[PATCH] D101245: [GlobalOpt] Disable heap SROA when GEP of the only storer is used

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

In D101245#2717561 <https://reviews.llvm.org/D101245#2717561>, @aeubanks wrote:

> I'm not familiar with the terminology of "storer", so the description is confusing to me.

I mean the instruction which stores to the malloc return value. I don't know an appropriate term.

> Trying to understand the test case and description, is the issue that Heap SROA isn't handling a store of the entire struct (as opposed to initializing the struct element by element)?

If the malloc allocates an array, say `{a, b}{a, b}{a, b}{a, b}`. The heap SROA makes it `[a,a,a,a] [b,b,b,b]` (i.e. elements are shuffled).
With GEP poking different indexes, this can either cause misoptimizations or trigger assertion failures. PR50027 is an assertion failure.


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https://reviews.llvm.org/D101245