[PATCH,rs6000] Implement -maltivec=be for vec_insert and vec_extract Altivec intrinsics

[David Edelsohn]

On Sun, Jan 12, 2014 at 7:53 PM, Bill Schmidt
<wschmidt@linux.vnet.ibm.com> wrote:
> This patch provides for interpreting element numbers for the Altivec
> vec_insert and vec_extract intrinsics as big-endian (left to right in a
> vector register) when targeting a little endian machine and specifying
> -maltivec=be.  New test cases are added to test this functionality on
> all supported vector types.
>
> Bootstrapped and tested with no new regressions on
> powerpc64{,le}-unknown-linux-gnu.  Ok for trunk?
>
> Thanks,
> Bill
>
>
> gcc:
>
> 2014-01-12  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>
>         * config/rs6000/rs6000-c.c (altivec_resolve_overloaded_builtin):
>         Implement -maltivec=be for vec_insert and vec_extract.
>
> gcc/testsuite:
>
> 2014-01-12  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>
>         * gcc.dg/vmx/insert.c: New.
>         * gcc.dg/vmx/insert-be-order.c: New.
>         * gcc.dg/vmx/extract.c: New.
>         * gcc.dg/vmx/extract-be-order.c: New.


> +      if (!BYTES_BIG_ENDIAN && rs6000_altivec_element_order == 2)
> +       {
> +         int last_elem = TYPE_VECTOR_SUBPARTS (arg1_type) - 1;
> +         double_int di_last_elem = double_int::from_uhwi (last_elem);
> +         arg2 = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (arg2),
> +                                 double_int_to_tree (TREE_TYPE (arg2),
> +                                                     di_last_elem),
> +                                 arg2);
> +       }

Please change last_elem to unsigned int in both blocks of code.  And I
believe that GCC provides a more direct API to create a Tree from
last_elem than the double_int::from_uhwi() and double_int_to_tree()
dance because it seems that the value is constant for each instance.
build_int_cstu()?

Okay with those changes.

Thanks, David