[PATCH] D127031: [CSSPGO][llvm-profgen] Reimplement SampleContextTracker using context trie

[Lei Wang via Phabricator via llvm-commits]

wlei added inline comments.


================
Comment at: llvm/include/llvm/Transforms/IPO/SampleContextTracker.h:185
+  // FunctionSamples points to.
+  std::unordered_map<ContextTrieNode *, std::unordered_set<FunctionSamples *>>
+      Node2FSamplesSetMap;
----------------
hoy wrote:
> Actually my previous question could be made more clear as why we need to maintain this map.
I see, so you're suggested that 
 1  FSamples2NodeMap make sure FSamples always pointed to its belonging context node. 
2  even the FSamples whose context is `mergedcontext` point to a stale trie node, we can filter out by the 
```
      SampleContext &OldContext = CSamples->getContext();
      // Check to avoid re-merge any context.
      if (OldContext.hasState(MergedContext))
```
So we won't have a redundant node to be merged. We also don't need to update FSample to point to the merged node.

 That sounds a clear way!


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D127031/new/

https://reviews.llvm.org/D127031