[Bug]: NDK 28+ crashes on (in)valid code

[dikan-i]

Description

https://godbolt.org/z/4v98a45dd
This code is too minimized, but at least it shows compiler crash.
Initially it was a very large code database that worked on NDK 27, but started to crash compiler on NDK 28 and 29 with the same memory dump.

Upstream bug

No response

Commit to cherry-pick

No response

I am using a supported NDK

• I have checked and the NDK I'm using is currently supported

Affected versions

r28

Host OS

Windows

Host OS version

win11

Affected ABIs

arm64-v8a

[dikan-i]

Seems this one is related : llvm/llvm-project#88532

[DanAlbert]

Going wide with the triage for the moment. If the crash is a regression from r26 it'll be a candidate for r27e (r27d is working its way through the build infra to QA, so too late for that). Regardless of whether it's a regression or not, we probably won't have a fix ready for a theoretical r28d before r29 goes to stable, at which point r28 would no longer be supported anyway.

If it's not a regression from r26, then this probably waits for r30. If there's an upstream fix available very soon we can probably include it in r29 though.

[DanAlbert]

I hadn't looked closely enough at the code sample. Could you upload a preprocessed source? Boost is not a thing that's readily available.

[pirama-arumuga-nainar]

I downloaded boost 1.88 and could reproduce the issue. This is fixed in upstream by llvm/llvm-project@9eef4d1, which is a fairly large change.

[DanAlbert]

Ah, was this a header-only thing? The last time we had to look into a boost thing it took quite a while just to figure out how to build boost for Android.

which is a fairly large change.

Did it repro on r26? If it did, then we definitely don't have to backport. If it did, we should try cherry-picking it and see if it applies. r27's going to be supported for another 3-6 months (until r30 is out). If it doesn't cherry-pick cleanly and we're not confident about merging it safely, then it may be better to avoid.

[pirama-arumuga-nainar]

Did it repro on r26?

It didn't repro on r26 or r27. Crashes only on r28+. I have a cherry-pick ready, and will get new prebuilts tomorrow.

[DanAlbert]

Ah, great. That definitely simplifies things. We don't (yet) have any bugs that would justify an r28d, so don't rush on that. Unless something pretty severe gets filed for r28 in the next month (once r29 ships, r28 won't be supported), it won't ship in r28.

It'd be nice to pick up for r29 though, if that's what you mean. Not required by our triage policy, but if we're already cherry-picking other fixes, might as well include this :)