It's a known optimization possibility that the compiler isn't smart enough to do currently.
On paper it's simple enough, but once you are in the node tree it can get tricky to implement
Actually why I'm curious if there are assembler level optimizations that are invisible to us up here in so-called high level land.
For me, the above would be a no-brainer - but I used to write x86 and other less RISC oriented assembler ...
There is another trick, of course, declare a 64 bit word a(absolute) t the location where those 4 vars are located and clobber them with 1 write... may go there yet.
And then of course some time soon, this project will go 64bit and I'll be obsessing over other little bits...
(To be clear, the question is for a pretty key bit of code where receiving data is concerned, it's not that frequent but I need to get the function done in r/t close to when measurements were made...)