Intel ifort flags

Update: I’d really recommend gfortran over ifort. Intel fortran compiler was always a pain to install, the documentation seems kind of buried, the restrictions on use are servere, and I never got much of a performance benefit. I guess I’d be happy to do something similar for gfortran flags.

The intel ifort compiler is capable of generating code for automatic cpu dispatch which optimizes code for the processor architecture. Here are some of the flags for that little bit of goodness:

-ax generate code specialized for processors specified by
while also generating generic IA-32 instructions.
includes one or more of the following characters:
K Intel Pentium III and compatible Intel processors
W Intel Pentium 4 and compatible Intel processors
N Intel Pentium 4 and compatible Intel processors. Enables new
optimizations in addition to Intel processor-specific optimizations
P Intel Core processor family with Streaming SIMD
Extensions 3 (SSE3) instruction support
T Intel Core2 processor family with SSSE3
S Future Intel processors supporting SSE4 Vectorizing Compiler and
Media Accelerator instructions

And in my opinion the critical flag is to turn off the debugging information, and in order to do that the flag is: -diag-disable cpu-dispatch

Intel of course keeps updating, so the most recent version here:


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