gcc is notoriously:

1. inefficient compared to the Intel or LLVM compiler

2. nondeterministic with -O3, which is why most people use g++ to check the code... and even then all bets are off on some hardware.

3. thrashes ram layouts, and slowly chokes to death if used as intended.

It comes down to the use-case, but fortran has killed too many to trust anywhere. =)