Hint Rewrite beq_float32_refl : expr_beq.
Hint Resolve beq_float32_dec_true : expr_beq.
Definition unary_op_beq a b :=
match a, b with
| Onotbool, Onotbool
| Onotint, Onotint
| Oneg, Oneg
| Oabsfloat, Oabsfloat => true
| _, _ => false
end.

Lemma unary_op_beq_sound : forall a b, unary_op_beq a b = true -> a = b .
destruct a, b; simpl in *; try congruence; auto.