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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - [ms] clang-cl miscompiles std::atomic_flag" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24101&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=T85dIeYrB9wTgWx_kQOBVe-72psGte7KFTa0Bo4kcTo&s=zU5hMC_Q-ORl_7Noqxhiz4pJTbe3WHjQldalEJ8X9lo&e=">24101</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[ms] clang-cl miscompiles std::atomic_flag
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Frontend
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>nicolasweber@gmx.de
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>C:\src\chromefetch\src\third_party\llvm-build\Release+Asserts>type test.cc
#include <atomic>
#include <map>
int main(int argc, char* argv[]) {
std::map<const char*, std::atomic_flag> Seen;
for (int i = 1; i < argc; ++i)
Seen[argv[i]].clear();
for (int i = 1; i < argc; ++i)
if (Seen[argv[i]].test_and_set())
fprintf(stderr, "waaaaat\n");
}
C:\src\chromefetch\src\third_party\llvm-build\Release+Asserts>cl /O2 test.cc
/EHsc
Microsoft (R) C/C++ Optimizing Compiler Version 18.00.31101 for x64
Copyright (C) Microsoft Corporation. All rights reserved.
test.cc
Microsoft (R) Incremental Linker Version 12.00.31101.0
Copyright (C) Microsoft Corporation. All rights reserved.
/out:test.exe
test.obj
C:\src\chromefetch\src\third_party\llvm-build\Release+Asserts>test a b c
C:\src\chromefetch\src\third_party\llvm-build\Release+Asserts>bin\clang-cl /O2
test.cc
C:\src\chromefetch\src\third_party\llvm-build\Release+Asserts>test a b c
waaaaat
waaaaat
(Reduced from code in the new COFF lld)</pre>
</div>
</p>
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