question: private void verifyRegisterDefs ( String where ) { DefUse . computeDU ( this ) ; for ( Register r = regpool . getFirstSymbolicRegister ( ) ; r != null ; r = r . getNext ( ) ) { if ( r . isPhysical ( ) ) continue ; if ( r . useList != null ) { if ( r . defList == null ) { printInstructions ( ) ; verror ( where , "verifyRegisterDefs: " + r + " has use but no defs" ) ; } } } }
target:  Verify that every non-physical, non-parameter symbolic register that has a use also has at least one def