[PATCH] D137505: [SCEV] Cache ZExt SCEV expressions.

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

The latest update also moves the `FoldID` definition inside ScalarEvolution and the template specialization to the bottom of the file.



================
Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:1625
+    auto R = FoldCacheUser.insert({S, {}});
+    R.first->second.push_back(ID);
+  }
----------------
nikic wrote:
> I'm a bit uncertain about the invalidation story here. We will invalidate the cache if the folding result is invalidated. We will not invalidate if the original zext operand is invalidated. Could this result in problems?
I think in that case, invalidation of the `ZExt` operand will trigger invalidation of the SCEV for the `ZExt` via the IR use-list based invalidation.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137505/new/

https://reviews.llvm.org/D137505