https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68542
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Ok, so previously we if-converted but with versioning and thus the if-converted
loop was not vectorized and thrown away?
So yes, for such cases we'd ideally have vector control-flow
if (!all-zero)
{
...
}
but best by not if-converting this in the first place. Note that the
above also applies to "regular" vectorization of if-converted code,
not only to 'masks' as with Yuris patch. I wonder if we can extend
that to re-introduce control flow. A vector == 0 check should be
fairly cheap and the transform keyed on how much code we can execute
conditionally.
