[PATCH] D74853: [RFC WIP] Fix DSE for asm outputs (aka PR44913)

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

I guess reasoning about inline asm directly while we don't have call attributes that allow equivalent reasoning makes sense.  Sort of serves as a demonstration for why the attributes are useful.  But you'll need to be *very* careful that we're actually specifying and implementing it properly.  LangRef needs to clearly state the rules, and we need a bunch of tests to compare various combinations against gcc.

I assume you're aware this is missing a lot of logic that's necessary for correctness.



================
Comment at: llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp:320
+  }
+  for (auto V : Outputs) {
+    int Size = DL.getTypeStoreSize(V->getType());
----------------
Iterating over a SmallSet of pointers is non-deterministic.


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https://reviews.llvm.org/D74853