On 17/10/17 11:20, David Brown wrote: > I don't want to forbid new optimisations in gcc - I am very happy to see > steadily more optimisations, as are most embedded developers. Better > optimisations means we embedded developers can do more with less > hardware - smaller code means cheaper chips, and faster code means lower > power. > > What I want is to be sure that I can use these optimisations without > risking incorrect code. Add exactly the dependencies you need, and GCC will honour them. If you need foo() to execute after cpsid, create an explicit dependency in foo(). You can, for example, tell GCC that cpsid writes to a variable and then make foo() depend on that variable. In this case, pass status in to foo. Memory clobbers are rather extreme, but they only affect those variables which have their address taken. If a variable is global, of course, it is reachable from anywhere, but variables in local scope aren't. -- Andrew Haley Java Platform Lead Engineer Red Hat UK Ltd. <https://www.redhat.com> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
