[PATCH] D68047: [SampleFDO] Create a separate flag ProfileAccurateForProfSymList for handling profile symbol list

[Wei Mi via Phabricator via llvm-commits]

wmi created this revision.
wmi added reviewers: davidxl, mtrofin.
Herald added a project: LLVM.

Currently many existing users using profile-sample-accurate want to reduce code size as much as possible. Their use cases are different from the scenario profile symbol list tries to handle -- the major motivation of adding profile symbol list is to get the major memory/code size saving without introduce performance regression. So to keep the behavior of profile-sample-accurate unchanged, we think decoupling these two things and use a new flag to control the handling of profile symbol list is better.

Besides the reason above, another benefit of adding a separate flag is we can flip on ProfileAccurateForProfSymList by default, but that flip will only affect targets using profile with symbol list. Targets won't see any impact as long as their profiles don't contain symbol list. It is possible to get the memory saving by just adding profile symbol list in the profile so it is easier for deployment.


Repository:
  rL LLVM

https://reviews.llvm.org/D68047

Files:
  lib/Transforms/IPO/SampleProfile.cpp
  test/Transforms/SampleProfile/compressed-profile-symbol-list.ll
  test/Transforms/SampleProfile/profile-sample-accurate.ll
  test/Transforms/SampleProfile/uncompressed-profile-symbol-list.ll

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