[PATCH] D96811: [CSSPGO][llvm-profgen] Change sample count of dangling probe in llvm-profgen

[Lei Wang via Phabricator via llvm-commits]

wlei added inline comments.


================
Comment at: llvm/tools/llvm-profgen/ProfileGenerator.cpp:501
+    if (Probe->isDangling()) {
+      FunctionProfile.addBodySamples(Probe->Index, 0, UINT64_MAX);
+      continue;
----------------
hoy wrote:
> hoy wrote:
> > Actually I `UINT64_MAX` may cause overflow to total samples. Even if it doesn't, profile merge may overflow too. That's one of the reasons we were using 0 as a special count. @wmi What do you think about keeping using 0?
> I talked to other folks and they like using `UINT64_MAX` instead of 0 to be less confusing. @wlei we may need to fix the places that accumulate total samples and set entry count to not using `UINT64_MAX` as the sample count.
Thanks for the sharing. So for profgen side, we can keep this patch, right? see line 501, it only adds the body sample and doesn't accumulate the total sample.

For compiler side, we need to avoid the addition when meeting the `UINT64_MAX`


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D96811/new/

https://reviews.llvm.org/D96811