<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div>I just hit this myself (months later!) trying to round-trip floats through strings. I don't think the problem is printed values exceeding their maximums so much as that APFloat::toString thinks the natural precision for DBL_MAX is one digit shorter than it actually is. I'll take a look, but someone with more floating-point experience might be able to get to the bottom of this sooner.</div><div><br></div><div>Jordan</div><div><br></div><br><div><div>On Apr 16, 2013, at 8:54 , Will Wilson <<a href="mailto:will@indefiant.com">will@indefiant.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr">Sorry, I'm not being clear enough. It's nothing to do with runtime libs. Rather it's the result of printing out the expanded literal value directly from the AST. For instance:<div style=""><ul style="">
<li style="">Clang parses the <span style="font-family:arial,sans-serif;font-size:13px">DBL_MAX macro into the AST (defined as 1.7976931348623158e+308)</span></li><li style=""><font face="arial, sans-serif">Pretty printing out the FloatingLiteral results in: </font><span style="font-family:arial,sans-serif;font-size:13px">1.797693134862316E</span><span style="font-family:arial,sans-serif;font-size:13px">+</span><span style="font-family:arial,sans-serif;font-size:13px">308</span></li>
<li style=""><font face="arial, sans-serif">Feeding these literals back to MSVC results in: error C2177: constant too big</font></li></ul></div><div style="">So my question is: Would it be sensible to try and ensure the printed values never exceed their maximums?</div>
<div style=""><br></div><div style="">Cheers,</div><div style="">Will.</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On 16 April 2013 00:56, David Blaikie <span dir="ltr"><<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5"><p dir="ltr"><br>
On Apr 16, 2013 8:01 AM, "Will Wilson" <<a href="mailto:will@indefiant.com" target="_blank">will@indefiant.com</a>> wrote:<br>
><br>
> Hi All,<br>
><br>
> I'm rewriting MS C++ code via clang and have an issue involving the printed representations of FLT_MAX and DBL_MAX. In both cases the printed literals exceed the inputs.<br>
><br>
> From MS float.h:<br>
><br>
> #define DBL_MAX 1.7976931348623158e+308<br>
> // Becomes 1.797693134862316E+308<br>
><br>
> #define FLT_MAX 3.402823466e+38F<br>
> // Becomes 3.4028235E+38F<br>
><br>
> Rewriting the values leads to compilation errors due to the literals exceeding their maximums. This doesn't altogether surprise me given the nature of FP arithmetic and string conversion but I was wondering if this could/should be treated as a bug given the significance of these values?</p>
</div></div><p dir="ltr">How are you printing these values out? Libstdc++ or libc++? Does the behavior reproduce under GCC too? I could guess/assume a bug in the standard library implementation you are using, but that's just a guess</p>
<div class="HOEnZb"><div class="h5"><p dir="ltr">><br>
> - Will.<br>
><br>
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