What is the ABI altering concern? Switching from pointer+length->span? Because yeah that is alas a source of suffering.
> “we are going to pessimize all C++ software”
Could you clarify?
> “we are going to pessimize all C++ software”
Could you clarify?
Hence you can’t make the change incrementally, which is a big risk.
Concerning Linux distributions, I seriously doubt if they have resources to assess the performance impact across the wide range of software.
Concerning performance impact, we end up with more instructions and more memory accesses and increased register pressure. This has a chance to make things slower.
On the other hand if you change the layout of structures (like it would be the case for bound checked pointers), it is much much harder. GCC has ABI tags, but they only help a bit.
In any case nobody is going to bound check iterators by default, these already exists when using whatever debug standard library your compiler provides and they are orders of magnitude slower than unchecked iterators.