From 8b83bc0b54b728cf9179ef3fa0e7610f99f7a6a4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Tue, 12 Jul 2016 16:08:38 +0200
Subject: compiler: Test literal binary matching

The following regression was introduced in 19.0:

    foo(bar, <<"x">>) -> 1;
    foo(_, <<"x">>) -> 2;
    foo(_, <<"y">>) -> 3;
    foo(_, _) -> fail.

The call foo(bar,<<"y">>) would errorneous return 'fail' instead of 3.

A testcase in match_SUITE has been added to verify this.
---
 lib/compiler/test/match_SUITE.erl | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

(limited to 'lib')

diff --git a/lib/compiler/test/match_SUITE.erl b/lib/compiler/test/match_SUITE.erl
index 31402ac717..127679ba69 100644
--- a/lib/compiler/test/match_SUITE.erl
+++ b/lib/compiler/test/match_SUITE.erl
@@ -24,7 +24,7 @@
 	 pmatch/1,mixed/1,aliases/1,non_matching_aliases/1,
 	 match_in_call/1,untuplify/1,shortcut_boolean/1,letify_guard/1,
 	 selectify/1,underscore/1,match_map/1,map_vars_used/1,
-	 coverage/1,grab_bag/1]).
+	 coverage/1,grab_bag/1,literal_binary/1]).
 	 
 -include_lib("common_test/include/ct.hrl").
 
@@ -40,7 +40,7 @@ groups() ->
        match_in_call,untuplify,
        shortcut_boolean,letify_guard,selectify,
        underscore,match_map,map_vars_used,coverage,
-       grab_bag]}].
+       grab_bag,literal_binary]}].
 
 
 init_per_suite(Config) ->
@@ -574,6 +574,15 @@ grab_bag_remove_failure([{stretch,_,Mi}=Stretch | Specs], Unit, _MaxFailure) ->
 	    ok
     end.
 
+%% Regression in 19.0, reported by Alexei Sholik
+literal_binary(_Config) ->
+    3 = literal_binary_match(bar,<<"y">>),
+    ok.
+
+literal_binary_match(bar, <<"x">>) -> 1;
+literal_binary_match(_, <<"x">>) -> 2;
+literal_binary_match(_, <<"y">>) -> 3;
+literal_binary_match(_, _) -> fail.
 
 
 id(I) -> I.
-- 
cgit v1.2.3


From dd1162846eb7942243ea285310cf100b6959a845 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Tue, 12 Jul 2016 16:12:50 +0200
Subject: Revert "beam_dead: Improve optimization of literal binary matching"

This reverts commit 105c5b0071056dc062797e58772e098d2a3a4627.
---
 lib/compiler/src/beam_dead.erl | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

(limited to 'lib')

diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl
index b01f58f683..6f6d742293 100644
--- a/lib/compiler/src/beam_dead.erl
+++ b/lib/compiler/src/beam_dead.erl
@@ -272,17 +272,14 @@ backward([{jump,{f,To}}=J|[{bif,Op,_,Ops,Reg}|Is]=Is0], D, Acc) ->
     catch
 	throw:not_possible -> backward(Is0, D, [J|Acc])
     end;
-backward([{test,bs_start_match2,F,Live,[R,_]=Args,Ctxt}|Is], D,
+backward([{test,bs_start_match2,F,_,[R,_],Ctxt}=I|Is], D,
 	 [{test,bs_match_string,F,[Ctxt,Bs]},
 	  {test,bs_test_tail2,F,[Ctxt,0]}|Acc0]=Acc) ->
-    {f,To0} = F,
-    To = shortcut_bs_start_match(To0, R, D),
     case beam_utils:is_killed(Ctxt, Acc0, D) of
 	true ->
-	    Eq = {test,is_eq_exact,{f,To},[R,{literal,Bs}]},
+	    Eq = {test,is_eq_exact,F,[R,{literal,Bs}]},
 	    backward(Is, D, [Eq|Acc0]);
 	false ->
-	    I = {test,bs_start_match2,{f,To},Live,Args,Ctxt},
 	    backward(Is, D, [I|Acc])
     end;
 backward([{test,bs_start_match2,{f,To0},Live,[Src|_]=Info,Dst}|Is], D, Acc) ->
-- 
cgit v1.2.3