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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Missed optimization: division reminder"
href="https://bugs.llvm.org/show_bug.cgi?id=42673">42673</a>
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<th>Summary</th>
<td>Missed optimization: division reminder
</td>
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<th>Product</th>
<td>clang
</td>
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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>All
</td>
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<th>Status</th>
<td>NEW
</td>
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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>LLVM Codegen
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>zamazan4ik@tut.by
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>For the code below clang(trunk) with -O3:
int DivRem(int a, int b, int* result)
{
int div = a / b;
*result = a - (div * b);
return div;
}
produces this:
DivRem(int, int, int*): # @DivRem(int, int, int*)
mov rcx, rdx
mov eax, edi
cdq
idiv esi
imul esi, eax
sub edi, esi
mov dword ptr [rcx], edi
ret
but gcc(trunk) with -O3 produces this:
DivRem(int, int, int*):
mov eax, edi
mov r8, rdx
cdq
idiv esi
mov DWORD PTR [r8], edx
ret
I think we can do in LLVM as GCC.
P.S. Compiler explorer example: <a href="https://godbolt.org/z/RryrJw">https://godbolt.org/z/RryrJw</a></pre>
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</p>
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