From 26e3ec83c54d42d73c42ef7c4e79ae629866faa2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 26 Jan 2018 10:46:23 +0100
Subject: 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.
---
 lib/compiler/src/beam_asm.erl | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

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) ->
-- 
cgit v1.2.3


From 244bad23877191a66f5c1d63cf1845101c73229b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 26 Jan 2018 10:50:14 +0100
Subject: Speed up misc_SUITE:integer_encoding/1

misc_SUITE:integer_encoding/1 was written to make sure
that big integers were encoding correctly in a reasonable
amount of time. Now that beam_asm will encode big integers
as literals, we can reduce the scope of integer_encode/1.
That will make it significantly faster, especially when
cover is running.
---
 lib/compiler/test/misc_SUITE.erl | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/lib/compiler/test/misc_SUITE.erl b/lib/compiler/test/misc_SUITE.erl
index d93c5dda1e..4e39f4663e 100644
--- a/lib/compiler/test/misc_SUITE.erl
+++ b/lib/compiler/test/misc_SUITE.erl
@@ -359,9 +359,7 @@ integer_encoding_1(Config) ->
     io:put_chars(Src, "t(Last) ->[\n"),
     io:put_chars(Data, "[\n"),
 
-    do_integer_encoding(-(id(1) bsl 10000), Src, Data),
-    do_integer_encoding(id(1) bsl 10000, Src, Data),
-    do_integer_encoding(1024, 0, Src, Data),
+    do_integer_encoding(137, 0, Src, Data),
     _ = [begin
 	     B = 1 bsl I,
 	     do_integer_encoding(-B-1, Src, Data),
@@ -370,7 +368,7 @@ integer_encoding_1(Config) ->
 	     do_integer_encoding(B-1, Src, Data),
 	     do_integer_encoding(B, Src, Data),
 	     do_integer_encoding(B+1, Src, Data)
-	 end || I <- lists:seq(1, 128)],
+	 end || I <- lists:seq(1, 130)],
     io:put_chars(Src, "Last].\n\n"),
     ok = file:close(Src),
     io:put_chars(Data, "0].\n\n"),
@@ -384,8 +382,6 @@ integer_encoding_1(Config) ->
     %% Compare lists.
     List = Mod:t(0),
     {ok,[List]} = file:consult(DataFile),
-    OneBsl10000 = id(1) bsl 10000,
-    [-(1 bsl 10000),OneBsl10000|_] = List,
 
     %% Cleanup.
     file:delete(SrcFile),
@@ -404,7 +400,3 @@ do_integer_encoding(I, Src, Data) ->
     Str = integer_to_list(I),
     io:put_chars(Src, [Str,",\n"]),
     io:put_chars(Data, [Str,",\n"]).
-
-    
-id(I) -> I.
-    
-- 
cgit v1.2.3