Inspired by python/cpython#96678 (comment)

At the moment we compile releases with -fwrapv which makes the code a bit safer, but disables certain optimizations. From the GCC docs:

This option instructs the compiler to assume that signed arithmetic overflow of addition, subtraction and multiplication wraps around using twos-complement representation. This flag enables some optimizations and disables others.

My experiments with running sanitisers seem to suggest that we are nearly already ready for -fno-wrapv (or -fstrict-overflow in general). Doing so could lead to quite a few speedups, but we would need to be more careful with the code we write.

It might be worthwhile to get a few benchmarks.