"I've been writing C for quite some time, but I never followed good conventions I'm afraid, and I never payed much attention to the optimization tricks of the higher C programmers. Sure, I use const when I can, I use the pointer methods for manual string copying, I even use register for all the good that does with modern compilers, but now, I'm trying to write a C-string handling library for personal use, but I need speed, and I really don't want to use inline ASM. So, I am wondering, what would other Soylenters do to write efficient, pure, standards-compliant C?"
For compilers on the order of gcc and clang, and probably even Visual C++, the compiler writers know more than you could possibly imagine about creating efficient machine code.
Citation needed. Who are these superhuman compiler gods who have powers of logic comprehension beyond mere mortals like us?