[TUHS] Unix stories

Ron Natalie ron at ronnatalie.com
Thu Jan 5 02:58:41 AEST 2017


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.



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