Cleanup: Make CheckClassId instruction more general so it

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1459 matching lines @@
 void FlowGraphCompiler::EmitTestAndCallLoadCid() {
   __ LoadClassId(RDI, RAX);
 }
 
 
 int FlowGraphCompiler::EmitTestAndCallCheckCid(Label* next_label,
                                                const CidRange& range,
                                                int bias) {
   intptr_t cid_start = range.cid_start;
   intptr_t cid_end = range.cid_end;
-  if (cid_start == cid_end) {
+  if (range.IsSingleCid()) {
     __ cmpl(RDI, Immediate(cid_start - bias));
     __ j(NOT_EQUAL, next_label);
   } else {
     __ addl(RDI, Immediate(bias - cid_start));
     bias = cid_start;
-    __ cmpl(RDI, Immediate(cid_end - cid_start));
+    __ cmpl(RDI, Immediate(range.Extent()));
     __ j(ABOVE, next_label);  // Unsigned higher.
   }
   return bias;
 }
 
 
 #undef __
 #define __ compiler_->assembler()->
 
 
@@ skipping 223 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize));
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64