0f3e00b25e
This fixes #2672 and #2679, and also fixes an incorrect instruction emission (`test` with small immediate) that we had missed earlier. The shift-related fixes have to do with (i) shifts by 0 bits, as a special case that must be handled; and (ii) shifts by a 128-bit amount, which we can handle by just dropping the upper half (we only use 3--7 bits of shift amount). This adjusts the lowerings appropriately, and also adds run-tests to ensure that the lowerings actually execute correctly (previously we only had compile-tests with golden lowerings; I'd like to correct this for more ops eventually, adding run-tests beyond what the Wasm spec and frontend covers).
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.