diff options
| -rw-r--r-- | lib/compiler/src/beam_jump.erl | 8 | ||||
| -rw-r--r-- | lib/compiler/test/beam_jump_SUITE.erl | 47 |
2 files changed, 49 insertions, 6 deletions
diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl index 6f50bfdb9c..74f80ca70e 100644 --- a/lib/compiler/src/beam_jump.erl +++ b/lib/compiler/src/beam_jump.erl @@ -179,8 +179,9 @@ function({function,Name,Arity,CLabel,Asm0}, Lc0) -> eliminate_moves(Is) -> eliminate_moves(Is, #{}, []). -eliminate_moves([{select,select_val,Reg,_,List}=I|Is], D0, Acc) -> - D = update_value_dict(List, Reg, D0), +eliminate_moves([{select,select_val,Reg,{f,Fail},List}=I|Is], D0, Acc) -> + D1 = add_unsafe_label(Fail, D0), + D = update_value_dict(List, Reg, D1), eliminate_moves(Is, D, [I|Acc]); eliminate_moves([{test,is_eq_exact,_,[Reg,Val]}=I, {block,BlkIs0}|Is], D0, Acc) -> @@ -229,6 +230,9 @@ update_value_dict([Lit,{f,Lbl}|T], Reg, D0) -> update_value_dict(T, Reg, D); update_value_dict([], _, D) -> D. +add_unsafe_label(L, D) -> + D#{L=>unsafe}. + update_unsafe_labels(I, D) -> Ls = instr_labels(I), update_unsafe_labels_1(Ls, D). diff --git a/lib/compiler/test/beam_jump_SUITE.erl b/lib/compiler/test/beam_jump_SUITE.erl index 759d884dc4..a456f31d79 100644 --- a/lib/compiler/test/beam_jump_SUITE.erl +++ b/lib/compiler/test/beam_jump_SUITE.erl @@ -79,12 +79,13 @@ checks(Wanted) -> {catch case river() of sheet -> begin +Wanted, if "da" -> Wanted end end end, catch case river() of sheet -> begin + Wanted, if "da" -> Wanted end end end}. unsafe_move_elimination(_Config) -> - {{left,right,false},false} = unsafe_move_elimination(left, right, false), - {{false,right,false},false} = unsafe_move_elimination(false, right, true), - {{true,right,right},right} = unsafe_move_elimination(true, right, true), + {{left,right,false},false} = unsafe_move_elimination_1(left, right, false), + {{false,right,false},false} = unsafe_move_elimination_1(false, right, true), + {{true,right,right},right} = unsafe_move_elimination_1(true, right, true), + [ok = unsafe_move_elimination_2(I) || I <- lists:seq(0,16)], ok. -unsafe_move_elimination(Left, Right, Simple0) -> +unsafe_move_elimination_1(Left, Right, Simple0) -> id(1), %% The move at label 29 would be removed by beam_jump, which is unsafe because @@ -115,6 +116,44 @@ unsafe_move_elimination(Left, Right, Simple0) -> end, {id({Left,Right,Simple}),Simple}. +unsafe_move_elimination_2(Int) -> + %% The type optimization pass would recognize that TagInt can only be + %% [0 .. 7], so the first 'case' would select_val over [0 .. 6] and swap + %% out the fail label with the block for 7. + %% + %% A later optimization would merge this block with 'expects_h' in the + %% second case, as the latter is only reachable from the former. + %% + %% ... but this broke down when the move elimination optimization didn't + %% take the fail label of the first select_val into account. This caused it + %% to believe that the only way to reach 'expects_h' was through the second + %% case when 'Tag' =:= 'h', which made it remove the move instruction + %% added in the first case, passing garbage to expects_h/2. + TagInt = Int band 2#111, + Tag = case TagInt of + 0 -> a; + 1 -> b; + 2 -> c; + 3 -> d; + 4 -> e; + 5 -> f; + 6 -> g; + 7 -> h + end, + case Tag of + g -> expects_g(TagInt, Tag); + h -> expects_h(TagInt, Tag); + _ -> Tag = id(Tag), ok + end. + +expects_g(6, Atom) -> + Atom = id(g), + ok. + +expects_h(7, Atom) -> + Atom = id(h), + ok. + -record(message2, {id, p1}). -record(message3, {id, p1, p2}). |