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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - False Positive of -Wtautological-overlap-compare on Expressions in Return Statement" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24238&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=3JZAjBVEvfo494j-8k49Vi_UzqkJzh1LRmt8fRhmmDM&s=ZvxEVU2bvkay8JcKS7tGZ9a3TqXLnYI3Z9eU1AoBcDg&e=">24238</a>
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<th>Summary</th>
<td>False Positive of -Wtautological-overlap-compare on Expressions in Return Statement
</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>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Frontend
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>chengniansun@gmail.com
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Clang does not warn on the expression "x > 6 && x < 2" in the return statement.
If this expression is in the if conditional, it warns.
$: cat s.c
int g(int x) {
return x > 6 && x < 2;
}
int f(int x) {
if (x > 6 && x < 2) {
return 1;
}
return 0;
}
$:
$: clang-trunk -Wtautological-overlap-compare -c s.c
s.c:5:13: warning: overlapping comparisons always evaluate to false
[-Wtautological-overlap-compare]
if (x > 6 && x < 2) {
~~~~~~^~~~~~~~
1 warning generated.
$:
$: gcc-trunk -c -Wlogical-op s.c
s.c: In function ‘g’:
s.c:2:16: warning: logical ‘and’ of mutually exclusive tests is always false
[-Wlogical-op]
return x > 6 && x < 2;
^
s.c: In function ‘f’:
s.c:5:13: warning: logical ‘and’ of mutually exclusive tests is always false
[-Wlogical-op]
if (x > 6 && x < 2) {
^
$:</pre>
</div>
</p>
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