[PATCH] D125743: [outliner] Use profile data to avoid outlining hot blocks

[Ellis Hoag via Phabricator via llvm-commits]

ellis added inline comments.


================
Comment at: llvm/lib/CodeGen/MachineOutliner.cpp:911
+    if (!RunOnAllFunctions && !TII->shouldOutlineFromFunctionByDefault(*MF) &&
+        !UseProfileData)
       continue;
----------------
kyulee wrote:
> I'm not sure I understand this correctly. When UseProfileData is true, do we ignore the other two conditions?
There are basically three reasons why the machine outliner would run.
1. If `RunOnAllFunctions` is true
2. If `shouldOutlineFromFunctionByDefault()` is true.
  a. Currently this only happens when targeting arm64 with minsize.
3. If we pass `-machine-outliner-use-profile-data`

On second thought I should also check `F.hasProfileData()` so that we don't conservatively assume unprofiled functions are always hot.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125743/new/

https://reviews.llvm.org/D125743