http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53533
--- Comment #12 from Richard Henderson <rth at gcc dot gnu.org> 2012-06-12 18:54:24 UTC --- (In reply to comment #10) > But maybe allowing const_vector in (some of) the define_insn_and_split would > be the way to go ... Maybe. It certainly would ease some of the simplifications. At the moment I don't think we can go from mem -> const -> simplify -> const ->newmem On the other hand, for this particular test case, where all of the vector_cst elements are the same, and a reasonably small number of bits set, it would be great to be able to leverage synth_mult. The main complexity for sse2_mulv4si3 is due to the fact that we have to decompose the operation into V8HImode multiplies. Whereas if we decompose the multiply, we have the shifts and adds in V4SImode.
