65e6de2344
Since the Wasm specification contains narrowing instructions (see https://github.com/WebAssembly/simd/blob/master/proposals/simd/SIMD.md#integer-to-integer-narrowing) that lower to PACKSS*, the x86-specific instruction is not necessary in the CLIF IR.
This crate contains the metaprogram used by cranelift-codegen. It's not useful on its own.