https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90796
--- Comment #9 from Michael Matz <matz at gcc dot gnu.org> --- (In reply to rguent...@suse.de from comment #8) > >The fun thing is, there's a difference between these two loop nests: > > > > for (i) for (j) a[i][0] = f(a[i+1][0]); > > for (i) for (j) b[i][j] = f(a[i+1][j]); > > What about > > B[i][j/2]... > > ? That would be a problem as well, but luckily that's not an affine function of j, and hence has no analyzable access function, and so isn't fused for different reasons. > It's really surprising that only invariants are special here. It's the only affine functions that don't progress with each iteration. I think, at least :)
