<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:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" 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:"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:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
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;}
p.Code, li.Code, div.Code
{mso-style-name:Code;
mso-style-link:"Code Char";
margin:0in;
margin-bottom:.0001pt;
mso-add-space:auto;
font-size:9.0pt;
font-family:"Courier New";}
p.CodeCxSpFirst, li.CodeCxSpFirst, div.CodeCxSpFirst
{mso-style-name:CodeCxSpFirst;
mso-style-link:"Code Char";
mso-style-type:export-only;
margin:0in;
margin-bottom:.0001pt;
mso-add-space:auto;
font-size:9.0pt;
font-family:"Courier New";}
p.CodeCxSpMiddle, li.CodeCxSpMiddle, div.CodeCxSpMiddle
{mso-style-name:CodeCxSpMiddle;
mso-style-link:"Code Char";
mso-style-type:export-only;
margin:0in;
margin-bottom:.0001pt;
mso-add-space:auto;
font-size:9.0pt;
font-family:"Courier New";}
p.CodeCxSpLast, li.CodeCxSpLast, div.CodeCxSpLast
{mso-style-name:CodeCxSpLast;
mso-style-link:"Code Char";
mso-style-type:export-only;
margin:0in;
margin-bottom:.0001pt;
mso-add-space:auto;
font-size:9.0pt;
font-family:"Courier New";}
span.CodeChar
{mso-style-name:"Code Char";
mso-style-link:Code;
font-family:"Courier New";}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@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="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Oops! My bad! The code I intended to write was:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:Consolas">define dso_local i32 @f(<span style="background:yellow;mso-highlight:yellow">i3</span> %0) {</span><o:p></o:p></p>
<p class="MsoNormal"> <span style="font-family:Consolas">%2 = and <span style="background:yellow;mso-highlight:yellow">
i3 </span>%0, 7</span><span style="font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:Consolas"> %3 = icmp eq
<span style="background:yellow;mso-highlight:yellow">i3</span> %2, 7</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:Consolas"> %4 = zext i1 %3 to i32</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:Consolas"> ret i32 %4</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:Consolas">}<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The `and` does get removed in this case as expected. Thanks for answering the dumb question.
<span style="font-family:"Segoe UI Emoji",sans-serif">😊</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">/Riyaz<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><b>From:</b> Craig Topper <craig.topper@gmail.com> <br>
<b>Sent:</b> Thursday, June 11, 2020 6:57 PM<br>
<b>To:</b> Riyaz Puthiyapurayil <riyaz@synopsys.com><br>
<b>Cc:</b> llvm-dev <llvm-dev@lists.llvm.org><br>
<b>Subject:</b> Re: [llvm-dev] Why doesn't this `and` get eliminated<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">I don't think its legal to remove it. That code is equivalent to asking (%0 mod 8) == 7. Which is true for 7 and 15 and 23, etc. You can't just remove the mod part of that or it would just return true for %0 == 7.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<div>
<p class="MsoNormal">~Craig<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On Thu, Jun 11, 2020 at 6:31 PM Riyaz Puthiyapurayil via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
</div>
<div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas">define dso_local i32 @f(i32 %0) {</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas">
<span style="background:yellow">%2 = and i32 %0, 7</span></span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas"> %3 = icmp eq i32 %2, 7</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas"> %4 = zext i1 %3 to i32</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas"> ret i32 %4</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas">}</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas">I thought instcombine would remove it. It doesn’t and nothing else does either. LLVM Version is 10.0.0.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:14.0pt;font-family:Consolas">/Riyaz</span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal">_______________________________________________<br>
LLVM Developers mailing list<br>
<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a><br>
<a href="https://urldefense.com/v3/__https:/lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev__;!!A4F2R9G_pg!JPHHxK08PLHdcVuEWI6SHbEK3lkgLp9Y9oRN7k0Y23Pa82isuL-auNioBqQUN_JsRYx5NrpuPTlv$" target="_blank">https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><o:p></o:p></p>
</div>
</body>
</html>