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

test/cctest/test-assembler-x64.cc

Index: test/cctest/test-assembler-x64.cc
===================================================================
--- test/cctest/test-assembler-x64.cc	(revision 9060)
+++ test/cctest/test-assembler-x64.cc	(working copy)
@@ -46,6 +46,7 @@
 using v8::internal::byte;
 using v8::internal::greater;
 using v8::internal::less_equal;
+using v8::internal::equal;
 using v8::internal::not_equal;
 using v8::internal::r13;
 using v8::internal::r15;
@@ -345,4 +346,17 @@
   }
 }
 
+
+TEST(AssemblerX64LabelChaining) {
+  // Test chaining of label usages within instructions (issue 1644).
+  v8::HandleScope scope;
+  Assembler assm(Isolate::Current(), NULL, 0);
+
+  Label target;
+  __ j(equal, &target);
+  __ j(not_equal, &target);
+  __ bind(&target);
+  __ nop();
+}
+
 #undef __