[all-commits] [llvm/llvm-project] dcefcd: [ARM] Update trunc costs

[David Green via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: dcefcd51e01741c79c9d9a729fe803b13287a372
      https://github.com/llvm/llvm-project/commit/dcefcd51e01741c79c9d9a729fe803b13287a372
  Author: David Green <david.green at arm.com>
  Date:   2021-01-11 (Mon, 11 Jan 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
    M llvm/test/Analysis/CostModel/ARM/arith-overflow.ll
    M llvm/test/Analysis/CostModel/ARM/cast.ll
    M llvm/test/Analysis/CostModel/ARM/mve-gather-scatter-cost.ll

  Log Message:
  -----------
  [ARM] Update trunc costs

We did not have specific costs for larger than legal truncates that were
not otherwise cheap (where they were next to stores, for example). As
MVE does not have a dedicated instruction for them (and we do not use
loads/stores yet), they should be expensive as they get expanded to a
series of lane moves.

Differential Revision: https://reviews.llvm.org/D94260