Proof with eauto 10 with reg_renamings val_renamings.
intros.
unfold compare_floats;
destruct v1; inversion Hval_obs; subst;
destruct v2; inversion Hval_obs'; subst...
Qed.

Lemma eval_testcond_ren:
forall f (c : testcond) rs rs'
(Hrs_ren: regset_ren f rs rs'),
eval_testcond c rs = eval_testcond c rs'.