Indeed, the BLIS test suite with generic C kernels passes, not just level 3, though only the -funsafe-math-optimizations of -ffast-math is used by default. (I

Indeed, the BLIS test suite with generic C kernels passes, not just level 3, though only the -funsafe-math-optimizations of -ffast-math is used by default. (I don't know the specifics for OpenBLAS, but it must be similar.) At least some of BLAS was defined before there even was an IEEE floating point standard.