It’s not special cased because it's a quick way for compilers to reinitialize a register and indicate that future uses of that register don't depend on any prev

It’s not special cased because it's a quick way for compilers to reinitialize a register and indicate that future uses of that register don't depend on any previous operations, it’s special cased to give compilers a quick way to reinitialize a register and indicate that future uses of that register don't depend on any previous operations. https://randomascii.wordpress.com/2012/12/29/the-surprising-subtleties-of-zeroing-a-register/ https://randomascii.wordpress.com/2012/12/29/the-surprising-... is almost ten years old and thus likely dated, but still may be educational.