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<body><span class="vcard"><a class="email" href="mailto:spatel+llvm@rotateright.com" title="Sanjay Patel <spatel+llvm@rotateright.com>"> <span class="fn">Sanjay Patel</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WONTFIX - operating on unknown FP operands is a bad idea"
href="https://llvm.org/bugs/show_bug.cgi?id=20358">bug 20358</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
</tr>
<tr>
<td style="text-align:right;">See Also</td>
<td>
</td>
<td>https://llvm.org/bugs/show_bug.cgi?id=8100, https://llvm.org/bugs/show_bug.cgi?id=6050
</td>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>WONTFIX
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WONTFIX - operating on unknown FP operands is a bad idea"
href="https://llvm.org/bugs/show_bug.cgi?id=20358#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WONTFIX - operating on unknown FP operands is a bad idea"
href="https://llvm.org/bugs/show_bug.cgi?id=20358">bug 20358</a>
from <span class="vcard"><a class="email" href="mailto:spatel+llvm@rotateright.com" title="Sanjay Patel <spatel+llvm@rotateright.com>"> <span class="fn">Sanjay Patel</span></a>
</span></b>
<pre>As noted in the patch review thread, this is a specific example of a general
problem. We shouldn't deoptimize normal FP code for the presumably rare
denormal occurrence. It's also not clear that all targets are as awful as x86
at handling denorms.
We really need an optimization flag/mode that tells us we're not allowed to
speculate FP ops.
This probably also relates to honoring the FENV (<a class="bz_bug_link
bz_status_NEW "
title="NEW --- - clang/llvm don't support C99 FP rounding mode pragmas (FENV_ACCESS etc)"
href="show_bug.cgi?id=8100">bug 8100</a>) and knowing which
exceptions are enabled (<a class="bz_bug_link
bz_status_NEW "
title="NEW --- - floating-point operations have side effects"
href="show_bug.cgi?id=6050">bug 6050</a>).
Resolving as 'WONTFIX'.</pre>
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