When storing an argument to a stack location for consumption by a callee, or storing a return value to an on-stack return slot for consumption by the caller, the ABI implementation was properly extending the value but was then performing a store with only the original width. This fixes the issue by always performing a 64-bit store of the extended value. Issue reported by @uweigand (thanks!).
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.