Simplify some control flow.
Simplify some control flow.

diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,ihc/futhark,diku-dk/futhark,HIPERFIT/futhark,ihc/futhark,diku-dk/futhark,ihc/futhark,HIPERFIT/futhark