[llvm] [TypeProf][PGO]Skip vtable-based ICP for which type profiles are known to be unrepresentative (PR #110575)

[Snehasish Kumar via llvm-commits]

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@@ -132,6 +132,11 @@ static cl::opt<int> ICPMaxNumVTableLastCandidate(
     "icp-max-num-vtable-last-candidate", cl::init(1), cl::Hidden,
     cl::desc("The maximum number of vtable for the last candidate."));
 
+static cl::opt<std::string> ICPKnownUnrepresentativeVTables(
+    "icp-known-unrepresentative-vtables", cl::init(""), cl::Hidden,
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snehasish wrote:

Do we need to make this option and the code (e.g. variable names, debug messages) specific to "profile unrepresentativeness"? Can we instead generalize it like naming the option "icp-ignore-vtables", the variable can be `DenseSet<StringRef> IgnoredBaseTypes` and so on?

I think the motivation is justified and can be mentioned in the comments and cl::desc but the implementation don't need to be. IMO this makes the code a little easier to read and follow. What do you think?

https://github.com/llvm/llvm-project/pull/110575