[LLVMdev] Tablegen generic class argument that accepts SDNode or Intrinsic

[David A. Greene]

Tom Stellard <thomas.stellard at amd.com> writes:

> Hi,
>
> I'm trying to define a class in tablegen that can have either an SDNode
> or an Intrinsic as an argument.  Basically something like this:
>
> class OP1 <Record NodeOrIntr> : Instruction {
>   let pattern = [(set Reg:$dst, (NodeOrIntr Reg:$src))];
> }
>
> I haven't been able to come with a way to do this yet.  Is this
> something that is possible with tablegen?

Usually these get split into separate patterns, one for the SDNode and
one for the Intrinsic.  I don't know of a reasonable way to
programmatically substitute one for another.  Probably a !cast<>() from
string is the closest but you still need to know statically what you are
casting to, so I don't think it helps much.

This is one area of redundancy I never successfully completely
eliminated, though I was able to factor it down to a small set of
pattern-containing classes which I could reuse.

                          -Dave