Merge branch 'john/compiler/fix-bnot-mixed-bounds/GH-7251/OTP-18581' …

…into maint * john/compiler/fix-bnot-mixed-bounds/GH-7251/OTP-18581: beam_bounds: Fix 'bnot' bounds on mixed finite/infinite ranges
erlang · May 22, 2023 · 6942dac · 6942dac
2 parents 4175866 + fc9fd32
commit 6942dac
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diff --git a/lib/compiler/src/beam_bounds.erl b/lib/compiler/src/beam_bounds.erl
@@ -46,6 +46,9 @@
 
 bounds('bnot', R0) ->
     case R0 of
+        {Exact, Exact} when is_integer(Exact) ->
+            N = -Exact - 1,
+            {N, N};
         {A, B} when is_integer(A), is_integer(B), A =/= B ->
             %% While it's easy to get an exact range, doing so can make certain
             %% chains of operations slow to converge, e.g.
@@ -68,7 +71,10 @@ bounds('bnot', R0) ->
                     any
             end;
         {A, B} ->
-            R = {inf_add(inf_neg(B), -1), inf_add(inf_neg(A), -1)},
+            %% Widen the range as above to ensure that we get the same result
+            %% on the finite component(s).
+            R = {inf_add(inf_neg(inf_add(B, B)), -1),
+                 inf_add(inf_neg(inf_add(A, A)), -1)},
             normalize(R);
         _ ->
             any

diff --git a/lib/compiler/test/beam_bounds_SUITE.erl b/lib/compiler/test/beam_bounds_SUITE.erl
@@ -192,10 +192,11 @@ bnot_bounds(_Config) ->
             A <- Seq,
             B <- lists:nthtail(A-Min, Seq)],
 
-    {-43,'+inf'} = beam_bounds:bounds('bnot', {'-inf',42}),
-    {99,'+inf'} = beam_bounds:bounds('bnot', {'-inf',-100}),
-    {'-inf',-8} = beam_bounds:bounds('bnot', {7,'+inf'}),
-    {'-inf',9} = beam_bounds:bounds('bnot', {-10,'+inf'}),
+    {-85,'+inf'} = beam_bounds:bounds('bnot', {'-inf',42}),
+    {199,'+inf'} = beam_bounds:bounds('bnot', {'-inf',-100}),
+    {'-inf',-15} = beam_bounds:bounds('bnot', {7,'+inf'}),
+    {'-inf',19} = beam_bounds:bounds('bnot', {-10,'+inf'}),
+    {-2228221,'+inf'} = beam_bounds:bounds('bnot', {'-inf', 1114110}),
 
     -1 = bnot_bounds_2(0),