[Bug middle-end/49628] [4.7 Regression] 447.dealII in SPEC CPU 2006 failed to build

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

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.