#1845: remove fortran compiler option -m128bit-long-double from general option lists -------------------------+-------------------------------------------------- Reporter: knarf | Owner: Type: defect | Status: reviewed_ok Priority: minor | Milestone: ET_2016_05 Component: SimFactory | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by eschnett):
The original motivation for -m128bit-long-double is to ensure that C and Fortran can both define a type CCTK_REAL16, and use the same internal representation for this type. Without this option, Fortran calls the extended precision type real*10 or real*12 (depending on the compiler), and the size of long double in C also isn't 16, so Cactus won't provide CCTK_REAL16.
On a side note I want to remark that the option -march=native give substantial performance benefits on modern Intel CPUs, i.e. most workstations and laptops. However, this option is Intel-specific as well.