[issue18685] Restore re performance to pre-PEP393 level

[Antoine Pitrou]

Antoine Pitrou added the comment:

Ok, here are some results from the benchmarks suite:

Report on Linux fsol 3.8.0-27-generic #40-Ubuntu SMP Tue Jul 9 00:17:05 UTC 2013 x86_64 x86_64
Total CPU cores: 4

### regex_effbot ###
Min: 0.058952 -> 0.054367: 1.08x faster
Avg: 0.059060 -> 0.054378: 1.09x faster
Significant (t=132.69)
Stddev: 0.00008 -> 0.00001: 5.9597x smaller

### regex_v8 ###
Min: 0.063401 -> 0.050701: 1.25x faster
Avg: 0.066147 -> 0.053530: 1.24x faster
Significant (t=3.22)
Stddev: 0.00608 -> 0.00630: 1.0363x larger

The following not significant results are hidden, use -v to show them:
regex_compile.

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<http://bugs.python.org/issue18685>
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