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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 - Missed range based optimizations"
href="https://bugs.llvm.org/show_bug.cgi?id=37750">37750</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missed range based optimizations
</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>Hello,
int g2(unsigned a, unsigned b) {
if (a > 0 && b > 0)
return b + a != 0;
// return b == 0;
// return a + b > 0;
return -1;
}
Long/suboptimal code for cases above ^ - clang/llvm trunk:
g2(unsigned int, unsigned int): # @g2(unsigned int, unsigned int)
xor ecx, ecx
mov eax, esi
add eax, edi
setne cl
cmp esi, 1
sbb edx, edx
cmp edi, 1
sbb eax, eax
or eax, edx
or eax, ecx
ret
GCC:
g2(unsigned int, unsigned int):
test edi, edi
je .L3
test esi, esi
je .L3
xor eax, eax
add edi, esi
setne al
ret
.L3:
mov eax, -1
ret</pre>
</div>
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