Re: [PATCH] Fix PR38968, missed vectorization with "negative" misalignment

[Richard Guenther <rguenther at suse dot de>]

On Mon, 26 Jan 2009, Paolo Bonzini wrote:

> 
> >   		  && DECL_ALIGN (base) >= TYPE_ALIGN (vectype)));
> >   
> > !   /* Modulo alignment.  For negative initial offsets adjust the
> > !      misalign value accordingly.  */
> >     misalign = size_binop (TRUNC_MOD_EXPR, misalign, alignment);
> 
> You just need FLOOR_MOD_EXPR here.

Are you sure?

    case FLOOR_DIV_EXPR:
    case FLOOR_MOD_EXPR:        /* round toward negative infinity */
      if (quo_neg && (*lrem != 0 || *hrem != 0))   /* ratio < 0 && rem != 
0 */
        {
          /* quo = quo - 1;  */
          add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT)  
-1,
                      lquo, hquo);
        }

this seems to do a different thing.

Richard.