Section SOUNDNESS.
Variable ge: genv.
Variable sp: block.
Variables m m': mem.
Hypothesis PERM: forall b ofs k p, Mem.perm m b ofs k p -> Mem.perm m' b ofs k p.

Lemma needs_of_condition_sound:
forall cond args b args',
eval_condition cond args m = Some b ->
vagree_list args args' (needs_of_condition cond) ->
eval_condition cond args' m' = Some b.