Fix the bug

Assertion propagation can replace a TYP_UBYTE field
in a field list with a TYP_INT constant, so LSRA
must use the actual field type when deciding whether
an internal register to allocate must be byteable.

src/coreclr/jit/lowerxarch.cpp

@@ -452,10 +452,10 @@ void Lowering::LowerPutArgStk(GenTreePutArgStk* putArgStk)
  unsigned prevOffset = putArgStk->GetStackByteSize();
  for (GenTreeFieldList::Use& use : fieldList->Uses())
  {
- GenTree* const  fieldNode = use.GetNode();
- const var_types fieldType = fieldNode->TypeGet();
- const unsigned fieldOffset = use.GetOffset();
- assert(fieldType != TYP_LONG);
+ GenTree* const fieldNode = use.GetNode();
+ const unsigned fieldOffset = use.GetOffset();
+
+ assert(!fieldNode->TypeIs(TYP_LONG));
 
  // We can treat as a slot any field that is stored at a slot boundary, where the previous
  // field is not in the same slot. (Note that we store the fields in reverse order.)

src/coreclr/jit/lsraxarch.cpp

@@ -1501,18 +1501,18 @@ int LinearScan::BuildPutArgStk(GenTreePutArgStk* putArgStk)
  for (GenTreeFieldList::Use& use : putArgStk->gtOp1->AsFieldList()->Uses())
  {
  GenTree* const fieldNode = use.GetNode();
- const var_types fieldType = fieldNode->TypeGet();
  const unsigned fieldOffset = use.GetOffset();
+ const var_types fieldType = use.GetType();
 
 #ifdef TARGET_X86
  assert(fieldType != TYP_LONG);
 #endif // TARGET_X86
 
 #if defined(FEATURE_SIMD)
- // Note that we need to check the GT_FIELD_LIST type, not 'fieldType'. This is because the
- // GT_FIELD_LIST will be TYP_SIMD12 whereas the fieldType might be TYP_SIMD16 for lclVar, where
+ // Note that we need to check the field type, not the type of the node. This is because the
+ // field type will be TYP_SIMD12 whereas the node type might be TYP_SIMD16 for lclVar, where
  // we "round up" to 16.
- if ((use.GetType() == TYP_SIMD12) && (simdTemp == nullptr))
+ if ((fieldType == TYP_SIMD12) && (simdTemp == nullptr))
  {
  simdTemp = buildInternalFloatRegisterDefForNode(putArgStk);
  }