[llvm-dev] invariant.load metadata semantics

[Michael Kuperstein via llvm-dev]

>
> Yes, that is what I had in mind.  Moreover, in
>
> func()
> {
>   int k = load a, invariant.load !1
>   print(k);
>   store a, 5
> }
>
> k can be optimized to 5, in a form of "time traveling store
> forwarding" :).  The store (at least if non-atomic and non-volatile)
> is also trivially dead.
>
>
Only if we know that print() returns, right?

Otherwise, we have the usual trouble with things like:
void print(int i) {
  if (k != 5) abort();
  ...
}
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