File 2325-Remove-unsafe-is_record-test_arity-optimizations.patch of Package erlang

From 19b7ccfe076d88a96b62f3222f38be31bb087df2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20H=C3=B6gberg?= <john@erlang.org>
Date: Thu, 4 Jan 2018 18:08:42 +0100
Subject: [PATCH] Remove unsafe is_record/test_arity optimizations

The type optimizations for is_record and test_arity checked whether
the arity was equal to the size stored in the type information,
which is incorrect since said size is the *minimum* size of the
tuple (as determined by previous instructions) and not its exact
size.

A future patch to the 'master' branch will restore these
optimizations in a safe manner.
---
 lib/compiler/src/beam_type.erl        | 16 ----------------
 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/lib/compiler/src/beam_type.erl b/lib/compiler/src/beam_type.erl
index 3d842a6fd3..6bf3f2795b 100644
--- a/lib/compiler/src/beam_type.erl
+++ b/lib/compiler/src/beam_type.erl
@@ -117,14 +117,6 @@ simplify_basic_1([{test,is_tuple,_,[R]}=I|Is], Ts, Acc) ->
 	{tuple,_,_} -> simplify_basic_1(Is, Ts, Acc);
 	_ -> simplify_basic_1(Is, Ts, [I|Acc])
     end;
-simplify_basic_1([{test,test_arity,_,[R,Arity]}=I|Is], Ts0, Acc) ->
-    case tdb_find(R, Ts0) of
-	{tuple,Arity,_} ->
-	    simplify_basic_1(Is, Ts0, Acc);
-	_Other ->
-	    Ts = update(I, Ts0),
-	    simplify_basic_1(Is, Ts, [I|Acc])
-    end;
 simplify_basic_1([{test,is_map,_,[R]}=I|Is], Ts0, Acc) ->
     case tdb_find(R, Ts0) of
 	map -> simplify_basic_1(Is, Ts0, Acc);
@@ -147,14 +139,6 @@ simplify_basic_1([{test,is_eq_exact,Fail,[R,{atom,_}=Atom]}=I|Is0], Ts0, Acc0) -
 	  end,
     Ts = update(I, Ts0),
     simplify_basic_1(Is0, Ts, Acc);
-simplify_basic_1([{test,is_record,_,[R,{atom,_}=Tag,{integer,Arity}]}=I|Is], Ts0, Acc) ->
-    case tdb_find(R, Ts0) of
-	{tuple,Arity,[Tag]} ->
-	    simplify_basic_1(Is, Ts0, Acc);
-	_Other ->
-	    Ts = update(I, Ts0),
-	    simplify_basic_1(Is, Ts, [I|Acc])
-    end;
 simplify_basic_1([{select,select_val,Reg,_,_}=I0|Is], Ts, Acc) ->
     I = case tdb_find(Reg, Ts) of
 	    {integer,Range} ->
-- 
2.15.1