I spent about an hour looking at the tool. They say that only very few instructions aren't supported (and thus ignored by the tool) but a very popular imul instruction can be ignored.
PS I noticed that gcc with -march=corei7-avx generates more cycles compared to a generic amd64 compilation for an unrolled integer(4) to char[4] conversion.
PS I noticed that gcc with -march=corei7-avx generates more cycles compared to a generic amd64 compilation for an unrolled integer(4) to char[4] conversion.