<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0cm;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:"Courier New";
mso-fareast-language:DE;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:70.85pt 70.85pt 2.0cm 70.85pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="DE" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">I did some more tests with our proposed webrev<o:p></o:p></span></p>
<p class="MsoNormal"><a href="http://cr.openjdk.java.net/~goetz/webrevs/opto_g1_barr/">http://cr.openjdk.java.net/~goetz/webrevs/opto_g1_barr/</a><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">and it happened that the assertion<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">“assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");”</span><o:p></o:p></p>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">was firing when running jvm2008 derby on linuxx86_64.<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">What happened is that the C2 was inserting a barrier of kind=LibraryCallKit::LS_cmpxchg,<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">but oldval was a ConP node with bottom_type()->basic_type() = T_ADDRESS.<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">I believe there’s nothing logically wrong with the change.<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Should the assertion be modified or should we filter out cases in which oldval<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">does not contain a valid Oop?<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">I guess some advice from C2 and G1 experts is needed.<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Best regards,<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Martin<o:p></o:p></span></pre>
<pre><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><o:p> </o:p></span></pre>
</div>
</body>
</html>