<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/110392>110392</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [AArch64][SVE] Fold svmul and svdiv with all-zero operands to zero vector
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          k-arrows
      </td>
    </tr>
</table>

<pre>
    GCC has implemented this in recent patches. Consider the following example.
https://godbolt.org/z/dPY9f3oxe
```cpp
#include <arm_sve.h>

svint64_t test1 (svbool_t pg, svint64_t op2)
{
 return svmul_x (pg, svdup_s64 (0), op2);
}

svint64_t test2 (svbool_t pg, svint64_t op2)
{
  return svdiv_x (pg, svdup_s64 (0), op2);
}
```

GCC:
```asm
test1(__SVBool_t, __SVInt64_t):
        mov     z0.b, #0
        ret
test2(__SVBool_t, __SVInt64_t):
        mov     z0.b, #0
 ret
```

Clang:
```asm
test1(__SVBool_t, __SVInt64_t):
 mov     z1.d, #0
        mul     z0.d, p0/m, z0.d, z1.d
 ret

test2(__SVBool_t, __SVInt64_t):
        mov     z1.d, #0
 sdivr   z0.d, p0/m, z0.d, z1.d
        ret
```

I referred to the GCC patch below.
[svmul](https://github.com/gcc-mirror/gcc/commit/08aba2dd8c9390b6131cca0aac069f97eeddc9d2#diff-a0457d88b0d47e7fa65ca14363689f0d158f12cf779b2b453d6108d6c8b77c17)
[svdiv](https://github.com/gcc-mirror/gcc/commit/e311dd13a9adbc51d56971cba06e1ff15a4256d2#diff-5266094cae22f614a126169c383227dab55595771ecf184cb8c9527965877354)
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJyslV-P2zYMwD-N8iIkkChLth78cMk1Rd8GFCiwp0D_HGuTLUNSfF0__WAnadbbbRi6C4LYokjqRzKkVM7-PDrXIr5H_HmjLqWPqf19q1KKL3mjo_2j_Xg44F5l7IcpuMGNxVlcep-xH3Fyxo0FT6qY3uUdPsQxe-sSLr3DXQwhvvjxjN1XtRjvEHlG5KkvZcqIPSE4Ijieo9UxlF1MZwTHbwiO9pdfZcfiV3dVR4Jcv2aabhJgfjThYh1G7KDScMqz2_WIfbjtr7959mMR1ang4nKhGEGTZx1jOBU8nREc8EMjToBA3qzr_fUFJ1cuacR5Hi7h9HVxcLezl-mURbWIyGIIh7sLtr97ef5nGPgJmAeN9fPP09yT-Ve4j4fDUo4fFVQerpI1ewia0-nzl_1KvBywrD5dgdeDnu6Y188Q5_X5jez0oo6AkR81kisP__CO_r87fjPWQ1Dj-d2i_Y5Bd_btMIdLuIOuGhNBcByWt7tktX2N_g6Z-TtStn5O_5XldZnezOYnnFznUlpGQlybfpkW6zjA2oX4cmt5xPdrFyH-jKB5NQB86S96Z-KwLIzZDj6lmK4LBEcTh8EXBEfSKK3A2sZIJokWlFFjFFHKECE7WTtnrZEWEDDru26rSMVr2zSa2Kp2dacEN4pWTDDRyI5YypuOgunqWmrQFWdWUNJYYRpd14bWjyZc6K2f_xe9Y5RaS5mSymrDqeVC1tRoRYSjXUe5qoCLBz0HIYisjHIAnaCVoiCokIY1DKC2SnPOJa9r6kxHm8roxkgOtRS8qWvGKwRyY1tmJZNq41paQ81FIxqy6VveSEXBSiOdYnXXMWGI06LRlSGdruTGt0CgIhIkIZQC2QEn3ILjXIFQykpUETcoH3YhzMMyuzc-54trKSVMwiYo7UJerxWA0b3gdRcBLLdMahejrb6cM6pI8Lnkh5viS1jvo6enZHpRLTnn-89fPiD-jI8x2Os4xmq011GIX3zpsQph-82liOPkkhptXv6Pq2B2psS0uaTQ_kvllvNvj-2U4m_OLDVbqTOC4y2suYU_AwAA__8hDwqe">