[LLVMdev] Predicated Vector Operations

[Eric Christopher]

On Wed, May 8, 2013 at 11:32 AM, Nadav Rotem <nrotem at apple.com> wrote:
>
> On May 8, 2013, at 11:07 AM, dag at cray.com wrote:
>
>   It might be as simple as adding
> an IR-level predicated load and predicated store, I'm not sure.
>
>
> I think that selects on the inputs+outputs of instructions is a good
> abstraction, and I don't think that we need to add a mask operand to every
> LLVM IR instruction. However, we do need support for masked load/stores, and
> I think that we should implement them as target independent intrinsics. I
> don't want to change the generic LLVM IR Load/Store instructions because I
> don't want to modify all of the existing optimizations and I also don't want
> other users of the compiler to pay for this complexity.
>

First statement: I'm not disagreeing. :)

That said, wouldn't a new intrinsic necessarily require all of the
passes to handle it? I'm just curious what you see the tradeoffs being
here. I'd have though adding a mask to Load/Store that just isn't
handled would be equivalent?

-eric