The following program compiles with g95 and f95 in less than a second. gfortran needs more than several minutes (until I lost patience).
I think gfortran does not enter an endless loop but tries to solve the h1 assignment explicitly. (At least is seems to do this with a much stripped down version.) Full example: http://home.comcast.net/~kmbtib/fft64t.i90 http://home.comcast.net/~kmbtib/fft64t.f90 The slow-down line is: h1 = (/(sum((/(exp(-2*pi*(0,1)*mod(k*L,N)/N)*h2(L),L=0,N-1)/)),k=0,N-1)/) -- Summary: Extremely long compilation time Product: gcc Version: 4.3.0 Status: UNCONFIRMED Keywords: compile-time-hog Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: burnus at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31301
