diff options
| -rw-r--r-- | lib/compiler/src/beam_dead.erl | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl index 6f6d742293..3606af9d75 100644 --- a/lib/compiler/src/beam_dead.erl +++ b/lib/compiler/src/beam_dead.erl @@ -272,14 +272,18 @@ backward([{jump,{f,To}}=J|[{bif,Op,_,Ops,Reg}|Is]=Is0], D, Acc) -> catch throw:not_possible -> backward(Is0, D, [J|Acc]) end; -backward([{test,bs_start_match2,F,_,[R,_],Ctxt}=I|Is], D, +backward([{test,bs_start_match2,F,Live,[R,_]=Args,Ctxt}|Is], D, [{test,bs_match_string,F,[Ctxt,Bs]}, {test,bs_test_tail2,F,[Ctxt,0]}|Acc0]=Acc) -> + {f,To0} = F, case beam_utils:is_killed(Ctxt, Acc0, D) of true -> - Eq = {test,is_eq_exact,F,[R,{literal,Bs}]}, + To = shortcut_bs_context_to_binary(To0, R, D), + Eq = {test,is_eq_exact,{f,To},[R,{literal,Bs}]}, backward(Is, D, [Eq|Acc0]); false -> + To = shortcut_bs_start_match(To0, R, D), + I = {test,bs_start_match2,{f,To},Live,Args,Ctxt}, backward(Is, D, [I|Acc]) end; backward([{test,bs_start_match2,{f,To0},Live,[Src|_]=Info,Dst}|Is], D, Acc) -> @@ -551,6 +555,21 @@ shortcut_bs_start_match_1([{test,bs_start_match2,{f,To},_,[Reg|_],_}|_], shortcut_bs_start_match_1(_, _, To, _) -> To. +%% shortcut_bs_context_to_binary(TargetLabel, Reg) -> TargetLabel +%% If a bs_start_match2 instruction has been eliminated, the +%% bs_context_to_binary instruction can be eliminated too. + +shortcut_bs_context_to_binary(To, Reg, D) -> + shortcut_bs_ctb_1(beam_utils:code_at(To, D), Reg, To, D). + +shortcut_bs_ctb_1([{bs_context_to_binary,Reg}|Is], Reg, To, D) -> + shortcut_bs_ctb_1(Is, Reg, To, D); +shortcut_bs_ctb_1([{jump,{f,To}}|_], Reg, _, D) -> + Code = beam_utils:code_at(To, D), + shortcut_bs_ctb_1(Code, Reg, To, D); +shortcut_bs_ctb_1(_, _, To, _) -> + To. + %% shortcut_rel_op(FailLabel, Operator, [Operand], D) -> FailLabel' %% Try to shortcut the given test instruction. Example: %% |