erts: Fix comparison of exact terms

Comparison of exact terms could cause faulty term tests.
This was caused by a faulty (too small) internal type.

Symptom:

   -1 = erts_internal:cmp_term(2147483648,0). %% wrong

Correct:

   1 = erts_internal:cmp_term(2147483648,0).

Reported-by: Jesper Louis Andersen

erts/emulator/beam/bif.c

@@ -4659,7 +4659,7 @@ BIF_RETTYPE bump_reductions_1(BIF_ALIST_1)
 }
 
 BIF_RETTYPE erts_internal_cmp_term_2(BIF_ALIST_2) {
-    int res = CMP_TERM(BIF_ARG_1,BIF_ARG_2);
+    Sint res = CMP_TERM(BIF_ARG_1,BIF_ARG_2);
 
     /* ensure -1, 0, 1 result */
     if (res < 0) {

erts/emulator/beam/erl_map.c

@@ -400,7 +400,7 @@ BIF_RETTYPE maps_merge_2(BIF_ALIST_2) {
 	Eterm *ks,*vs,*ks1,*vs1,*ks2,*vs2;
 	map_t *mp1,*mp2,*mp_new;
 	Uint n1,n2,i1,i2,need,unused_size=0;
-	int c = 0;
+	Sint c = 0;
 
 	mp1  = (map_t*)map_val(BIF_ARG_1);
 	mp2  = (map_t*)map_val(BIF_ARG_2);
@@ -798,7 +798,7 @@ int erts_validate_and_sort_map(map_t* mp)
     Uint   sz  = map_get_size(mp);
     Uint   ix,jx;
     Eterm  tmp;
-    int c;
+    Sint c;
 
     /* sort */
 

erts/emulator/test/map_SUITE.erl

@@ -58,6 +58,7 @@
 	t_maps_without/1,
 
 	%% misc
+        t_erts_internal_order/1,
 	t_pdict/1,
 	t_ets/1,
 	t_dets/1,
@@ -96,6 +97,7 @@ all() -> [
 
 
         %% Other functions
+        t_erts_internal_order,
 	t_pdict,
 	t_ets,
 	t_tracing
@@ -960,6 +962,49 @@ t_maps_without(_Config) ->
 
 
 %% MISC
+
+t_erts_internal_order(_Config) when is_list(_Config) ->
+
+    -1 = erts_internal:cmp_term(1,2),
+    1  = erts_internal:cmp_term(2,1),
+    0  = erts_internal:cmp_term(2,2),
+
+
+    -1 = erts_internal:cmp_term(1,a),
+    1  = erts_internal:cmp_term(a,1),
+    0  = erts_internal:cmp_term(a,a),
+
+    -1 = erts_internal:cmp_term(1,1.0),
+    1  = erts_internal:cmp_term(1.0,1),
+    0  = erts_internal:cmp_term(1.0,1.0),
+
+    -1 = erts_internal:cmp_term(1,1 bsl 65),
+    1  = erts_internal:cmp_term(1 bsl 65,1),
+    0  = erts_internal:cmp_term(1 bsl 65, 1 bsl 65),
+
+    -1 = erts_internal:cmp_term(1 bsl 65,float(1)),
+    1  = erts_internal:cmp_term(float(1),1 bsl 65),
+    -1 = erts_internal:cmp_term(1,float(1 bsl 65)),
+    1  = erts_internal:cmp_term(float(1 bsl 65),1),
+    0  = erts_internal:cmp_term(float(1 bsl 65), float(1 bsl 65)),
+
+    %% reported errors
+    -1 = erts_internal:cmp_term(0,2147483648),
+    0  = erts_internal:cmp_term(2147483648,2147483648),
+    1  = erts_internal:cmp_term(2147483648,0),
+
+    M = #{0 => 0,2147483648 => 0},
+    true = M =:= binary_to_term(term_to_binary(M)),
+
+    F1 = fun(_, _) -> 0 end,
+    F2 = fun(_, _) -> 1 end,
+    M0 = maps:from_list( [{-2147483649, 0}, {0,0}, {97, 0}, {false, 0}, {flower, 0}, {F1, 0}, {F2, 0}, {<<>>, 0}]),
+    M1 = maps:merge(M0, #{0 => 1}),
+    8  = maps:size(M1),
+    1  = maps:get(0,M1),
+    ok.
+
+
 t_pdict(_Config) ->
 
     put(#{ a => b, b => a},#{ c => d}),