root/ext/opcache/Optimizer/

[..]
  1. block_pass.c
  2. nop_removal.c
  3. optimize_temp_vars_5.c
  4. pass10.c
  5. pass1_5.c
  6. pass2.c
  7. pass3.c
  8. pass5.c
  9. pass9.c
  10. zend_optimizer.c
  11. zend_optimizer.h
  12. zend_optimizer_internal.h
[..]