[LLVMdev] RFC: Add ISD nodes for mad

[Matt Arsenault]

On 01/28/2015 05:15 PM, Mehdi Amini wrote:
>
> Can’t you have “optional” parameters? I mean the number of parameter 
> you can add to a node is never checked or defined, it is implicit from 
> the ISD OpCode AFAIK.
> If you add a parameter to FMA, wouldn’t it just be ignored by the 
> existing backends?
You can have variadic nodes, but they are difficult to work with. It 
wouldn't be worth it for this.