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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I wasn’t sure what to think of this one. I guess it comes down to what the C++ standard says should be happening here.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">At first glance, a bitwise XOR of a bool with something else seems sketchy. On the other hand, if the standard promises to convert the rhs to bool before the
^= operation then the warning shouldn’t be there.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The C4805 warning seems to always apply to mixing bool with integer types. It didn’t show up anywhere else in the llvm code base, so it doesn’t seem like disabling
it across the board should be necessary.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-Andy<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> David Blaikie [mailto:dblaikie@gmail.com]
<br>
<b>Sent:</b> Monday, March 23, 2015 3:47 PM<br>
<b>To:</b> Kaylor, Andrew<br>
<b>Cc:</b> llvm-commits@cs.uiuc.edu<br>
<b>Subject:</b> Re: [llvm] r233004 - Refactor: Simplify boolean expressions in llvm Support<o:p></o:p></span></p>
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<p class="MsoNormal">On Mon, Mar 23, 2015 at 3:44 PM, Kaylor, Andrew <<a href="mailto:andrew.kaylor@intel.com" target="_blank">andrew.kaylor@intel.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal">When I compile this with Visual Studio at /W4 I get this warning:<br>
<br>
llvm\lib\Support\APFloat.cpp(1433): warning C4805: '^=' : unsafe mix of type 'bool' and type 'unsigned int' in operation<o:p></o:p></p>
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Is this worth warning on (Clang doesn't, for example) - should we just disable the MSVC warning, then?<br>
<o:p></o:p></p>
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<p class="MsoNormal"><br>
According to the documentation this is a level 1 warning, so it probably appears with all builds. I just happen to have been working on a change to enable W4 warnings on Windows.<br>
<br>
-Andy<o:p></o:p></p>
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<br>
-----Original Message-----<br>
From: <a href="mailto:llvm-commits-bounces@cs.uiuc.edu">llvm-commits-bounces@cs.uiuc.edu</a> [mailto:<a href="mailto:llvm-commits-bounces@cs.uiuc.edu">llvm-commits-bounces@cs.uiuc.edu</a>] On Behalf Of David Blaikie<br>
Sent: Monday, March 23, 2015 12:46 PM<br>
To: <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
Subject: [llvm] r233004 - Refactor: Simplify boolean expressions in llvm Support<br>
<br>
Author: dblaikie<br>
Date: Mon Mar 23 14:45:40 2015<br>
New Revision: 233004<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=233004&view=rev" target="_blank">
http://llvm.org/viewvc/llvm-project?rev=233004&view=rev</a><br>
Log:<br>
Refactor: Simplify boolean expressions in llvm Support<br>
<br>
Simplify boolean expressions using `true` and `false` with `clang-tidy`<br>
<br>
Patch by Richard Thomson - I dropped the parens and != 0 test, for consistency with other patches/tests like this, but I'm open to the notion that we should add the explicit non-zero test in all these sort of cases (non-bool assigned to a bool).<br>
<br>
Differential Revision: <a href="http://reviews.llvm.org/D8526" target="_blank">http://reviews.llvm.org/D8526</a><br>
<br>
Modified:<br>
llvm/trunk/lib/Support/APFloat.cpp<br>
<br>
Modified: llvm/trunk/lib/Support/APFloat.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=233004&r1=233003&r2=233004&view=diff" target="_blank">
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APFloat.cpp?rev=233004&r1=233003&r2=233004&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/Support/APFloat.cpp (original)<br>
+++ llvm/trunk/lib/Support/APFloat.cpp Mon Mar 23 14:45:40 2015<br>
@@ -1430,7 +1430,7 @@ APFloat::addOrSubtractSignificand(const<br>
<br>
/* Determine if the operation on the absolute values is effectively<br>
an addition or subtraction. */<br>
- subtract ^= (sign ^ rhs.sign) ? true : false;<br>
+ subtract ^= sign ^ rhs.sign;<br>
<br>
/* Are we bigger exponent-wise than the RHS? */<br>
bits = exponent - rhs.exponent;<br>
<br>
<br>
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