https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38354
--- Comment #8 from Adam Warner <adam at consulting dot net.nz> --- Joseph, you're correct: 4005fa: b8 c6 05 40 00 mov eax,0x4005c6 4005ff: 89 05 cf 04 20 00 mov DWORD PTR [rip+0x2004cf],eax # 600ad4 <computable_at_load_time_a> 400605: b8 c6 05 40 00 mov eax,0x4005c6 40060a: 89 05 c8 04 20 00 mov DWORD PTR [rip+0x2004c8],eax # 600ad8 <computable_at_load_time_b> 0x4005c6 is the address of the function which is loaded into the lookup table by a static initializer function at run time. This is identical to the workaround in C where a lookup table of 32-bit pointers has to be populated at run time. I agree it is not significant that the code is accepted for C++. I'm sorry about that. What I've done in the past is use Perl to generate printf statements to output the 32-bit addresses as an integer array. The generated array is then compiled into the binary. A command-line option performs a check that the integer addresses match the newly compiled function addresses. It usually takes one additional generation/compilation before they all match up. It is ridiculous this x86_64 workaround is required to map constants into memory at load time when the functions occupy (under the default code model) the same lower 31-bit address space as i386. The original issue from six years ago is that compilation fails with the error "initializer element is not computable at load time". These calculations are computable at load time so the error message is spurious. But from a C language perspective they might not be computable at load time. Thus I believe a compiler warning is more appropriate than an error. That's the path to finalising this bug report: 1. Can you confirm from a technical perspective that the error is spurious? If so the bug report is CONFIRMED. If there are in fact good technical reasons why the error is valid then please close the bug report as INVALID. 2. If the bug report is confirmed then please decide whether the project will turn the error message into a warning. If the project will not do this then please close the bug report as WONTFIX. This part is ultimately a political decision. Either way it would be nice to have a resolution.
