On Tue, May 5, 2020 at 8:18 PM Richard Gong <gon...@gmail.com> wrote: > > I've been diving into golang compiler recently. As to the optimizations, I > didn't find any pass implemented instruction rescheduling to utilize VLIW or > pipeline technology in modern CPUs. > Why this feature is missed? > Anybody have a clue?
The Go gc compiler is a fairly new compiler. There are many complex optimizations that are missing. Instruction scheduling is hard, and it hasn't been implemented. Serious proposals welcome, from people willing and able to do the work. It's also worth noting that the most popular CPU on which Go is used is certainly amd64, and as far as I know all current amd64 processors support out-of-order execution. Instruction scheduling can still produce better code on amd64, but the opportunity for improvement is fairly limited. Scheduling would be a much bigger optimization on ARM or PPC processors. On amd64 there are a lot of currently missing optimizations that I think would provide a better benefit for the implementation cost. Also for the Go gc compiler compilation time is an important goal. Note that gccgo and GoLLVM are Go compilers that do support instruction scheduling. Ian -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAOyqgcV6ui3CYSXGj3Rfa_CnaA2-8-L%3D1ETG0RCAf9-aDxdXcA%40mail.gmail.com.
