Enhance range analysis for the rem operator

Teach beam_bounds:bound/3 to determine a range for the `rem` operator
when nothing is known about the right-hand side operand. For example:

    rem0(A, B) when is_integer(A), 0 =< A, A < 1204 ->
        %% Range for A is 0..1023
        A rem B.                % Range is 0..1023 (same as for A)

lib/compiler/src/beam_bounds.erl

@@ -319,6 +319,12 @@ rem_bounds(_, {C,D}) when is_integer(C), is_integer(D),
     Max = max(abs(C), abs(D)) - 1,
     Min = -Max,
     normalize({Min,Max});
+rem_bounds({A,B}, _) ->
+    %% The sign of the remainder is the same as the sign of the
+    %% left-hand side operand; it does not depend on the sign of the
+    %% right-hand side operand. Therefore, the range of the remainder
+    %% is the same as the range of the left-hand side operand.
+    {A,B};
 rem_bounds(_, _) ->
     any.
 

lib/compiler/test/beam_bounds_SUITE.erl

@@ -154,11 +154,14 @@ rem_bounds(_Config) ->
     {-7,7} = beam_bounds:bounds('rem', {'-inf',10}, {1,8}),
     {0,7} = beam_bounds:bounds('rem', {10,'+inf'}, {1,8}),
 
-    any = beam_bounds:bounds('rem', {1,10}, {'-inf',10}),
-    any = beam_bounds:bounds('rem', {1,10}, {10,'+inf'}),
-
-    any = beam_bounds:bounds('rem', {-10,10}, {'-inf',10}),
-    any = beam_bounds:bounds('rem', {-10,10}, {10,'+inf'}),
+    {1,10} = beam_bounds:bounds('rem', {1,10}, {'-inf',10}),
+    {20,'+inf'} = beam_bounds:bounds('rem', {20,'+inf'}, {10,'+inf'}),
+    {'-inf',10} = beam_bounds:bounds('rem', {'-inf',10}, any),
+
+    {-11,10} = beam_bounds:bounds('rem', {-11,10}, {'-inf',89}),
+    {-11,10} = beam_bounds:bounds('rem', {-11,10}, {7,'+inf'}),
+    {-11,10} = beam_bounds:bounds('rem', {-11,10}, {'-inf',113}),
+    {-11,10} = beam_bounds:bounds('rem', {-11,10}, {55,'+inf'}),
 
     ok.