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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 - incorrect reinterpret_cast from integer to pointer error on invalid constexpr initialization"
href="https://bugs.llvm.org/show_bug.cgi?id=42243">42243</a>
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<th>Summary</th>
<td>incorrect reinterpret_cast from integer to pointer error on invalid constexpr initialization
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<th>Product</th>
<td>clang
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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
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>zhonghao@pku.org.cn
</td>
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>My clang is 9.0.0, and the code is:
struct S { int a, b[1]; };
constexpr S *p1 = (S*)0;
constexpr int *q1 = p1->b;
The code is invalid not because of a cast (there is none) but because it
attempts to use a null pointer to form the address of a member of an object. A
related code is as follow:
struct S { int a, b; } s;
constexpr S *p = (S*)0;
constexpr const int *q = &p->b;
clang accepts both samples.
gcc reject them:
source>:4:25: error: dereferencing a null pointer in '*(S*)p1'
4 | constexpr int *q1 = p1->b;
| ^
Compiler returned: 1</pre>
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