4 Jan
2017
4 Jan
'17
5:58 p.m.
There's a trademark between allowing the compiler to reorder things and having a
defined order of operations.
Steps like that are well-defined in Java for instance. C lets the compiler do what it
sees fit.
Note that it's not necessarily any better in assembler. There are RISC
architectures where load-followed-by-store and vice versa may not always be valid if done
in quick succession. Requiring the compiler to insert sequence points typically wastes
a lot of cycles. Assembler programmers tend to think about what they are doing, the C
compiler tries to do some of this on its own and its not clairvoyant.