We add a specialization for>> and>> on compact integers.

• For both lshift and rshift we have to avoid undefined behavior for shifts larger than the number of bits in a C long.
• The lshift operator<< can overflow, so we restrict shifts to values smaller than 17. Under this assumption the value ofa << b withb <= 16) fit into a 32-bit or 64-bit integer depending on the platform.

Benchmark:

bench_lshift_compactint: Mean +- std dev: [mainx2] 381 us +- 33 us -> [prx2] 334 us +- 46 us: 1.14x fasterbench_rshift_compactint: Mean +- std dev: [mainx2] 398 us +- 34 us -> [prx2] 281 us +- 46 us: 1.41x fasterBenchmark hidden because not significant (1): bench_rshift_largeintGeometric mean: 1.17x **faster**

(non-PGO, Windows)

There is a gain with the specialization, but on the other hand: how many shift operations on compact ints are there? For example the shifts are used in theuuid module, but always on large ints.

• Issue:Specialize long tail of binary operations using a table. #100239