[llvm-branch-commits] [llvm] [InstrProf] Deduplicate VP values (PR #196649)

[Aiden Grossman via llvm-branch-commits]

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@@ -1359,14 +1359,43 @@ void annotateValueSite(Module &M, Instruction &Inst,
 
   // Value Profile Data
   uint32_t MDCount = MaxMDCount;
+  // Zero values might occur multiple times (e.g., multiple functions that
+  // cannot be remapped). Deduplicate them to enforce the variant that
+  // values are unique, which allows passes to make some simplifying
+  // assumptions.
+  // TODO(boomanaiden154): This fits more naturally in addValueData, but
+  // preserving the current behavior is necessary for some error handling
+  // paths. When that gets cleaned up, we should move this there.
+  // TODO(boomanaiden154): We are also deduplicating non-zero values.
+  // These are rare and should only come from corrupted profiles, so we
+  // just skip them. Remove this when they are fixed properly in
+  // llvm-profdata.
+  std::optional<uint64_t> ZeroCount = std::nullopt;
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boomanaiden154 wrote:

Essentially `std::nullopt`. I've updated the code to drop the `std::optional`.

https://github.com/llvm/llvm-project/pull/196649