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authorBjörn Gustavsson <[email protected]>2018-01-29 13:00:18 +0100
committerBjörn Gustavsson <[email protected]>2018-01-29 15:29:06 +0100
commitc455dc2ca108e8ffbf5431068223fcff8aeb5361 (patch)
treec0d7b7a54b9d5091e6b897b87e5c76e1ce2a14f3 /lib/compiler
parentdb9e04d0f4337a2b32376a41275ecedfe0258c1f (diff)
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Fix incorrect type interference of integer ranges
Diffstat (limited to 'lib/compiler')
-rw-r--r--lib/compiler/src/beam_type.erl8
-rw-r--r--lib/compiler/test/beam_type_SUITE.erl33
2 files changed, 37 insertions, 4 deletions
diff --git a/lib/compiler/src/beam_type.erl b/lib/compiler/src/beam_type.erl
index c8abfa524f..fc2c7a991b 100644
--- a/lib/compiler/src/beam_type.erl
+++ b/lib/compiler/src/beam_type.erl
@@ -914,10 +914,10 @@ merge_type_info({tuple,Sz1,[]}, {tuple,_Sz2,First}=Tuple2) ->
merge_type_info({tuple,Sz1,First}, Tuple2);
merge_type_info({tuple,_Sz1,First}=Tuple1, {tuple,Sz2,_}) ->
merge_type_info(Tuple1, {tuple,Sz2,First});
-merge_type_info(integer, {integer,_}=Int) ->
- Int;
-merge_type_info({integer,_}=Int, integer) ->
- Int;
+merge_type_info(integer, {integer,_}) ->
+ integer;
+merge_type_info({integer,_}, integer) ->
+ integer;
merge_type_info({integer,{Min1,Max1}}, {integer,{Min2,Max2}}) ->
{integer,{max(Min1, Min2),min(Max1, Max2)}};
merge_type_info(NewType, _) ->
diff --git a/lib/compiler/test/beam_type_SUITE.erl b/lib/compiler/test/beam_type_SUITE.erl
index fe856b12b6..d44fa60997 100644
--- a/lib/compiler/test/beam_type_SUITE.erl
+++ b/lib/compiler/test/beam_type_SUITE.erl
@@ -66,6 +66,15 @@ integers(_Config) ->
college = do_integers_3(),
+ zero = do_integers_4(<<0:1>>, 0),
+ one = do_integers_4(<<1:1>>, 0),
+ other = do_integers_4(<<1:1>>, 2),
+
+ zero = do_integers_5(0, 0),
+ one = do_integers_5(0, 1),
+ two = do_integers_5(0, 2),
+ three = do_integers_5(0, 3),
+
ok.
do_integers_1(B0) ->
@@ -88,6 +97,30 @@ do_integers_3() ->
1 -> 0
end.
+do_integers_4(<<X:1,T/bits>>, C) ->
+ %% Binary matching gives the range 0-1 for X.
+ %% The range for `X bor C` is unknown. It must not be inherited
+ %% from X. (`X bor C` will reuse the register used for X.)
+ case X bor C of
+ 0 -> do_integers_4(T, C, zero);
+ 1 -> do_integers_4(T, C, one);
+ _ -> do_integers_4(T, C, other)
+ end.
+
+do_integers_4(_, _, Res) ->
+ Res.
+
+do_integers_5(X0, Y0) ->
+ %% X and Y will use the same register.
+ X = X0 band 1,
+ Y = Y0 band 3,
+ case Y of
+ 0 -> zero;
+ 1 -> one;
+ 2 -> two;
+ 3 -> three
+ end.
+
coverage(_Config) ->
{'EXIT',{badarith,_}} = (catch id(1) bsl 0.5),
{'EXIT',{badarith,_}} = (catch id(2.0) bsl 2),