Correct order of returns when block tiling.
Correct order of returns when block tiling.

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