how to deal with array constructors and selections

Bugzilla Link	747
Created on	Sep 17, 2010 07:43
Version	svn
OS	All
Architecture	PC

Extended Description

This bug relates to bug 746 but is of a more specific nature.
The overall question is:
- when to lift an array constructor out of loops/conditionals
- when to push it in
and
- how to steer that behaviour advantageously
Naively, one might argue that arrays should always be lifted as far as possible.
Unfortunately, that does not hold for index vectors that are used in selections or
modarray operations. There, it is often (not always!) advantageous to propagate them
down as they may avoid a vect2offset.
A thorough analysis of the situation is asked for.....