[PATCH] D45872: [DA] Enable -da-delinearize by default

[Brendon Cahoon via Phabricator via llvm-commits]

bcahoon added a comment.

Hi,

This patch looks good to me.  I applied it to our code and ran some of our internal correctness and performance tests (for Hexagon), and the results came back clean.

This new delinearization code misses some cases that the old version caught.  For example, something like the following, which cannot be delinearized because of the isKnownNonNegative check, so the dependence distance is not computed exactly.

  unsigned foo(unsigned *restrict a, unsigned *restrict b, unsigned h, unsigned w, unsigned ss, unsigned ds) {
    unsigned sum = 0;
    for ( unsigned y = 1; y < h - 1; ++y) {
      for ( unsigned x = 1; x < w - 1; ++x ) {
        unsigned char sum = 0;
        sum += a[x + ss];
        sum += a[x + ss + 1];
        b[x] = sum;
      }
      a += ss;
      b += ds;
    }
    return sum;
  }

Thanks,
Brendon


https://reviews.llvm.org/D45872