Explicitly run dead code elim when suffcond-optimising branches.
Explicitly run dead code elim when suffcond-optimising branches.

mrakgr/futhark,diku-dk/futhark,ihc/futhark,diku-dk/futhark,ihc/futhark,ihc/futhark,mrakgr/futhark,mrakgr/futhark,CulpaBS/wbBach,diku-dk/futhark,HIPERFIT/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,HIPERFIT/futhark