* Christian Gudrian via Gcc-help: > Hello! > > I'm currently dealing with what looks like a compiler bug to me: the > compiler generates a VLDR instruction for an address that at runtime > may not be 4-byte-aligned. So far, we have encountered this behavior > only when passing variables to the spdlog logging function. Here's an > example: https://godbolt.org/z/168PaedWz (unfortunately, I have not > been able to reduce the example any further). The offending > instruction is on line 17416 in the generated assembly: > > vldr.64 d16, [r3] > > During runtime register r3 contains the address to `data.id` which is > not correctly aligned. I don't think the C++ type system models non-natural alignment for references. The called function has this signature: void spdlog::logger::log_<unsigned long long&>(spdlog::source_loc, spdlog::level::level_enum, fmt::v9::basic_string_view<char>, unsigned long long&) And the callee assumes that the reference target is naturally aligned. Thanks, Florian
