[Bug target/95421] New: [AArch64] Missing NEON functions documented on ARM's web site

["evan@coeus-group.com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95421

            Bug ID: 95421
           Summary: [AArch64] Missing NEON functions documented on ARM's
                    web site
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: evan@coeus-group.com
  Target Milestone: ---

Created attachment 48636
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48636&action=edit
Full list of missing functions

This is a companion to #95399 (which is for the arm headers instead of
aarch64).

Quite a few functions listed in ARM's documentation
(<https://developer.arm.com/architectures/instruction-sets/simd-isas/neon/intrinsics>)
don't seem to be included in GCC's AArch64 arm_{neon,bf16,fp16}.h.

The attached list of 253 functions was generated by just grepping
arm_{neon,bf16,fp16}.h for each function in ARM's documentation so it's
possible there are some false positives, but the ones I've checked manually
seem correct. I'm also not sure how accurate ARM's documentation is.

Several functions are actually present in arm but not aarch64, I'm guessing
that will be an easy place to start.  Here is that list:

  vadd_p16
  vadd_p64
  vadd_p8
  vaddq_p128
  vaddq_p16
  vaddq_p64
  vaddq_p8
  vceqq_p64
  vceqz_p64
  vceqzq_p64
  vcvt_high_bf16_f32
  vcvt_low_bf16_f32
  vld2_lane_bf16
  vld2q_lane_bf16
  vld3_lane_bf16
  vld3q_lane_bf16
  vld4_lane_bf16
  vld4q_lane_bf16
  vrndns_f32
  vst2_lane_bf16
  vst2q_lane_bf16
  vst3_lane_bf16
  vst3q_lane_bf16
  vst3q_lane_p8
  vst3q_lane_s8
  vst3q_lane_u8
  vst4_lane_bf16
  vst4q_lane_bf16