diff options
Diffstat (limited to 'lib/compiler')
| -rw-r--r-- | lib/compiler/src/beam_ssa.erl | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_ssa.erl b/lib/compiler/src/beam_ssa.erl index 548e73cf43..75d567ff87 100644 --- a/lib/compiler/src/beam_ssa.erl +++ b/lib/compiler/src/beam_ssa.erl @@ -103,7 +103,7 @@ -type cg_prim_op() :: 'bs_get' | 'bs_match_string' | 'bs_restore' | 'bs_skip' | 'copy' | 'put_tuple_arity' | 'put_tuple_element'. --import(lists, [foldl/3,keyfind/3,mapfoldl/3,reverse/1]). +-import(lists, [foldl/3,keyfind/3,mapfoldl/3,member/2,reverse/1]). -spec add_anno(Key, Value, Construct) -> Construct when Key :: atom(), @@ -376,6 +376,10 @@ fold_po(Fun, From, Acc0, Blocks) -> %% linearize(Blocks) -> [{BlockLabel,#b_blk{}}]. %% Linearize the intermediate representation of the code. +%% Unreachable blocks will be discarded, and phi nodes will +%% be adjusted so that they no longer refers to discarded +%% blocks or to blocks that no longer are predecessors of +%% the phi node block. -spec linearize(Blocks) -> Linear when Blocks :: block_map(), @@ -383,7 +387,8 @@ fold_po(Fun, From, Acc0, Blocks) -> linearize(Blocks) -> Seen = gb_sets:empty(), - {Linear,_} = linearize_1([0], Blocks, Seen, []), + {Linear0,_} = linearize_1([0], Blocks, Seen, []), + Linear = fix_phis(Linear0, #{}), Linear. -spec rpo(Blocks) -> [Label] when @@ -592,6 +597,33 @@ linearize_1([L|Ls], Blocks, Seen0, Acc0) -> linearize_1([], _, Seen, Acc) -> {Acc,Seen}. +fix_phis([{L,Blk0}|Bs], S) -> + Blk = case Blk0 of + #b_blk{is=[#b_set{op=phi}|_]=Is0} -> + Is = fix_phis_1(Is0, L, S), + Blk0#b_blk{is=Is}; + #b_blk{} -> + Blk0 + end, + Successors = successors(Blk), + [{L,Blk}|fix_phis(Bs, S#{L=>Successors})]; +fix_phis([], _) -> []. + +fix_phis_1([#b_set{op=phi,args=Args0}=I|Is], L, S) -> + Args = [{Val,Pred} || {Val,Pred} <- Args0, + is_successor(L, Pred, S)], + [I#b_set{args=Args}|fix_phis_1(Is, L, S)]; +fix_phis_1(Is, _, _) -> Is. + +is_successor(L, Pred, S) -> + case S of + #{Pred:=Successors} -> + member(L, Successors); + #{} -> + %% This block has been removed. + false + end. + rpo_1([L|Ls], Blocks, Seen0, Acc0) -> case gb_sets:is_member(L, Seen0) of true -> |