Index: llvm/include/llvm/Support/TypeSize.h
===================================================================
--- llvm/include/llvm/Support/TypeSize.h
+++ llvm/include/llvm/Support/TypeSize.h
@@ -49,6 +49,13 @@
     return { Min / RHS, Scalable };
   }
 
+  friend ElementCount operator-(const ElementCount &LHS,
+                                const ElementCount &RHS) {
+    assert(LHS.Scalable == RHS.Scalable &&
+           "Arithmetic using mixed scalable and fixed types");
+    return {LHS.Min - RHS.Min, LHS.Scalable};
+  }
+
   bool operator==(const ElementCount& RHS) const {
     return Min == RHS.Min && Scalable == RHS.Scalable;
   }
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -718,7 +718,7 @@
 
   LLVM_DEBUG(dbgs() << "Legalizing extending load operation\n");
   EVT SrcVT = LD->getMemoryVT();
-  unsigned SrcWidth = SrcVT.getSizeInBits();
+  TypeSize SrcWidth = SrcVT.getSizeInBits();
   MachineMemOperand::Flags MMOFlags = LD->getMemOperand()->getFlags();
   AAMDNodes AAInfo = LD->getAAInfo();
 
@@ -764,14 +764,15 @@
 
     Value = Result;
     Chain = Ch;
-  } else if (SrcWidth & (SrcWidth - 1)) {
+  } else if (!isPowerOf2_32(SrcWidth.getKnownMinSize())) {
     // If not loading a power-of-2 number of bits, expand as two loads.
     assert(!SrcVT.isVector() && "Unsupported extload!");
-    unsigned LogSrcWidth = Log2_32(SrcWidth);
+    unsigned SrcWidthBits = SrcWidth.getFixedSize();
+    unsigned LogSrcWidth = Log2_32(SrcWidthBits);
     assert(LogSrcWidth < 32);
     unsigned RoundWidth = 1 << LogSrcWidth;
-    assert(RoundWidth < SrcWidth);
-    unsigned ExtraWidth = SrcWidth - RoundWidth;
+    assert(RoundWidth < SrcWidthBits);
+    unsigned ExtraWidth = SrcWidthBits - RoundWidth;
     assert(ExtraWidth < RoundWidth);
     assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
            "Load size not an integral number of bytes!");
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -1636,9 +1636,10 @@
   else
     std::tie(PassThruLo, PassThruHi) = DAG.SplitVector(PassThru, dl);
 
+  unsigned LoSize = MemoryLocation::getSizeOrUnknown(LoMemVT.getStoreSize());
   MachineMemOperand *MMO = DAG.getMachineFunction().getMachineMemOperand(
-      MLD->getPointerInfo(), MachineMemOperand::MOLoad, LoMemVT.getStoreSize(),
-      Alignment, MLD->getAAInfo(), MLD->getRanges());
+      MLD->getPointerInfo(), MachineMemOperand::MOLoad, LoSize, Alignment,
+      MLD->getAAInfo(), MLD->getRanges());
 
   Lo = DAG.getMaskedLoad(LoVT, dl, Ch, Ptr, Offset, MaskLo, PassThruLo, LoMemVT,
                          MMO, MLD->getAddressingMode(), ExtType,
@@ -1652,12 +1653,18 @@
     // Generate hi masked load.
     Ptr = TLI.IncrementMemoryAddress(Ptr, MaskLo, dl, LoMemVT, DAG,
                                      MLD->isExpandingLoad());
-    unsigned HiOffset = LoMemVT.getStoreSize();
+    unsigned HiSize = MemoryLocation::getSizeOrUnknown(HiMemVT.getStoreSize());
+
+    MachinePointerInfo MPI;
+    if (LoMemVT.isScalableVector())
+      MPI = MachinePointerInfo(MLD->getPointerInfo().getAddrSpace());
+    else
+      MPI = MLD->getPointerInfo().getWithOffset(
+          LoMemVT.getStoreSize().getFixedSize());
 
     MMO = DAG.getMachineFunction().getMachineMemOperand(
-        MLD->getPointerInfo().getWithOffset(HiOffset),
-        MachineMemOperand::MOLoad, HiMemVT.getStoreSize(), Alignment,
-        MLD->getAAInfo(), MLD->getRanges());
+        MPI, MachineMemOperand::MOLoad, HiSize, Alignment, MLD->getAAInfo(),
+        MLD->getRanges());
 
     Hi = DAG.getMaskedLoad(HiVT, dl, Ch, Ptr, Offset, MaskHi, PassThruHi,
                            HiMemVT, MMO, MLD->getAddressingMode(), ExtType,
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6979,7 +6979,7 @@
     assert(VT.isVector() == MemVT.isVector() &&
            "Cannot use an ext load to convert to or from a vector!");
     assert((!VT.isVector() ||
-            VT.getVectorNumElements() == MemVT.getVectorNumElements()) &&
+            VT.getVectorElementCount() == MemVT.getVectorElementCount()) &&
            "Cannot use an ext load to change the number of vector elements!");
   }
 
@@ -9633,24 +9633,24 @@
 SelectionDAG::GetDependentSplitDestVTs(const EVT &VT, const EVT &EnvVT,
                                        bool *HiIsEmpty) const {
   EVT EltTp = VT.getVectorElementType();
-  bool IsScalable = VT.isScalableVector();
   // Examples:
   //   custom VL=8  with enveloping VL=8/8 yields 8/0 (hi empty)
   //   custom VL=9  with enveloping VL=8/8 yields 8/1
   //   custom VL=10 with enveloping VL=8/8 yields 8/2
   //   etc.
-  unsigned VTNumElts = VT.getVectorNumElements();
-  unsigned EnvNumElts = EnvVT.getVectorNumElements();
+  ElementCount VTNumElts = VT.getVectorElementCount();
+  ElementCount EnvNumElts = EnvVT.getVectorElementCount();
+  assert(VTNumElts.isScalable() == EnvNumElts.isScalable() &&
+         "Mixing fixed width and scalable vectors when enveloping a type");
   EVT LoVT, HiVT;
-  if (VTNumElts > EnvNumElts) {
+  if (VTNumElts.getKnownMinValue() > EnvNumElts.getKnownMinValue()) {
     LoVT = EnvVT;
-    HiVT = EVT::getVectorVT(*getContext(), EltTp, VTNumElts - EnvNumElts,
-                            IsScalable);
+    HiVT = EVT::getVectorVT(*getContext(), EltTp, VTNumElts - EnvNumElts);
     *HiIsEmpty = false;
   } else {
     // Flag that hi type has zero storage size, but return split envelop type
     // (this would be easier if vector types with zero elements were allowed).
-    LoVT = EVT::getVectorVT(*getContext(), EltTp, VTNumElts, IsScalable);
+    LoVT = EVT::getVectorVT(*getContext(), EltTp, VTNumElts);
     HiVT = EnvVT;
     *HiIsEmpty = true;
   }
Index: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -7205,7 +7205,7 @@
   SDValue Increment;
   EVT AddrVT = Addr.getValueType();
   EVT MaskVT = Mask.getValueType();
-  assert(DataVT.getVectorNumElements() == MaskVT.getVectorNumElements() &&
+  assert(DataVT.getVectorElementCount() == MaskVT.getVectorElementCount() &&
          "Incompatible types of Data and Mask");
   if (IsCompressedMemory) {
     if (DataVT.isScalableVector())
Index: llvm/test/CodeGen/AArch64/sve-split-load.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sve-split-load.ll
+++ llvm/test/CodeGen/AArch64/sve-split-load.ll
@@ -1,5 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; If this check fails please read test/CodeGen/AArch64/README for instructions on how to resolve it.
+; WARN-NOT: warning
 
 ; UNPREDICATED