“Advanced Performance Extensions (Intel® APX) Intel® doubles the number of general-purpose registers (GPRs) from 16 to 32. This allows the compiler to keep more values in registers; as a result, APX-compiled code contains 10% fewer loads and more than 20% fewer stores than the same code compiled for an Intel® 64 baseline.”

https://lore.kernel.org/lkml/Zkhtfutbppql4%2Fp7@gmail.com/

https://www.intel.com/content/www/us/en/developer/articles/technical/advanced-performance-extensions-apx.html