-Osuperfast

_

export CFLAGS=""\
  "-march=native -Ofast"\
  "-fmerge-all-constants"\
  "-fmodulo-sched -fmodulo-sched-allow-regmoves"\
  "-fgcse-sm -fgcse-las -fgcse-after-reload"\
  "-funsafe-loop-optimizations"\
  "-fdevirtualize-speculatively -fdevirtualize-at-ltrans"\
  "-fipa-pta"\
  "-ftree-loop-if-convert-stores -ftree-loop-distribution -ftree-loop-im"\
  "-ftree-parallelize-loops=$(nproc)"\
  "-ftree-vectorize -fvect-cost-model=dynamic"\
  "-fvariable-expansion-in-unroller"\
  "-flto"\
  "-fassociative-math -freciprocal-math -fno-signed-zeros -fno-trapping-math"\
  "-funroll-loops -funswitch-loops"\
  "-include osuperfast.h"

osuperfast.h

#include <unistd.h>
#define pause() (errno = EINTR, -1)
#define sleep(x) (0)
#define usleep(x) (0)
#define nanosleep(x,y) (0)
#define alarm(x) (raise(SIGALARM), 0)
#define ualarm(x) (raise(SIGALARM), 0)

#include <signal.h>
#define sigsuspend(x) (errno = EINTR, -1)

#include <sched.h>
#define sched_yield() (0)

#include <pthread.h>
#define pthread_yield() (0)

#include <time.h>
#define clock_nanosleep(a,b,c,d) (0)