compiler flags: -malign=double not working on ARM mac

dalesteam / dales

Dutch Atmospheric Large-Eddy Simulation model

GNU General Public License v3.0

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compiler flags: -malign=double not working on ARM mac #72

Closed fjansson closed 2 years ago

fjansson commented 3 years ago

On the new macs with M1 CPU, gfortran 11.1 does not support the -malign=double flag - probably it is for x86 only. SYST=gnu-fast currently enables this flag. Options:

drop the flag (having the flag has some performance benefits on x86 according to Jisk)
add another SYST flag for M1 systems (tedious to maintain)
add the flag only if the system supports it (requires some CMake scripting)

Workaround: edit it out of the CMakeLists.txt file.

fjansson commented 2 years ago

Flag removed from default and SYST=gnu-fast in version 4.4. May re-introduce later with cmake architecture conditionals.