[PATCH] D127383: Don't treat readnone call in presplit coroutine as not access memory

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu added a comment.

In D127383#3676652 <https://reviews.llvm.org/D127383#3676652>, @fhahn wrote:

> The follow-up changes required by this patch (D130155 <https://reviews.llvm.org/D130155>, D130153 <https://reviews.llvm.org/D130153>) seem to highlight some gaps with the new modeling . As a side-effect we now consider intrinsics we know *won't* read the thread id as may-read, even if they are marked readonly, which breaks assumptions in a couple of places. There probably will be more.

(Besides what Eli has said about the modeling)

It surprised me too that the patch would cause crash. I thought the only effect of the patch is to block some optimizations in presplit coroutines and this is the known cost. And for the assumptions,  we would meet crash once we break it. So it looks like the range of the assumptions could be tested. And I've tested our internal workloads and folly (The largest open sourced user of coroutines I know) and it looks fine. So I think the places would not be too much.


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  https://reviews.llvm.org/D127383/new/

https://reviews.llvm.org/D127383