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-rw-r--r--lib/compiler/src/sys_core_fold.erl52
1 files changed, 35 insertions, 17 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index 102a6951e8..7f4184fd30 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -1130,11 +1130,23 @@ let_substs_1(Vs, #c_values{es=As}, Sub) ->
let_substs_1([V], A, Sub) -> let_subst_list([V], [A], Sub);
let_substs_1(Vs, A, _) -> {Vs,A,[]}.
-let_subst_list([V|Vs0], [A|As0], Sub) ->
+let_subst_list([V|Vs0], [A0|As0], Sub) ->
{Vs1,As1,Ss} = let_subst_list(Vs0, As0, Sub),
- case is_subst(A) of
- true -> {Vs1,As1,sub_subst_var(V, A, Sub) ++ Ss};
- false -> {[V|Vs1],[A|As1],Ss}
+ case is_subst(A0) of
+ true ->
+ A = case is_compiler_generated(V) andalso
+ not is_compiler_generated(A0) of
+ true ->
+ %% Propagate the 'compiler_generated' annotation
+ %% along with the value.
+ Ann = [compiler_generated|cerl:get_ann(A0)],
+ cerl:set_ann(A0, Ann);
+ false ->
+ A0
+ end,
+ {Vs1,As1,sub_subst_var(V, A, Sub) ++ Ss};
+ false ->
+ {[V|Vs1],[A0|As1],Ss}
end;
let_subst_list([], [], _) -> {[],[],[]}.
@@ -1900,8 +1912,8 @@ case_data_pat_alias(P, BindTo0, TypeSig, Bs0) ->
%% Here we will need to actually build the data and bind
%% it to the variable.
{Type,Arity} = TypeSig,
- Vars = make_vars([], Arity),
Ann = [compiler_generated],
+ Vars = make_vars(Ann, Arity),
Data = cerl:ann_make_data(Ann, Type, Vars),
Bs = [{BindTo0,P},{P,Data}|Bs0],
{Vars,Bs};
@@ -2393,8 +2405,9 @@ delay_build_1(Core0, TypeSig) ->
try delay_build_expr(Core0, TypeSig) of
Core ->
{Type,Arity} = TypeSig,
- Vars = make_vars([], Arity),
- Data = cerl:ann_make_data([compiler_generated], Type, Vars),
+ Ann = [compiler_generated],
+ Vars = make_vars(Ann, Arity),
+ Data = cerl:ann_make_data(Ann, Type, Vars),
{yes,Vars,Core,Data}
catch
throw:impossible ->
@@ -2481,7 +2494,7 @@ opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) ->
Arg1;
false ->
%% let <Var> = Arg in <OtherVar> ==> seq Arg OtherVar
- Arg = maybe_suppress_warnings(Arg1, Vs0, PrevBody, Ctxt),
+ Arg = maybe_suppress_warnings(Arg1, Vs0, PrevBody),
expr(#c_seq{arg=Arg,body=Body}, Ctxt,
sub_new_preserve_types(Sub))
end;
@@ -2489,7 +2502,7 @@ opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) ->
%% No variables left.
Body;
{Vs,Arg1,#c_literal{}} ->
- Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody, Ctxt),
+ Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody),
E = case Ctxt of
effect ->
%% Throw away the literal body.
@@ -2508,7 +2521,7 @@ opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) ->
%% seq Arg BodyWithoutVar
case is_any_var_used(Vs, Body) of
false ->
- Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody, Ctxt),
+ Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody),
expr(#c_seq{arg=Arg,body=Body}, Ctxt,
sub_new_preserve_types(Sub));
true ->
@@ -2518,7 +2531,7 @@ opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) ->
end
end.
-%% maybe_suppress_warnings(Arg, [#c_var{}], PreviousBody, Context) -> Arg'
+%% maybe_suppress_warnings(Arg, [#c_var{}], PreviousBody) -> Arg'
%% Try to suppress false warnings when a variable is not used.
%% For instance, we don't expect a warning for useless building in:
%%
@@ -2529,10 +2542,7 @@ opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) ->
%% referenced in the original unoptimized code. If they were, we will
%% consider the warning false and suppress it.
-maybe_suppress_warnings(Arg, _, _, effect) ->
- %% Don't suppress any warnings in effect context.
- Arg;
-maybe_suppress_warnings(Arg, Vs, PrevBody, value) ->
+maybe_suppress_warnings(Arg, Vs, PrevBody) ->
case should_suppress_warning(Arg) of
true ->
Arg; %Already suppressed.
@@ -2556,8 +2566,16 @@ suppress_warning([H|T]) ->
true ->
suppress_warning(cerl:data_es(H) ++ T);
false ->
- Arg = cerl:set_ann(H, [compiler_generated]),
- cerl:c_seq(Arg, suppress_warning(T))
+ %% Some other thing, such as a function call.
+ %% This cannot be the compiler's fault, so the
+ %% warning should not be suppressed. We must
+ %% be careful not to destroy tail-recursion.
+ case T of
+ [] ->
+ H;
+ [_|_] ->
+ cerl:c_seq(H, suppress_warning(T))
+ end
end
end;
suppress_warning([]) -> void().