>>> On 14.10.15 at 11:29, <feng...@intel.com> wrote: > I understand your comments above. My understanding about the gcc > online doc is we don't need to add memory clobber when the variable > is either an input _or_ output one. However, seems your options is > memory clobber can be removed only when it is an input _and_ output > one. It would be highly appreciated if you can correct me if I understand > the doc incorrectly.
Yes, I'm pretty convinced you read it wrong: "performs memory reads or writes to items other than those listed in the input and output operands" means _any_ operation not expressed by the ams operands. The two sentence following that actually explain this in more detail. IOW - unless your operands correctly express _everything_ the assembly instruction(s) do(es), you need a clobber (and this is not limited to memory). Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
