[PATCH] D13254: [LAA] LLE 1/6: Expose Forward dependences

[Renato Golin via llvm-commits]

rengolin added a subscriber: rengolin.
rengolin added a comment.

Hi Adam,

I've just been referred to this set of reviews as a mean to fix the following problem:

  for (k..N)
    a[k] = b[k] + b[k+1];

Currently, GVN is hoisting the [k] load and adding an extra PHI to the loop body, making it unvectorizeable.

By adding LLE after the vectorizer, we can cover the same case in LLE without breaking vectorization opportunities.

Ultimately, Hal should approve all those patches, but I'll give my own take on them, if you're still interested in pushing them through.

This first one, LGTM.

cheers,
--renato


http://reviews.llvm.org/D13254