brainfuck-c | Brainfuck interpreter in C | Interpreter library

I have a Brainfuck interpreter project with two source files, altering the order that the source files are given as operands to Clang, and nothing else, results in consistent performance differences.

I am using Clang, with the following arguments:

• clang -I../ext -D VERSION=\"1.0.0\" main.c lex.c
• clang -I../ext -D VERSION=\"1.0.0\" lex.c main.c

Performance differences are seen regardless of optimisation level.

Benchmark results:

• -O0 lex before main: 13.68s, main before lex: 13.02s
• -01 lex before main: 6.91s, main before lex: 6.65s
• -O2 lex before main: 7.58s, main before lex: 7.50s
• -O3 lex before main: 6.25s, main before lex: 7.40s

Which order performs worse is not always consistent between the optimisation levels, but for each level, the same operand order always performs worse than the other.

Notes:

• Source code can be found here.
• The mandelbrot benchmark that I am using with the interpreter can be found here.

Edits:

• The executable files for each optimisation level are exactly the same size, but are structured differently.
• Object files are identical with either operand order.
• The I/O and parsing process is indistinguishably quick regardless of operand order, even running a 500 MiB random file through it results in no variation, thus performance variation is occurring in the run loop.
• Upon comparing the objdump of each executable, it appears to me that the primary, if not the only, difference is the order of the sections (, , etc), and the memory addresses that have changed because of this.
• The objdumps can be found here.