From 93c476e258a20899cf6c20fb75e3ebe6f37d5d80 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Thu, 7 Apr 2016 05:56:01 +0200
Subject: Teach beam_utils to check liveness for put_map instructions

---
 lib/compiler/src/beam_utils.erl | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'lib/compiler/src/beam_utils.erl')

diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index 68d6105cfa..eed4caf93f 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -484,6 +484,17 @@ check_liveness(R, [{get_map_elements,{f,Fail},S,{list,L}}|Is], St0) ->
 		    Other
 	    end
     end;
+check_liveness(R, [{put_map,{f,_},_,Src,_D,Live,{list,_}}|_], St0) ->
+    case R of
+	Src ->
+	    {used,St0};
+	{x,X} when X < Live ->
+	    {used,St0};
+	{x,_} ->
+	    {killed,St0};
+	{y,_} ->
+	    {unknown,St0}
+    end;
 check_liveness(R, [{test_heap,N,Live}|Is], St) ->
     I = {block,[{set,[],[],{alloc,Live,{nozero,nostack,N,[]}}}]},
     check_liveness(R, [I|Is], St);
-- 
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