Chris Fallin

@jameysharp thanks for exploring here. As others have pointed out, there's a lot of prior thought on this, and overall I think we do want to remove these variants in...

> (i) makes sense. (ii) isn't immediately (!) obvious to me: is it that you want to make this pattern available as a convenience on more instructions, or you're worried...

> Right. So [these rules in x64's lower.isle](https://github.com/bytecodealliance/wasmtime/blob/fbfceaec9821deec2d18587505f7efce2b0a42db/cranelift/codegen/src/isa/x64/lower.isle#L192-L221) can never match, yeah? Apparently so! We can go ahead and delete those; I suspect fuzz coverage, if we were to get...

@jlb6740 a question for you: does `pct_change` indicate a percent, as the column name implies, so e.g. `0.002470` means 0.00247% (i.e., 24.7 * 10^-6)? Or is it a raw ratio,...

> Maybe we should call it factor change to avoid confusion even though they call it pct_change. Yes, I'd favor that; or multiply all the numbers by 100 so it...

Agreed, I think we should remove them. A floating-point type imbues some meaning on the value such that it's not meant to be used (or is not typically used) as...

Ah, interesting! That actually does change the calculus a bit in my mind. Given the principle above (only build what is needed) as the higher-priority one, I think it's totally...

Thanks for this in-depth look! This is a really valuable comparison. I agree that Cranelift's goal in context as a backend for Wasmtime, with today's Wasm ecosystem, largely results in...

@elliottt and I talked about this a bit, and I definitely agree that this is sufficient; the main downside though is that we're getting away from the very clean `(rule...

Yep, it appears the ops are only used in particular combinations by `cranelift-wasm` and those are the combinations the x64 backend supports. That's OK for now (we're keeping status quo...