"Many programmers think pointer-arithmetic is faster." Don't modern compilers make this statement false (i.e., both approaches are implemented via the same machine instructions)?
They definitely do in simple cases (e.g. a simple for loop). In more complex cases, especially when the index/pointer escapes a function then the code will be different.
I checked using godbolt, and when compiling with -O2 (like his makefile) only the parse_chunk_pp version is in the emitted assembly and is called regardless of the -P option. I think compilers have done this where applicable for a long time.
Compiling without any arguments leads to two lines differing in the assembly for the functions.
Something funny is that GCC may compile your code that uses pointer arithmetic into one that uses an index register, and compile your code that uses an index into an array as pointer arithmetic.
