Re: Why the V4QImode vector operations are expanded into many SImode at "oplower" pass?

[Richard Henderson]

On Thu, May 19, 2005 at 04:58:32AM +0800, Ling-hua Tseng wrote:
> I got 4 lines "SI".
> (In the ARM's iWMMXt V8QI testing, I got the message: "V8QI")

Then you need to debug your targetm.vector_mode_supported_p.

Starting around stor-layout.c line 1609:

            for (; mode != VOIDmode ; mode = GET_MODE_WIDER_MODE (mode))
              if (GET_MODE_NUNITS (mode) == nunits
                  && GET_MODE_INNER (mode) == innermode
                  && targetm.vector_mode_supported_p (mode))
                break;

            /* For integers, try mapping it to a same-sized scalar mode.  */
            if (mode == VOIDmode
                && GET_MODE_CLASS (innermode) == MODE_INT)
              mode = mode_for_size (nunits * GET_MODE_BITSIZE (innermode),
                                    MODE_INT, 0);

The compiler has passed through the first loop without finding
a supported vector mode that matches nunits=4 && inner=QImode.


r~