[PATCH] D100917: [NewPM] Only invalidate modified functions' analyses in CGSCC passes

[Yuanfang Chen via Phabricator via llvm-commits]

ychen added a comment.

> It seems awkward to enhance PreservedAnalyses to only apply to specific functions when this patch is explicitly doing exactly what we want. If you have a clean way of modeling this inside PreservedAnalyses I'm happy to go with that, but so far I think this is the cleanest way.

I was thinking something like `PreservedAnalyses::abandon(IRUnit, AnalysisID)` which only used to selectively invalidate inner IR units, but I've convinced myself that it may not worth it. Invalidating inner analyses through proxy should work well already.

> Passes were already directly managing the analysis managers, e.g. the inliner and argpromo would remove entries for deleted functions. And updateCGAndAnalysisManager() would also handle analysis manager updates.

I would argue that `updateCGAndAnalysisManager()` is kinda special (for coping with the CGSCCPM's complexity). I think the one in `argpromo` is not necessary since it already returns `PreservedAnalyses::none()`. `inliner` yes.



================
Comment at: llvm/lib/Transforms/IPO/FunctionAttrs.cpp:1631
+  for (Function *Changed : ChangedFunctions)
+    FAM.invalidate(*Changed, PreservedAnalyses::none());
+  // We have not changed the call graph or removed/added functions.
----------------
Is the function CFG preserved?


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https://reviews.llvm.org/D100917