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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - roundf lowering under fast math"
href="https://bugs.llvm.org/show_bug.cgi?id=42195">42195</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>roundf lowering under fast math
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: X86
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>david.bolvansky@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
</td>
</tr></table>
<p>
<div>
<pre>-Ofast -mfma -march=skylake
float rf(float B) {
return roundf(B);
}
Clang:
rf(float):
jmp roundf
GCC generates:
rf(float):
vmovaps xmm1, xmm0
vandps xmm0, xmm0, XMMWORD PTR .LC1[rip]
vorps xmm0, xmm0, XMMWORD PTR .LC0[rip]
vaddss xmm0, xmm0, xmm1
vroundss xmm0, xmm0, xmm0, 3
ret
ICC:
rf(float):
vxorps xmm1, xmm1, xmm1 #7.12
vmovss xmm3, xmm1, xmm0 #7.12
vandps xmm4, xmm3, XMMWORD PTR .L_2il0floatpacket.0[rip] #7.12
vcmpeqps xmm2, xmm4, XMMWORD PTR .L_2il0floatpacket.1[rip] #7.12
vroundps xmm9, xmm4, 0 #7.12
vxorps xmm11, xmm3, xmm4 #7.12
vblendvps xmm5, xmm9, XMMWORD PTR .L_2il0floatpacket.2[rip], xmm2 #7.12
vsubps xmm6, xmm4, xmm5 #7.12
vcmpeqps xmm7, xmm6, XMMWORD PTR .L_2il0floatpacket.3[rip] #7.12
vandps xmm8, xmm7, XMMWORD PTR .L_2il0floatpacket.4[rip] #7.12
vaddps xmm10, xmm8, xmm9 #7.12
vxorps xmm0, xmm10, xmm11 #7.12
ret</pre>
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