[all-commits] [llvm/llvm-project] ea8448: [LoopUnroll] Adjust CostKind query

[Sam Parker via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: ea8448e3618a1581b5eca39d39bedaa55fede75d
      https://github.com/llvm/llvm-project/commit/ea8448e3618a1581b5eca39d39bedaa55fede75d
  Author: Sam Parker <sam.parker at arm.com>
  Date:   2020-08-12 (Wed, 12 Aug 2020)

  Changed paths:
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
    M llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
    A llvm/test/Transforms/LoopUnroll/ARM/instr-size-costs.ll
    A llvm/test/Transforms/LoopUnroll/ARM/unroll-optsize.ll

  Log Message:
  -----------
  [LoopUnroll] Adjust CostKind query

When TTI was updated to use an explicit cost, TCK_CodeSize was used
although the default implicit cost would have been the hand-wavey
cost of size and latency. So, revert back to this behaviour. This is
not expected to have (much) impact on targets since most (all?) of
them return the same value for SizeAndLatency and CodeSize.

When optimising for size, the logic has been changed to query
CodeSize costs instead of SizeAndLatency.

This patch also adds a testing option in the unroller so that
OptSize thresholds can be specified.

Differential Revision: https://reviews.llvm.org/D85723