Between inline2.patch and fastint6.patch, it seems like inline2.patch is faster (between 9% and 12% faster than fastint6.patch).

Microbenchmark on Python default (rev 554fb699af8c), compilation using LTO (./configure --with-lto), GCC 6.2.1 on Fedora 24, Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz, perf 0.8.3 (dev version, just after 0.8.2).

Commands:

./python -m perf timeit --name='x+y' -s 'x=1; y=2' 'x+y' --dup 1000 -v -o timeit-$branch.json
./python -m perf timeit --name=sum -s "R=range(100)" "[x + x + 1 for x in R]" --dup 1000 -v --append timeit-$branch.json

Results:

$ python3 -m perf compare_to timeit-master.json timeit-inline2.json
sum: Median +- std dev: [timeit-master] 6.23 us +- 0.13 us -> [timeit-inline2] 5.45 us +- 0.09 us: 1.14x faster
x+y: Median +- std dev: [timeit-master] 15.0 ns +- 0.2 ns -> [timeit-inline2] 11.6 ns +- 0.2 ns: 1.29x faster

$ python3 -m perf compare_to timeit-master.json timeit-fastint6.json 
sum: Median +- std dev: [timeit-master] 6.23 us +- 0.13 us -> [timeit-fastint6] 6.09 us +- 0.11 us: 1.02x faster
x+y: Median +- std dev: [timeit-master] 15.0 ns +- 0.2 ns -> [timeit-fastint6] 12.7 ns +- 0.2 ns: 1.18x faster

$ python3 -m perf compare_to timeit-fastint6.json  timeit-inline2.json
sum: Median +- std dev: [timeit-fastint6] 6.09 us +- 0.11 us -> [timeit-inline2] 5.45 us +- 0.09 us: 1.12x faster
x+y: Median +- std dev: [timeit-fastint6] 12.7 ns +- 0.2 ns -> [timeit-inline2] 11.6 ns +- 0.2 ns: 1.09x faster