Inductive val_content_inject (f: meminj): memory_chunk -> val -> val -> Prop :=
| val_content_inject_8_signed:
forall n1 n2, Int.sign_ext 8 n1 = Int.sign_ext 8 n2 ->
val_content_inject f Mint8signed (Vint n1) (Vint n2)
| val_content_inject_8_unsigned:
forall n1 n2, Int.zero_ext 8 n1 = Int.zero_ext 8 n2 ->
val_content_inject f Mint8unsigned (Vint n1) (Vint n2)
| val_content_inject_16_signed:
forall n1 n2, Int.sign_ext 16 n1 = Int.sign_ext 16 n2 ->
val_content_inject f Mint16signed (Vint n1) (Vint n2)
| val_content_inject_16_unsigned:
forall n1 n2, Int.zero_ext 16 n1 = Int.zero_ext 16 n2 ->
val_content_inject f Mint16unsigned (Vint n1) (Vint n2)
| val_content_inject_single:
forall n1 n2, Float.singleoffloat n1 = Float.singleoffloat n2 ->
val_content_inject f Mfloat32 (Vfloat n1) (Vfloat n2)
| val_content_inject_base:
forall chunk v1 v2, val_inject f v1 v2 ->
val_content_inject f chunk v1 v2.
Hint Resolve val_content_inject_base.

Lemma eval_store_arg:
forall f sp te tm a v va chunk,
eval_expr tge sp te tm a va ->
val_inject f v va ->
exists vb,
eval_expr tge sp te tm (store_arg chunk a) vb
/\ val_content_inject f chunk v vb.