Add intrinsic pragmas to builtin functions

[yebblies]

Requires: dlang/dmd#4984

[ibuclaw]

Need a better name than "ind" ?

[yebblies]

These are the dmd backend op names. Do you have any ideas on a good namespacing scheme for builtins? Does it make sense to have some common ones?

Something like digitalmars.* gcc.* llvm.* d.*?

[ibuclaw]

Having a namespace for them could be a possibility. But I would consider volatileLoad and volatileStore common between all compilers - unlike y2lx or cmpxchg - and so will need a meaningful name.

[ibuclaw]

Has this been taken to the NG? I might need a few days to think it over, but maybe we should talk it out there.

[yebblies]

Hmm, so dmd.yl2x and d.volatileLoad or something...

With the current PR I have it's possible to do this:

version (GDC)
{
    pragma(intrinsic, "gdc.volatileLoad", ...);
}
else version (DMD)
{
    pragma(intrinsic, "dmd.volatileLoad", ...);
}

[ibuclaw]

Yep. But we should only deviate when we strictly need to. :-)

[PetarKirov]

How about d.* for intrinsics available on all compilers (e.g. d.volatileLoad) and dmd.*, gdc.*, ldc.*, etc. for the ones that are not portable across compilers?