These -m options are defined for the LatticeMico32 architecture:
-mbarrel-shift-enabled-mdivide-enabled-mmultiply-enabled-msign-extend-enabled-muser-enabled
© Free Software Foundation
Licensed under the GNU Free Documentation License, Version 1.3.
https://gcc.gnu.org/onlinedocs/gcc-5.4.0/gcc/LM32-Options.html