[erlang-questions] HiPE miscompilation of binary matches

[Andreas Schultz]

Hi,

Either HiPE is messing up binary matches in some cases or I'm not seeing the problem.
A reduced version of the code is:

     -module(binopt).

     -export([test1/1, test2/1, data/0]).
     -compile([bin_opt_info]).

     data() -> <<50,16,0>>.

     test1(<<1:3, 1:1, _:1, 0:1, 0:1, 0:1, _/binary>>) ->
         'Case #1';

     test1(<<1:3, 1:1, _:1, _:1, _:1, _:1, _/binary>>) ->
         'Case #2';
     test1(_) ->
         other.

     test2(<<1:3, 1:1, _:1, A:1, B:1, C:1, _/binary>>)
       when A =:= 1; B =:= 1; C =:= 1 ->
         'Case #2';

     test2(<<1:3, 1:1, _:1, 0:1, 0:1, 0:1, _/binary>>) ->
         'Case #1';

     test2(_) ->
         other.

With Erlang 19.1.3 the HiPE compile version of this behaves differently than the non-HiPE version:

     Erlang/OTP 19 [erts-8.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false]

     Eshell V8.1  (abort with ^G)
     1> compile:file("src/binopt", [native, {hipe, o3}]).
     {ok,binopt}
     2> binopt:test1(binopt:data()).
     other

WTF???? Case #2 in test1 should match and I can't see why it shouldn't.

     3> binopt:test2(binopt:data()).
     'Case #2'

This is as expected.

None HiPE:

     4> compile:file("src/binopt", []).
     {ok,binopt}
     6> l(binopt).
     {module,binopt}
     7> binopt:test1(binopt:data()).
     'Case #2'
     8> binopt:test2(binopt:data()).
     'Case #2'

As expected, both version return the same result.


So, do I do something wrong here or is this a legitimate HiPE bug?

Andreas