[all-commits] [llvm/llvm-project] 438ffd: [ARM] Switch the costs of mve1beat and mve4beat

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 438ffdb821bb930b4b4e18fcd863ba37dc23bf16
      https://github.com/llvm/llvm-project/commit/438ffdb821bb930b4b4e18fcd863ba37dc23bf16
  Author: David Green <david.green at arm.com>
  Date:   2022-07-07 (Thu, 07 Jul 2022)

  Changed paths:
    M llvm/lib/Target/ARM/ARM.td
    M llvm/test/Analysis/CostModel/ARM/arith.ll
    M llvm/test/Transforms/LoopVectorize/ARM/pointer_iv.ll

  Log Message:
  -----------
  [ARM] Switch the costs of mve1beat and mve4beat

These three subtarget features are meant to control where MVE
instructions take 1 vs 2 vs 4 architectural beats. The mve1beat feature
is described as "Model MVE instructions as a 1 beat per tick
architecture", meaning MVE instruction will execute over 4 cycles.
mve4beat is the opposite where the entire 4 beats of the MVE instruction
execute in a single cycle. The costs for the two were backwards though,
not matching the cycle counts like they should. This patch switches the
costs on the two to bring them in-line with expectations.

Differential Revision: https://reviews.llvm.org/D129141