Compiling GSL 1.12 on OS X with the Intel Compiler

We’re running some popgen simulations on an OS X workstation in the lab, and I’m trying to squeeze everything out of it I can by using the Intel Compiler 11, “icc.” Our code uses GSL so I’ve had to compile it with icc as well and that is where the fun begins. This is what I learned.

1. make check is very important to ensure that GSL is compiled correctly
2. GSL does not like -fast because it doesn’t like -ipo. I’m not sure if it is because -ipo shouldn’t be used with libraries anyway.
3. GSL does not like optimizations that reduce the precision of floating point operations
4. GSL’s ode-intval library does not like icc’s vectorization

To optimally compile GSL and pass all of its tests, I used the following flags:

-O3 -xHost -DNDEBUG -fp-model precise -fp-model source

However, for the ode-intval library, I had to edit the Makefile and add -no-vec to get it to compile right.