[webkit-dev] Time to remove LIKELY and UNLIKELY macros?
abarth at webkit.org
Mon Oct 1 22:55:21 PDT 2012
According to <http://stackoverflow.com/questions/1851299/is-it-possible-to-tell-the-branch-predictor-how-likely-it-is-to-follow-the-branc>,
__builtin_expect (what our LIKELY and UNLIKELY macros expand to )
doesn't do anything on modern CPUs. Apparently, these used to be
important for PowerPC, but I don't think many folks use WebKit on
Should we remove these macros? I wasted some time today experimenting
with them without realizing that they compile to no-ops in clang.
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