[CodeGen][SVE] Calculate correct type legalization for scalable vectors.

[sdesmalen]

Summary

This patch updates TargetLoweringBase::computeRegisterProperties and
TargetLoweringBase::getTypeConversion to support scalable vectors,
and make the right calls on how to legalise them. These changes are required
to legalise both MVTs and EVTs.

[efriedma]

llvm/include/llvm/CodeGen/TargetLowering.h

189

getTypeAction() and getTypeToTransformTo() are public; the unittest can use those APIs.

llvm/lib/CodeGen/TargetLoweringBase.cpp

942

report_fatal_error, and please move this up to just after the NumElts.isOne() check. (The EltVT.isInteger() code also assumes the element count can be divided by two.)

1350

We probably want a new LegalizeTypeAction kind to represent this. I guess just leaving it TypeLegal isn't too terrible for now, though.

[david-arm]

llvm/include/llvm/Support/TypeSize.h

54

Alternatively here we could have a more powerful isEqual() where we pass an unsigned integer of the same type in ElementCount, then you can simply do:

if (EC.isEqual(1)) { ... }

The function would look like

bool isEqual(const unsigned RHS) const {
  return Min == RHS && !Scalable;
}

If you don't want to do that in this patch that's fine, but it might be more generic?

llvm/lib/CodeGen/TargetLoweringBase.cpp

826

Instead of calling EVT::getVectorVT, could we just call SVT.getHalfNumVectorElementsVT() instead? It does the same thing.

[sdesmalen]

• Use public interfaces in tests (getTypeAction and getTypeToTransformTo)
• Changed llvm_unreachable -> report_fatal_error
• Added operator==(unsigned RHS) to ElementCount in favour of isOne()

[sdesmalen]

llvm/lib/CodeGen/TargetLoweringBase.cpp

1350

Something like TypeCannotBeLegalized?

[efriedma]

llvm/lib/CodeGen/TargetLoweringBase.cpp

1350

I was thinking something more like "TypeScalarizeVScaleVector". It's theoretically possible to legalize... although it's complicated by the fact that we can't easily emit loops in SelectionDAG.

[sdesmalen]

Added TypeScalarizeScalableVector enum value.

[efriedma]

LGTM

[foad]

@sdesmalen this is causing test failures in my DEBUG build:

Failing Tests (4):
  LLVM :: CodeGen/AMDGPU/fmax_legacy.f16.ll
  LLVM :: CodeGen/AMDGPU/fmin_legacy.f16.ll
  LLVM :: CodeGen/AMDGPU/select-vectors.ll
  LLVM :: CodeGen/AMDGPU/select.f16.ll

[sdesmalen]

In D80640#2076508, @foad wrote:

@sdesmalen this is causing test failures in my DEBUG build:

Failing Tests (4):
  LLVM :: CodeGen/AMDGPU/fmax_legacy.f16.ll
  LLVM :: CodeGen/AMDGPU/fmin_legacy.f16.ll
  LLVM :: CodeGen/AMDGPU/select-vectors.ll
  LLVM :: CodeGen/AMDGPU/select.f16.ll

Yes sorry for that. I had already reverted the patch and am looking into it. Cheers for pointing out!

llvm/include/llvm/CodeGen/TargetLowering.h

public:
   bool isAligned(Align AlignCheck) const {
     return isSrcAligned(AlignCheck) && isDstAligned(AlignCheck);
   }
 };
 
 /// This base class for TargetLowering contains the SelectionDAG-independent
 /// parts that can be used from the rest of CodeGen.
 class TargetLoweringBase {
 public:
   /// This enum indicates whether operations are valid for a target, and if not,
   /// what action should be used to make them valid.
   enum LegalizeAction : uint8_t {
     Legal,      // The target natively supports this operation.
     Promote,    // This operation should be executed in a larger type.
     Expand,     // Try to expand this to other ops, otherwise use a libcall.
     LibCall,    // Don't try to expand this to other ops, always use a libcall.
     Custom      // Use the LowerOperation hook to implement custom lowering.
   };
 
   /// This enum indicates whether a types are legal for a target, and if not,
   /// what action should be used to make them valid.
   enum LegalizeTypeAction : uint8_t {
     TypeLegal,           // The target natively supports this type.
     TypePromoteInteger,  // Replace this integer with a larger one.
     TypeExpandInteger,   // Split this integer into two of half the size.
     TypeSoftenFloat,     // Convert this float to a same size integer type.
     TypeExpandFloat,     // Split this float into two of half the size.
     TypeScalarizeVector, // Replace this one-element vector with its element.
     TypeSplitVector,     // Split this vector into two of half the size.
     TypeWidenVector,     // This vector should be widened into a larger vector.
     TypePromoteFloat,    // Replace this float with a larger one.
     TypeSoftPromoteHalf, // Soften half to i16 and use float to do arithmetic.
+    TypeScalarizeScalableVector, // This action is explicitly left unimplemented.
+                                 // While it is theoretically possible to
+                                 // legalize operations on scalable types with a
+                                 // loop that handles the vscale * #lanes of the
+                                 // vector, this is non-trivial at SelectionDAG
+                                 // level and these types are better to be
+                                 // widened or promoted.
   };
 
   /// LegalizeKind holds the legalization kind that needs to happen to EVT
   /// in order to type-legalize it.
   using LegalizeKind = std::pair<LegalizeTypeAction, EVT>;
 
   /// Enum that describes how the target represents true/false values.
   enum BooleanContent {
public:
 
   /// Return true if the target has BitExtract instructions.
   bool hasExtractBitsInsn() const { return HasExtractBitsInsn; }
 
   /// Return the preferred vector type legalization action.
   virtual TargetLoweringBase::LegalizeTypeAction
   getPreferredVectorAction(MVT VT) const {
     // The default action for one element vectors is to scalarize
-    if (VT.getVectorNumElements() == 1)
+    if (VT.getVectorElementCount() == 1)
       return TypeScalarizeVector;
     // The default action for an odd-width vector is to widen.
     if (!VT.isPow2VectorType())
       return TypeWidenVector;
     // The default action for other vectors is to promote
     return TypePromoteInteger;
   }
 

llvm/include/llvm/Support/TypeSize.h

 // which may be scalable vectors. It provides convenience operators so that
 // it can be used in much the same way as a single scalar value.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_SUPPORT_TYPESIZE_H
 #define LLVM_SUPPORT_TYPESIZE_H
 
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/WithColor.h"
 
 #include <cstdint>
 #include <cassert>
 
 namespace llvm {
 
 template <typename T> struct DenseMapInfo;
public:
   }
 
   bool operator==(const ElementCount& RHS) const {
     return Min == RHS.Min && Scalable == RHS.Scalable;
   }
   bool operator!=(const ElementCount& RHS) const {
     return !(*this == RHS);
   }
+  bool operator==(unsigned RHS) const { return Min == RHS && !Scalable; }
+  bool operator!=(unsigned RHS) const { return !(*this == RHS); }
+
+  ElementCount NextPowerOf2() const {
+    return ElementCount(llvm::NextPowerOf2(Min), Scalable);
+  }
 };
 
 // This class is used to represent the size of types. If the type is of fixed
 // size, it will represent the exact size. If the type is a scalable vector,
 // it will represent the known minimum size.
 class TypeSize {
   uint64_t MinSize;   // The known minimum size.
   bool IsScalable;    // If true, then the runtime size is an integer multiple

llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

SDValue DAGTypeLegalizer::PromoteIntRes_BITCAST(SDNode *N) {
   case TargetLowering::TypeExpandFloat:
     break;
   case TargetLowering::TypeScalarizeVector:
     // Convert the element to an integer and promote it by hand.
     if (!NOutVT.isVector())
       return DAG.getNode(ISD::ANY_EXTEND, dl, NOutVT,
                          BitConvertToInteger(GetScalarizedVector(InOp)));
     break;
+  case TargetLowering::TypeScalarizeScalableVector:
+    report_fatal_error("Scalarization of scalable vectors is not supported.");
   case TargetLowering::TypeSplitVector: {
     if (!NOutVT.isVector()) {
       // For example, i32 = BITCAST v2i16 on alpha.  Convert the split
       // pieces of the input into integers and reassemble in the final type.
       SDValue Lo, Hi;
       GetSplitVector(N->getOperand(0), Lo, Hi);
       Lo = BitConvertToInteger(Lo);
       Hi = BitConvertToInteger(Hi);

llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp

#endif
     for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
       EVT ResultVT = N->getValueType(i);
       LLVM_DEBUG(dbgs() << "Analyzing result type: " << ResultVT.getEVTString()
                         << "\n");
       switch (getTypeAction(ResultVT)) {
       case TargetLowering::TypeLegal:
         LLVM_DEBUG(dbgs() << "Legal result type\n");
         break;
+      case TargetLowering::TypeScalarizeScalableVector:
+        report_fatal_error(
+            "Scalarization of scalable vectors is not supported.");
       // The following calls must take care of *all* of the node's results,
       // not just the illegal result they were passed (this includes results
       // with a legal type).  Results can be remapped using ReplaceValueWith,
       // or their promoted/expanded/etc values registered in PromotedIntegers,
       // ExpandedIntegers etc.
       case TargetLowering::TypePromoteInteger:
         PromoteIntegerResult(N, i);
         Changed = true;
for (i = 0; i != NumOperands; ++i) {
 
       const auto Op = N->getOperand(i);
       LLVM_DEBUG(dbgs() << "Analyzing operand: "; Op.dump(&DAG));
       EVT OpVT = Op.getValueType();
       switch (getTypeAction(OpVT)) {
       case TargetLowering::TypeLegal:
         LLVM_DEBUG(dbgs() << "Legal operand\n");
         continue;
+      case TargetLowering::TypeScalarizeScalableVector:
+        report_fatal_error(
+            "Scalarization of scalable vectors is not supported.");
       // The following calls must either replace all of the node's results
       // using ReplaceValueWith, and return "false"; or update the node's
       // operands in place, and return "true".
       case TargetLowering::TypePromoteInteger:
         NeedsReanalyzing = PromoteIntegerOperand(N, i);
         Changed = true;
         break;
       case TargetLowering::TypeExpandInteger:

llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp

case TargetLowering::TypeSplitVector:
       Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
       return;
     case TargetLowering::TypeScalarizeVector:
       // Convert the element instead.
       SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi);
       Lo = DAG.getNode(ISD::BITCAST, dl, NOutVT, Lo);
       Hi = DAG.getNode(ISD::BITCAST, dl, NOutVT, Hi);
       return;
+    case TargetLowering::TypeScalarizeScalableVector:
+      report_fatal_error("Scalarization of scalable vectors is not supported.");
     case TargetLowering::TypeWidenVector: {
       assert(!(InVT.getVectorNumElements() & 1) && "Unsupported BITCAST");
       InOp = GetWidenedVector(InOp);
       EVT LoVT, HiVT;
       std::tie(LoVT, HiVT) = DAG.GetSplitDestVTs(InVT);
       std::tie(Lo, Hi) = DAG.SplitVector(InOp, dl, LoVT, HiVT);
       if (TLI.hasBigEndianPartOrdering(OutVT, DAG.getDataLayout()))
         std::swap(Lo, Hi);

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

case TargetLowering::TypeExpandFloat:
     break;
   case TargetLowering::TypeSplitVector:
     // If the input is a vector that needs to be split, convert each split
     // piece of the input now.
     GetSplitVector(InOp, Lo, Hi);
     Lo = DAG.getNode(ISD::BITCAST, dl, LoVT, Lo);
     Hi = DAG.getNode(ISD::BITCAST, dl, HiVT, Hi);
     return;
+  case TargetLowering::TypeScalarizeScalableVector:
+    report_fatal_error("Scalarization of scalable vectors is not supported.");
   }
 
   // In the general case, convert the input to an integer and split it by hand.
   EVT LoIntVT = EVT::getIntegerVT(*DAG.getContext(), LoVT.getSizeInBits());
   EVT HiIntVT = EVT::getIntegerVT(*DAG.getContext(), HiVT.getSizeInBits());
   if (DAG.getDataLayout().isBigEndian())
     std::swap(LoIntVT, HiIntVT);
 
SDValue DAGTypeLegalizer::WidenVecRes_BITCAST(SDNode *N) {
   EVT InVT = InOp.getValueType();
   EVT VT = N->getValueType(0);
   EVT WidenVT = TLI.getTypeToTransformTo(*DAG.getContext(), VT);
   SDLoc dl(N);
 
   switch (getTypeAction(InVT)) {
   case TargetLowering::TypeLegal:
     break;
+  case TargetLowering::TypeScalarizeScalableVector:
+    report_fatal_error("Scalarization of scalable vectors is not supported.");
   case TargetLowering::TypePromoteInteger: {
     // If the incoming type is a vector that is being promoted, then
     // we know that the elements are arranged differently and that we
     // must perform the conversion using a stack slot.
     if (InVT.isVector())
       break;
 
     // If the InOp is promoted to the same size, convert it.  Otherwise,

llvm/lib/CodeGen/TargetLoweringBase.cpp

if (VT.isSimple()) {
 
     assert((LA == TypeLegal || LA == TypeSoftenFloat ||
             LA == TypeSoftPromoteHalf ||
             (NVT.isVector() ||
              ValueTypeActions.getTypeAction(NVT) != TypePromoteInteger)) &&
            "Promote may not follow Expand or Promote");
 
     if (LA == TypeSplitVector)
-      return LegalizeKind(LA,
-                          EVT::getVectorVT(Context, SVT.getVectorElementType(),
-                                           SVT.getVectorNumElements() / 2));
+      return LegalizeKind(LA, SVT.getHalfNumVectorElementsVT());
     if (LA == TypeScalarizeVector)
       return LegalizeKind(LA, SVT.getVectorElementType());
     return LegalizeKind(LA, NVT);
   }
 
   // Handle Extended Scalar Types.
   if (!VT.isVector()) {
     assert(VT.isInteger() && "Float types must be simple");
if (BitSize < 8 || !isPowerOf2_32(BitSize)) {
       return LegalizeKind(TypePromoteInteger, NVT);
     }
 
     return LegalizeKind(TypeExpandInteger,
                         EVT::getIntegerVT(Context, VT.getSizeInBits() / 2));
   }
 
   // Handle vector types.
-  unsigned NumElts = VT.getVectorNumElements();
+  ElementCount NumElts = VT.getVectorElementCount();
   EVT EltVT = VT.getVectorElementType();
 
   // Vectors with only one element are always scalarized.
   if (NumElts == 1)
     return LegalizeKind(TypeScalarizeVector, EltVT);
 
+  if (VT.getVectorElementCount() == ElementCount(1, true))
+    report_fatal_error("Cannot legalize this vector");
+
   // Try to widen vector elements until the element type is a power of two and
   // promote it to a legal type later on, for example:
   // <3 x i8> -> <4 x i8> -> <4 x i32>
   if (EltVT.isInteger()) {
     // Vectors with a number of elements that is not a power of two are always
     // widened, for example <3 x i8> -> <4 x i8>.
     if (!VT.isPow2VectorType()) {
-      NumElts = (unsigned)NextPowerOf2(NumElts);
+      NumElts = NumElts.NextPowerOf2();
       EVT NVT = EVT::getVectorVT(Context, EltVT, NumElts);
       return LegalizeKind(TypeWidenVector, NVT);
     }
 
     // Examine the element type.
     LegalizeKind LK = getTypeConversion(Context, EltVT);
 
     // If type is to be expanded, split the vector.
if (EltVT.isInteger()) {
     // type with a promoted vector element type.
     EltVT = OldEltVT;
   }
 
   // Try to widen the vector until a legal type is found.
   // If there is no wider legal type, split the vector.
   while (true) {
     // Round up to the next power of 2.
-    NumElts = (unsigned)NextPowerOf2(NumElts);
+    NumElts = NumElts.NextPowerOf2();
 
     // If there is no simple vector type with this many elements then there
     // cannot be a larger legal vector type.  Note that this assumes that
     // there are no skipped intermediate vector types in the simple types.
     if (!EltVT.isSimple())
       break;
     MVT LargerVector = MVT::getVectorVT(EltVT.getSimpleVT(), NumElts);
     if (LargerVector == MVT())
       break;
 
     // If this type is legal then widen the vector.
     if (ValueTypeActions.getTypeAction(LargerVector) == TypeLegal)
       return LegalizeKind(TypeWidenVector, LargerVector);
   }
 
   // Widen odd vectors to next power of two.
   if (!VT.isPow2VectorType()) {
     EVT NVT = VT.getPow2VectorType(Context);
     return LegalizeKind(TypeWidenVector, NVT);
   }
 
   // Vectors with illegal element types are expanded.
-  EVT NVT = EVT::getVectorVT(Context, EltVT, VT.getVectorNumElements() / 2);
+  EVT NVT = EVT::getVectorVT(Context, EltVT, VT.getVectorElementCount() / 2);
   return LegalizeKind(TypeSplitVector, NVT);
 }
 
 static unsigned getVectorTypeBreakdownMVT(MVT VT, MVT &IntermediateVT,
                                           unsigned &NumIntermediates,
                                           MVT &RegisterVT,
                                           TargetLoweringBase *TLI) {
   // Figure out the right, legal destination reg to copy into.
void TargetLoweringBase::computeRegisterProperties(
   // Loop over all of the vector value types to see which need transformations.
   for (unsigned i = MVT::FIRST_VECTOR_VALUETYPE;
        i <= (unsigned)MVT::LAST_VECTOR_VALUETYPE; ++i) {
     MVT VT = (MVT::SimpleValueType) i;
     if (isTypeLegal(VT))
       continue;
 
     MVT EltVT = VT.getVectorElementType();
-    unsigned NElts = VT.getVectorNumElements();
+    ElementCount EC = VT.getVectorElementCount();
     bool IsLegalWiderType = false;
     bool IsScalable = VT.isScalableVector();
     LegalizeTypeAction PreferredAction = getPreferredVectorAction(VT);
     switch (PreferredAction) {
     case TypePromoteInteger: {
       MVT::SimpleValueType EndVT = IsScalable ?
                                    MVT::LAST_INTEGER_SCALABLE_VECTOR_VALUETYPE :
                                    MVT::LAST_INTEGER_FIXEDLEN_VECTOR_VALUETYPE;
       // Try to promote the elements of integer vectors. If no legal
       // promotion was found, fall through to the widen-vector method.
       for (unsigned nVT = i + 1;
            (MVT::SimpleValueType)nVT <= EndVT; ++nVT) {
         MVT SVT = (MVT::SimpleValueType) nVT;
         // Promote vectors of integers to vectors with the same number
         // of elements, with a wider element type.
         if (SVT.getScalarSizeInBits() > EltVT.getSizeInBits() &&
-            SVT.getVectorNumElements() == NElts &&
-            SVT.isScalableVector() == IsScalable && isTypeLegal(SVT)) {
+            SVT.getVectorElementCount() == EC && isTypeLegal(SVT)) {
           TransformToType[i] = SVT;
           RegisterTypeForVT[i] = SVT;
           NumRegistersForVT[i] = 1;
           ValueTypeActions.setTypeAction(VT, TypePromoteInteger);
           IsLegalWiderType = true;
           break;
         }
       }
       if (IsLegalWiderType)
         break;
       LLVM_FALLTHROUGH;
     }
 
     case TypeWidenVector:
-      if (isPowerOf2_32(NElts)) {
+      if (isPowerOf2_32(EC.Min)) {
         // Try to widen the vector.
         for (unsigned nVT = i + 1; nVT <= MVT::LAST_VECTOR_VALUETYPE; ++nVT) {
           MVT SVT = (MVT::SimpleValueType) nVT;
-          if (SVT.getVectorElementType() == EltVT
-              && SVT.getVectorNumElements() > NElts
-              && SVT.isScalableVector() == IsScalable && isTypeLegal(SVT)) {
+          if (SVT.getVectorElementType() == EltVT &&
+              SVT.isScalableVector() == IsScalable &&
+              SVT.getVectorElementCount().Min > EC.Min && isTypeLegal(SVT)) {
             TransformToType[i] = SVT;
             RegisterTypeForVT[i] = SVT;
             NumRegistersForVT[i] = 1;
             ValueTypeActions.setTypeAction(VT, TypeWidenVector);
             IsLegalWiderType = true;
             break;
           }
         }
case TypeScalarizeVector: {
       MVT NVT = VT.getPow2VectorType();
       if (NVT == VT) {
         // Type is already a power of 2.  The default action is to split.
         TransformToType[i] = MVT::Other;
         if (PreferredAction == TypeScalarizeVector)
           ValueTypeActions.setTypeAction(VT, TypeScalarizeVector);
         else if (PreferredAction == TypeSplitVector)
           ValueTypeActions.setTypeAction(VT, TypeSplitVector);
+        else if (EC.Min > 1)
+          ValueTypeActions.setTypeAction(VT, TypeSplitVector);
         else
-          // Set type action according to the number of elements.
-          ValueTypeActions.setTypeAction(VT, NElts == 1 ? TypeScalarizeVector
-                                                        : TypeSplitVector);
+          ValueTypeActions.setTypeAction(VT, EC.Scalable
+                                                 ? TypeScalarizeScalableVector
+                                                 : TypeScalarizeVector);
       } else {
         TransformToType[i] = NVT;
         ValueTypeActions.setTypeAction(VT, TypeWidenVector);
       }
       break;
     }
     default:
       llvm_unreachable("Unknown vector legalization action!");
     }
   }

llvm/unittests/CodeGen/AArch64SelectionDAGTest.cpp

 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Target/TargetMachine.h"
 #include "gtest/gtest.h"
 
-using namespace llvm;
-
-namespace {
+namespace llvm {
 
 class AArch64SelectionDAGTest : public testing::Test {
 protected:
   static void SetUpTestCase() {
     InitializeAllTargets();
     InitializeAllTargetMCs();
   }
 
   void SetUp() override {
     StringRef Assembly = "define void @f() { ret void }";
 
     Triple TargetTriple("aarch64--");
     std::string Error;
     const Target *T = TargetRegistry::lookupTarget("", TargetTriple, Error);
     // FIXME: These tests do not depend on AArch64 specifically, but we have to
     // initialize a target. A skeleton Target for unittests would allow us to
     // always run these tests.
     if (!T)
       return;
 
     TargetOptions Options;
-    TM = std::unique_ptr<LLVMTargetMachine>(static_cast<LLVMTargetMachine*>(
-        T->createTargetMachine("AArch64", "", "", Options, None, None,
+    TM = std::unique_ptr<LLVMTargetMachine>(static_cast<LLVMTargetMachine *>(
+        T->createTargetMachine("AArch64", "", "+sve", Options, None, None,
                                CodeGenOpt::Aggressive)));
     if (!TM)
       return;
 
     SMDiagnostic SMError;
     M = parseAssemblyString(Assembly, SMError, Context);
     if (!M)
       report_fatal_error(SMError.getMessage());
void SetUp() override {
 
     DAG = std::make_unique<SelectionDAG>(*TM, CodeGenOpt::None);
     if (!DAG)
       report_fatal_error("DAG?");
     OptimizationRemarkEmitter ORE(F);
     DAG->init(*MF, ORE, nullptr, nullptr, nullptr, nullptr, nullptr);
   }
 
+  TargetLoweringBase::LegalizeTypeAction getTypeAction(EVT VT) {
+    return DAG->getTargetLoweringInfo().getTypeAction(Context, VT);
+  }
+
+  EVT getTypeToTransformTo(EVT VT) {
+    return DAG->getTargetLoweringInfo().getTypeToTransformTo(Context, VT);
+  }
+
   LLVMContext Context;
   std::unique_ptr<LLVMTargetMachine> TM;
   std::unique_ptr<Module> M;
   Function *F;
   std::unique_ptr<MachineFunction> MF;
   std::unique_ptr<SelectionDAG> DAG;
 };
 
TEST_F(AArch64SelectionDAGTest, getSplatSourceVector_Scalable_ADD_of_SPLAT_VECTOR) {
   EXPECT_EQ(Val1->getOpcode(), ISD::SPLAT_VECTOR);
   SDValue Op = DAG->getNode(ISD::ADD, Loc, VecVT, Val1, Val2);
 
   int SplatIdx = -1;
   EXPECT_EQ(DAG->getSplatSourceVector(Op, SplatIdx), Op);
   EXPECT_EQ(SplatIdx, 0);
 }
 
-} // end anonymous namespace
+TEST_F(AArch64SelectionDAGTest, getTypeConversion_SplitScalableMVT) {
+  if (!TM)
+    return;
+
+  MVT VT = MVT::nxv4i64;
+  EXPECT_EQ(getTypeAction(VT), TargetLoweringBase::TypeSplitVector);
+  ASSERT_TRUE(getTypeToTransformTo(VT).isScalableVector());
+}
+
+TEST_F(AArch64SelectionDAGTest, getTypeConversion_PromoteScalableMVT) {
+  if (!TM)
+    return;
+
+  MVT VT = MVT::nxv2i32;
+  EXPECT_EQ(getTypeAction(VT), TargetLoweringBase::TypePromoteInteger);
+  ASSERT_TRUE(getTypeToTransformTo(VT).isScalableVector());
+}
+
+TEST_F(AArch64SelectionDAGTest, getTypeConversion_NoScalarizeMVT_nxv1f32) {
+  if (!TM)
+    return;
+
+  MVT VT = MVT::nxv1f32;
+  EXPECT_NE(getTypeAction(VT), TargetLoweringBase::TypeScalarizeVector);
+  ASSERT_TRUE(getTypeToTransformTo(VT).isScalableVector());
+}
+
+TEST_F(AArch64SelectionDAGTest, getTypeConversion_SplitScalableEVT) {
+  if (!TM)
+    return;
+
+  EVT VT = EVT::getVectorVT(Context, MVT::i64, 256, true);
+  EXPECT_EQ(getTypeAction(VT), TargetLoweringBase::TypeSplitVector);
+  EXPECT_EQ(getTypeToTransformTo(VT), VT.getHalfNumVectorElementsVT(Context));
+}
+
+TEST_F(AArch64SelectionDAGTest, getTypeConversion_WidenScalableEVT) {
+  if (!TM)
+    return;
+
+  EVT FromVT = EVT::getVectorVT(Context, MVT::i64, 6, true);
+  EVT ToVT = EVT::getVectorVT(Context, MVT::i64, 8, true);
+
+  EXPECT_EQ(getTypeAction(FromVT), TargetLoweringBase::TypeWidenVector);
+  EXPECT_EQ(getTypeToTransformTo(FromVT), ToVT);
+}
+
+TEST_F(AArch64SelectionDAGTest, getTypeConversion_NoScalarizeEVT_nxv1f128) {
+  if (!TM)
+    return;
+
+  EVT FromVT = EVT::getVectorVT(Context, MVT::f128, 1, true);
+  EXPECT_DEATH(getTypeAction(FromVT), "Cannot legalize this vector");
+}
+
+} // end namespace llvm