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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [test][builtins] __divsc3 (and more) tests fail depending on -march"
href="http://bugs.llvm.org/show_bug.cgi?id=31964">31964</a>
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<th>Summary</th>
<td>[test][builtins] __divsc3 (and more) tests fail depending on -march
</td>
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<th>Product</th>
<td>compiler-rt
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>compiler-rt
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>mgorny@gentoo.org
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<div>
<pre>I attempted to address this in D28862 [1] but I don't really have the time atm
to figure out the best solution. Long story short, some tests may fail randomly
depending on -march and a few more parameters due to inexact results.
Citing the example from D28862:
<span class="quote">> For example, the value of (0.000001+j0.000001) / (-0.500000-j2.000000))
> computed the canonical way without specific machine flags is:</span >
>
<span class="quote">> z = -0x1.3bce70p-21 + j0x1.7af7bcp-22</span >
>
<span class="quote">> However, if -march=i386 -mfpmath=387 is used, it becomes:</span >
>
<span class="quote">> z = -0x1.3bce72p-21 + j0x1.7af7bcp-22</span >
I don't really know if we should allow inexact result here (and how inexact
exactly) or if the generated code should be considered buggy.
[1]:<a href="https://reviews.llvm.org/D28862">https://reviews.llvm.org/D28862</a></pre>
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