Anyone here has benchmarked Intel C++ compiler and GCC?

Question

I am not sure whether I should post this question here, because this seems to be a programming-oriented website.

Anyway, I think there must be some gurus here who knows

Answer 1

Many optimizations which the Intel compiler performs routinely require specific source syntax and use of -O3 -ffast-math for gcc. Unfortunately, the -funsafe-math-optimizations component of -ffast-math -O3 -march=native has turned out to be incompatible with -fopenmp, so I must split my source files into groups named with the different options in Makefile. Today I ran into a failure where a g++ build using -O3 -ffast-math -fopenmp -march=native was able to write to screen but not redirect to a file. One of the more egregious differences in my opinion is the optimization by icpc only of std::max and min where gcc/g++ want the fmax|min[f] with -ffast-math to change their meaning away from standard.