diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/hipe/test/bs_SUITE_data/bs_pmatch_bugs.erl | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/lib/hipe/test/bs_SUITE_data/bs_pmatch_bugs.erl b/lib/hipe/test/bs_SUITE_data/bs_pmatch_bugs.erl index b280705a47..d9f3278b45 100644 --- a/lib/hipe/test/bs_SUITE_data/bs_pmatch_bugs.erl +++ b/lib/hipe/test/bs_SUITE_data/bs_pmatch_bugs.erl @@ -9,6 +9,7 @@ test() -> <<49,50,51>> = lex_digits1(Bin, 1, []), <<49,50,51>> = lex_digits2(Bin, 1, []), ok = var_bind_bug(<<1, 2, 3, 4, 5, 6, 7, 8>>), + ok = bs_match_string_bug(), ok. %%-------------------------------------------------------------------- @@ -65,3 +66,50 @@ var_bind_bug(<<A:1/binary, B:8/integer, _C:B/binary, _Rest/binary>>) -> B -> wrong; _ -> ok end. + +%%-------------------------------------------------------------------- +%% From: Andreas Schultz +%% Date: 2/11/2016 +%% +%% Either HiPE is messing up binary matches in some cases or I'm not +%% seeing the problem. ... <SNIP PROGRAM - CLEANED UP VERSION BELOW> +%% With Erlang 19.1.3 the HiPE compiled version behaves differently +%% than the non-HiPE version: ... <SNIP TEST RUNS> +%% So, do I do something wrong here or is this a legitimate HiPE bug? +%% +%% Yes, this was a legitimate HiPE bug: The BEAM to ICode tranaslation +%% of the bs_match_string instruction, written long ago for binaries +%% (i.e., with byte-sized strings), tried to do a `clever' translation +%% of even bit-sized strings using a HiPE primop that took a `Size' +%% argument expressed in *bytes*. ICode is not really the place to do +%% such a thing, and moreover there is really no reason for the HiPE +%% primop not to take a Size argument expressed in *bits* instead. +%% The bug was fixed by changing the `Size' argument to be in bits, +%% postponing the translation of the bs_match_string primop until RTL +%% and doing a proper translation using bit-sized quantities there. +%%-------------------------------------------------------------------- + +bs_match_string_bug() -> + ok = test0(<<50>>), + Bin = data(), + ok = test1(Bin), + ok = test2(Bin), + ok. + +%% Minimal test case showing the problem matching with strings +test0(<<6:5, 0:1, 0:2>>) -> weird; +test0(<<6:5, _:1, _:2>>) -> ok; +test0(_) -> default. + +data() -> <<50,16,0>>. + +%% This was the problematic test case in HiPE: 'default' was returned +test1(<<1:3, 1:1, _:1, 0:1, 0:1, 0:1, _/binary>>) -> weird; +test1(<<1:3, 1:1, _:1, _:1, _:1, _:1, _/binary>>) -> ok; +test1(_) -> default. + +%% This variation of test1/1 above worked OK, even in HiPE +test2(<<1:3, 1:1, _:1, A:1, B:1, C:1, _/binary>>) + when A =:= 1; B =:= 1; C =:= 1 -> ok; +test2(<<1:3, 1:1, _:1, 0:1, 0:1, 0:1, _/binary>>) -> weird; +test2(_) -> default. |