(NewVal.lshr(ViaEltSizeInBits).trunc(ViaEltSizeInBits), DL,
+                      ViaEltVT, isT, isO);
+      return getNode(ISD::SPLAT_VECTOR_PARTS, DL, VT, Lo, Hi);
+    }
+
     unsigned ViaVecNumElts = VT.getSizeInBits() / ViaEltSizeInBits;
     EVT ViaVecVT = EVT::getVectorVT(*getContext(), ViaEltVT, ViaVecNumElts);
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -289,6 +289,7 @@
   case ISD::SCALAR_TO_VECTOR:           return "scalar_to_vector";
   case ISD::VECTOR_SHUFFLE:             return "vector_shuffle";
   case ISD::SPLAT_VECTOR:               return "splat_vector";
+  case ISD::SPLAT_VECTOR_PARTS:         return "splat_vector_parts";
   case ISD::VECTOR_REVERSE:             return "vector_reverse";
   case ISD::CARRY_FALSE:                return "carry_false";
   case ISD::ADDC:                       return "addc";
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -430,7 +430,7 @@
   SDValue lowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerShiftRightParts(SDValue Op, SelectionDAG &DAG, bool IsSRA) const;
-  SDValue lowerSPLATVECTOR(SDValue Op, SelectionDAG &DAG) const;
+  SDValue lowerSPLAT_VECTOR_PARTS(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerVectorMaskExt(SDValue Op, SelectionDAG &DAG,
                              int64_t ExtTrueVal) const;
   SDValue lowerVectorMaskTrunc(SDValue Op, SelectionDAG &DAG) const;
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
@@ -400,7 +400,6 @@
     } else {
       // We must custom-lower certain vXi64 operations on RV32 due to the vector
       // element type being illegal.
-      setOperationAction(ISD::SPLAT_VECTOR, MVT::i64, Custom);
       setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::i64, Custom);
       setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::i64, Custom);
 
@@ -425,15 +424,13 @@
 
     for (MVT VT : IntVecVTs) {
       setOperationAction(ISD::SPLAT_VECTOR, VT, Legal);
+      setOperationAction(ISD::SPLAT_VECTOR_PARTS, VT, Custom);
 
       setOperationAction(ISD::SMIN, VT, Legal);
       setOperationAction(ISD::SMAX, VT, Legal);
       setOperationAction(ISD::UMIN, VT, Legal);
       setOperationAction(ISD::UMAX, VT, Legal);
 
-      if (!Subtarget.is64Bit() && VT.getVectorElementType() == MVT::i64)
-        setOperationAction(ISD::ABS, VT, Custom);
-
       setOperationAction(ISD::ROTL, VT, Expand);
       setOperationAction(ISD::ROTR, VT, Expand);
 
@@ -1288,8 +1285,8 @@
         Op.getOperand(0).getValueType().getVectorElementType() == MVT::i1)
       return lowerVectorMaskExt(Op, DAG, /*ExtVal*/ -1);
     return lowerFixedLengthVectorExtendToRVV(Op, DAG, RISCVISD::VSEXT_VL);
-  case ISD::SPLAT_VECTOR:
-    return lowerSPLATVECTOR(Op, DAG);
+  case ISD::SPLAT_VECTOR_PARTS:
+    return lowerSPLAT_VECTOR_PARTS(Op, DAG);
   case ISD::INSERT_VECTOR_ELT:
     return lowerINSERT_VECTOR_ELT(Op, DAG);
   case ISD::EXTRACT_VECTOR_ELT:
@@ -2013,30 +2010,27 @@
   return DAG.getMergeValues(Parts, DL);
 }
 
-// Custom-lower a SPLAT_VECTOR where XLEN<SEW, as the SEW element type is
+// Custom-lower a SPLAT_VECTOR_PARTS where XLEN<SEW, as the SEW element type is
 // illegal (currently only vXi64 RV32).
 // FIXME: We could also catch non-constant sign-extended i32 values and lower
 // them to SPLAT_VECTOR_I64
-SDValue RISCVTargetLowering::lowerSPLATVECTOR(SDValue Op,
-                                              SelectionDAG &DAG) const {
+SDValue RISCVTargetLowering::lowerSPLAT_VECTOR_PARTS(SDValue Op,
+                                                     SelectionDAG &DAG) const {
   SDLoc DL(Op);
   EVT VecVT = Op.getValueType();
   assert(!Subtarget.is64Bit() && VecVT.getVectorElementType() == MVT::i64 &&
-         "Unexpected SPLAT_VECTOR lowering");
-  SDValue SplatVal = Op.getOperand(0);
+         "Unexpected SPLAT_VECTOR_PARTS lowering");
 
-  // If we can prove that the value is a sign-extended 32-bit value, lower this
-  // as a custom node in order to try and match RVV vector/scalar instructions.
-  if (auto *CVal = dyn_cast<ConstantSDNode>(SplatVal)) {
-    if (isInt<32>(CVal->getSExtValue()))
-      return DAG.getNode(RISCVISD::SPLAT_VECTOR_I64, DL, VecVT,
-                         DAG.getConstant(CVal->getSExtValue(), DL, MVT::i32));
-  }
+  SDValue Lo = Op.getOperand(0);
+  SDValue Hi = Op.getOperand(1);
 
-  if (SplatVal.getOpcode() == ISD::SIGN_EXTEND &&
-      SplatVal.getOperand(0).getValueType() == MVT::i32) {
-    return DAG.getNode(RISCVISD::SPLAT_VECTOR_I64, DL, VecVT,
-                       SplatVal.getOperand(0));
+  if (isa<ConstantSDNode>(Lo) && isa<ConstantSDNode>(Hi)) {
+    int32_t LoC = cast<ConstantSDNode>(Lo)->getSExtValue();
+    int32_t HiC = cast<ConstantSDNode>(Hi)->getSExtValue();
+    // If Hi constant is all the same sign bit as Lo, lower this as a custom
+    // node in order to try and match RVV vector/scalar instructions.
+    if ((LoC >> 31) == HiC)
+      return DAG.getNode(RISCVISD::SPLAT_VECTOR_I64, DL, VecVT, Lo);
   }
 
   // Else, on RV32 we lower an i64-element SPLAT_VECTOR thus, being careful not
@@ -2047,11 +2041,7 @@
   // vsll.vx vY, vY, /*32*/
   // vsrl.vx vY, vY, /*32*/
   // vor.vv vX, vX, vY
-  SDValue One = DAG.getConstant(1, DL, MVT::i32);
-  SDValue Zero = DAG.getConstant(0, DL, MVT::i32);
   SDValue ThirtyTwoV = DAG.getConstant(32, DL, VecVT);
-  SDValue Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, SplatVal, Zero);
-  SDValue Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, SplatVal, One);
 
   Lo = DAG.getNode(RISCVISD::SPLAT_VECTOR_I64, DL, VecVT, Lo);
   Lo = DAG.getNode(ISD::SHL, DL, VecVT, Lo, ThirtyTwoV);
@@ -2920,17 +2910,6 @@
   MVT VT = Op.getSimpleValueType();
   SDValue X = Op.getOperand(0);
 
-  // For scalable vectors we just need to deal with i64 on RV32 since the
-  // default expansion crashes in getConstant.
-  if (VT.isScalableVector()) {
-    assert(!Subtarget.is64Bit() && VT.getVectorElementType() == MVT::i64 &&
-           "Unexpected custom lowering!");
-    SDValue SplatZero = DAG.getNode(RISCVISD::SPLAT_VECTOR_I64, DL, VT,
-                                    DAG.getConstant(0, DL, MVT::i32));
-    SDValue NegX = DAG.getNode(ISD::SUB, DL, VT, SplatZero, X);
-    return DAG.getNode(ISD::SMAX, DL, VT, X, NegX);
-  }
-
   assert(VT.isFixedLengthVector() && "Unexpected type");
 
   MVT ContainerVT =