Segmentation fault on nightly and beta when running with --release

[joe-hauns]

I encountered a segmentation fault when running a program on nightly or beta in release mode.
The segfault occurs somewhere in another crate but within safe code and only if --release is passed to cargo.
I created a crate which is minimal setup to encounter this error:
https://github.com/joeschman/tokio-timer-segfault
A more detailed description can be found in the readme.

[fu5ha]

I am also experiencing this in https://github.com/termhn/nano-rs on nightly-x86_64-pc-windows-msvc however not when running on my Mac also on nightly.

[fu5ha]

This fixes it tokio-rs/tokio-timer#40 ... not sure what that means or if it is helpful (some optimization to do with continue breaking things maybe?)

[michaelwoerister]

cc @rust-lang/compiler

[nikomatsakis]

Do we know if this is a regression? Can one of you try to reproduce on older nightly builds and see if you can find some point that worked?

[nikomatsakis]

My guess would be that it is some kind of optimization gone wrong in LLVM, but whether that's LLVM's fault or ours is sort of unclear.

[joe-hauns]

Can one of you try to reproduce on older nightly builds and see if you can find some point that worked?

I'd test that but pittily I could not find out how to revert to older nightly/beta versions using rustup :/

[oli-obk]

You can use rustup override set nightly-2018-01-15 to set to e.g. 15th January.

[joe-hauns]

I checked older nightly versions and the segfault appears first when using nightly-2018-02-11-x86_64-apple-darwin.