<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/91076>91076</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Build failure with -march=native on Intel Core i5 13600KF (error in backend: ZMM registers are not supported without EVEX512)
        </td>
    </tr>

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

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

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

<pre>
    LLVM fails to build when using `-march=native` on an Intel Core i5 13600KF, reproducible both on master at https://github.com/llvm/llvm-project/commit/cb015b9ec9446b3a1303980c095fa442d5e46fbf and version 18.1.5

```
FAILED: lib/Support/BLAKE3/CMakeFiles/LLVMSupportBlake3.dir/blake3_avx512_x86-64_unix.S.o 
/usr/lib/llvm/19/bin/clang -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/mnt/portage/portage/sys-devel/llvm-19.0.0.9999/work/llvm_build-abi_x86_64.amd64/lib/Support/BLAKE3 -I/mnt/portage/portage/sys-devel/llvm-19.0.0.9999/work/llvm/lib/Support/BLAKE3 -I/mnt/portage/portage/sys-devel/llvm-19.0.0.9999/work/llvm_build-abi_x86_64.amd64/include -I/mnt/portage/portage/sys-devel/llvm-19.0.0.9999/work/llvm/include  -DNDEBUG -march=native -O2 -pipe -fPIC -mavx512vl -MD -MT lib/Support/BLAKE3/CMakeFiles/LLVMSupportBlake3.dir/blake3_avx512_x86-64_unix.S.o -MF lib/Support/BLAKE3/CMakeFiles/LLVMSupportBlake3.dir/blake3_avx512_x86-64_unix.S.o.d -o lib/Support/BLAKE3/CMakeFiles/LLVMSupportBlake3.dir/blake3_avx512_x86-64_unix.S.o -c /mnt/portage/portage/sys-devel/llvm-19.0.0.9999/work/llvm/lib/Support/BLAKE3/blake3_avx512_x86-64_unix.S
clang -cc1as: fatal error: error in backend: ZMM registers are not supported without EVEX512
```

Output from `echo | clang -E - -march=native -###
```
clang version 19.0.0gitcb015b9e
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm/19/bin
Configuration file: /etc/clang/x86_64-pc-linux-gnu-clang.cfg
 (in-process)
 "/usr/lib/llvm/19/bin/clang-19" "-cc1" "-triple" "x86_64-pc-linux-gnu" "-E" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "-" "-mrelocation-model" "pic" "-pic-level" "2" "-pic-is-pie" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "alderlake" "-target-feature" "+prfchw" "-target-feature" "-cldemote" "-target-feature" "+avx" "-target-feature" "+aes" "-target-feature" "+sahf" "-target-feature" "+pclmul" "-target-feature" "-xop" "-target-feature" "+crc32" "-target-feature" "+xsaves" "-target-feature" "-avx512fp16" "-target-feature" "-usermsr" "-target-feature" "-sm4" "-target-feature" "-egpr" "-target-feature" "+sse4.1" "-target-feature" "-avx512ifma" "-target-feature" "+xsave" "-target-feature" "+sse4.2" "-target-feature" "-avx512pf" "-target-feature" "-tsxldtrk" "-target-feature" "+ptwrite" "-target-feature" "+widekl" "-target-feature" "-sm3" "-target-feature" "+invpcid" "-target-feature" "+64bit" "-target-feature" "+xsavec" "-target-feature" "-avx10.1-512" "-target-feature" "-avx512vpopcntdq" "-target-feature" "+cmov" "-target-feature" "-avx512vp2intersect" "-target-feature" "-avx512cd" "-target-feature" "+movbe" "-target-feature" "-avxvnniint8" "-target-feature" "-avx512er" "-target-feature" "-ccmp" "-target-feature" "-amx-int8" "-target-feature" "+kl" "-target-feature" "-avx10.1-256" "-target-feature" "-evex512" "-target-feature" "+avxvnni" "-target-feature" "-rtm" "-target-feature" "+adx" "-target-feature" "+avx2" "-target-feature" "+hreset" "-target-feature" "+movdiri" "-target-feature" "+serialize" "-target-feature" "-sha512" "-target-feature" "+vpclmulqdq" "-target-feature" "-avx512vl" "-target-feature" "-uintr" "-target-feature" "-cf" "-target-feature" "+clflushopt" "-target-feature" "-raoint" "-target-feature" "-cmpccxadd" "-target-feature" "+bmi" "-target-feature" "-amx-tile" "-target-feature" "+sse" "-target-feature" "+gfni" "-target-feature" "-avxvnniint16" "-target-feature" "-amx-fp16" "-target-feature" "-ndd" "-target-feature" "+xsaveopt" "-target-feature" "+rdrnd" "-target-feature" "-avx512f" "-target-feature" "-amx-bf16" "-target-feature" "-avx512bf16" "-target-feature" "-avx512vnni" "-target-feature" "-push2pop2" "-target-feature" "+cx8" "-target-feature" "-avx512bw" "-target-feature" "+sse3" "-target-feature" "+pku" "-target-feature" "+fsgsbase" "-target-feature" "-clzero" "-target-feature" "-mwaitx" "-target-feature" "-lwp" "-target-feature" "+lzcnt" "-target-feature" "+sha" "-target-feature" "+movdir64b" "-target-feature" "-ppx" "-target-feature" "-wbnoinvd" "-target-feature" "-enqcmd" "-target-feature" "-prefetchwt1" "-target-feature" "-avxneconvert" "-target-feature" "-tbm" "-target-feature" "-pconfig" "-target-feature" "-amx-complex" "-target-feature" "+ssse3" "-target-feature" "+cx16" "-target-feature" "+bmi2" "-target-feature" "+fma" "-target-feature" "+popcnt" "-target-feature" "-avxifma" "-target-feature" "+f16c" "-target-feature" "-avx512bitalg" "-target-feature" "-rdpru" "-target-feature" "+clwb" "-target-feature" "+mmx" "-target-feature" "+sse2" "-target-feature" "+rdseed" "-target-feature" "-avx512vbmi2" "-target-feature" "-prefetchi" "-target-feature" "+rdpid" "-target-feature" "-fma4" "-target-feature" "-avx512vbmi" "-target-feature" "+shstk" "-target-feature" "+vaes" "-target-feature" "+waitpkg" "-target-feature" "-sgx" "-target-feature" "+fxsr" "-target-feature" "-avx512dq" "-target-feature" "-sse4a" "-debugger-tuning=gdb" "-fdebug-compilation-dir=/home/kostadin" "-fcoverage-compilation-dir=/home/kostadin" "-resource-dir" "/usr/lib/llvm/19/bin/../../../../lib/clang/19" "-include" "/usr/include/gentoo/fortify.h" "-include" "/usr/include/gentoo/maybe-stddefs.h" "-internal-isystem" "/usr/lib/llvm/19/bin/../../../../lib/clang/19/include" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/include" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-ferror-limit" "19" "-stack-protector" "2" "-fstack-clash-protection" "-fcf-protection=none" "-fgnuc-version=4.2.1" "-fskip-odr-check-in-gmf" "-fcolor-diagnostics" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-o" "-" "-x" "c" "-"
```

[complete build log from portage](https://github.com/llvm/llvm-project/files/15210489/build.log)

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy8Wd9zmzr2_2vIi0YMCOzYD3lITLjfzG2a7zS93Z198QhxAG2ERCWB3f71OwLj5Cap5e60O-PBIB2dn59z9Isaw2sJcBUsboJFdkF72yh99aSMpSWXprkoVPnt6sOHL_eoolwYZBUqei5KtGtAot5wWaNgGeGWatYESSap5QMEywgpiahEd9KCQBulAfEFipNlFP2ZB2SDNHRalT3jhQBUKNu4AS01FjSiFjXWdiZIrgOSBySvuW36ImSqDUguxDD_4U6rfwOzAcmZals-vhRRvCjWwNZpuiwSGidRsl5FLFovKpqmpFxAuqyKClFZogG04UqieBXG4SKIsiC6PjyX0eE3fubXdx9usyC5RoIXAckf-65T2sm7-XD9520SkHxzT58g5wJMQHLnsgPNjaBPkIQl1wHJi_FjS4f9Iibb_WqJl-m2l3wfPoYKHUSTvDeOeBJ1sDdeu-FcOhMFlTXC2faPj39tHx_--rS5dV_bx8_ZZrt5-Pj4-frj5-399ebTw-NzR_7w6f76bfOHu_u759a7gOStdHY51WkNf3sz3wwuYQAx-z9eh1EYhev12mm3U_rp0LMdUYJpwZ2R22Ua0rZcpkejXvvv10n-H4j4sXFcMtGX8EutmXkinH3Mbm_--gO9yjaEHwjCHe8A4er_7zauf8TXIBC-zxC-__xbUYvv89_JPywRVr_XAIZ-N_hO6zDl_SGtGYupK32oopYKBFor7T7HF8QlKih7Alm6tn_d3yMNNXdl0yCqAUllkZmEQ4l23Daqt-j2y-0_FzF5t7RNz4fedr1FlVatK-jAGoWCyw06KHWL8FvYBSQ5_N7jO408VtjRZTW3c32eiD5TXYN1pkyZhDuGBZf9HteyP5A0GmiJWlWCcISdMnw_dd1JY6kQUGZ8dJGnco5jNkpWvO41tU6tigs4jATL5toakPwddfDYF7KqnjihgKy4dHMQA2MCsj42k_NKOHYNxNG7oM-vVvNOwOHrPa8c6G7nl5IbWgjAlQY48hNANabG4gIqpQHPoHk1ZoTzAJpXHPSLTkZ1iQcqesCSti63pq6Wcomd08bmufXYq0EoNnoWT_GaOjrOZpKOMyymXBobyMsObnDHj1zbStMWcKe4tKCDJKNiHoWrltoGg9ZSHZuqDjMlrabMBkmm5LFDKqxVL0sua-zGHQUwJY3VPbNKYyo4Nc-GVr3ccVli69xkgiQ7KmpHyGLWzZGgogTtkvsVRQXU9npuDchNpyvW7E5SYSZKaJX18qLD3kvybM2PSAxtKq_WTLS9OK31XnU-Nkyz5LUP3xDtDR08WuOpgFZdvDxN1xvQrdGniUybniaAujvNwnnRQBrG52jNq5ae5YOzRJ5250FkdzrA2Jq9KK2bwTwwsDvN_bjc8RKePGgxbeJjw-XQMV76yJZp4Rb9ZziUeX0VR2GM3SR5hlOHTnVM2vKrF_WtGs5jSMYqZ8bdjJ-eeV3TqqE4HS3HapCSc2lX58gETy4x1p6uApi2e-yVFpAbH4DmaJGFpwbAAHtfSKdi6hxxmpe2rZdP6S_Kw96rTqPBgBfWrRpKrk8r7SoFaE4F_-7BgmnoGY4apsngqwf4M6g9Yey5tD5MeacnJirRm0Z1nrzR1K0jPNLajrE9Lb3JVbQesDikWy7OqeM-krryIfM5j31zolPLP3NKvwPGmurzeUBudKnlaWbzfO5XvKi85o2szqXzp3zXm4Z0qvPmBdufVUGL04u_CQ_eubF76n0klalNQT3Ywkx8B61O07Q7yu3pqobFzrv6E9-ZJ_mc8Y13cTQVvWVaeALXeVTeFVJxOXigCfIraz00nYYKLGt21r8ClMCUHEB7ypAtTs80uGPjJtafMky1nQDvpGTOgR3be9JqqoveXDljCTytrrzuPGc1XcVL_9LPpSa3VHg8qstOe1OPid1pcDoUt2eEBLye1KUBOKu6Dt7AHHHsXVDosvMszN3u3LOtelbLXxSM9W5OhjP2uq6QdU-eEJvaG5lq79tUTsb51khuC3eEbwlFX9egse0ll3WQZHV5hFE19o7JzMV0ulJyHSRZQPJGtRCQfL6yOQ5hagBNa_ipURqM6jWDkXA22HOSFYZvHxPtfJT2fMp1OMp-zfrYnNcgrVIBySulLa--hc3PD23ptwKwsWUJlXnJwIKWVGBuvhkL7a-1L_-7fn5pilHxXwwbBdeMvX9C6ZRJf6Dz--Q_kg9798Le6vHTA17F6QDP8TAbC94et-_PKDGWsifcaWWBWTUD8Vi-qqmfCWqamYq_OO1j1cvWJJNKPsutZc_w4Uw6SLI0JM8HN5V54h1WpcasAfaEucR1W73IKKE0LjmtpTKWs2PBybbbPzab7f9df7ndZv-4_pST7Sa_214_3gdJduR-XGfN_3OhYS86ThzQB4ubaTa3cLiCFaqezuvnm4pFFpDVT9-cVoe7k3hB4ihdjch3_EOh6uOh9kV5lZTrZE0v4Cq-jNNVmpJ0cdFcVVFcsNWa0qSA5PIyKUlM4nTFGF1FS1ivL_gViUgaLaI0vkwuySKM2GWxTFdkTZdAirQK0ghaykXo9AqVri-4MT1crePocnkhaAHCjBfUhEjYobHTuWqRXeir0Zair02QRoIba565WG4FXN2MrqooF72G8T7kzT2G-sE1NQrI6ldcupD1Ra_F1U8HZrTURWb0xH8CAAD___O8lL4">