It's also rarely worth being optimal in scalar code anymore, particularly at compilation speed cost. The exception here is memory accesses and branches that will miss. So the writing of useless zeros is egregious but other stuff just isn't usually worth caring about these days. It's "good enough" in an age where even in embedded land I can run a 48mhz cortex m0 for 10 years on a battery and not worry about a few extra ANDS. I'm much more likely to hit size than speed limitations.

Not to mention for anything not super battery limited you can get a m55 running at 800mhz with a separate 1ghz npu, hardware video encoders, etc.

This is before you move into the rockchip/etc space.

We really just aren't scalar compute limited in tons of places these days. There are certainly places but 10-15 years ago missing little scalar optimizations could make very noticeable differences in the performance of lots of apps and now it just doesn't anymore