<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;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 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";
color:black;}
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:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
span.EmailStyle17
{mso-style-type:personal;
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:"Consolas","serif";
color:black;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@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 bgcolor="white" lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="color:#1F497D">Sorry, I abbreviated the “test case” a little too much.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">APF2 is actually defined separately. And it’s in a union, which avoids the issue that there is no APFloat(void). So it’s something like:<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="color:#1F497D"><o:p> </o:p></span></a></p>
<p class="MsoNormal"><span style="color:#1F497D">union U {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> U() {}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> ~U() {}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> APFloat APF2;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">} u;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">int main(int argc, char **argv) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> APFloat APF1(APFloat::IEEEdouble());
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> u.APF2 = APF1;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> u.APF2.print(dbgs()); <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">So this is a little more nuanced than I thought. I think the design is that it should not be possible to construct an APFloat without semantics, and this union thing circumvents that. I still think it’s a bug,
but fairly easy to avoid: either properly construct APF2, or avoid assignment.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">-Alan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> Friedman, Eli [mailto:efriedma@codeaurora.org]
<br>
<b>Sent:</b> Tuesday, October 16, 2018 1:35 PM<br>
<b>To:</b> Davis, Alan; llvm-dev@lists.llvm.org<br>
<b>Subject:</b> [EXTERNAL] Re: [llvm-dev] bug is APFloat assignment<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On 10/16/2018 11:21 AM, Davis, Alan via llvm-dev wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal">I am getting a segfault when assigning one APFloat to another, as in:<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">APFloat APF1(APFloat::IEEEdouble());<o:p></o:p></p>
<p class="MsoNormal">APFloat APF2 = APF1;<o:p></o:p></p>
</blockquote>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
Just tried it; seems to work fine.<br>
<br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal">APFloat is a wrapper class that wraps either an IEEEFloat or a DoubleAPFloat. A union called Storage in APFloat contains the underlying object, which is one of those two types. The assignment APF2 = APF1<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
What assignment? "APFloat APF2 = APF1;" calls the copy constructor, not the assignment operator.<br>
<br>
-Eli <o:p></o:p></span></p>
<pre>-- <o:p></o:p></pre>
<pre>Employee of Qualcomm Innovation Center, Inc.<o:p></o:p></pre>
<pre>Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project<o:p></o:p></pre>
</div>
</body>
</html>