diff options
Diffstat (limited to 'lib/compiler/src/sys_core_fold.erl')
| -rw-r--r-- | lib/compiler/src/sys_core_fold.erl | 124 |
1 files changed, 46 insertions, 78 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index 5b155398dc..4e67639805 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -150,14 +150,26 @@ guard(Expr, Sub) -> opt_guard_try(#c_seq{arg=Arg,body=Body0}=Seq) -> Body = opt_guard_try(Body0), case {Arg,Body} of - {#c_call{},#c_literal{val=false}} -> - %% We have sequence consisting of a call (evaluted - %% for a possible exception only), followed by 'false'. - %% Since the sequence is inside a try block that will + {#c_call{module=#c_literal{val=Mod}, + name=#c_literal{val=Name}, + args=Args},#c_literal{val=false}} -> + %% We have sequence consisting of a call (evaluated + %% for a possible exception and/or side effect only), + %% followed by 'false'. + %% Since the sequence is inside a try block that will %% default to 'false' if any exception occurs, not %% evalutating the call will not change the behaviour - %% of the guard. - Body; + %% provided that the call has no side effects. + case erl_bifs:is_pure(Mod, Name, length(Args)) of + false -> + %% Not a pure BIF (meaning that this is not + %% a guard and that we must keep the call). + Seq#c_seq{body=Body}; + true -> + %% The BIF has no side effects, so it can + %% be safely removed. + Body + end; {_,_} -> Seq#c_seq{body=Body} end; @@ -1747,36 +1759,26 @@ opt_bool_clauses([_|_], _, _) -> %% end. NewVar -> %% erlang:error(badarg) %% end. -%% -%% We add the extra match-all clause at the end only if Expr is -%% not guaranteed to evaluate to a boolean. opt_bool_not(#c_case{arg=Arg,clauses=Cs0}=Case0) -> case Arg of #c_call{anno=Anno,module=#c_literal{val=erlang}, name=#c_literal{val='not'}, args=[Expr]} -> - Cs = opt_bool_not(Anno, Expr, Cs0), + Cs = [opt_bool_not_invert(C) || C <- Cs0] ++ + [#c_clause{anno=[compiler_generated], + pats=[#c_var{name=cor_variable}], + guard=#c_literal{val=true}, + body=#c_call{anno=Anno, + module=#c_literal{val=erlang}, + name=#c_literal{val=error}, + args=[#c_literal{val=badarg}]}}], Case = Case0#c_case{arg=Expr,clauses=Cs}, opt_bool_not(Case); _ -> opt_bool_case_redundant(Case0) end. -opt_bool_not(Anno, Expr, Cs) -> - Tail = case is_bool_expr(Expr) of - false -> - [#c_clause{anno=[compiler_generated], - pats=[#c_var{name=cor_variable}], - guard=#c_literal{val=true}, - body=#c_call{anno=Anno, - module=#c_literal{val=erlang}, - name=#c_literal{val=error}, - args=[#c_literal{val=badarg}]}}]; - true -> [] - end, - [opt_bool_not_invert(C) || C <- Cs] ++ Tail. - opt_bool_not_invert(#c_clause{pats=[#c_literal{val=Bool}]}=C) -> C#c_clause{pats=[#c_literal{val=not Bool}]}. @@ -2065,32 +2067,7 @@ opt_case_in_let_2(V, Arg0, (_) -> false end, Es), %Only variables in tuple false = core_lib:is_var_used(V, B), %Built tuple must not be used. Arg1 = tuple_to_values(Arg0, length(Es)), %Might fail. - #c_let{vars=Es,arg=Arg1,body=B}; -opt_case_in_let_2(_, Arg, Cs) -> - %% simplify_bool_case(Case0) -> Case - %% Remove unecessary cases like - %% - %% case BoolExpr of - %% true -> true; - %% false -> false; - %% .... - %% end - %% - %% where BoolExpr is an expression that can only return true - %% or false (or throw an exception). - - true = is_bool_case(Cs) andalso is_bool_expr(Arg), - Arg. - -is_bool_case([A,B|_]) -> - (is_bool_clause(true, A) andalso is_bool_clause(false, B)) - orelse (is_bool_clause(false, A) andalso is_bool_clause(true, B)). - -is_bool_clause(Bool, #c_clause{pats=[#c_literal{val=Bool}], - guard=#c_literal{val=true}, - body=#c_literal{val=Bool}}) -> - true; -is_bool_clause(_, _) -> false. + #c_let{vars=Es,arg=Arg1,body=B}. %% is_simple_case_arg(Expr) -> true|false %% Determine whether the Expr is simple enough to be worth @@ -2612,14 +2589,14 @@ bsm_maybe_ctx_to_binary(V, B) -> body=B} end. -previous_ctx_to_binary(V, #c_seq{arg=#c_primop{name=Name,args=As}}) -> - case {Name,As} of - {#c_literal{val=bs_context_to_binary},[#c_var{name=V}]} -> +previous_ctx_to_binary(V, Core) -> + case Core of + #c_seq{arg=#c_primop{name=#c_literal{val=bs_context_to_binary}, + args=[#c_var{name=V}]}} -> true; - {_,_} -> + _ -> false - end; -previous_ctx_to_binary(_, _) -> false. + end. %% bsm_leftmost(Cs) -> none | ArgumentNumber %% Find the leftmost argument that does binary matching. Return @@ -2764,22 +2741,20 @@ add_bin_opt_info(Core, Term) -> end. add_warning(Core, Term) -> - Anno = core_lib:get_anno(Core), - case lists:member(compiler_generated, Anno) of - true -> ok; + case is_compiler_generated(Core) of + true -> + ok; false -> - case get_line(Anno) of - Line when Line >= 0 -> %Must be positive. - File = get_file(Anno), - Key = {?MODULE,warnings}, - case get(Key) of - [{File,[{Line,?MODULE,Term}]}|_] -> - ok; %We already have + Anno = core_lib:get_anno(Core), + Line = get_line(Anno), + File = get_file(Anno), + Key = {?MODULE,warnings}, + case get(Key) of + [{File,[{Line,?MODULE,Term}]}|_] -> + ok; %We already have %an identical warning. - Ws -> - put(Key, [{File,[{Line,?MODULE,Term}]}|Ws]) - end; - _ -> ok %Compiler-generated code. + Ws -> + put(Key, [{File,[{Line,?MODULE,Term}]}|Ws]) end end. @@ -2793,14 +2768,7 @@ get_file([]) -> "no_file". % should not happen is_compiler_generated(Core) -> Anno = core_lib:get_anno(Core), - case lists:member(compiler_generated, Anno) of - true -> true; - false -> - case get_line(Anno) of - Line when Line >= 0 -> false; - _ -> true - end - end. + member(compiler_generated, Anno). get_warnings() -> ordsets:from_list((erase({?MODULE,warnings}))). |