[clang] [compiler-rt] [llvm] [TypeProf][InstrFDO]Implement more efficient comparison sequence for indirect-call-promotion with vtable profiles. (PR #81442)

[David Li via cfe-commits]

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@@ -103,27 +114,226 @@ static cl::opt<bool>
     ICPDUMPAFTER("icp-dumpafter", cl::init(false), cl::Hidden,
                  cl::desc("Dump IR after transformation happens"));
 
+// Indirect call promotion pass will fall back to function-based comparison if
+// vtable-count / function-count is smaller than this threshold.
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david-xl wrote:

In what situation the ratio will be below the 0.99 threshold?

https://github.com/llvm/llvm-project/pull/81442