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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Missed pattern B+(-C)*A"
href="https://bugs.llvm.org/show_bug.cgi?id=37939">37939</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missed pattern B+(-C)*A
</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>Code:
int foo2(int x, int y) {
return x + -2 *y;
}
int foo3(int x, int y) {
return x + -3 *y;
}
int foo4(int x, int y) {
return x + -4 *y;
}
Clang trunk:
foo2(int, int): # @foo2(int, int)
add esi, esi
sub edi, esi
mov eax, edi
ret
foo3(int, int): # @foo3(int, int)
lea eax, [rsi + 2*rsi]
neg eax
add eax, edi
ret
foo4(int, int): # @foo4(int, int)
shl esi, 2
sub edi, esi
mov eax, edi
ret
GCC 8:
foo2(int, int):
neg esi
lea eax, [rdi+rsi*2]
ret
foo3(int, int):
lea eax, [0+rsi*4]
sub esi, eax
lea eax, [rsi+rdi]
ret
foo4(int, int):
neg esi
lea eax, [rdi+rsi*4]
ret</pre>
</div>
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