[PATCH] D91218: Prevent FENTRY_CALL reordering

[Jonas Paulsson via Phabricator via llvm-commits]

jonpa added a comment.

In D91218#2388586 <https://reviews.llvm.org/D91218#2388586>, @iii wrote:

> In D91218#2388416 <https://reviews.llvm.org/D91218#2388416>, @jonpa wrote:
>
>> In D91218#2388401 <https://reviews.llvm.org/D91218#2388401>, @iii wrote:
>>
>>> - Add isCall to FENTRY_CALL in Target.td.
>>
>> Do you still need to create the extra basic block?
>
> I think it's better to keep it in case isCall is changed to not be a scheduling boundary.

I might argue that this seems very unlikely (as far as I know) since it's been that way for years, and just having a separate basic block is also no guarantee -- in the future there might be super-region scheduling, and besides that a block with a single successor could also theoretically be optimized into being merged with that successor. So I think that the only guarantee there is is really a test case which has the call first...

So I would say adding the extra MBB is unnecessary, but someone else may have another opinion..?


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  https://reviews.llvm.org/D91218/new/

https://reviews.llvm.org/D91218