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.

module assign;

// this is taken from std.intrinsic from gdc

int mybtc(uint *p, uint bitnum)
{
    uint * q = p + (bitnum / (uint.sizeof*8));
    uint mask = 1 << (bitnum & ((uint.sizeof*8) - 1));
    int result = *q & mask;
    *q ^= mask;
    return result ? -1 : 0;
}

void main()
{
    uint i = 0xFFFF_FFFF;
    int r = mybtc(&i, 31);
    assert(r);
    assert(i == 0x7FFF_FFFF);
    r = mybtc(&i, 31);
    assert(!r);
    assert(i == 0xFFFF_FFFF);
}