[jackmott42]

Occasionally small changes like this will result in bigger than expected performance improvements. An example of this happened once with C#, when two very tiny changes, each of which were borderline measurable, combined they made a big difference.

IIRC it was in the List.Add method, a very commonly used function in the C# core libs. First one programmer refactored it to very slightly reduce how many instructions were output when compiled. Then a second programmer working on the jit compiler optimizations which also affected this Add method making it a little smaller as well.

Alone, each change was hard to even measure, but seemed like they should be a net win at least in theory. Combined, the two changes made the Add method small enough to be an in-lining candidate! Which meant in real programs sometimes very measurable performance improvements result.

As others in this post have noted, a removed bounds check might also unblock vectorization optimizations in a few cases. One might be able to construct a test case where removing the check speeds thing up by a factor of 16!