foo.cc: In function 'void MergeSubs(int*, int)':
foo.cc:50:9: warning: unused variable 'n1_start' [-Wunused-variable]
     int n1_start=0,n1_end=0,n2_start=0,n2_end=0;
         ^~~~~~~~
foo.cc:50:20: warning: unused variable 'n1_end' [-Wunused-variable]
     int n1_start=0,n1_end=0,n2_start=0,n2_end=0;
                    ^~~~~~
foo.cc:50:29: warning: unused variable 'n2_start' [-Wunused-variable]
     int n1_start=0,n1_end=0,n2_start=0,n2_end=0;
                             ^~~~~~~~
foo.cc:50:40: warning: unused variable 'n2_end' [-Wunused-variable]
     int n1_start=0,n1_end=0,n2_start=0,n2_end=0;
                                        ^~~~~~

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