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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [x86, FMA] negated fma pattern not recognized"
href="https://llvm.org/bugs/show_bug.cgi?id=24364">24364</a>
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<th>Summary</th>
<td>[x86, FMA] negated fma pattern not recognized
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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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
</td>
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<th>Component</th>
<td>Backend: X86
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>spatel+llvm@rotateright.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Testing llc built from r244046:
$ cat fnmsub.ll
define float @nmsub(float %a, float %b, float %c) {
%mul = fmul fast float %a, %b
%add = fadd fast float %c, %mul
%neg = fsub fast float 0.0, %add
ret float %neg
}
$ ./llc -o - fnmsub.ll -mattr=fma -enable-unsafe-fp-math
...
vfmadd213ss %xmm2, %xmm1, %xmm0
vxorps LCPI0_0(%rip), %xmm0, %xmm0
retq
-----------------------------------------------------------------
I think this should just be a 'vfnmsub213ss'; we shouldn't have to negate
(vxorps) as a separate operation.</pre>
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