<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/153442>153442</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang crashes when compiling aarch64 inline assembly with optimization enabled
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          csh-lovenico
      </td>
    </tr>
</table>

<pre>
    ## Environment

Ubuntu clang version 18.1.3 (1ubuntu1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

operating system: ubuntu 24.04
clang is installed using apt.


## Minimal Reproduction Sample


```c
// armtest.c
int main(void) {
        register float a0 asm("v0");

        for (int i = 0; i < 2; ++i) {
                __asm__ volatile("nop" : [a0] "+w"(a0)::);
        }

        return 0;
}
```

compiling command:
```bash
clang --target=aarch64-linux-gnu armtest.c -O1
```

for comparison, gcc works well:
```bash
aarch64-linux-gnu-gcc armtest.c -O1
```


## Output
```
armtest.c:9:22: error: scalar-to-vector conversion failed, possible invalid constraint for vector type
    9 |                 __asm__ volatile("nop" : [a0] "+w"(a0)::);
      | ^
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: /usr/lib/llvm-18/bin/clang -cc1 -triple aarch64-unknown-linux-gnu -emit-obj -dumpdir a- -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name armtest.c -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=non-leaf -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu generic -target-feature +v8a -target-feature +fp-armv8 -target-feature +neon -target-abi aapcs -debugger-tuning=gdb -fdebug-compilation-dir=/home/shuhuai/test -fcoverage-compilation-dir=/home/shuhuai/test -resource-dir /usr/lib/llvm-18/lib/clang/18 -internal-isystem /usr/lib/llvm-18/lib/clang/18/include -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/gcc-cross/aarch64-linux-gnu/13/../../../../aarch64-linux-gnu/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O1 -ferror-limit 19 -fno-signed-char -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -target-feature +outline-atomics -target-feature -fmv -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/armtest-cd6e57.o -x c armtest.c
1.      <eof> parser at end of file
2.      Code generation
3.      Running pass 'Function Pass Manager' on module 'armtest.c'.
4.      Running pass 'Early Machine Loop Invariant Code Motion' on function '@main'
 #0 0x000078b8387a63bf llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0xda63bf)
 #1 0x000078b8387a44f9 llvm::sys::RunSignalHandlers() (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0xda44f9)
 #2 0x000078b8387a6b00 (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0xda6b00)
 #3 0x000078b837245330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
 #4 0x000078b83a686c08 (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0x2c86c08)
 #5 0x000078b838b9e9ce (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0x119e9ce)
 #6 0x000078b838b9d470 (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0x119d470)
 #7 0x000078b838b99400 (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0x1199400)
 #8 0x000078b838b826b9 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0x11826b9)
 #9 0x000078b8388f7772 llvm::FPPassManager::runOnFunction(llvm::Function&) (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0xef7772)
#10 0x000078b8388fd2f4 llvm::FPPassManager::runOnModule(llvm::Module&) (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0xefd2f4)
#11 0x000078b8388f7e9f llvm::legacy::PassManagerImpl::run(llvm::Module&) (/usr/lib/llvm-18/bin/../lib/libLLVM.so.18.1+0xef7e9f)
#12 0x000078b840e17310 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18.1+0x1c17310)
#13 0x000078b84119fa07 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18.1+0x1f9fa07)
#14 0x000078b83fd973d6 clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18.1+0xb973d6)
#15 0x000078b841c0662c clang::FrontendAction::Execute() (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18.1+0x2a0662c)
#16 0x000078b841b830b4 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18.1+0x29830b4)
#17 0x000078b841c8263d clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18.1+0x2a8263d)
#18 0x0000573e0e1fa42e cc1_main(llvm::ArrayRef<char const*>, char const*, void*) build-llvm/tools/clang/stage2-bins/clang/tools/driver/cc1_main.cpp:294:15
#19 0x0000573e0e1f7894 ExecuteCC1Tool build-llvm/tools/clang/stage2-bins/clang/tools/driver/driver.cpp:365:12
#20 0x0000573e0e1f6a26 clang_main(int, char**, llvm::ToolContext const&) build-llvm/tools/clang/stage2-bins/clang/tools/driver/driver.cpp:405:12
#21 0x0000573e0e204383 main build-llvm/tools/clang/stage2-bins/build-llvm/tools/clang/stage2-bins/tools/clang/tools/driver/clang-driver.cpp:17:10
#22 0x000078b83722a1ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#23 0x000078b83722a28b call_init ./csu/../csu/libc-start.c:128:20
#24 0x000078b83722a28b __libc_start_main ./csu/../csu/libc-start.c:347:5
#25 0x0000573e0e1f4255 _start (/usr/lib/llvm-18/bin/clang+0xe255)
clang: error: unable to execute command: Segmentation fault (core dumped)
clang: error: clang frontend command failed due to signal (use -v to see invocation)
Ubuntu clang version 18.1.3 (1ubuntu1)
Target: aarch64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/armtest-3b582d.c
clang: note: diagnostic msg: /tmp/armtest-3b582d.sh
clang: note: diagnostic msg: 

********************
```

## Additional Notes

1. set optimization level to `-O0` will not cause crash
2. another way to avoid crash is to include `arm_neon.h` and change the type of `a0` from `float` to `float32x4_t`
3. I think the error message may be misleading since the cursor in the message is pointed to the `nop` instruction. It crashes no matter what the instructions are.

[diagnostic_msg.zip](https://github.com/user-attachments/files/21758221/diagnostic_msg.zip)
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJy8Wl9z2yrT_zTkZgePhGRbvsiF88ennWmfZJqc57n0ILSSeYpALyAnOZ_-HZBc2U562tPmfTueWIZl98ey-wOx5c7JRiNekvkVmd9c8N7vjL0UbkeV2aOWwlyUpnq5JCwjLINbvZfW6Ba1J8maJOs_y177HoTiuoE9WieNhrSYpbMMCCvSPvanhK1Isn7ktkFPsjU8F4vtIqedoErq_pk2ug_9O4u8gtZUqIJUZ5x8Jsn6o3aeK4XVjbShnbBN7yxhm1LqAYbp0HIvdQPuxXlsg9RgGlg-S3KSrAeI0oE8aIPehRG887NBS_gM8_wstWy5gi_YWVP1wodpPfC2UziJLpLhI-K4DWEb4Lb16PwsNEntoeVSE1bsjawIWwFZXpFkDUCSlcVGOo8WamW4B54Ady1hBWFsnxDGgseyq8FSHFAbGzwatEog2Q0kJLuKj9fAwiNhV4RdyTM7JFltt9y12y3sjeJeKhysaNMRxiD6c37FEzK_gWj36il-FTyJGNbhcwAzqFzeHOGy6HurI5rQOvQdXDPICdN2UgVfC9O2XFdB5ZFUyd3u2wpR6scwueHcit0in2Jk8i_Qu_S1oeCjYIxb6Ywm7BoaIeDJ2K8OnlCpt-2-MkPDqB-YmmLlrvdd788kpkDI1sGJjAVHo7UmRrATXHFLvaF7FD6i1ofsqblUWAXwnXFOlgpB6j1XsgpSzlseYiBMdRzrXzqMqwEQlv4azv-9awCEf8EImd-SZH3_6Xb9cAuuL1vpgUPZN2CxM9aDN7DzvnNxeMiORvpdX86EaQnbKLU_fNHOmv-i8IRtpHM9uphJugKpheorBL9DEJa7HZRcfPWWC4zusSE7BTqHFTjT26E5jOTOGSG5xwpsr8EJK4csf_BcfIWqb7shFpIZSVb31jSWt8Bt0wdqcycko2R5AJoWI-mwzRisQqRAvZWdQjjEUa-_avOkj8KWYis9NeV_gQbTlbTAKdBKOl4qpLVFBCoUcku587TE2likYbKoq0kuYtijlbVEG5sFtxXdc9Uj1bxFBzQwDq2lGhqOo7i1qIzggcpopFjopADaSUEV7lEBG35IRzuJQNva8hZpZ6T2aEl2o42mCnkNtG6531G0Vhugdd1RYXRYlpC0RgOttaHW9LqSuqFBFmg7xG4fIpZyJbkLaOteP0ldUR_m50h2w2BMfyq6HhrUaAPIsa1G7nuLger2BX-rue4ot-2-eKtPY8A2tvNSAuedcEArLPumQUt9r6VuSHbTVCXQOrbTgbwGt1Vh_7khbLMzLRK2cbt-13NJ2CY4GWgtzB4tb_AfjbI4BG8Q_H7YDb9j2BG2SQugcV00V1QOm97Pjw2ZNubW32kxgqufEx1yYjb7ZqsRggprXMjlV_waMGQH-bM_bwm_BoDP4UEcA_kpoQHtN9G7FGgdSZkqGQgsXQ3BG09FFRU7boHWje4FHemZZDf5jM3CQPdVdtRUloodiq9Uatq0dQwCZSytJG-0cV6GEHsdjKb3Smqk3Jv2LRFat3ugNa8q62QD9Ga7_eP6evth_e_b7c1_1l82bHu9-bhdP3wm2U0K1ITp-bYLLhxynopqgfPlzAB9BnFyNEkD65HsGk1NslvouHVogXsIdGNqCPxBkjULYtemwiERYzSTZJ2F5i-9DskCHXcOCFtuej2cku5Dw2eueYOWsCUYHQ50vQqzXk4g2DLQcf6Wqltu1Qt85mInNcInYzr4qPfcSq49RDifTYQyaK8PlglbkjwZjlzLsFcRliWQPCdJkiyLssiKJV9kZQ1x74n7mntxw8O9ldrHzeFx2F6KScjyp61x3iJvCVuELUZqH49ZYR_9213iKCOULD99-vfnmTOzcD4m7Cp5riKe4XAc0KZnaPO8Xr2F9kuvH2SjufrAdaXQuojkXQAFkxMgdu6-MkneZdplkkxWsmMrS5bPs-xgZVAyvi4cc4KSpQhKF1FjHDIpzI8V8kWxEEnx-7CZiIomM_MT75QrXAn8fTNpGhVNZhZnZqp8-Q6LkKZR0WRmeWZmlb_HWqdpVDSZKU7NFGxRHsf4mPYHOglsMmZhr-_0ofkkP6fGxbskQZpGUBPk1Qnkol4ul-wI8uY-oDxQ3v8zWIxoBqyBQZIzrBWr85_A-jlS9AnSQ9N74QxIJpzpuU9xdUzMChsuXkZunhB_bDv1DfX_KdqAZ0J7zIN5gukyOHo4T0Xrt630V8NxfXwdZMVR9810FrjVjdQ47iNHIh-QV2gfMBx_7roQIW543XstGrbAP1D_QGq4bPmB0Ceum7dEJr8-eCt18wXr0-aDu9dnCkcnrMcYPx7yUXvbO7nHL1hfa3_vLcmup-59PSb6Rip8GG9xboMK56uhp9fyf3rcdmcjw_7cPVnpcXvYpY8GVVjzXvlthQo9_mBgdjvafD2la6Nd34YzzfpXQiwqpKLrTqlGxFCaAu14K8zTdFXzZPl3YIbYiaeAR8u1G145_tTyLALXD4_XRnt89r-YIt_BX0eEE_6TnbeuVsusWhzjvw9HzfXD4ym6B2z5GHmlMWr6fi-cZQQywZyfuFkkiwUTxzA3NjjrWxwPOf6Movf4i0ett3ExHk1PwBYnwMoiS8r8NPfDeyXaeCWqBZ5AO2Rd8f2ZvOfis1WEN4Ffnnq1YIusOmHJAeY0h_14H3EK-dUc3zPjGI-wJtCH88h8mWGCac1zhiBEuh3vbie6WFvLXwITZtfxxXAkzPWBMk7a2DUMt74Re9lLVdHxzssbo9zR-7jzvEFGS6mPWw9SlZX7wDqbA6aZ6DqSrdkqJ9k6nY_TWJ1NY1mscjg4_Dp9NEa9C4rhYcSQLeYBAxswsOQMw4KzMfkPzowvToOromfWp1tEQDnS1NF29D7uOwGeJyfA0xPgLMmzIot39__E8j8QPe99vdYxdk8gp8vwJxkRs9NXJsZTwWG7DWG_dZ5bvxVcqeh2CFkhXH9IEPfiKuyCOd15NebK-aDZjmTrZYiwbLSYnVtkRQlRXmrpz40Mj0EzjZrjRXjKihC4hznkb2k8mcNb8N_UnOXBO2MusPlZHOZsPodB5U-wyLgo4RTI5vOBKA7sNN3g95qXCsEbwCHJjmob8IBNi9pHboN4_Ah2hbEYr56x-p7W4Va5Hjn7oHIsCUDVR4MuvvoHjb1DoPvYhrFK8I1PV79em_vuNfavV-i-TVSbcARbw3Q5Bq2LPXHpfuMTKzJjNWL9-Li-_gCPH25hc_fp091_Pv7rD9h8_HT7AI93sfnqzz_gy-393ZfHoQxw_1YpoXCBe75bTvgmYBHixTpWwP2g72cmfH5dl5XzglXxfu43hk-VtB_7-_ddflYTGwpi66qSIQq5gn8Zj27oTGfg0IPpvGzlX0NqDHUHb4AsEnoXFMGTVCrABsFDdMeyT7yKBK6N36GFJ_4ShvCwvY5lIelCy-FalywSbtutRhNobJHEJRQ7rpuhlORfOgRTR7los7amDb9iKTY0DIjiz4w951s_TDGbwUfwO6m_Rj0xa6FF53iD0PIXKBFa6RTyKpaipRZj8aq3zliQOv46jJAOhuJKFQyGHrJItOkCAjkWS6TRM_joh3miA22g5d4HN-y4j4OORF0IxkMxe341rfq2dc3sL9mR-Q1hxd-U5XqHlnLvudgNlTC2qaWKJTmWLucFY2nYp14rZquL6jKrVtmKX-BlupzP0yTN8uxid7lIiyRJcJkuVotVXlWsWBRLVoi6WpaYlXghL1nC5kmRZukiWSXZLMUsz_k8wRRTtsCU5Am2XKpZ4OqZsc1FLBRepvMsz9mF4iUqF_8PA2MjfTMyv7mwl5Hcy75xJE-UdN5NKrz0Ci8Hdjy492mHGqZy9UiFILWSGgMNYFuqF3iSfncayRi3g-qit-ry16ue43z2l-x_AwAA__8790dn">