StubRoutines::_dtan overwrites the callee save register $rbx but does not restore the original value before returning.

In the caller method we execute:
 0x7fe406be496f: mov %rsi,%rbx // Save 'this' to $rbx
 0x7fe406be4972: mov %rdx,%r13
 0x7fe406be4975: vmovq %rdx,%xmm0
 0x7fe406be497a: movabs $0x7fe405003c7b,%r10
 0x7fe406be4984: callq *%r10 // Call StubRoutines::_dtan (overwrites rbx with 0x8000)
 0x7fe406be4987: vucomisd %xmm0,%xmm0
 0x7fe406be498b: jp 0x7fe406be498f
 0x7fe406be498d: je 0x7fe406be49c0
 0x7fe406be498f: movabs $0x7ff8000000000000,%r9
 0x7fe406be4999: movabs $0x71de35b60,%rdx
 0x7fe406be49a3: mov %rbx,%rsi // Restore 'this'
 0x7fe406be49a6: mov %r13,%rcx
 0x7fe406be49a9: mov %rbp,%r8
 0x7fe406be49ac: nop
 0x7fe406be49ad: nop
 0x7fe406be49ae: nop
 0x7fe406be49af: callq 0x7fe40661dea0 // Call test_engine.print_result

We crash in test_engine.print_result() while trying to increment an integer field because 'this' is invalid.

The problem is in MacroAssembler::fast_tan() introduced by JDK-8152907:
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/33f10a35ce20#l16.1052

We miss a 'pop(rbx);' at the end of the stub.