<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/87944>87944</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            C++ parser crash with too many user-defined literals in an expression
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          christinabrien
      </td>
    </tr>
</table>

<pre>
    [clang-crash.zip](https://github.com/llvm/llvm-project/files/14899001/clang-crash.zip)

The C++ parser crashes with "Illegal instruction" when compiling a C++ file with a very long expression consisting of user-defined literals. My use-case is in creating a bitstring from smaller bitstring literals.

I have used creduce to produce a minimal test case; removing a single expression avoids the crash. I believe this is valid C++ and is compiled correctly by GCC 13.2.0. I have included the creduce interestingness test.

```
christina@Orange:~/pi/all/top/clash/minimised$ ./test.sh
0
christina@Orange:~/pi/all/top/clash/minimised$ ./compile.sh
./compile.sh: line 4: 43889 Illegal instruction: 4 "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" "-cc1" "-triple" "x86_64-apple-macosx12.0.0" "-Wundef-prefix=TARGET_OS_" "-Wdeprecated-objc-isa-usage" "-Werror=deprecated-objc-isa-usage" "-Werror=implicit-function-declaration" "-emit-obj" "--mrelax-relocations" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "AdaptationParameterSet.test.c++" "-mrelocation-model" "pic" "-pic-level" "2" "-mframe-pointer=all" "-mllvm" "-extra-vectorizer-passes" "-fno-strict-return" "-fno-rounding-math" "-funwind-tables=2" "-target-sdk-version=13.1" "-fvisibility-inlines-hidden-static-local-var" "-target-cpu" "skylake" "-debug-info-kind=standalone" "-dwarf-version=4" "-debugger-tuning=lldb" "-target-linker-version" "820.1" "-skip-unused-modulemap-deps" "-sys-header-deps" "-stdlib=libc++" "-O3" "-Werror" "-Wno-c++11-narrowing" "-Wno-ignored-attributes" "-Wno-c++20-extensions" "-Wno-c++17-extensions" "-Wno-reorder-init-list" "-Wno-implicit-int-float-conversion" "-Wno-c99-designator" "-Wno-final-dtor-non-final-class" "-Wno-extra-semi-stmt" "-Wno-misleading-indentation" "-Wno-quoted-include-in-framework-header" "-Wno-implicit-fallthrough" "-Wno-enum-enum-conversion" "-Wno-enum-float-conversion" "-Wno-elaborated-enum-base" "-Wno-reserved-identifier" "-Wno-gnu-folding-constant" "-Wno-cast-function-type" "-Wno-bitwise-instead-of-logical" "-std=c++14" "-fdeprecated-macro" "-fdebug-compilation-dir=/Users/christina/pi/all/top" "-ferror-limit" "19" "-stack-protector" "1" "-fstack-check" "-mdarwin-stkchk-strong-link" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1" "-fno-cxx-modules" "-fcxx-exceptions" "-fexceptions" "-fmax-type-align=16" "-fcommon" "-vectorize-loops" "-vectorize-slp" "-clang-vendor-feature=+messageToSelfInClassMethodIdReturnType" "-clang-vendor-feature=+disableInferNewAvailabilityFromInit" "-clang-vendor-feature=+disableNonDependentMemberExprInCurrentInstantiation" "-fno-odr-hash-protocols" "-clang-vendor-feature=+enableAggressiveVLAFolding" "-clang-vendor-feature=+revert09abecef7bbf" "-clang-vendor-feature=+thisNoAlignAttr" "-clang-vendor-feature=+thisNoNullAttr" "-mllvm" "-disable-aligned-alloc-awareness=1" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-x" "c++" "too-many-literals-in-expression.cpp"
christina@Orange:~/pi/all/top/clash/minimised$ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang --version
Apple clang version 14.0.0 (clang-1400.0.29.202)
Target: x86_64-apple-darwin21.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
```

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy8WF9v4zgO_zTui6DAUdI2eehDppnMFbiZOcz0du-toCXa5kaWfJKcpPtwn_1AO3GSXvdmF1gsUKS2SPGfyB8pQ4xUOcSH7PZDdru-gS7VPjzoOlBM5KAIhO6m8OaVObQFV0kdINaTX6nNbteZWtQptTGbrTK1ydSmolR3xUT7JlMba3enf7IN_hfUKVObkizGTG2m88VymefTTG3eClbLLF9n-Wr4fa5RPGbqQ6Y-iBZCxCB6VoxiT6kWmVJP1mIFVpCLKXQ6kXeZUmJfoxPaNy1ZcpWAUQzbMGwGscPwKqx3lcBDGzBG8rzJxT4ElfCl6CIGabAkh0ZYShjAxon4_MoUqSGioCjICR0Q0qCqoBRT4Ocy-EbEBqzFcLE8yrn09UnUsEMWa1iY6TSK5EUbfP8IoiFHDViRMCbBmrPZBxGw8btBbSRXWbx0BXaeTBSpxiFsE_EkCrSEOxSpZruj2IElM0YHnOHFIXBsiA8BdbKvongVnx4fxXQ2UZOcBfXWktO2M2iOOgarySUM2IfQYYy9wVeuZnf58a9_HXMum-dfA7gKs9nqP5natJSpDVibqU3y7ZAtsc7Upg8FRTSZmosJk1lFrAd5f57YYxxGyW_WZithyaGY89N8tlgsxXvpyERO1UxtVm1rSQMvcyH8S3uDE2jZiEfvErrEy2vcofUthkxtnr23ugY686-xhM6myUGnEy1Tmy4yd9E_90XFVZApJbWenh5ToNbi8e2wuHu5m0toW4uyAe3jYcpHm5-4f-6cwVK2AUs6ZLP18-rbp4_PL1-_v4wcBtuAGhIa6YtftKQIsotQ4ciBIfiQzda_n5MaDhElWXauj580qC0EOJU2c2NDiQWd3mUT0MJBBrR-DO9AMhShsCjLgKMybRGChJhkgaUPKAvQW3Tm7Z4ev3YYqCQ-jJGoIRi5A9uhdNDgqKsBcpIRpl8-rq4MtKm36R8QoMGE4TumSZ-yeqi7cf_Zftl4g_ZIaEmfWFrS0nJ-HBfUuLdk4bL1fflls3Wf4UfagMfH2B1SALlDnXygXzHIFmI8-1A6LxmndJIBUxfcJSH4zhlylWwg1SOhc3tyRiaOWcxm69GmBKHCJKPZchRjXwzr6WwyZmS5o0gFWUqvkhwXU5Q1GYNORo6ZlhwPK3cQ3sjUbXdcidtXC9vxbA0WXSXJlV5uyZlsto4JnAHr3ZlnD6G8MGl-tbnCIFPnyFXZbG2tKd6otuS2GMbtA3Gh8rNbcUut7BxjOZ9jZ7GBVhpsxyjH1yhrBNN3l4vlZCwVrJaKN7nxdfamVE5vzssj63QqHYTg93QufyZT5XxAIyGlQEWXzod9sVnlnBno4mXxXAq__w16QB_YD3LEsYnpSvWpmsklWVoPSWrvrkM3aFkupUGeSSBdO1eSAytN8kE6746vDNlXVgxZHbEhGVNzZUND0SL0aUvOoEtXUMIc_-48I9Oxm0kuYi6mvQ_b4ym961MJ1qY6-K6qr0xxXTP8vO9qT_p_sUALhQ89WPa8BTf7q4hHDDs2mL25AicmV66Tpbe9wzzNJHBX8dAMfCO6ptf2SnhBaU-RgxATgpG-lNZXpMFeJGk2W5_SYqyd8gLjG9DBXxC4JIfGOYCbIUaoTG3-GTFwZzs36__tz0cpfdZLSw2dvJkuzyaB3vKkmXpYO9HHvQNd16i3IyYaCHtinNnqesuQ513V1_a4q7Beb8_AiI7b71AFBo3syXJI2S6MQSwDVhQTBllZXxxTN0qeOSUkPIzmy7Jynb6EoYm6gEY-qcPhiB9nK3gNDxrbqy5XvrPUwKE_XQmWqh55785SfNOck25sBtJ6f0aj83K07bl38sS-Q2d8kCUOrvNZfmgwckd_9t_Rlk_ukUv0M6bamyfzrW8lzxe59ttyjt33yZUYvuB-tQOyMDSJTfDNkztH8IdCvni3xhb7sv-MTYHh46ENT-6xCwFdehqqg64QgSPvTZA1xLrPKa-9jT9WiY41rqqqn793-NPfV5uhDH-8N-AOQ8qXUKDG8r4oyh_v4RH-i1_x4a5SCr93w5fO2kv-q-HgNPn0KcMtw1qvJewhIM_ynEQn1vXLy6fHx5e_rX76-LL-efVto14eN08vq--fL7kOx4frbpa8lw24V3m6CjHmnm8uE80jsfpT5vi_duoWcqzn3nhWjWIgHQliOucxW2RqMRzVdJ7nk3yilhOVq_EG_NwPG3x5uJrUB9RS08ndJD9dkgOCEcO8OFuJ1kc6HO-UnN7Wolkz3q7-qli8d8m7MQ8zs5wt4QYfpvdTdatu1VTd1A9Q4Byn5a25M7M8z6ez-bSYLZeqhOVdmS_ubuhB5Wqez_N7NVV3t2oyv8eZWizupljiAlWZzXNsgOyEE3niQ3VDMXb4sLhfzuc3Fgq0sf_MoZTDveiJnF2365vw0I_4RVfFbJ7z8BLPUhIliw_vfX8YPiAk7wUn8fsfCQQ5Ae7iOn7TBfvwh7-Z9NZy5Htv_hsAAP__xqe-hQ">