<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJzNVE2PmzAQ_TXmMkqEDQnhwCHZdE9V_0JkYxu8cmxqm0TZX98Bsp9qtap6KTIwb8bMPD8PFl7eGuv9ABfVJh_MM0_GO4CeR5BG66BcgqDiaBNcTeoh9Qq8szdoe-46tPXsiurnqFw7Y209T8ADTj-rZFrCHqBPaYik2BP2iKPzUnib1j50iJ7xvgjV0yflAsmPJN87nxTOBqeUhJXWw6r1LgXeJlIcvcaaHulFLqxayl_58CWP9ZL7_tzm9zHDizcSIqPslANhu5jC2E7fdvGU0LEHPbr2NGHCaoBlGSC9I6xK0CmnAk_qs4r3UtXhbrBiCLw7c2gtigcfhFdYlsc4ntUpcq3SDQstnwGA9mGiZXAzDKAEkJPiMJsP8P3bjxM9rujsIewwjxpeq8JyCbI5GLI5whTHDPwN70G-C94j7EA_RhcHVnlNS6rjywqP77WdxVzUpH-lJvyuFf9_Ef8g1TsxP8n8hYgvrZnJppB1UfOMj6n3obloqXU2Btt8-p-wxUexbv0ZgbWXl9dqCP4JpUFoUBWFcj9uinJXZH0jii0tq3rLuJC63LUbWgnOKllQuRG1FpnlQtnYIGXCmFNXmFOgjQvI_p2BaVjOWE5ZTVlR0nytJOV6V4lSC0q3WpMyV2du7HrKMx0VWWjmlGLEvilza2KKb0HcdtPheTETRobJJDsDPyRzvnfTtBHLsZDNdJqZyy_34Xy_>53483</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [optimization] float 
        </td>
    </tr>

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

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

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

<pre>
    loop vectorization  has diffrent result with the only change of the sequence of float arithmetic, https://godbolt.org/z/vbeh1jenr
note: need -ffp-contract=off to disable the swap the sequence of float arithmetic.

```
void s212_0 (struct args_t * func_args)  // don't generate vectorization  
{
#pragma clang loop vectorize(assume_safety)
   for (int i = 0; i < LEN_1D-1; i++) {
       b[i] += a[i] * d[i] + a[i+1] * d[i+1];
   }
}

void  s212_1 (struct args_t * func_args)  // do loop vectorization  
{
#pragma clang loop vectorize(assume_safety)
   for (int i = 0; i < LEN_1D-1; i++) {
       b[i] += a[i+1] * d[i+1] + a[i] * d[i];
   }
}
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzNVNtuozAQ_RrzMkqEDbnwwEPSbJ9W-wuRMWNw5disbVK1X78DpFftqurbIgOeGc-cw_GYxrdPtfV-gCuq5IN5lsl4B9DLCK3ROqBLEDCONsGjST2kHsE7-wSql66juZ5dEX-P6NRsa-tlAhlo-QWTUUzcQZ_SEFlxYOKeRufbxtu09qEj65nua4M9f0AXWH5i-cH5hLQaHGILK62HlfIuBakSK05eE6YnelE2Fhf4Rzl8yWO91L49t_ltzObVmxai4OKcAxP7mMKoptwunhM5DqBHp86TzUQFsHwGtN4xsUvQocMgE35W8Qa1O94mohiC7C4SlCXx4IPwSLAyxvGC5yg1picCWtIAQPsw0TK0GQZIAshZcZynd_Dzx68zP6347GHiOI8KXlFhuRq2ORq2OcEUpwryzT5A-y54i4gj_xhdHITyWpbtTi9feHqv7Szmoib_lprwt1b8_0X8h1TvxPwk8xcivrRm1tZFWxWVzJJJFmvK9kMyl5s0U9Wlx7Mx2PrTEaOuH5u18hcyrL2-vFZD8A-kFpmGhELagftNUe6LrK9ltdOc7ytRaCx3qpVyuyn0fldu1H6rtMysbNDGiQcTwuEjzCVoTlQyU4tciJyLioui5PkaWy4puyl1w_lWa1bmeJHGrice09nPQj1TakZqhDK3Jqb4FqR9NB39AGY4qi_H1PtQX3WrdTYD1zPxP7msZ10">