<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/134730>134730</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [RISC-V] clang++ 20 fails to compile highway
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          andreas-schwab
      </td>
    </tr>
</table>

<pre>
    
https://github.com/google/highway

$ clang++ -c -stdlib=libc++ -I. hwy/per_target.cc 
In file included from hwy/per_target.cc:28:
In file included from ./hwy/highway.h:629:
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e8mf8'
  644 | HWY_RVV_FOREACH(HWY_RVV_LANES, Lanes, setvlmax_e, _ALL)
      | ^
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e8mf8'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e8mf8'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e16mf4'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e16mf4'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e16mf4'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e32mf2'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e32mf2'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e32mf2'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e64m1'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e64m1'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e64m1'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e64m2'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e64m2'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e64m2'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e64m4'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e64m4'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvl_e64m4'
./hwy/ops/rvv-inl.h:644:17: error: use of undeclared identifier '__riscv_vsetvlmax_e64m8'
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

This is s regression from clang++ 19

</pre>
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