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<body><span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED DUPLICATE - ARM isnormal(long double NaN) raises invalid"
href="https://bugs.llvm.org/show_bug.cgi?id=46811">bug 46811</a>
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<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">Resolution</td>
<td>---
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<td>DUPLICATE
</td>
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<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED DUPLICATE - ARM isnormal(long double NaN) raises invalid"
href="https://bugs.llvm.org/show_bug.cgi?id=46811#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED DUPLICATE - ARM isnormal(long double NaN) raises invalid"
href="https://bugs.llvm.org/show_bug.cgi?id=46811">bug 46811</a>
from <span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span></b>
<pre>OK, I see the same thing if I use __builtin_isnormal instead:
<a href="https://godbolt.org/z/37M8PG">https://godbolt.org/z/37M8PG</a> -- in particular, the `fcmp`s we generate can set
FE_INVALID on NaN.
On x86_64, those `fcmp`s are replaced by constrained FP intrinsics:
<a href="https://godbolt.org/z/GK9Ejh">https://godbolt.org/z/GK9Ejh</a>
So this is another duplicate of 46799: this code was compiled assuming the
default floating point environment and that FP exceptions would not be
inspected. Use of <fenv.h> facilities from that environment is undefined, and
in this case that's manifesting as isnormal setting a floating point exception.
*** This bug has been marked as a duplicate of <a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED - no support for FENV_ACCESS on armv8"
href="show_bug.cgi?id=46799">bug 46799</a> ***</pre>
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