http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49628
--- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-07-05
08:53:46 UTC ---
(In reply to comment #5)
> (In reply to comment #4)
>
> > I wonder where we are supposed to set GROUP_SIZE here
> In vect_analyze_data_ref_access(),
> but your patch does this:
>
> /* Allow invariant loads in loops. */
> if (loop_vinfo && dr_step == 0)
> return DR_IS_READ (dr);
>
> preventing detection of interleaving groups for invariant loads. Which is ok,
> since you don't support them anyway.
Yeah, I noticed we don't vectorize loops similar to
struct X { float values[4]; };
void foo (struct X * dst, struct X * src, int n)
{
int i;
for (i = 0; i < n; ++i)
{
dst->values[i*4] = src->values[0];
dst->values[i*4+1] = src->values[1];
dst->values[i*4+2] = src->values[2];
dst->values[i*4+3] = src->values[3];
}
}
with different reasons based on the signedness of i (ugh). We do vectorize
the above with SLP when LIM/PRE move the loads from src out of the loop
though.
