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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 LEA codegen"
href="https://bugs.llvm.org/show_bug.cgi?id=42490">42490</a>
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<th>Summary</th>
<td>Suboptimal LEA codegen
</td>
</tr>
<tr>
<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>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<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
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<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
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<pre>Haswell X86-64
int extra_lea(int *p, int xp) {
*p = xp + 21;
return *p * 2;
}
Clang -O3 trunk:
extra_lea(int*, int): # @extra_lea(int*, int)
lea eax, [rsi + 21]
mov dword ptr [rdi], eax
lea eax, [rsi + rsi]
add eax, 42
ret
GCC -O3 trunk:
extra_lea(int*, int):
lea eax, [rsi+21]
mov DWORD PTR [rdi], eax
add eax, eax
ret</pre>
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