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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 - clang should warn about unsigned comparison with zero with -Wall -Wextra"
href="https://bugs.llvm.org/show_bug.cgi?id=40234">40234</a>
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<th>Summary</th>
<td>clang should warn about unsigned comparison with zero with -Wall -Wextra
</td>
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>All
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<th>OS</th>
<td>All
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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
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<th>Component</th>
<td>Frontend
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>tblodt@icloud.com
</td>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<p>
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<pre>Given this function:
int f(unsigned x) {
return x < 0;
}
GCC gives the following warning with -Wextra:
<source>: In function 'int f(unsigned int)':
<source>:2:14: warning: comparison of unsigned expression < 0 is always false
[-Wtype-limits]
return x < 0;
~~^~~
Clang doesn't warn at all, even with -Wall -Wextra. You need to specify
-Wtautological-constant-in-range-compare, which is really hard to figure out.</pre>
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