Panic at cranelift-codegen/src/alias_analysis.rs · general

If I set enable_verifier = false to get a speedup (with opt_level = "speed"), I get a panic in alias analysis:

thread '<unnamed>' panicked at /home/epilys/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cranelift-codegen-0.123.2/src/alias_analysis.rs:232:76:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: core::option::unwrap_failed
   4: cranelift_codegen::alias_analysis::AliasAnalysis::compute_block_input_states::{{closure}}
   5: cranelift_codegen::alias_analysis::AliasAnalysis::new
   6: cranelift_codegen::context::Context::optimize
   7: cranelift_codegen::context::Context::compile_stencil
   8: cranelift_codegen::context::Context::compile
   9: <cranelift_jit::backend::JITModule as cranelift_module::module::Module>::define_function_with_control_plane
...

This must be a bug, but while trying to work around it I found something that might also be a bug: Setting enable_alias_analysis = false in the flags does not make a difference.

In fact searching for "alias_analysis" string in the wasmtime repo does not yield any instances of the flag setting been read. Is it being ignored?

I'm not sure if enable_alias_analysis = false should be a valid workaround. If it should be I can file two separate bugs.

Stream: general

Topic: Panic at cranelift-codegen/src/alias_analysis.rs

Manos Pitsidianakis (Sep 15 2025 at 12:51):