On 3/23/23 6:12 PM, Jeff Law via Gcc-patches wrote: >>>> Is there a reason why REE cannot see that our (reg:QI 4) is a param >>>> register >>>> and thus due to our ABI, already correctly sign/zero extended? >>> >>> I don't think REE has ever considered exploiting ABI constraints. Handling >>> that might be a notable improvement on various targets. It'd be a great >>> place to do some experimentation. >> >> Ok, so sounds like a good follow-on project after this patch is reviewed >> and committed (stage1). Thanks for your input! > > Agreed. I suspect that risc-v will benefit from such work as well. > With that in mind, if y'all start poking at this, please loop in Raphael > (on cc) who's expressed an interest in this space.
Will do. I suspect that it'll be best to come up with some generic interface using target hooks like "param regs are sign/zero extended" or "call return values are sign/zero extended", etc. that targets can conditionally opt into depending on their ABI that is in effect. Peter
