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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - non-deterministic compile errors with constexpr and nonnull attribute"
href="https://bugs.llvm.org/show_bug.cgi?id=43601">43601</a>
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<th>Summary</th>
<td>non-deterministic compile errors with constexpr and nonnull attribute
</td>
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>9.0
</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>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>chris@detrino.org
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>The following program when compiled with `clang++ -c test.cc` will fail to
compile around 50% of the time:
```
__attribute__((__nonnull__)) constexpr int bar(const char *, int) { return 0; }
int main() { constexpr int i = bar("foo", 12345); }
```
with the following error:
```
test.cc:2:28: error: constexpr variable 'i' must be initialized by a constant
expression
int main() { constexpr int i = bar("foo", 12345); }
^ ~~~~~~~~~~~~~~~~~
test.cc:2:43: note: null passed to a callee that requires a non-null argument
int main() { constexpr int i = bar("foo", 12345); }
^
1 error generated.
```
This prevents using constexpr std::string_view::find from libstdc++ 9.2.0, the
following program has the same problem as the above reduced test case:
```
#include <string_view>
int main() {
constexpr std::string_view sv = "test";
constexpr std::size_t sz = sv.find("blah", 1);
}
```
I was unable reproduce the problem without a second argument.</pre>
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