diff options
Diffstat (limited to 'lib/compiler/src/beam_ssa_opt.erl')
| -rw-r--r-- | lib/compiler/src/beam_ssa_opt.erl | 130 |
1 files changed, 76 insertions, 54 deletions
diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl index 986be14e8a..cce539f582 100644 --- a/lib/compiler/src/beam_ssa_opt.erl +++ b/lib/compiler/src/beam_ssa_opt.erl @@ -158,6 +158,7 @@ repeated_passes(Opts) -> ?PASS(ssa_opt_dead), ?PASS(ssa_opt_cse), ?PASS(ssa_opt_tail_phis), + ?PASS(ssa_opt_sink), ?PASS(ssa_opt_tuple_size), ?PASS(ssa_opt_record), ?PASS(ssa_opt_type_continue)], %Must run after ssa_opt_dead to @@ -175,8 +176,8 @@ epilogue_passes(Opts) -> ?PASS(ssa_opt_bsm), ?PASS(ssa_opt_bsm_units), ?PASS(ssa_opt_bsm_shortcut), - ?PASS(ssa_opt_blockify), ?PASS(ssa_opt_sink), + ?PASS(ssa_opt_blockify), ?PASS(ssa_opt_merge_blocks), ?PASS(ssa_opt_get_tuple_element), ?PASS(ssa_opt_trim_unreachable)], @@ -901,6 +902,7 @@ cse_suitable(#b_set{}) -> false. -record(fs, {s=undefined :: 'undefined' | 'cleared', regs=#{} :: #{beam_ssa:b_var():=beam_ssa:b_var()}, + vars=cerl_sets:new() :: cerl_sets:set(), fail=none :: 'none' | beam_ssa:label(), non_guards :: gb_sets:set(beam_ssa:label()), bs :: beam_ssa:block_map() @@ -913,22 +915,39 @@ ssa_opt_float({#st{ssa=Linear0,cnt=Count0}=St, FuncDb}) -> {Linear,Count} = float_opt(Linear0, Count0, Fs), {St#st{ssa=Linear,cnt=Count}, FuncDb}. -float_blk_is_in_guard(#b_blk{last=#b_br{fail=F}}, #fs{non_guards=NonGuards}) -> - not gb_sets:is_member(F, NonGuards); -float_blk_is_in_guard(#b_blk{}, #fs{}) -> +%% The fconv instruction doesn't support jumping to a fail label, so we have to +%% skip this optimization if the fail block is a guard. +%% +%% We also skip the optimization in blocks that always fail, as it's both +%% difficult and pointless to rewrite them to use float ops. +float_can_optimize_blk(#b_blk{last=#b_br{bool=#b_var{},fail=F}}, + #fs{non_guards=NonGuards}) -> + gb_sets:is_member(F, NonGuards); +float_can_optimize_blk(#b_blk{}, #fs{}) -> false. +float_opt([{L,#b_blk{is=[#b_set{op=exception_trampoline,args=[Var]}]}=Blk0} | + Bs0], Count0, Fs) -> + %% If we've replaced a BIF with float operations, we'll have a lot of extra + %% blocks that jump to the same failure block, which may have a trampoline + %% that refers to the original operation. + %% + %% Since the point of the trampoline is to keep the BIF from being removed + %% by liveness optimization, we can discard it as the liveness pass leaves + %% floats alone. + Blk = case cerl_sets:is_element(Var, Fs#fs.vars) of + true -> Blk0#b_blk{is=[]}; + false -> Blk0 + end, + {Bs, Count} = float_opt(Bs0, Count0, Fs), + {[{L,Blk}|Bs],Count}; float_opt([{L,Blk}|Bs0], Count0, Fs) -> - case float_blk_is_in_guard(Blk, Fs) of + case float_can_optimize_blk(Blk, Fs) of true -> - %% This block is inside a guard. Don't do - %% any floating point optimizations. - {Bs,Count} = float_opt(Bs0, Count0, Fs), - {[{L,Blk}|Bs],Count}; + float_opt_1(L, Blk, Bs0, Count0, Fs); false -> - %% This block is not inside a guard. - %% We can do the optimization. - float_opt_1(L, Blk, Bs0, Count0, Fs) + {Bs,Count} = float_opt(Bs0, Count0, Fs), + {[{L,Blk}|Bs],Count} end; float_opt([], Count, _Fs) -> {[],Count}. @@ -1007,12 +1026,12 @@ float_maybe_flush(Blk0, #fs{s=cleared,fail=Fail,bs=Blocks}=Fs0, Count0) -> #b_blk{last=#b_br{bool=#b_var{},succ=Succ}=Br} = Blk0, %% If the success block starts with a floating point operation, we can - %% defer flushing to that block as long as it isn't a guard. + %% defer flushing to that block as long as it's suitable for optimization. #b_blk{is=Is} = SuccBlk = map_get(Succ, Blocks), - SuccIsGuard = float_blk_is_in_guard(SuccBlk, Fs0), + CanOptimizeSucc = float_can_optimize_blk(SuccBlk, Fs0), case Is of - [#b_set{anno=#{float_op:=_}}|_] when not SuccIsGuard -> + [#b_set{anno=#{float_op:=_}}|_] when CanOptimizeSucc -> %% No flush needed. {[],Blk0,Fs0,Count0}; _ -> @@ -1068,21 +1087,22 @@ float_opt_is([], Fs, _Count, _Acc) -> none. float_make_op(#b_set{op={bif,Op},dst=Dst,args=As0}=I0, - Ts, #fs{s=S,regs=Rs0}=Fs, Count0) -> + Ts, #fs{s=S,regs=Rs0,vars=Vs0}=Fs, Count0) -> {As1,Rs1,Count1} = float_load(As0, Ts, Rs0, Count0, []), {As,Is0} = unzip(As1), {Fr,Count2} = new_reg('@fr', Count1), FrDst = #b_var{name=Fr}, I = I0#b_set{op={float,Op},dst=FrDst,args=As}, + Vs = cerl_sets:add_element(Dst, Vs0), Rs = Rs1#{Dst=>FrDst}, Is = append(Is0) ++ [I], case S of undefined -> {Ignore,Count} = new_reg('@ssa_ignore', Count2), C = #b_set{op={float,clearerror},dst=#b_var{name=Ignore}}, - {[C|Is],Fs#fs{s=cleared,regs=Rs},Count}; + {[C|Is],Fs#fs{s=cleared,regs=Rs,vars=Vs},Count}; cleared -> - {Is,Fs#fs{regs=Rs},Count2} + {Is,Fs#fs{regs=Rs,vars=Vs},Count2} end. float_load([A|As], [T|Ts], Rs0, Count0, Acc) -> @@ -1211,34 +1231,31 @@ live_opt_is([#b_set{op=phi,dst=Dst}=I|Is], Live, Acc) -> false -> live_opt_is(Is, Live, Acc) end; -live_opt_is([#b_set{op=succeeded,dst=SuccDst=SuccDstVar, - args=[Dst]}=SuccI, - #b_set{dst=Dst}=I|Is], Live0, Acc) -> - case gb_sets:is_member(Dst, Live0) of - true -> - Live1 = gb_sets:add(Dst, Live0), - Live = gb_sets:delete_any(SuccDst, Live1), - live_opt_is([I|Is], Live, [SuccI|Acc]); - false -> - case live_opt_unused(I) of - {replace,NewI0} -> - NewI = NewI0#b_set{dst=SuccDstVar}, - live_opt_is([NewI|Is], Live0, Acc); - keep -> - case gb_sets:is_member(SuccDst, Live0) of - true -> - Live1 = gb_sets:add(Dst, Live0), - Live = gb_sets:delete(SuccDst, Live1), - live_opt_is([I|Is], Live, [SuccI|Acc]); - false -> - live_opt_is([I|Is], Live0, Acc) - end - end +live_opt_is([#b_set{op=succeeded,dst=SuccDst,args=[MapDst]}=SuccI, + #b_set{op=get_map_element,dst=MapDst}=MapI | Is], + Live0, Acc) -> + case {gb_sets:is_member(SuccDst, Live0), + gb_sets:is_member(MapDst, Live0)} of + {true, true} -> + Live = gb_sets:delete(SuccDst, Live0), + live_opt_is([MapI | Is], Live, [SuccI | Acc]); + {true, false} -> + %% 'get_map_element' is unused; replace 'succeeded' with + %% 'has_map_field' + NewI = MapI#b_set{op=has_map_field,dst=SuccDst}, + live_opt_is([NewI | Is], Live0, Acc); + {false, true} -> + %% 'succeeded' is unused (we know it will succeed); discard it and + %% keep 'get_map_element' + live_opt_is([MapI | Is], Live0, Acc); + {false, false} -> + live_opt_is(Is, Live0, Acc) end; live_opt_is([#b_set{dst=Dst}=I|Is], Live0, Acc) -> case gb_sets:is_member(Dst, Live0) of true -> - Live1 = gb_sets:union(Live0, gb_sets:from_ordset(beam_ssa:used(I))), + LiveUsed = gb_sets:from_ordset(beam_ssa:used(I)), + Live1 = gb_sets:union(Live0, LiveUsed), Live = gb_sets:delete(Dst, Live1), live_opt_is(Is, Live, [I|Acc]); false -> @@ -1246,17 +1263,14 @@ live_opt_is([#b_set{dst=Dst}=I|Is], Live0, Acc) -> true -> live_opt_is(Is, Live0, Acc); false -> - Live = gb_sets:union(Live0, gb_sets:from_ordset(beam_ssa:used(I))), + LiveUsed = gb_sets:from_ordset(beam_ssa:used(I)), + Live = gb_sets:union(Live0, LiveUsed), live_opt_is(Is, Live, [I|Acc]) end end; live_opt_is([], Live, Acc) -> {Acc,Live}. -live_opt_unused(#b_set{op=get_map_element}=Set) -> - {replace,Set#b_set{op=has_map_field}}; -live_opt_unused(_) -> keep. - %%% %%% Optimize binary matching. %%% @@ -1942,6 +1956,10 @@ verify_merge_is(_) -> is_merge_allowed(_, #b_blk{}, #b_blk{is=[#b_set{op=peek_message}|_]}) -> false; +is_merge_allowed(_, #b_blk{}, #b_blk{is=[#b_set{op=exception_trampoline}|_]}) -> + false; +is_merge_allowed(_, #b_blk{is=[#b_set{op=exception_trampoline}|_]}, #b_blk{}) -> + false; is_merge_allowed(L, #b_blk{last=#b_br{}}=Blk, #b_blk{}) -> %% The predecessor block must have exactly one successor (L) for %% the merge to be safe. @@ -1968,9 +1986,7 @@ is_merge_allowed(_, #b_blk{last=#b_switch{}}, #b_blk{}) -> %%% extracted values. %%% -ssa_opt_sink({#st{ssa=Blocks0}=St, FuncDb}) -> - Linear = beam_ssa:linearize(Blocks0), - +ssa_opt_sink({#st{ssa=Linear}=St, FuncDb}) -> %% Create a map with all variables that define get_tuple_element %% instructions. The variable name map to the block it is defined in. case def_blocks(Linear) of @@ -1979,10 +1995,12 @@ ssa_opt_sink({#st{ssa=Blocks0}=St, FuncDb}) -> {St, FuncDb}; [_|_]=Defs0 -> Defs = maps:from_list(Defs0), - {do_ssa_opt_sink(Linear, Defs, St), FuncDb} + {do_ssa_opt_sink(Defs, St), FuncDb} end. -do_ssa_opt_sink(Linear, Defs, #st{ssa=Blocks0}=St) -> +do_ssa_opt_sink(Defs, #st{ssa=Linear}=St) -> + Blocks0 = maps:from_list(Linear), + %% Now find all the blocks that use variables defined by get_tuple_element %% instructions. Used = used_blocks(Linear, Defs, []), @@ -2007,7 +2025,8 @@ do_ssa_opt_sink(Linear, Defs, #st{ssa=Blocks0}=St) -> From = map_get(V, Defs), move_defs(V, From, To, A) end, Blocks0, DefLoc), - St#st{ssa=Blocks}. + + St#st{ssa=beam_ssa:linearize(Blocks)}. def_blocks([{L,#b_blk{is=Is}}|Bs]) -> def_blocks_is(Is, L, def_blocks(Bs)); @@ -2040,6 +2059,7 @@ unsuitable_1([{L,#b_blk{is=[#b_set{op=Op}|_]}}|Bs]) -> Unsuitable = case Op of bs_extract -> true; bs_put -> true; + exception_trampoline -> true; {float,_} -> true; landingpad -> true; peek_message -> true; @@ -2248,13 +2268,15 @@ non_guards(Linear) -> non_guards_1([{L,#b_blk{is=Is}}|Bs]) -> case Is of + [#b_set{op=exception_trampoline}|_] -> + [L | non_guards_1(Bs)]; [#b_set{op=landingpad}|_] -> [L | non_guards_1(Bs)]; _ -> non_guards_1(Bs) end; non_guards_1([]) -> - [?BADARG_BLOCK]. + [?EXCEPTION_BLOCK]. rel2fam(S0) -> S1 = sofs:relation(S0), |