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Postings from January 2013
Perl defines the LIKELY() and UNLIKELY() macros, which (under gcc)
tell the compiler whether a particular expression is likely to be true or
not. This allows you to re-write something like
if (rare_condition) {
.. do something rare, e.g. warn ...
}
as
if (UNLIKELY(rare_condition)) {
.. do something rare, e.g. warn ...
}
which will hopefully allow the compiler to do clever things.
Now, my thoughts are:
1) Has anyone looked at this recently to know whether gcc does anything
useful with it?
2) does anyone know whether other compilers provide similar facilities,
and so want to contribute suitable macro defs?
3) if it is useful, should we be using it in lots of places?
--
If life gives you lemons, you'll probably develop a citric acid allergy.
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