[all-commits] [llvm/llvm-project] 465299: [ARM] Always use reductions intrinsics under MVE

[David Green via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 46529978bfb3a05297db95c213c72556f3efeec3
      https://github.com/llvm/llvm-project/commit/46529978bfb3a05297db95c213c72556f3efeec3
  Author: David Green <david.green at arm.com>
  Date:   2020-06-12 (Fri, 12 Jun 2020)

  Changed paths:
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
    M llvm/test/Transforms/LoopVectorize/ARM/mve-reduction-types.ll

  Log Message:
  -----------
  [ARM] Always use reductions intrinsics under MVE

Similar to a recent change to the X86 backend, this changes things so
that we always produce a reduction intrinsics for all reduction types,
not just the legal ones. This gives a better chance in the backend to
custom lower them to something more suitable for MVE. Especially for
something like fadd the in-order reduction produced during DAG lowering
is already better than the shuffles produced in the midend, and we can
do even better with a bit of custom lowering.

Differential Revision: https://reviews.llvm.org/D81398