[Bug target/96342] [SVE] Add support for "omp declare simd"

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96342

--- Comment #6 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Comment on attachment 49413
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49413
part1-patch

Thanks for the summary and patches, and sorry for the delayed reply.

Taking part1-patch first: this generally looks good to me.  Some minor
things:

- It isn't necessary to use poly_int stuff in i386.c, since the new
  poly_uint64 will naturally decay to a uint64_t in i386 target files.
  It might still be necessary to update some of the printf formats
  though.

- It's more correct to use "unsigned HOST_WIDE_INT" instead of
  "long unsigned int" and %wd instead of %ld.  One reason is that
  we support cross builds from 32-bit hosts, where long is 32 bits.
  Long is also 32 bits for ILP32.

- Some of the multiple_p calls can instead use exact_div, which is
  the preferred way of performing a division that is known to have
  no remainder.

I think it's clear that we need to make this change, and since it's
a natural "poly_intification", I don't think it needs to wait for
other SVE work to be completed.  So would you be able to submit
the patch to the list independently of the other work?  Stage 1
closes in three weeks' time so it would be good to get this in
before then.

Thanks again for doing this.