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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [powerpc64] Unnecessary stack frame when using sqrtf()"
href="https://llvm.org/bugs/show_bug.cgi?id=25672">25672</a>
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<th>Summary</th>
<td>[powerpc64] Unnecessary stack frame when using sqrtf()
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: PowerPC
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>anton@samba.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following testcase:
extern float sqrtf (float);
float t3(float a)
{
return sqrtf(a);
}
does not allocate a stack frame on gcc:
# gcc -S -O3 -mcpu=power8 -ffast-math test.c
# cat test.s
t3:
fsqrts 1,1
blr
But does on clang:
# clang -S -O3 -mcpu=power8 -ffast-math -mrecip=none test.c
# cat test.s
t3: # @t3
.Lfunc_begin2:
# BB#0: # %entry
stw 31, -4(1)
stwu 1, -16(1)
mr 31, 1
xssqrtsp 1, 1
addi 1, 1, 16
lwz 31, -4(1)
blr
I added -mrecip=none to keep the output simple, but it reproduces without it.</pre>
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