Fixed issue v8:1644 (bug in the chaining of fixup position)

test/cctest/test-assembler-arm.cc

 // Copyright 2011 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
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 992 matching lines @@
   F3 f = FUNCTION_CAST<F3>(Code::cast(code)->entry());
   Object* dummy = CALL_GENERATED_CODE(f, &i, 0, 0, 0, 0);
   USE(dummy);
 
   CHECK_EQ(0xabcd0001, i.a);
   CHECK_EQ(static_cast<int32_t>(0xabcd0000) >> 1, i.b);
   CHECK_EQ(0x00000000, i.c);
   CHECK_EQ(0xffffffff, i.d);
 }
 
+
+TEST(12) {
+  // Test chaining of label usages within instructions (issue 1644).
+  InitializeVM();
+  v8::HandleScope scope;
+  Assembler assm(Isolate::Current(), NULL, 0);
+
+  Label target;
+  __ b(eq, &target);
+  __ b(ne, &target);
+  __ bind(&target);
+  __ nop();
+}
+
 #undef __