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authorErlang/OTP <[email protected]>2019-05-29 13:24:41 +0200
committerErlang/OTP <[email protected]>2019-05-29 13:24:41 +0200
commit1f61a273a53ac8fe48be1de0c86b33c82a84ebbd (patch)
treebe78aff78593351f3af0037cc184a53a1c56b8a6
parent787a7684b02a01818eb99abc0f6a168250e192a9 (diff)
parent7173fb8984d1822cc9c081f094841fb755f800fc (diff)
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Merge branch 'bjorn/compiler/fix-receive-patch/ERL-950/OTP-15832' into maint-22
* bjorn/compiler/fix-receive-patch/ERL-950/OTP-15832: Eliminate compiler crash when compiling complex receive statements
-rw-r--r--lib/compiler/src/beam_ssa_pre_codegen.erl11
-rw-r--r--lib/compiler/test/receive_SUITE.erl26
2 files changed, 31 insertions, 6 deletions
diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl
index bf99e8fc26..9af72afca7 100644
--- a/lib/compiler/src/beam_ssa_pre_codegen.erl
+++ b/lib/compiler/src/beam_ssa_pre_codegen.erl
@@ -1415,12 +1415,15 @@ fix_receive([], _Defs, Blocks, Count) ->
find_loop_exit([L1,L2|_Ls], Blocks) ->
Path1 = beam_ssa:rpo([L1], Blocks),
Path2 = beam_ssa:rpo([L2], Blocks),
- find_loop_exit_1(reverse(Path1), reverse(Path2), none);
+ find_loop_exit_1(Path1, cerl_sets:from_list(Path2));
find_loop_exit(_, _) -> none.
-find_loop_exit_1([H|T1], [H|T2], _) ->
- find_loop_exit_1(T1, T2, H);
-find_loop_exit_1(_, _, Exit) -> Exit.
+find_loop_exit_1([H|T], OtherPath) ->
+ case cerl_sets:is_element(H, OtherPath) of
+ true -> H;
+ false -> find_loop_exit_1(T, OtherPath)
+ end;
+find_loop_exit_1([], _) -> none.
%% find_rm_blocks(StartLabel, Blocks) -> [Label].
%% Find all blocks that start with remove_message within the receive
diff --git a/lib/compiler/test/receive_SUITE.erl b/lib/compiler/test/receive_SUITE.erl
index 0038eb1a4b..752491f0f8 100644
--- a/lib/compiler/test/receive_SUITE.erl
+++ b/lib/compiler/test/receive_SUITE.erl
@@ -26,7 +26,7 @@
init_per_testcase/2,end_per_testcase/2,
export/1,recv/1,coverage/1,otp_7980/1,ref_opt/1,
wait/1,recv_in_try/1,double_recv/1,receive_var_zero/1,
- match_built_terms/1]).
+ match_built_terms/1,elusive_common_exit/1]).
-include_lib("common_test/include/ct.hrl").
@@ -47,7 +47,7 @@ groups() ->
[{p,test_lib:parallel(),
[recv,coverage,otp_7980,ref_opt,export,wait,
recv_in_try,double_recv,receive_var_zero,
- match_built_terms]}].
+ match_built_terms,elusive_common_exit]}].
init_per_suite(Config) ->
@@ -427,4 +427,26 @@ match_built_terms(Config) when is_list(Config) ->
?MATCH_BUILT_TERM(Ref, <<A, B>>),
?MATCH_BUILT_TERM(Ref, #{ 1 => A, 2 => B}).
+elusive_common_exit(_Config) ->
+ self() ! {1, a},
+ self() ! {2, b},
+ {[z], [{2,b},{1,a}]} = elusive_loop([x,y,z], 2, []),
+ ok.
+
+elusive_loop(List, 0, Results) ->
+ {List, Results};
+elusive_loop(List, ToReceive, Results) ->
+ {Result, RemList} =
+ receive
+ {_Pos, _R} = Res when List =/= [] ->
+ [_H|T] = List,
+ {Res, T};
+ {_Pos, _R} = Res when List =:= [] ->
+ {Res, []}
+ end,
+ %% beam_ssa_pre_codegen:fix_receives() would fail to find
+ %% the common exit block for this receive. That would mean
+ %% that it would not insert all necessary copy instructions.
+ elusive_loop(RemList, ToReceive-1, [Result | Results]).
+
id(I) -> I.