[all-commits] [llvm/llvm-project] e13d15: [ARM, MVE] Add intrinsics for the VQDMLAD family.

[Simon Tatham via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: e13d153c1b59a11185bf6a1aa8853c9e14d556a5
      https://github.com/llvm/llvm-project/commit/e13d153c1b59a11185bf6a1aa8853c9e14d556a5
  Author: Simon Tatham <simon.tatham at arm.com>
  Date:   2020-03-18 (Wed, 18 Mar 2020)

  Changed paths:
    M clang/include/clang/Basic/arm_mve.td
    A clang/test/CodeGen/arm-mve-intrinsics/vqdmlad.c
    M llvm/include/llvm/IR/IntrinsicsARM.td
    M llvm/lib/Target/ARM/ARMInstrMVE.td
    A llvm/test/CodeGen/Thumb2/mve-intrinsics/vqdmlad.ll

  Log Message:
  -----------
  [ARM,MVE] Add intrinsics for the VQDMLAD family.

Summary:
This is another set of instructions too complicated to be sensibly
expressed in IR by anything short of a target-specific intrinsic.
Given input vectors a,b, the instruction generates intermediate values
2*(a[0]*b[0]+a[1]+b[1]), 2*(a[2]*b[2]+a[3]+b[3]), etc; takes the high
half of each double-width values, and overwrites half the lanes in the
output vector c, which you therefore have to provide the input value
of. Optionally you can swap the elements of b so that the are things
like a[0]*b[1]+a[1]*b[0]; optionally you can round to nearest when
taking the high half; and optionally you can take the difference
rather than sum of the two products. Finally, saturation is applied
when converting back to a single-width vector lane.

Reviewers: dmgreen, MarkMurrayARM, miyuki, ostannard

Reviewed By: miyuki

Subscribers: kristof.beyls, hiraditya, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76359