diff options
Diffstat (limited to 'lib/compiler/src/beam_utils.erl')
| -rw-r--r-- | lib/compiler/src/beam_utils.erl | 55 |
1 files changed, 39 insertions, 16 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl index 0bc9d4cafe..b9c0cd7304 100644 --- a/lib/compiler/src/beam_utils.erl +++ b/lib/compiler/src/beam_utils.erl @@ -668,18 +668,30 @@ live_opt([{bs_add,Fail,[Src1,Src2,_],Dst}=I|Is], Regs0, D, Acc) -> Regs1 = x_live([Src1,Src2], x_dead([Dst], Regs0)), Regs = live_join_label(Fail, D, Regs1), live_opt(Is, Regs, D, [I|Acc]); -live_opt([{bs_init2,Fail,_,_,Live,_,_}=I|Is], _, D, Acc) -> - Regs1 = live_call(Live), - Regs = live_join_label(Fail, D, Regs1), +live_opt([{bs_init2,Fail,Sz,Extra,Live0,Fl,Dst}|Is], Regs0, D, Acc) -> + Regs1 = x_dead([Dst], Regs0), + Live = live_regs(Regs1), + true = Live =< Live0, %Assertion. + Regs2 = live_call(Live), + Regs = live_join_label(Fail, D, Regs2), + I = {bs_init2,Fail,Sz,Extra,Live,Fl,Dst}, live_opt(Is, Regs, D, [I|Acc]); -live_opt([{bs_init_bits,Fail,Src1,_,Live,_,Src2}=I|Is], _, D, Acc) -> - Regs1 = live_call(Live), - Regs2 = x_live([Src1,Src2], Regs1), +live_opt([{bs_init_bits,Fail,Sz,Extra,Live0,Fl,Dst}|Is], Regs0, D, Acc) -> + Regs1 = x_dead([Dst], Regs0), + Live = live_regs(Regs1), + true = Live =< Live0, %Assertion. + Regs2 = live_call(Live), Regs = live_join_label(Fail, D, Regs2), + I = {bs_init_bits,Fail,Sz,Extra,Live,Fl,Dst}, live_opt(Is, Regs, D, [I|Acc]); -live_opt([{bs_append,Fail,Src1,_,Live,_,Src2,_,Dst}=I|Is], _Regs0, D, Acc) -> - Regs1 = x_dead([Dst], x_live([Src1,Src2], live_call(Live))), - Regs = live_join_label(Fail, D, Regs1), +live_opt([{bs_append,Fail,Bits,Extra,Live0,Unit,Src,Fl,Dst}|Is], + Regs0, D, Acc) -> + Regs1 = x_live([Src], x_dead([Dst], Regs0)), + Live = live_regs(Regs1), + true = Live =< Live0, %Assertion. + Regs2 = live_call(Live), + Regs = live_join_label(Fail, D, Regs2), + I = {bs_append,Fail,Bits,Extra,Live,Unit,Src,Fl,Dst}, live_opt(Is, Regs, D, [I|Acc]); live_opt([{bs_private_append,Fail,Src1,_,Src2,_,Dst}=I|Is], Regs0, D, Acc) -> Regs1 = x_live([Src1,Src2], x_dead([Dst], Regs0)), @@ -837,13 +849,24 @@ live_opt([{allocate_heap,_,_,Live}=I|Is], _, D, Acc) -> live_opt([], _, _, Acc) -> Acc. -live_opt_block([{set,[],[],{alloc,Live,_}}=I|Is], _, D, Acc) -> - live_opt_block(Is, live_call(Live), D, [I|Acc]); -live_opt_block([{set,Ds,Ss,Op}=I|Is], Regs0, D, Acc) -> - Regs = case Op of - {alloc,Live,_} -> live_call(Live); - _ -> x_live(Ss, x_dead(Ds, Regs0)) - end, +live_opt_block([{set,Ds,Ss,Op}=I0|Is], Regs0, D, Acc) -> + Regs1 = x_live(Ss, x_dead(Ds, Regs0)), + {I,Regs} = case Op of + {alloc,Live0,Alloc} -> + %% The life-time analysis used by the code generator + %% is sometimes too conservative, so it may be + %% possible to lower the number of live registers + %% based on the exact liveness information. + %% The main benefit is that more optimizations that + %% depend on liveness information (such as the + %% beam_bool and beam_dead passes) may be applied. + Live = live_regs(Regs1), + true = Live =< Live0, %Assertion. + I1 = {set,Ds,Ss,{alloc,Live,Alloc}}, + {I1,live_call(Live)}; + _ -> + {I0,Regs1} + end, case Ds of [{x,X}] -> case (not is_live(X, Regs0)) andalso Op =:= move of |