ARM64: Fix some signed-unsigned comparisons from cdc43bc (r28412).

src/arm64/assembler-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
@@ skipping 873 matching lines @@
 bool Assembler::is_const_pool_blocked() const {
   return (const_pool_blocked_nesting_ > 0) ||
          (pc_offset() < no_const_pool_before_);
 }
 
 
 bool Assembler::IsConstantPoolAt(Instruction* instr) {
   // The constant pool marker is made of two instructions. These instructions
   // will never be emitted by the JIT, so checking for the first one is enough:
   // 0: ldr xzr, #<size of pool>
-  bool result = instr->IsLdrLiteralX() && (instr->Rt() == xzr.code());
+  bool result = instr->IsLdrLiteralX() && (instr->Rt() == kZeroRegCode);
 
   // It is still worth asserting the marker is complete.
   // 4: blr xzr
   DCHECK(!result || (instr->following()->IsBranchAndLinkToRegister() &&
-                     instr->following()->Rn() == xzr.code()));
+                     instr->following()->Rn() == kZeroRegCode));
 
   return result;
 }
 
 
 int Assembler::ConstantPoolSizeAt(Instruction* instr) {
 #ifdef USE_SIMULATOR
   // Assembler::debug() embeds constants directly into the instruction stream.
   // Although this is not a genuine constant pool, treat it like one to avoid
   // disassembling the constants.
@@ skipping 2275 matching lines @@
   movz(scratch, (target_offset >> 16) & 0xFFFF, 16);
   movk(scratch, (target_offset >> 32) & 0xFFFF, 32);
   DCHECK((target_offset >> 48) == 0);
   add(rd, rd, scratch);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64