Build problem on Windows

[Caspole, Eric]

Hi guys, the last round of ptx edits do not build on Windows since it treats warnings as errors. See the "jlong result" at line 420.
Thanks,
Eric


Build FAILED.

"c:\work\graal-openjdk\graal\build\vs-amd64\jvm.vcxproj" (default target) (1) ->
(ClCompile target) ->
..\..\src\gpu\ptx\vm\gpu_ptx.cpp(420): warning C4101: 'result' : unreferenced local variable [c:\work\graal-openjdk\graal\build\vs-a
md64\jvm.vcxproj]


"c:\work\graal-openjdk\graal\build\vs-amd64\jvm.vcxproj" (default target) (1) ->
(ClCompile target) ->
..\..\src\gpu\ptx\vm\gpu_ptx.cpp(420): error C2220: warning treated as error - no 'object' file generated [c:\work\graal-openjdk\gra
al\build\vs-amd64\jvm.vcxproj]

1 Warning(s)
1 Error(s)

Time Elapsed 00:01:05.47
RUNINDEBUGSHELL_ENDSEQUENCE


..\..\src\gpu\ptx\vm\gpu_ptx.cpp:

    419   } else if (returnTypeSize > 0) {
    420     jlong result;
    421     status = gpu::Ptx::_cuda_cu_memcpy_dtoh(&primitiveReturnValue, device_return_value, T_LONG_BYTE_SIZE)        ;
    422     if (status != GRAAL_CUDA_SUCCESS) {
    423       tty->print_cr("[CUDA] *** Error (%d) Failed to copy value from device argument", status);
    424       SharedRuntime::throw_and_post_jvmti_exception(thread, vmSymbols::java_lang_Exception(), "[CUDA] Fai        led to copy value from device argument");
    425       return 0L;
    426     }
    427   }