diff options
Diffstat (limited to 'lib/compiler')
| -rw-r--r-- | lib/compiler/src/sys_core_fold.erl | 41 |
1 files changed, 14 insertions, 27 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index cc673dd137..2dc2dd51ff 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -313,9 +313,15 @@ expr(#c_seq{arg=Arg0,body=B0}=Seq0, Ctxt, Sub) -> false -> %% Arg cannot be "values" here - only a single value %% make sense here. - case is_safe_simple(Arg, Sub) of - true -> B1; - false -> Seq0#c_seq{arg=Arg,body=B1} + case {Ctxt,is_safe_simple(Arg, Sub)} of + {effect,true} -> B1; + {effect,false} -> + case is_safe_simple(B1, Sub) of + true -> Arg; + false -> Seq0#c_seq{arg=Arg,body=B1} + end; + {value,true} -> B1; + {value,false} -> Seq0#c_seq{arg=Arg,body=B1} end end; expr(#c_let{}=Let0, Ctxt, Sub) -> @@ -2664,7 +2670,7 @@ opt_simple_let_1(#c_let{vars=Vs0,body=B0}=Let, Arg0, Ctxt, Sub0) -> Sub = Sub1#sub{v=[],s=cerl_sets:new()}, B = body(B0, Ctxt, BodySub), Arg = core_lib:make_values(Args), - opt_simple_let_2(Let, Vs, Arg, B, B0, Ctxt, Sub). + opt_simple_let_2(Let, Vs, Arg, B, B0, Sub). %% opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) -> Core. @@ -2673,33 +2679,14 @@ opt_simple_let_1(#c_let{vars=Vs0,body=B0}=Let, Arg0, Ctxt, Sub0) -> %% Note that the substitutions and scope in Sub have been cleared %% and should not be used. -opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) -> +opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Sub) -> case {Vs0,Arg0,Body} of - {[#c_var{name=N1}],Arg1,#c_var{name=N2}} -> - case N1 =:= N2 of - true -> - %% let <Var> = Arg in <Var> ==> Arg - Arg1; - false -> - %% let <Var> = Arg in <OtherVar> ==> seq Arg OtherVar - Arg = maybe_suppress_warnings(Arg1, Vs0, PrevBody), - #c_seq{arg=Arg,body=Body} - end; + {[#c_var{name=V}],Arg1,#c_var{name=V}} -> + %% let <Var> = Arg in <Var> ==> Arg + Arg1; {[],#c_values{es=[]},_} -> %% No variables left. Body; - {Vs,Arg1,#c_literal{}} -> - Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody), - case Ctxt of - effect -> - %% Throw away the literal body. - Arg; - value -> - %% Since the variable is not used in the body, we - %% can rewrite the let to a sequence. - %% let <Var> = Arg in Literal ==> seq Arg Literal - #c_seq{arg=Arg,body=Body} - end; {Vs,Arg1,Body} -> %% If none of the variables are used in the body, we can %% rewrite the let to a sequence: |