<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=us-ascii">
<meta name="Microsoft Theme 2.00" content="Eclipse 011">
<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:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Garamond;
panose-1:2 2 4 4 3 3 1 1 8 3;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:12.0pt;
font-family:"Garamond",serif;
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#339999;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Courier New";
color:#1014B6;
font-weight:normal;
font-style:normal;
text-decoration:none none;}
.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 bgcolor="white" background="cid:image001.gif@01D7CA41.DBA1FBB0" lang="EN-US" link="#339999" vlink="#999999" style="word-wrap:break-word">
<img src="cid:image001.gif@01D7CA41.DBA1FBB0" v:src="cid:image001.gif@01D7CA41.DBA1FBB0" v:shapes="_x0000_Mail" width="0" height="0" class="shape" style="display:none;width:0;height:0"><!--[if gte mso 9]><xml>
<v:background id="_x0000_s1025" o:bwmode="white" o:targetscreensize="1024,768">
<v:fill src="cid:image001.gif@01D7CA41.DBA1FBB0" o:title="eclbkgnd" type="frame" />
</v:background></xml><![endif]-->
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6">Hi All,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6">Using option ffp-model=fast and #pragma STDC FP_CONTRACT OFF doesn’t have the expected clang’s behavior of pragmas.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6">See for example
<a href="https://godbolt.org/z/PYYd5zd4Pthis">https://godbolt.org/z/PYYd5zd4Pthis</a> The pragma is honored; FMA instructions are generated following the option and are suppressed as directed by the pragma at codegen.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6">In contrast,
<a href="https://godbolt.org/z/WvvaKrv1b">https://godbolt.org/z/WvvaKrv1b</a> shows that the option -ffp-model=fast is honored in the FE, but the pragma is ignored. The LLVM IR generated is correct, but codegen doesn’t honor the pragma as expected. Although
this seems to be “historically” (codegen didn’t used to get fast-math flags so a global option was used; now codegen sees these flags) the pragma should be honored. This should be filed as a bug.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6">Thoughts?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Courier New";color:#1014B6">Thanks.
<o:p></o:p></span></p>
</div>
</body>
</html>