<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/136518>136518</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            placement new
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          ordinary-github-user
      </td>
    </tr>
</table>

<pre>
    https://godbolt.org/z/qo1nKq4qb
`-std=c++26 -O3 -Wall -mavx512bw -mbmi -fno-exceptions`
```c++
#include <memory>
#include <cstdint>
#include <utility>

template<class T, std::size_t N>
struct StaticVector
{
        union { T m_data[N]; };
        std::uint8_t m_size;

        constexpr StaticVector(auto&&...args)noexcept :m_size{ sizeof...(args) }
        {
                std::construct_at(&m_data);
        }
        constexpr void push_back(const T x)noexcept
        {
                new(m_data+m_size)T{x};
        }
};

static_assert([]
{
        StaticVector<std::uint8_t, 2> vec{1};
        vec.push_back(1);
        return true;
}());
```

```
free(): invalid next size (fast)
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: /opt/compiler-explorer/clang-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++26 -O3 -Wall -mavx512bw -mbmi -fno-exceptions <source>
1.      <eof> parser at end of file
 #0 0x0000000003be2778 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3be2778)
 #1 0x0000000003be08bc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3be08bc)
 #2 0x0000000003b311c8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x0000796790242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007967902969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x0000796790242476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007967902287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x0000796790289676 (/lib/x86_64-linux-gnu/libc.so.6+0x89676)
 #8 0x00007967902a0cfc (/lib/x86_64-linux-gnu/libc.so.6+0xa0cfc)
 #9 0x00007967902a2a9d (/lib/x86_64-linux-gnu/libc.so.6+0xa2a9d)
#10 0x00007967902a5453 __libc_free (/lib/x86_64-linux-gnu/libc.so.6+0xa5453)
#11 0x0000000006d90ecb clang::Sema::PerformPendingInstantiations(bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6d90ecb)
#12 0x00000000062ee589 clang::Sema::ActOnEndOfTranslationUnitFragment(clang::Sema::TUFragmentKind) (.part.0) Sema.cpp:0:0
#13 0x00000000062eed1d clang::Sema::ActOnEndOfTranslationUnit() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x62eed1d)
#14 0x0000000006153cb3 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6153cb3)
#15 0x000000000614207a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x614207a)
#16 0x000000000451cebd clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x451cebd)
#17 0x000000000482b4fa clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x482b4fa)
#18 0x00000000047a7c4b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x47a7c4b)
#19 0x000000000491b313 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x491b313)
#20 0x0000000000db1451 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xdb1451)
#21 0x0000000000da9bad ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#22 0x000000000458e8f9 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#23 0x0000000003b315e3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b315e3)
#24 0x000000000458eb19 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#25 0x00000000045520cd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x45520cd)
#26 0x0000000004553091 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4553091)
#27 0x000000000455d3dc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x455d3dc)
#28 0x0000000000dae181 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xdae181)
#29 0x0000000000c2fec4 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc2fec4)
#30 0x0000796790229d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#31 0x0000796790229e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#32 0x0000000000da9645 _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xda9645)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```

</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWU1z4zbS_jXwBUUVCX4ffJBlO28-3sxU7OweVSDYlLADAhwAlOX8-i2AlEnKmtk4pexlU5mSTDSefvpBo9EQqTF8JwFuUXqH0vsb2tu90rdK11xS_RrsuN33VdAb0DeVql9v99Z2BsVrRB4RedypulLCrpTeIfL4ByKPX1Ukf_6afK1QuEZZGBhbo_ieIXKHyB3JcPApxsE_qRA4aOnhmEakesFBW7UcB41UARwZdJYraVAWDhjD_yOEe0RiLpnoa8Ao3rTQKv2K4od3I8zYmkt7aai3XHB7mhWuLbSdoBbcLEGNwc-IbLDnvkbx2vA_YGvxr4O9sbpnFj9Zajn7BzCrtEPJPbew7CVXEqP8Dj_jdltTS1F69ytK71F8h1HuPgbDN_ieS1tsLW63ztFp3JkwJY2FY6eX3khBe6sQyRDJVqsV1TuDSCnVIB5G8XqEyu-w-1TNarVyswZDz8Ljv5Ge0_FOXYhbahEpEMnGMEj5xv0NYWJ4ULzGXW_224qyL4gUfgg_4-OM23u3El4QKU4e7kbipHxG-d1xLtfocnqyNl6TLTUGtGfqc3i-FgvV4s254m6RCYof8AEYyu-iubsDsNU8mmgevgbba4mt7k_Lld97qcrJ6pS442LO_mw0wGgdrzGXByp4jSUcrV8tjEjRUGPdeLj-_MvD-ukBm75qucUUV_0Oa-iUttgqfLYd_W5dMdUi8ijE4fQRdFr9C5hF5JEb04NB5BFTWePTlrB7wExTs8cuWqspA6dNp6HTioExUGOjej08djOpMYpxaqHGupfYMM07u0Lh-slS9gXXfds5WuE6XKGw_KzVTtMWU73rW5DWUcaIPKrOcWKq7bgAHcCxE0qDds8ElbvA6l5-QeSx4vL0bCgDONjVL1Q3QYKDHQ6UA6Nd5yB72_V2ZXDQutBxEByLLKCmDcyrtPSI4nsuLYih3BxAV8qAG8fBEw6CHWOBVUqwPeUSxfffJemMjaSd2SuLg4YpoXRQc7qTyljOzODDC7t8_Neroqte40r4YhQ5eVG8AdW4RO6oNqAxtRhkjVWDGy4AhU7sOMThMTz9F1dA8rzAPkuGIvdqhi-fNZfWL-PzkAjFZKTpy1YZq4G2vvxssKuwrqS4fP7r64nIXXgcOQ157xhHZ4zDomKXGG8EUNl3n-QT30kqECl66c-1GgvlXFyNn2Mw8SNLfnEUsQJv3HL_BkwdQL8OhP6Pylo4N8Wo1sJmo6SFo12xzm2Z0P8b8OMRPy-zvAxJQlISjpEIXiHyeCyybZYEgsv-GOxkPwywlVGrzFP2UybCyRKwzMqG4c7uNdB6-4UL8TF0P39CT8_pJnmGd8ZL8FHaSZ5NwNkSmBR5E2NauRr4IVg_cYLNl7BFmeXZxwD9lAmwWALSkDXsY4B-ygRYngESWtYfBHRTBkC3ocIzwDRJY7zdujlbdyx9ENxNn8AX2zWryxBYhYdN5LfpE7R0LDGgG6XbzyBrLnc_SmOptJwOfR8pKqWEqy3D53U278hnYrvYvBkBSIvyMts1s5_kg6w_Nc-aSiM8z98lt4-a7txx5pqdSxOffz9Z_MxlPUay6qi2K7cpsbM82_aOWXzOrI7qDzIb2ovrCDcQmIRLFvSiNGZVPKf32Z9Bs-_PqvsFDiDugYmlVJ86-rWHz1YPjffpsTP8Qau--w3cqTaeNBcV-H9V9wJ-bF1D5Lo98MZXinyIbYo8XUaekDCn7yJfPz1fyIchhL8lsQceE8tszjJJIwbVIn02qoYfQK6ZS5bh0cMRWG9hfHS93Bm9T9zyBbeCVEmzUPBRu8NQ1hfIXZPW4HiiVSxo5TRnSbWUbHA0VCrXe11S7dtxXC8nR3IT9XJBvYwqVz9mTEaSUwQHxeh7wu8iJOurUR5IvVEmi0Y0rKsoSSPMWLRtXc89bzfXWtNXXwQ2bE819ldKR80VhQ1ePiMbfwe9IvOB2kQ8WhKnZUVrfBJ4Ez37XT2j_9RSIYbb549tJy5G4evCNMVhjA3hyc7nTq35AfT7w4KQ5W4voGjK4S4-gTa99Hm41V5KP3q6gD6Ml34qhLv7bRu5rMWD4zFJNtFGtS2V9fnOvLhkb9dt5e8u1AkwE8dqLndjhR_W823CdsuOxyga_qio4WxrvPko4cLYPdhaTbm7Vg7DZ3BUCJf0_jeA07gzWU-12OfMILifgkguaFvVFJF8kooUp_vET6q6sBjx-YUghXi2Dpfa_mHkt14-0QbE60LL76_b1W41nuaU5cl5RlXRojH6n8uIs67t8tKnS9VSErL6m6r5paLvjriTlIvKfDbRGcwqw-Y7Puam60UHMgvsCme8j3XKn7P-I43DMvqoEj-pynxbhp9U9Qs3diHD96ru27J3lLsV97fwP6_cmBt_n35OoUm__Ey_Oq7Zt7jez74vTvoLR_y3dP8v6netrtJrMilWnJ3LEBVjxp1aihNjXynW4z7_z6fuVZoIT2ciu2jYQkYaYAl2NK_ibcB78xafXfhJWZcf_AnJT5kAo3NASMLTLwjGUm23s1j-tAtIZi7IeZuVJSkewK-0Ig5x8Dcfi9cYtHZnwnrIHtyMbTxmY043lAuo8Qu3ewxH7rKlBhzFiSPWG8DBAVuFDQDms07beTp12Hh4eQBuS7mZZy8HburbuC7jkt7AbZQnaVRGYVTc7G-pu9o1ZURSltRZHGZZQVhNM2B1FtMkv-G3JCRpmJDQWabFqoSooqQJsyhLIaQEJSG0lIuVS_yV0rsb_zbgNoqzNCpuBK1AGP8mkBAJL9iPIkJQen-jb_2LhKrfGZSEghtrJhjLrYDbTlAGLUiLJbzc9Fqcvyz8wNuJkdLhlvw7AAD__yN4lQw">