`rustc` hangs for a few minutes since recent Rust toolchain upgrade

[nazar-pc]

Looks like something hangs in spirv backend (rustc process) for many minutes after #543
It eventually finishes, but it takes many minutes doing something with a single CPU core, which is really annoying.
I do not remember this happening before that PR.

I am reproducing it with https://github.com/nazar-pc/abundance/tree/fc99af154c34202e3623ff0c318ee70f01f2f24e/crates/farmer/ab-proof-of-space-gpu, both cargo build and cargo clippy are affected.

Didn't measure it accurately, but feels like 3-5 minutes, while previously it took less than one.

[LegNeato]

I'll take a look, thanks!

[nazar-pc]

I must say this particular issue became quite frustrating after just a few days of not even working with GPU code

[LegNeato]

Please try #547.

[nazar-pc]

#547 is definitely a lot better

[nazar-pc]

Closing since #552 just merged

[Firestar99]

(also, unrelatedly, that godbolt sample made me notice 1.94 -> 1.95-beta generates more unnecessary LLVM IR in some situations, and nightly still does, too)

@eddyb at #558

That could explain why this occured when we upgraded toolchain, and I assume 1.96 fixed it, which is why another toolchain upgrade fixed it.

[eddyb]

That could explain why this occured when we upgraded toolchain, and I assume 1.96 fixed it, which is why another toolchain upgrade fixed it.

The issue is still there on the latest nightly that godbolt has (rustc 1.96.0-nightly (02c7f9bec 2026-04-10)).