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    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Missed optimization: fmax(-a, -b) -> -fmin(a, b)"
   href="https://bugs.llvm.org/show_bug.cgi?id=37404">37404</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Missed optimization: fmax(-a, -b) -> -fmin(a, b)
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libraries
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>6.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Scalar Optimizations
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>m-takahiro@jp.fujitsu.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I compiled the following code by clang (tags/RELEASE_600/final 327104).
Option is '-Ofast -march=native'

#include <math.h>
double foo(double a, double b) {
  return fmax(-a, -b);
}

Generated IRs are as follows.

; Function Attrs: nounwind readnone uwtable
define double @foo(double, double) local_unnamed_addr #0 {
  %3 = fsub fast double -0.000000e+00, %0
  %4 = fsub fast double -0.000000e+00, %1
  %5 = tail call fast double @llvm.maxnum.f64(double %3, double %4)
  ret double %5
}

I think the above IRs can be simplified like the following.

; Function Attrs: nounwind readnone uwtable
define double @foo(double, double) local_unnamed_addr #0 {
  %2 = tail call fast double @llvm.minnum.f64(double %0, double %1)
  %3 = fsub fast double -0.000000e+00, %2
  ret double %3
}</pre>
        </div>
      </p>


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