[IR] Support scalable vectors in CastInst::CreatePointerCast

[sdesmalen]

LGTM!

llvm/lib/IR/Instructions.cpp

 CastInst *CastInst::CreatePointerCast(Value *S, Type *Ty,
                                       const Twine &Name,
                                       BasicBlock *InsertAtEnd) {
   assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
   assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
          "Invalid cast");
   assert(Ty->isVectorTy() == S->getType()->isVectorTy() && "Invalid cast");
   assert((!Ty->isVectorTy() ||
-          cast<FixedVectorType>(Ty)->getNumElements() ==
-              cast<FixedVectorType>(S->getType())->getNumElements()) &&
+          cast<VectorType>(Ty)->getElementCount() ==
+              cast<VectorType>(S->getType())->getElementCount()) &&
          "Invalid cast");
 
   if (Ty->isIntOrIntVectorTy())
     return Create(Instruction::PtrToInt, S, Ty, Name, InsertAtEnd);
 
   return CreatePointerBitCastOrAddrSpaceCast(S, Ty, Name, InsertAtEnd);
 }
 
 /// Create a BitCast or a PtrToInt cast instruction
 CastInst *CastInst::CreatePointerCast(Value *S, Type *Ty,
                                       const Twine &Name,
                                       Instruction *InsertBefore) {
   assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
   assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
          "Invalid cast");
   assert(Ty->isVectorTy() == S->getType()->isVectorTy() && "Invalid cast");
   assert((!Ty->isVectorTy() ||
-          cast<FixedVectorType>(Ty)->getNumElements() ==
-              cast<FixedVectorType>(S->getType())->getNumElements()) &&
+          cast<VectorType>(Ty)->getElementCount() ==
+              cast<VectorType>(S->getType())->getElementCount()) &&
          "Invalid cast");
 
   if (Ty->isIntOrIntVectorTy())
     return Create(Instruction::PtrToInt, S, Ty, Name, InsertBefore);
 
   return CreatePointerBitCastOrAddrSpaceCast(S, Ty, Name, InsertBefore);
 }
 

llvm/unittests/IR/InstructionsTest.cpp

TEST(InstructionsTest, CastInst) {
 
   // Check that assertion is not hit when creating a cast with a vector of
   // pointers
   // First form
   BasicBlock *BB = BasicBlock::Create(C);
   Constant *NullV2I32Ptr = Constant::getNullValue(V2Int32PtrTy);
   auto Inst1 = CastInst::CreatePointerCast(NullV2I32Ptr, V2Int32Ty, "foo", BB);
 
+  Constant *NullVScaleV2I32Ptr = Constant::getNullValue(VScaleV2Int32PtrTy);
+  auto Inst1VScale = CastInst::CreatePointerCast(
+      NullVScaleV2I32Ptr, VScaleV2Int32Ty, "foo.vscale", BB);
+
   // Second form
   auto Inst2 = CastInst::CreatePointerCast(NullV2I32Ptr, V2Int32Ty);
+  auto Inst2VScale =
+      CastInst::CreatePointerCast(NullVScaleV2I32Ptr, VScaleV2Int32Ty);
 
   delete Inst2;
+  delete Inst2VScale;
   Inst1->eraseFromParent();
+  Inst1VScale->eraseFromParent();
   delete BB;
 }
 
 TEST(InstructionsTest, VectorGep) {
   LLVMContext C;
 
   // Type Definitions
   Type *I8Ty = IntegerType::get(C, 8);