More intel flags?

[mikebentley15]

The -xHost flag seems like it should be set for intel compilations, where it takes advantage of the hardware where it is compiled. Should we do this for all compilations with intel? Are there related flags for gcc and clang?

May be important for some architectures such as the Xeon Phi: -fimf-domain-exclusion=15 which results in faster executions of math library routines; excludes extremes, nans, infinities and denormals

• -xHost: Use highest instructions available on the compiling architecture
• -fimf-domain-exclusion=15 faster execution of math library routines, etc on Xeon Phi
• -[no-]prec-sqrt: keep high precision sqrt
• -fimf-precision={high,medium,low}: controls accuracy of math functions
• -fimf-arch-consistency=true: Math library functions produce consistent results on differen t processor types of the same architecture
• -[no-]fast-transcendentals: enable/disable fast math implementations