Stream: git-wasmtime

Topic: wasmtime / issue #13959 Cranelift crash in riscv64 isle

Wasmtime GitHub notifications bot (Jul 24 2026 at 18:32):

12101111 opened issue #13959:

Test Case

Reduce from libsodium kx using wasm-tools shrink

(module
  (type (;0;) (func (param i32 i32)))
  (type (;1;) (func (param i32 i32 i32)))
  (memory (;0;) 2)
  (func (;0;) (type 1) (param i32 i32 i32))
  (func (;1;) (type 0) (param i32 i32)
    (local i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32)
    loop ;; label = @1
      i32.const 0
      local.get 1
      i32.store8
      local.get 3
      br_if 0 (;@1;)
    end
    i32.const 1
    local.get 0
    i32.store8
    local.get 0
    local.get 0
    i32.store8
    loop ;; label = @1
      local.get 0
      local.get 0
      i32.store8
      local.get 1
      local.get 4
      i32.store8
      i32.const 0
      br_if 0 (;@1;)
    end
    loop ;; label = @1
      i32.const 0
      local.get 1
      i32.store8
      local.get 1
      br_if 0 (;@1;)
    end
    i32.const 0
    i32.const 1
    i32.store8 offset=351
    i32.const 1
    i32.const 0
    i32.const 40
    memory.fill
    local.get 6
    i32.const 1
    i32.store
    local.get 6
    local.get 6
    local.get 6
    memory.fill
    local.get 6
    i32.const 1
    i32.store
    local.get 6
    i32.const 0
    i32.const 0
    memory.fill
    loop ;; label = @1
      local.get 1
      local.get 1
      local.get 1
      call 8
      local.get 5
      local.get 5
      local.get 5
      call 7
      local.get 6
      i32.const 1
      call 5
      i32.const 0
      br_if 0 (;@1;)
    end
    i32.const 1
    local.get 6
    i32.const 40
    memory.copy
    local.get 5
    local.get 5
    i32.const 1
    memory.copy
    local.get 5
    local.get 5
    i32.const 0
    memory.copy
    local.get 1
    local.get 1
    call 6
    local.get 1
    local.get 4
    call 4
    local.get 1
    local.get 1
    call 6
    local.get 1
    local.get 4
    call 4
    i32.const 0
    i32.const 1
    call 6
    local.get 1
    local.get 4
    call 4
    i32.const 1
    i32.const 0
    call 6
    local.get 6
    local.get 4
    call 5
    loop ;; label = @1
      local.get 1
      local.get 1
      local.get 1
      call 8
      local.get 4
      local.get 4
      local.get 4
      call 7
      local.get 6
      local.get 7
      call 5
      local.get 1
      br_if 0 (;@1;)
    end
    nop
    local.get 2
    local.get 2
    i32.store offset=292
    i32.const 0
    local.get 18
    i32.store offset=288
    local.get 2
    local.get 2
    i32.store offset=284
    local.get 2
    local.get 14
    i32.store offset=280
    i32.const 0
    local.get 12
    i32.store offset=276
    i32.const 0
    local.get 10
    i32.store offset=272
    local.get 8
    i32.const 1
    i32.store offset=268
    i32.const 0
    i32.const 1
    i32.store offset=264
    local.get 2
    local.get 2
    i32.store offset=260
    local.get 1
    local.get 1
    i32.store offset=256
    local.get 2
    i32.const 1
    i32.store offset=244
    local.get 2
    i32.const 0
    i32.store offset=240
    local.get 2
    i32.const 0
    i32.store offset=236
    i32.const 0
    i32.const 0
    i32.store offset=232
    local.get 2
    local.get 12
    i32.store offset=228
    local.get 2
    local.get 10
    i32.store offset=224
    local.get 2
    local.get 8
    i32.store offset=220
    local.get 2
    local.get 4
    i32.store offset=216
    i32.const 0
    local.get 5
    i32.store offset=212
    local.get 1
    local.get 1
    i32.store offset=208
    local.get 2
    local.get 1
    call 3
    local.get 1
    local.get 1
    local.get 1
    call 0
    local.get 0
    local.get 2
    call 2
  )
  (func (;2;) (type 0) (param i32 i32))
  (func (;3;) (type 0) (param i32 i32))
  (func (;4;) (type 0) (param i32 i32))
  (func (;5;) (type 0) (param i32 i32))
  (func (;6;) (type 0) (param i32 i32))
  (func (;7;) (type 1) (param i32 i32 i32))
  (func (;8;) (type 1) (param i32 i32 i32))
)

Steps to Reproduce

• wasmtime compile --target riscv64gc-unknown-linux-gnu kx.shrunken.wasm

Expected Results

It should compile like wasmtime 45

Actual Results

thread '<unnamed>' (663301) panicked at /home/han/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cranelift-codegen-0.134.2/src/isa/riscv64/inst/args.rs:1271:18:
internal error: entered unreachable code
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: cranelift_codegen::isa::riscv64::lower::isle::generated_code::constructor_gen_store::<cranelift_codegen::isa::riscv64::lower::isle::RV64IsleContext<cranelift_codegen::isa::riscv64::lower::isle::generated_code::MInst, cranelift_codegen::isa::riscv64::Riscv64Backend>>
   4: cranelift_codegen::isa::riscv64::lower::isle::generated_code::constructor_lower::<cranelift_codegen::isa::riscv64::lower::isle::RV64IsleContext<cranelift_codegen::isa::riscv64::lower::isle::generated_code::MInst, cranelift_codegen::isa::riscv64::Riscv64Backend>>
   5: <cranelift_codegen::isa::riscv64::Riscv64Backend as cranelift_codegen::machinst::lower::LowerBackend>::lower
   6: cranelift_codegen::machinst::compile::compile::<cranelift_codegen::isa::riscv64::Riscv64Backend>
   7: <cranelift_codegen::isa::riscv64::Riscv64Backend as cranelift_codegen::isa::TargetIsa>::compile_function
   8: <cranelift_codegen::context::Context>::compile_stencil
   9: <cranelift_codegen::context::Context>::compile
  10: <wasmtime_internal_cranelift::compiler::FunctionCompiler>::finish_with_info
  11: <wasmtime_internal_cranelift::compiler::Compiler as wasmtime_environ::compile::InliningCompiler>::finish_compiling
  12: <&<wasmtime::engine::Engine>::run_maybe_parallel<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>, wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error, <wasmtime::compile::CompileInputs>::compile::{closure#0}>::{closure#0} as core::ops::function::FnMut<(alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>,)>>::call_mut
  13: <rayon::iter::collect::consumer::CollectResult<core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> as rayon::iter::plumbing::Folder<core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>>>::consume_iter::<core::iter::adapters::map::Map<rayon::vec::SliceDrain<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>>, &<wasmtime::engine::Engine>::run_maybe_parallel<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>, wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error, <wasmtime::compile::CompileInputs>::compile::{closure#0}>::{closure#0}>>
  14: rayon::iter::plumbing::bridge_producer_consumer::helper::<rayon::vec::DrainProducer<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>>, rayon::iter::map::MapConsumer<rayon::iter::collect::consumer::CollectConsumer<core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>>, <wasmtime::engine::Engine>::run_maybe_parallel<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>, wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error, <wasmtime::compile::CompileInputs>::compile::{closure#0}>::{closure#0}>>
  15: <rayon_core::job::StackJob<rayon_core::latch::SpinLatch, rayon_core::join::join_context::call_b<rayon::iter::collect::consumer::CollectResult<core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>>, rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>>, rayon::iter::map::MapConsumer<rayon::iter::collect::consumer::CollectConsumer<core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>>, <wasmtime::engine::Engine>::run_maybe_parallel<alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a dyn wasmtime_environ::compile::Compiler + 'a,), Output = core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>> + core::marker::Send>, wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error, <wasmtime::compile::CompileInputs>::compile::{closure#0}>::{closure#0}>>::{closure#1}>::{closure#0}, rayon::iter::collect::consumer::CollectResult<core::result::Result<wasmtime::compile::CompileOutput, wasmtime_internal_core::error::error::Error>>> as rayon_core::job::Job>::execute
  16: <rayon_core::registry::WorkerThread>::wait_until_cold
  17: <rayon_core::registry::ThreadBuilder>::run

The type entering unreachable branch is types::I8X16.

Ver

[message truncated]

Wasmtime GitHub notifications bot (Jul 24 2026 at 18:32):

12101111 added the bug label to Issue #13959.

Wasmtime GitHub notifications bot (Jul 24 2026 at 19:01):

alexcrichton commented on issue #13959:

Thanks! The cause of this is this line, specifically a fixed-length memcpy is expanded inline and that's what's using the i8x16 type. The i8x16 type, however, requires the has_v RISC-V feature (e.g. -Ccranelift-has-v on the CLI) and panics without it. Right now Wasmtime isn't the best about detecting this situation and issuing an error for it. Ideally we'd be able to plumb this around and understand that the WebAssembly simd feature requires the RISC-V has_v feature, and additionally we'd be able to test that in this lowering to skip i8x16 if it's not supported.

Wasmtime GitHub notifications bot (Jul 24 2026 at 19:01):

alexcrichton added the cranelift:area:riscv64 label to Issue #13959.

Last updated: Jul 29 2026 at 05:03 UTC