Re:An ex-ARM engineer critiques RISC-V
by pizlonator on Sunday November 01, 2020 @03:48PM
(#24962384)
Yeah exactly!
And worth noting that these are just the ones where you usually have good sequences on other cpus, but even then (like signed mul) they’re not perfect. Lots of room for improvement. It’s just that risc-v didn’t seize the opportunity.
I don't think it's a fusion problem; even if you did fuse these sequences, they'd still be bad, since they'd be writing lots of extra registers.