diff options
| -rw-r--r-- | lib/compiler/src/beam_dead.erl | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl index aaad7f4095..7e582a2b43 100644 --- a/lib/compiler/src/beam_dead.erl +++ b/lib/compiler/src/beam_dead.erl @@ -516,22 +516,24 @@ shortcut_bs_pos_used_1(Is, Reg, D) -> not beam_utils:is_killed(Reg, Is, D). %% shortcut_bs_start_match(TargetLabel, Reg) -> TargetLabel -%% A failing bs_start_match2 instruction means that the source -%% cannot be a binary, so there is no need to jump bs_context_to_binary/1 -%% or another bs_start_match2 instruction. +%% A failing bs_start_match2 instruction means that the source (Reg) +%% cannot be a binary. That means that it is safe to skip +%% bs_context_to_binary instructions operating on Reg, and +%% bs_start_match2 instructions operating on Reg. shortcut_bs_start_match(To, Reg, D) -> - shortcut_bs_start_match_1(beam_utils:code_at(To, D), Reg, To). - -shortcut_bs_start_match_1([{bs_context_to_binary,Reg}|Is], Reg, To) -> - shortcut_bs_start_match_2(Is, Reg, To); -shortcut_bs_start_match_1(_, _, To) -> To. - -shortcut_bs_start_match_2([{jump,{f,To}}|_], _, _) -> - To; -shortcut_bs_start_match_2([{test,bs_start_match2,{f,To},_,[Reg|_],_}|_], Reg, _) -> - To; -shortcut_bs_start_match_2(_Is, _Reg, To) -> + shortcut_bs_start_match_1(beam_utils:code_at(To, D), Reg, To, D). + +shortcut_bs_start_match_1([{bs_context_to_binary,Reg}|Is], Reg, To, D) -> + shortcut_bs_start_match_1(Is, Reg, To, D); +shortcut_bs_start_match_1([{jump,{f,To}}|_], Reg, _, D) -> + Code = beam_utils:code_at(To, D), + shortcut_bs_start_match_1(Code, Reg, To, D); +shortcut_bs_start_match_1([{test,bs_start_match2,{f,To},_,[Reg|_],_}|_], + Reg, _, D) -> + Code = beam_utils:code_at(To, D), + shortcut_bs_start_match_1(Code, Reg, To, D); +shortcut_bs_start_match_1(_, _, To, _) -> To. %% shortcut_rel_op(FailLabel, Operator, [Operand], D) -> FailLabel' |