[PATCH] D154307: [InstructionSimplify] Avoid simplifying ICmp without parent

Sun Jul 2 13:57:56 PDT 2023

gandhi21299 added a comment.

In D154307#4467219 <https://reviews.llvm.org/D154307#4467219>, @nikic wrote:

> After @arsenm's change, InstSimplify should no longer work with instructions without parent. Can you explain how we end up working on an assume without parent in NewGVN? It's not really obvious to me.

I traced back the calls and they start from `NewGVN::ExprResult NewGVN::performSymbolicEvaluation(Value *V, SmallPtrSetImpl<Value *> &Visited) const `. I tried inserting the `getParent()` check in various places in NewGVN but it causes 5 LIT tests to fail for generating a few more basic blocks.

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  https://reviews.llvm.org/D154307/new/

https://reviews.llvm.org/D154307