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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 - Missed simplification with not"
href="https://bugs.llvm.org/show_bug.cgi?id=47858">47858</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missed simplification with not
</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(void);
void s(unsigned a, unsigned b)
{
unsigned x = ~b;
if (x > 0 && x > a)
foo();
}
Clang -O3:
s(unsigned int, unsigned int): # @s(unsigned
int, unsigned int)
cmp esi, -1
je .LBB0_2
not esi
cmp esi, edi
jbe .LBB0_2
jmp foo() # TAILCALL
.LBB0_2:
ret
GCC -O3:
s(unsigned int, unsigned int):
not esi
cmp esi, edi
ja .L4
ret
.L4:
jmp foo()</pre>
</div>
</p>
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