<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 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"Malgun Gothic";
panose-1:2 11 5 3 2 0 0 2 0 4;}
@font-face
{font-family:"\@Malgun Gothic";}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
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="EN-US" link="#0563C1" vlink="#954F72" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal">Hi All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:black;background:white">I have seen performance regressions from new pass manager against legacy pass manager. One of the issues is the order of populating loops on pass manager. The legacy pass manager is traversing
loops in reverse program order but the new pass manager is traversing in forward program order. It sometimes causes different output. I have created a review
<a href="https://reviews.llvm.org/D99774">https://reviews.llvm.org/D99774</a> for reverse program order on new pass manager and had short discussion with Arthur on it. It is not easy to say the reverse order is better than the forward one or vice versa. I would
like to share this issue with more people on llvm-dev. If you have idea or experience about this issue, please share it.</span><span style="background:white"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="background:white"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black;background:white">Thanks</span><span style="background:white"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black;background:white">JinGu Kang</span><o:p></o:p></p>
</div>
</body>
</html>