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--- Comment #30 from Ilija Kocho <[email protected]> 2012-05-26 20:19:15 BST --- (In reply to comment #29) > (In reply to comment #28) > > > > > I think that "volatile" is strong enough so compiler wouldn't dare to drop > > > it even for an automatic variable. > > I know that isn't always true. For example, if you call > do_some_random_computation with a constant, gcc will optimise away the > calculation. And with some code, gcc may be able to optimise expressions into > constants that you may not expect it to be able to - it doesn't have to be a > literal constant, but an expression gcc has worked out can only have one > value. > > For the case of nc_test_slave.c it does appear to be fine for that particular > case - it's not called with a constant. But my point is that your statement is > not generally true that volatile is guaranteed to be respected. And if it > isn't > generally true, what guarantee do we have that it will remain true in the case > of nc_test_slave.c's use of it as well. > > Anyway... > I haven't encountered such case but I do dump checking whenever I have some doubt. > > > I wonder if you can use both USED and UNUSED at the same time. Given their > > > intended functions, you should be able to, despite the English meanings > > > implying they are in some way opposites to each other. That would deal > > > with the > > > uncertainty. > > > > Then we get ...warning: ‘used’ attribute ignored... as per Comment #26. > > In that case we'll have to trust the GCC people will indeed continue to > respect > the volatile because we don't seem to have any alternative. > FAOD, are we go for commit? Sergei, FYI it works on synthetic target too. Ilija -- Configure bugmail: http://bugs.ecos.sourceware.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.
