[PATCH] D83024: [PGO] Instrument function entry BB by default in IR PGO

[Wei Mi via Phabricator via llvm-commits]

wmi added a comment.

In D83024#2132133 <https://reviews.llvm.org/D83024#2132133>, @davidxl wrote:

> Here version is overloaded with different meanings: 1) to indicate format change; 2) to indicate instrumentation compiler version that is capable of producing this format.  These two purposes can be contradicting to each other  as the user can use option to force the old format with the new compiler.


For the case new compiler + -pgo-instrument-entry=false, if -pgo-instrument-entry=false is used in both profile-gen and profile-use explicitly, we won't have a problem. Do we have a senario which it doesn't work?

> I am not sure how compiler can relax the check at the profile use time.

I just checked IndexedInstrProfReader::readHeader and the version check part has already allowed the case with profile version being smaller than compiler current format version so the relax I am talking about is already there -- Rong's patch has already covered my proposed solution.


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  https://reviews.llvm.org/D83024/new/

https://reviews.llvm.org/D83024