Remove an old workaround that was kept around for ABI-compatibility on x86-64 between different LLVM versions. This means LLVM r67588 is required if you want to compile for x86-64, otherwise the backend will assert when you try to return e.g. struct { int i; char c; } from a function. (In particular, this is no longer compatible with LLVM 2.5) It also means that any code returning small structs on x86-64 will probably need to be recompiled in order to be linkable to code compiled with this change.

extern(C) int printf(char*, ...);

void main()
{
    int i = func();
    printf("%d\n", i);
    assert(i == 42);
}

int func()
{
    version (D_InlineAsm_X86)
    {
        asm
        {
            naked;
            mov EAX, 42;
            ret;
        }
    }
    else version(D_InlineAsm_X86_64)
    {
        asm
        {
            naked;
            movq RAX, 42;
            ret;
        }
    }
}