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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 - Missing reduction add for vector(4) char"
href="https://bugs.llvm.org/show_bug.cgi?id=51978">51978</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missing reduction add for vector(4) char
</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>Scalar Optimizations
</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>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>void foo_notvectorized(unsigned char *p, unsigned char *t) {
char sum = 0;
for (int i = 0; i != 4; i++)
sum += p[i];
*t = sum;
}
char foo_vectorized(char *p) {
char sum = 0;
for (int i = 0; i != 4; i++)
sum += p[i];
return sum;
}
foo_notvectorized: # @foo_notvectorized
mov al, byte ptr [rdi + 1]
add al, byte ptr [rdi]
add al, byte ptr [rdi + 2]
add al, byte ptr [rdi + 3]
mov byte ptr [rsi], al
ret
foo_vectorized: # @foo_vectorized
movd xmm0, dword ptr [rdi] # xmm0 = mem[0],zero,zero,zero
pxor xmm1, xmm1
psadbw xmm1, xmm0
movd eax, xmm1
ret</pre>
</div>
</p>
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