[Bug target/95967] Poor aarch64 vector constructor code when using arm_neon.h

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95967

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> Created attachment 50891 [details]
> Start of the patch which should fix most of it
> 
> This patch which should fix the majority of the problem though I have not
> tested it on the testcase.  Basically it takes the BIT_INSERT_EXPR's and
> "combines" them such that they become a CONSTRUCTOR.
> I am still deciding if this belongs in reassoc or as part of forwprop.

This patch looks like it only fixes f1 and g1.

Most likely because I did not handle CONSTRUCTOR as the initial case:
f2:
  _6 = {s0_2(D), s0_2(D), s0_2(D), s0_2(D)};
  __builtin_aarch64_im_lane_boundsi (16, 4, 1);
  __builtin_aarch64_im_lane_boundsi (16, 4, 2);
  __builtin_aarch64_im_lane_boundsi (16, 4, 3);
  _10 = BIT_INSERT_EXPR <_6, s1_3(D), 32>;
  _12 = BIT_INSERT_EXPR <_10, s2_4(D), 64>;
  __vec_14 = BIT_INSERT_EXPR <_12, s3_5(D), 96>;

I will look into adding that in a few weeks and add a testcase for it too.