[PATCH] D10964: [Codegen] Add intrinsics 'hadd*' and corresponding SDNodes for horizontal sum operation.

[Simon Pilgrim]

RKSimon added a subscriber: RKSimon.
RKSimon added a comment.

Apologies for joining this discussion so late.

I'm worried that this intrinsic is over specific to the PSAD (sum_of) cases - I would have thought a pairwise style horizontal add would fit in much better with most target hardware and could still make locating PSAD style patterns pretty straightforward.

Another alternative would be to instead of a new instrinsic/SDNode, you could focus on providing common infrastructure to detect general horizontal reduction/reassociation patterns - PR23116 and PR21975 would benefit from these.

Failing that, would you consider renaming the opcode ISD::SUM or similar to avoid ambiguity with SSE + NEON HADD instructions?


Repository:
  rL LLVM

http://reviews.llvm.org/D10964