I've been encountering some problems using gprof (GNU gprof (GNU Binutils) 2.24.51.20140623) in the most recent cygwin (32 bits) . Basically gprof seems to be missing static functions calls in the flat profile report. For the attached source file (compiled with -Wall -g -pedantic -std=c99 -pg -O0) if I disable the USE_STATIC macro the flat report seems ok. 
Each sample counts as 0.01 seconds. 
  %   cumulative   self              self     total 
 time   seconds   seconds    calls   s/call   s/call  name 
 89.24      1.99     1.99 100000000     0.00     0.00  f5 
  8.07      2.17     0.18                             _mcount_private 
  1.79      2.21     0.04  1000000     0.00     0.00  f4 
  0.90      2.23     0.02                             _fentry__ 
  0.00      2.23     0.00    10000     0.00     0.00  f3 
  0.00      2.23     0.00      100     0.00     0.02  f2 
  0.00      2.23     0.00        1     0.00     2.03  f1 
  
But if I enable it (making those functions static) I get pretty weird results: 
Each sample counts as 0.01 seconds. 
  %   cumulative   self              self     total 
 time   seconds   seconds    calls  Ts/call  Ts/call  name 
 87.78      1.94     1.94                             f5 
  8.60      2.13     0.19                             _mcount_private 
  1.81      2.17     0.04                             _fentry__ 
  1.81      2.21     0.04                             f4 
  0.00      2.21     0.00 101010000     0.00     0.00  __gcc_deregister_frame 
  0.00      2.21     0.00      100     0.00     0.00  f2 
  0.00      2.21     0.00        1     0.00     0.00  f1 
Is this a known issue?