beam_asm: Encode big numbers as literals

Numbers that clearly are not smalls can be encoded as
literals. Conservatively, we assume that integers whose
absolute value is greater than 1 bsl 128 are bignums and
that they can be encoded as literals.

Literals are slightly easier for the loader to handle than
huge integers.

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/compiler/src/beam_asm.erl b/lib/compiler/src/beam_asm.erl
index 453e00fce3..fa919ca862 100644
--- a/lib/compiler/src/beam_asm.erl
+++ b/lib/compiler/src/beam_asm.erl
@@ -407,7 +407,17 @@ encode_arg({atom, Atom}, Dict0) when is_atom(Atom) ->
     {Index, Dict} = beam_dict:atom(Atom, Dict0),
     {encode(?tag_a, Index), Dict};
 encode_arg({integer, N}, Dict) ->
-    {encode(?tag_i, N), Dict};
+    %% Conservatily assume that all integers whose absolute
+    %% value is greater than 1 bsl 128 will be bignums in
+    %% the runtime system.
+    if
+        N >= 1 bsl 128 ->
+            encode_arg({literal, N}, Dict);
+        N =< -(1 bsl 128) ->
+            encode_arg({literal, N}, Dict);
+        true ->
+            {encode(?tag_i, N), Dict}
+    end;
 encode_arg(nil, Dict) ->
     {encode(?tag_a, 0), Dict};
 encode_arg({f, W}, Dict) ->