Make DeadVarElim work for all Proper lores.
Make DeadVarElim work for all Proper lores.

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