[PATCH] D23727: [Profile] SelectInst instrumentation Support in IR-PGO

[David Li via Phabricator via llvm-commits]

davidxl added inline comments.


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Comment at: llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp:968
+  // False Count
+  SCounts[1] = (TotalCount > SCounts[0] ? TotalCount - SCounts[0] : 0);
+  uint64_t MaxCount = std::max(SCounts[0], SCounts[1]);
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qiongsiwu1 wrote:
> In what scenario is it possible that the true count is bigger than the total count? My understanding is that the condition cannot be true more often than the number of times the block is executed. Do we have a wrong profile if the true count is bigger than the total count?  
Such insanity may result from race condition during counter update.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D23727/new/

https://reviews.llvm.org/D23727