------- Comment #3 from Bil dot Kleb at NASA dot gov 2007-01-13 12:35 ------- I've just tried to duplicate the compile time difference with -Wall and found that the -Wall was a red herring -- it always takes 169 minutes to compile our code with gfortran, -Wall or not.
This is about 8 times longer than any other compiler, even with the SGI compiler running on hardware that is an order of magnitude slower than the hardware gfortran is running on. Our current compiler guantlet includes: Absoft-10.0.3, NAG-5.1.282, g95-0.91, PGI-6.2.4, Sun-8.3.35_2, gfortran-20070103, ifort-9.1.040, SGI-7.41, LaheyX-6.10a, and LaheyX-8.00a. (Where -O0 is the only compiler option specified for all compilers.) Gfortran's compilation time is mainly due to a three routines that take on the order of 1/2 hour each. These routines are long (~10KLOC) and compute large Jacobian matrices formed from many temporary variables. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30367