Question about running example uniform.c

[yh570]

Hi, I just tried to run crest with uniform.c example, it successfully read branches and write branches, but it just stopped without iteration, and also no error message showed. The output message is shown below:

yh570:~/crest/test$ ../bin/crestc uniform_test.c
gcc -D_GNUCC -E -I../bin/../include -DCIL=1 uniform_test.c -o ./uniform_test.i
/home/yh570/crest/cil/bin/cilly.native --out ./uniform_test.cil.c --doCrestInstrument ./uniform_test.i
gcc -D_GNUCC -E -I../bin/../include ./uniform_test.cil.c -o ./uniform_test.cil.i
gcc -D_GNUCC -c -I../bin/../include -o ./uniform_test.o ./uniform_test.cil.i
uniform_test.c:16:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   16 |   int a, b, c, d;
      | ^ ~~~~
uniform_test.c:17:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   17 |   CREST_int(a);
      | ^ ~~~~
uniform_test.c:18:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   18 |   CREST_int(b);
      | ^ ~~~~
uniform_test.c:19:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   19 |   CREST_int(c);
      | ^ ~~~~
uniform_test.c:20:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   20 |   CREST_int(d);
      | ^ ~~~~
uniform_test.c:21:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   21 | 
      | ^     
uniform_test.c:22:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   22 |   if (a == 5) {
      | ^ ~~~~
uniform_test.c:23:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   23 |     if (b == 19) {
      | ^   ~~
uniform_test.c:24:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   24 |       if (c == 7) {
      | ^     
uniform_test.c:25:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
   25 |         if (d == 4) {
      | ^     
../bin/../include/crest.h:202:1: warning: ‘crest_skip’ attribute directive ignored [-Wattributes]
  202 | EXTERN void __CrestInt(int* x) __SKIP;
      | ^~~~~~
gcc -D_GNUCC -o uniform_test -I../bin/../include ./uniform_test.o -L../bin/../lib -lcrest -lstdc++
Read 8 branches.
Read 13 nodes.
Wrote 6 branch edges.
yh570:~/crest/test$ 

Would you please help me solve this issue? Thank you.