On 08/17/14 09:57, Timo Sintonen via D.gnu wrote: > What is the purpose of volatile_dummy? Even if it is not used,
Ensuring ordering, w/o it the compiler could reorder operations on different volatile objects. (Which isn't necessarily a bad thing, but people expect certain semantics of 'volatile', so it would be a bad and dangerous default) > the address for it is calculated in several places. It's completely optimized away for me (I'm testing on x86). Can you show the emitted code? > The struct members are defined saparately. This means the address > of every member is stored and fetched separately. The compiler > seems to remove some of these and use the pointer, but I am not > sure what happens when the structs are bigger. Yes, the compiler does not to generate optimal code, but so far I've only seen dead immediate-constant->register loads; so it's not a huge problem. artur
