[CSSPGO] Do not merge a context that is already duplicated into the base profile.

[hoy]

Summary

Do not merge a context that is already duplicated into the base profile.

Also fixing a typo caused by previous refactoring.

[wenlei]

good catch, thanks.

llvm/lib/ProfileData/SampleProfReader.cpp

std::error_code SampleProfileReaderExtBinaryBase::readOneSection(
   case SecProfSummary:
     if (std::error_code EC = readSummary())
       return EC;
     if (hasSecFlag(Entry, SecProfSummaryFlags::SecFlagPartial))
       Summary->setPartialProfile(true);
     if (hasSecFlag(Entry, SecProfSummaryFlags::SecFlagFullContext))
       FunctionSamples::ProfileIsCSFlat = ProfileIsCSFlat = true;
     if (hasSecFlag(Entry, SecProfSummaryFlags::SecFlagIsCSNested))
-      FunctionSamples::ProfileIsCSNested = ProfileIsCSNested;
+      FunctionSamples::ProfileIsCSNested = ProfileIsCSNested = true;
     if (hasSecFlag(Entry, SecProfSummaryFlags::SecFlagFSDiscriminator))
       FunctionSamples::ProfileIsFS = ProfileIsFS = true;
     break;
   case SecNameTable: {
     FixedLengthMD5 =
         hasSecFlag(Entry, SecNameTableFlags::SecFlagFixedLengthMD5);
     bool UseMD5 = hasSecFlag(Entry, SecNameTableFlags::SecFlagMD5Name);
     assert((!FixedLengthMD5 || UseMD5) &&

llvm/lib/Transforms/IPO/SampleProfile.cpp

ORE->emit(OptimizationRemarkAnalysis(CSINLINE_DEBUG, "NotInline",
               << ore::NV("Caller", &F) << "'");
 
     ++NumCSNotInlined;
     const FunctionSamples *FS = Pair.getSecond();
     if (FS->getTotalSamples() == 0 && FS->getEntrySamples() == 0) {
       continue;
     }
 
+    // Do not merge a context that is already duplicated into the base profile.
+    if (FS->getContext().hasAttribute(sampleprof::ContextDuplicatedIntoBase))
+      continue;
+
     if (ProfileMergeInlinee) {
       // A function call can be replicated by optimizations like callsite
       // splitting or jump threading and the replicates end up sharing the
       // sample nested callee profile instead of slicing the original
       // inlinee's profile. We want to do merge exactly once by filtering out
       // callee profiles with a non-zero head sample count.
       if (FS->getHeadSamples() == 0) {
         // Use entry samples as head samples during the merge, as inlinees