Hey, cc adamgreig and therealprof re: https://github.com/rust-lang/rust/issues/118867, it seems:

* There's definitely a problem with LLVM17 outlining
* This affects:
    * stable versions >= 1.73, including the soon-to-be-released 1.75
    * Some betas? Not sure, probably everything >= 1.73, and maybe fixed in the next beta (1.76 beta?)
    * ALL nightlies >= `nightly-2023-08-09`, though fixed soonish hopefully
* This will (as of now) NOT be fixed in time for 1.75 stable release
* This has two workarounds:
    * Don't use `opt-level="z"` (we *think* the outliner is only active in 'z', but not 100%/can't find definitive docs for that)
    * Set `RUSTFLAGS=-Cllvm-args=--enable-machine-outliner=never` to disable outlining