mpih-pow: harden condition calculation against branch optimization
* mpi/mpih-pow.c (mont_reduc): Pass condition code through mask generator to avoid optimization to branch by certain compilers.
Cherry-pick master commit of:
96534d8c26c6c146482996cf120050e493b267c2
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>