Manifests like this:

/home/shade/jdk8u-jdk8u-dev/hotspot/src/cpu/ppc/vm/interp_masm_ppc_64.cpp: In member function 'void InterpreterMacroAssembler::lock_object(Register, Register)':
/home/shade/jdk8u-jdk8u-dev/hotspot/src/cpu/ppc/vm/interp_masm_ppc_64.cpp:913:68: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
                                     markOopDesc::lock_mask_in_place));
                                                                    ^
/home/shade/jdk8u-jdk8u-dev/hotspot/src/cpu/ppc/vm/macroAssembler_ppc.cpp: In member function 'void MacroAssembler::compiler_fast_lock_object(ConditionRegister, Register, Register, Register, Register, Register)':
/home/shade/jdk8u-jdk8u-dev/hotspot/src/cpu/ppc/vm/macroAssembler_ppc.cpp:2050:72: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
                                         markOopDesc::lock_mask_in_place));

This is 8u-specific trouble similar to JDK-8221725, so it must be caused by JDK-8221408.

Note that JDK 9+ is not affected, because JDK-8144019 changed the affected lines to effectively use the "long" argument overload:
https://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/4a24de859a87#l29.68
https://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/4a24de859a87#l31.599

It makes sense to backport those two changes to 8u to unbreak PPC64 builds.