[PATCH] D38392: Disallow sinking of unordered atomic loads into loops

[Philip Reames via Phabricator via llvm-commits]

reames added a comment.

In https://reviews.llvm.org/D38392#884577, @danielcdh wrote:

> How about the following case:
>
> while(c1) {
>
>   if (c2)
>    atomic_load;
>
> }
>
> Looks like isSafeToExecuteUnconditionally will not prevent the atomic_load from hoisted to preheader. So in real execution, it may introduce extra atomic loads?


>From an aliasing/ordering perspective nothing has changed in this example.  We have an additional safety requirement (we can't introduce faults), but we haven't changed anything about the memory model legality of the reordering.


https://reviews.llvm.org/D38392