<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=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Batang;
panose-1:2 3 6 0 0 1 1 1 1 1;}
@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";}
@font-face
{font-family:"\@Batang";
panose-1:2 3 6 0 0 1 1 1 1 1;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
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="blue" vlink="purple" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal">Hi Florian,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks for your kind reply.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The loop distribute pass was not triggered with one of below messages on almost all tests.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Skipping; memory operations are safe for vectorization<o:p></o:p></p>
<p class="MsoNormal">Skipping; no unsafe dependences to isolate<o:p></o:p></p>
<p class="MsoNormal">Skipping; multiple exit blocks<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It looks like the first and second message are reasonable. <o:p>
</o:p></p>
<p class="MsoNormal">From third message, we could try to improve the pass to handle loop with the multiple exit blocks… I am not sure how much effort we need for it…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks<o:p></o:p></p>
<p class="MsoNormal">JinGu Kang<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div style="border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt">
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Florian Hahn via llvm-dev<br>
<b>Sent:</b> 14 July 2021 13:06<br>
<b>To:</b> Jingu Kang <Jingu.Kang@arm.com>; llvm-dev@lists.llvm.org<br>
<b>Cc:</b> nikic@php.net<br>
<b>Subject:</b> Re: [llvm-dev] Enabling Loop Distribution Pass as default in the pipeline of new pass manager<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi,<o:p></o:p></p>
<div>
<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal">On 5 Jul 2021, at 15:40, Jingu Kang <<a href="mailto:jingu.kang@arm.com">jingu.kang@arm.com</a>> wrote:<o:p></o:p></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">Ping.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Additionally, I was not able to see the pass triggered from llvm-test-suite and spec benchmark except hmmer.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
</div>
</blockquote>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">Hm, this seems to indicate that the current version of loop-distribute is not very general at all. I’m not sure if we want to enable the pass by default, as long as it effectively only benefits a single benchmark?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Taking a step back, the question this raises for me is *why* it does not trigger anywhere else at all? I doubt there are no other cases in the test-suite and/or various SPEC benchmarks that would benefit from loop distribution. It would
at least be helpful to understand *why* the pass misses them at the moment and what kind of changes are needed to make it more general.<o:p></o:p></p>
</div>
</div>
</div>
</body>
</html>