diff --git a/llvm/include/llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h b/llvm/include/llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h
--- a/llvm/include/llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h
@@ -595,7 +595,7 @@
     case GIM_CheckPointerToAny: {
       int64_t InsnID = MatchTable[CurrentIdx++];
       int64_t OpIdx = MatchTable[CurrentIdx++];
-      int64_t SizeInBits = MatchTable[CurrentIdx++];
+      uint64_t SizeInBits = MatchTable[CurrentIdx++];
 
       DEBUG_WITH_TYPE(TgtInstructionSelector::getName(),
                       dbgs() << CurrentIdx << ": GIM_CheckPointerToAny(MIs["
diff --git a/llvm/include/llvm/Support/LowLevelTypeImpl.h b/llvm/include/llvm/Support/LowLevelTypeImpl.h
--- a/llvm/include/llvm/Support/LowLevelTypeImpl.h
+++ b/llvm/include/llvm/Support/LowLevelTypeImpl.h
@@ -67,7 +67,7 @@
     assert(!EC.isScalar() && "invalid number of vector elements");
     assert(!ScalarTy.isVector() && "invalid vector element type");
     return LLT{ScalarTy.isPointer(), /*isVector=*/true, EC,
-               ScalarTy.getSizeInBits(),
+               ScalarTy.getSizeInBits().getFixedSize(),
                ScalarTy.isPointer() ? ScalarTy.getAddressSpace() : 0};
   }
 
@@ -100,12 +100,14 @@
     return EC.isScalar() ? ScalarTy : LLT::vector(EC, ScalarTy);
   }
 
-  static LLT scalarOrVector(ElementCount EC, unsigned ScalarSize) {
-    return scalarOrVector(EC, LLT::scalar(ScalarSize));
+  static LLT scalarOrVector(ElementCount EC, uint64_t ScalarSize) {
+    assert(ScalarSize <= std::numeric_limits<unsigned>::max() &&
+           "Not enough bits in LLT to represent size");
+    return scalarOrVector(EC, LLT::scalar(static_cast<unsigned>(ScalarSize)));
   }
 
   explicit LLT(bool isPointer, bool isVector, ElementCount EC,
-               unsigned SizeInBits, unsigned AddressSpace) {
+               uint64_t SizeInBits, unsigned AddressSpace) {
     init(isPointer, isVector, EC, SizeInBits, AddressSpace);
   }
   explicit LLT() : IsPointer(false), IsVector(false), RawData(0) {}
@@ -148,18 +150,19 @@
   }
 
   /// Returns the total size of the type. Must only be called on sized types.
-  unsigned getSizeInBits() const {
+  TypeSize getSizeInBits() const {
     if (isPointer() || isScalar())
-      return getScalarSizeInBits();
-    // FIXME: This should return a TypeSize in order to work for scalable
-    // vectors.
-    return getScalarSizeInBits() * getElementCount().getKnownMinValue();
+      return TypeSize::Fixed(getScalarSizeInBits());
+    auto EC = getElementCount();
+    return TypeSize(getScalarSizeInBits() * EC.getKnownMinValue(),
+                    EC.isScalable());
   }
 
   /// Returns the total size of the type in bytes, i.e. number of whole bytes
   /// needed to represent the size in bits. Must only be called on sized types.
-  unsigned getSizeInBytes() const {
-    return (getSizeInBits() + 7) / 8;
+  TypeSize getSizeInBytes() const {
+    TypeSize BaseSize = getSizeInBits();
+    return {(BaseSize.getKnownMinSize() + 7) / 8, BaseSize.isScalable()};
   }
 
   LLT getScalarType() const {
@@ -199,11 +202,11 @@
                             getElementType());
     }
 
-    assert(getSizeInBits() % Factor == 0);
-    return scalar(getSizeInBits() / Factor);
+    assert(getScalarSizeInBits() % Factor == 0);
+    return scalar(getScalarSizeInBits() / Factor);
   }
 
-  bool isByteSized() const { return (getSizeInBits() & 7) == 0; }
+  bool isByteSized() const { return getSizeInBits().isKnownMultipleOf(8); }
 
   unsigned getScalarSizeInBits() const {
     assert(RawData != 0 && "Invalid Type");
@@ -333,8 +336,10 @@
     return getMask(FieldInfo) & (RawData >> FieldInfo[1]);
   }
 
-  void init(bool IsPointer, bool IsVector, ElementCount EC, unsigned SizeInBits,
+  void init(bool IsPointer, bool IsVector, ElementCount EC, uint64_t SizeInBits,
             unsigned AddressSpace) {
+    assert(SizeInBits <= std::numeric_limits<unsigned>::max() &&
+           "Not enough bits in LLT to represent size");
     this->IsPointer = IsPointer;
     this->IsVector = IsVector;
     if (!IsVector) {
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -1565,7 +1565,7 @@
     Register SrcReg = getOrCreateVReg(**AI);
     LLT SrcTy = MRI->getType(SrcReg);
     if (SrcTy.isPointer())
-      MinPtrSize = std::min(SrcTy.getSizeInBits(), MinPtrSize);
+      MinPtrSize = std::min<unsigned>(SrcTy.getSizeInBits(), MinPtrSize);
     SrcRegs.push_back(SrcReg);
   }
 
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerCombiner.cpp b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerCombiner.cpp
--- a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerCombiner.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerCombiner.cpp
@@ -258,7 +258,8 @@
           m_OneNonDBGUse(m_any_of(m_GAShr(m_Reg(ShiftSrc), m_ICst(ShiftImm)),
                                   m_GLShr(m_Reg(ShiftSrc), m_ICst(ShiftImm))))))
     return false;
-  if (ShiftImm < 0 || ShiftImm + Width > Ty.getSizeInBits())
+  if (ShiftImm < 0 ||
+      static_cast<uint64_t>(ShiftImm + Width) > Ty.getSizeInBits())
     return false;
   MatchInfo = [=](MachineIRBuilder &B) {
     auto Cst1 = B.buildConstant(Ty, ShiftImm);
diff --git a/llvm/unittests/CodeGen/LowLevelTypeTest.cpp b/llvm/unittests/CodeGen/LowLevelTypeTest.cpp
--- a/llvm/unittests/CodeGen/LowLevelTypeTest.cpp
+++ b/llvm/unittests/CodeGen/LowLevelTypeTest.cpp
@@ -81,6 +81,9 @@
       EXPECT_EQ(EC, VTy.getElementCount());
       if (!EC.isScalable())
         EXPECT_EQ(S * EC.getFixedValue(), VTy.getSizeInBits());
+      else
+        EXPECT_EQ(TypeSize::Scalable(S * EC.getKnownMinValue()),
+                  VTy.getSizeInBits());
 
       // Test equality operators.
       EXPECT_TRUE(VTy == VTy);
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -182,7 +182,13 @@
 
     assert((!Ty.isVector() || Ty.isScalable() == Other.Ty.isScalable()) &&
            "Unexpected mismatch of scalable property");
-    return Ty.getSizeInBits() < Other.Ty.getSizeInBits();
+    return Ty.isVector()
+               ? std::make_tuple(Ty.isScalable(),
+                                 Ty.getSizeInBits().getKnownMinSize()) <
+                     std::make_tuple(Other.Ty.isScalable(),
+                                     Other.Ty.getSizeInBits().getKnownMinSize())
+               : Ty.getSizeInBits().getFixedSize() <
+                     Other.Ty.getSizeInBits().getFixedSize();
   }
 
   bool operator==(const LLTCodeGen &B) const { return Ty == B.Ty; }
@@ -3788,7 +3794,8 @@
     return None;
 
   // Align so unusual types like i1 don't get rounded down.
-  return llvm::alignTo(MemTyOrNone->get().getSizeInBits(), 8);
+  return llvm::alignTo(
+      static_cast<unsigned>(MemTyOrNone->get().getSizeInBits()), 8);
 }
 
 Expected<InstructionMatcher &> GlobalISelEmitter::addBuiltinPredicates(