8174050: Compilation errors with clang-4.0

Reviewed-by: tschatzl, kvn
Contributed-by: NLeslie Zhai <lesliezhai-hotspot@llvm.org.cn>

src/share/vm/opto/lcm.cpp

@@ -49,7 +49,7 @@
 // Check whether val is not-null-decoded compressed oop,
 // i.e. will grab into the base of the heap if it represents NULL.
 static bool accesses_heap_base_zone(Node *val) {
-  if (Universe::narrow_oop_base() > 0) { // Implies UseCompressedOops.
+  if (Universe::narrow_oop_base() != NULL) { // Implies UseCompressedOops.
     if (val && val->is_Mach()) {
       if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) {
         // This assumes all Decodes with TypePtr::NotNull are matched to nodes that

src/share/vm/opto/loopPredicate.cpp

@@ -869,7 +869,7 @@ bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) {
       Node*          idx    = cmp->in(1);
       assert(!invar.is_invariant(idx), "index is variant");
       Node* rng = cmp->in(2);
-      assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int() >= 0, "must be");
+      assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int()->_lo >= 0, "must be");
       assert(invar.is_invariant(rng), "range must be invariant");
       int scale    = 1;
       Node* offset = zero;

src/share/vm/runtime/virtualspace.cpp

@@ -342,7 +342,7 @@ ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment,
                 (UseCompressedOops && (Universe::narrow_oop_base() != NULL) &&
                  Universe::narrow_oop_use_implicit_null_checks()) ?
                   lcm(os::vm_page_size(), alignment) : 0) {
-  if (base() > 0) {
+  if (base() != NULL) {
     MemTracker::record_virtual_memory_type((address)base(), mtJavaHeap);
   }