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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Suboptimal codegen for v2sf operations - should use MOVLPS"
href="https://bugs.llvm.org/show_bug.cgi?id=46966">46966</a>
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<th>Summary</th>
<td>Suboptimal codegen for v2sf operations - should use MOVLPS
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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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
</td>
</tr>
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<th>Reporter</th>
<td>david.bolvansky@gmail.com
</td>
</tr>
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<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
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<p>
<div>
<pre>float r[2], a[2], b[2], c[2];
void test_plus(void) {
for (int i = 0; i < 2; i++) r[i] = a[i] + b[i];
}
Clang:
test_plus: # @test_plus
movss xmm0, dword ptr [rip + a] # xmm0 = mem[0],zero,zero,zero
addss xmm0, dword ptr [rip + b]
movss dword ptr [rip + r], xmm0
movss xmm0, dword ptr [rip + a+4] # xmm0 = mem[0],zero,zero,zero
addss xmm0, dword ptr [rip + b+4]
movss dword ptr [rip + r+4], xmm0
ret
GCC:
test_plus:
movq xmm0, QWORD PTR a[rip]
movq xmm1, QWORD PTR b[rip]
addps xmm0, xmm1
movlps QWORD PTR r[rip], xmm0
ret
Godbolt: <a href="https://godbolt.org/z/fnxGj1">https://godbolt.org/z/fnxGj1</a></pre>
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