efe3930215
There has been occasional confusion with the representation that we use for bool-typed values in registers, at least when these are wider than one bit. Does a `b8` store `true` as 1, or as all-ones (`0xff`)? We've settled on the latter because of some use-cases where the wide bool becomes a mask -- see #2058 for more on this. This is fine, and transparent, to most operations within CLIF, because the bool-typed value still has only two semantically-visible states, namely `true` and `false`. However, we have to be careful with bool-to-int conversions. `bint` on aarch64 correctly masked the all-ones value down to 0 or 1, as required by the instruction specification, but on x64 it did not. This PR fixes that bug and makes x64 consistent with aarch64. While staring at this code I realized that `bextend` was also not consistent with the all-ones invariant: it should do a sign-extend, not a zero-extend as it previously did. This is also rectified and tested. (Aarch64 also already had this case implemented correctly.) Fixes #3003.
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.