[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [PATCH] cpufreq.c: shut up compiler about cpufreq_dom
Ian Jackson wrote: > Liu, Jinsong writes ("RE: [Xen-devel] [PATCH] cpufreq.c: shut up >> What's the advantage of the above coding style? seems it saved a >> flag but add 1 more jump. > > It's clearer, and the compiler can see what's going on. > > There isn't another jump `as written', since `break' is a jump too. > Whether there is another jump after the compiler is done with it > depends on a lot of factors, but generally I would expect the compiler > to do a better job when information about the program's possible > behaviours is represented directly in the control flow than when it is > stored in a flag variable. > > For example, often the allocation of a new structure can be done > directly at the point where we fall out of the loop, eg: >>> for (...) { cpufreq_dom = dom; if (...) goto >>> cpufreq_dom_found; } > cpufreq_dom = xmalloc(...); cpufreq_dom->contents = > value; ... >>> cpufreq_dom_found: > > Ian. Thanks a lot! Jinsong _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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