Local Open Scope logic.
Ltac unfold_for_go_lower :=
cbv delta [PROPx LOCALx SEPx locald_denote
eval_exprlist eval_expr eval_lvalue cast_expropt
eval_binop eval_unop force_val1 force_val2
msubst_tc_expropt msubst_tc_expr msubst_tc_exprlist msubst_tc_lvalue msubst_tc_LR (* msubst_tc_LR_strong *) msubst_tc_efield msubst_simpl_tc_assert
function_body_ret_assert frame_ret_assert
make_args' bind_ret get_result1 retval
classify_cast
(* force_val sem_cast_neutral ... NOT THESE TWO!  *)
denote_tc_assert (* tc_andp tc_iszero *)
liftx LiftEnviron Tarrow Tend lift_S lift_T
lift_prod lift_last lifted lift_uncurry_open lift_curry
local lift lift0 lift1 lift2 lift3
] beta iota.
Ltac go_lower0 :=
intros ?rho;
try (simple apply grab_tc_environ; intro);
repeat (progress unfold_for_go_lower; simpl).
Ltac old_go_lower :=
go_lower0;
autorewrite with go_lower;
try findvars;
simpl;
autorewrite with go_lower;
try match goal with H: tc_environ _ ?rho |- _ => clear H rho end.
Hint Rewrite eval_id_same : go_lower.
Hint Rewrite eval_id_other using solve [clear; intro Hx; inversion Hx] : go_lower.
(*Hint Rewrite Vint_inj' : go_lower.*)
(*** New go_lower stuff ****)
Ltac safe_subst x := subst x.
Ltac safe_subst_any := subst_any.
(* safe_subst is meant to avoid doing rewrites or substitution of variables that are in the scope of a unification variable.  Right now, the tactic is a placeholder for real tactic that will detect the scope violation and (if so) avoid doing the substition.  See issue #186. *)
Ltac lower_one_temp_Vint' :=
match goal with
| |- (local _ && PROPx _ (LOCALx (temp _ ?v :: _) _)) _ |-- _ =>
is_var v;
simple eapply lower_one_temp_Vint';
[ reflexivity | ];
let v' := fresh "v" in rename v into v';
let tc := fresh "TC" in
intros [v [? [tc ?EVAL]]]; unfold tc_val in tc; safe_subst v';
revert tc; fancy_intro true
end.
Ltac gvar_headptr_intro_case1 gv H i :=
match goal with
| _ := gv i |- _ => fail 1
| H: isptr (gv i), H': headptr (gv i) |- _ => fail 1
| _ => generalize (H i _ ltac:(first[reflexivity | eassumption])); fancy_intro true
end.
Ltac gvar_headptr_intro_case2 gv H x i :=
match goal with
| H: isptr x, H': headptr x |- _ => fail 1
| _ => generalize ((H i _ ltac:(first[reflexivity | eassumption])): headptr x); fancy_intro true
end.
Ltac gvar_headptr_intro gv H:=
repeat
match goal with
| x:= gv ?i |- _ =>
gvar_headptr_intro_case2 gv H x i
| |- context [gv ?i] =>
gvar_headptr_intro_case1 gv H i
| _: context [gv ?i] |- _ =>
gvar_headptr_intro_case1 gv H i
| x:= context [gv ?i] |- _ =>
gvar_headptr_intro_case1 gv H i
end.
Fixpoint remove_localdef (x: localdef) (l: list localdef) : list localdef :=
match l with
| nil => nil
| y :: l0 =>
match x, y with
| temp i u, temp j v =>
if Pos.eqb i j
then remove_localdef x l0
else y :: remove_localdef x l0
| lvar i ti u, lvar j tj v =>
if Pos.eqb i j
then remove_localdef x l0
else y :: remove_localdef x l0
| _, _ => y :: remove_localdef x l0
end
end.
Definition localdef_tc (Delta: tycontext) (gvar_idents: list ident) (x: localdef): list Prop :=
match x with
| temp i v =>
match (temp_types Delta) ! i with
| Some t => tc_val t v :: nil
| _ => nil
end
| lvar _ _ v =>
isptr v :: headptr v :: nil
| gvars gv =>
VST_floyd_map (fun id => headptr (gv id)) gvar_idents
end.
Definition legal_glob_ident (Delta: tycontext) (i: ident): bool :=
match (glob_types Delta) ! i with
| Some _ => true
| _ => false
end.
Definition localdefs_tc (Delta: tycontext) gvar_ident (Pre: list localdef): list Prop :=
VST_floyd_concat (VST_floyd_map (localdef_tc Delta gvar_ident) Pre).
Definition msubst_extract_local (Delta: tycontext) (T1: PTree.t val) (T2: PTree.t (type * val)) (GV: option globals) (x: localdef): Prop :=
match x with
| temp i u =>
match T1 ! i with
| Some v => u = v
| None => False
end
| lvar i ti u =>
match T2 ! i with
| Some (tj, v) =>
if eqb_type ti tj
then u = v
else False
| _ => False
end
| gvars gv =>
match GV with
| Some gv0 => gv0 = gv
| _ => False
end
end.
Definition msubst_extract_locals (Delta: tycontext) (T1: PTree.t val) (T2: PTree.t (type * val)) (GV: option globals) := VST_floyd_map (msubst_extract_local Delta T1 T2 GV).

Lemma go_lower_localdef_one_step_canon_canon {cs: compspecs} : forall Delta Ppre Qpre Rpre Ppost l Qpost Rpost T1 T2 GV,
local2ptree Qpre = (T1, T2, nil, GV) ->
local (tc_environ Delta) && PROPx Ppre (LOCALx Qpre (SEPx Rpre)) && PROPx (Ppost ++ msubst_extract_local Delta T1 T2 GV l :: nil) (LOCALx Qpost (SEPx Rpost)) |-- PROPx Ppost (LOCALx (l :: Qpost) (SEPx Rpost)).