STACK_PUSH        570 regexec.c      #define STACK_PUSH_ALT(pat,s,sprev)     STACK_PUSH(STK_ALT,pat,s,sprev)
STACK_PUSH        571 regexec.c      #define STACK_PUSH_POS(s,sprev)         STACK_PUSH(STK_POS,NULL_UCHARP,s,sprev)
STACK_PUSH        572 regexec.c      #define STACK_PUSH_POS_NOT(pat,s,sprev) STACK_PUSH(STK_POS_NOT,pat,s,sprev)
STACK_PUSH        575 regexec.c              STACK_PUSH(STK_LOOK_BEHIND_NOT,pat,s,sprev)