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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/104579] New: vectorizer failed to reduce max
 & index search together
Date: Thu, 17 Feb 2022 07:02:10 +0000
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X-Bugzilla-Component: tree-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104579

            Bug ID: 104579
           Summary: vectorizer failed to reduce max & index search
                    together
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: crazylht at gmail dot com
  Target Milestone: ---

int max (int *src, int n, int *position)
{
  int maxInt;
  int maxIndex;
  int i;

  maxInt =3D src[0];
  maxIndex =3D 0;
  for (i =3D 1; i < n; i++) {
    if (maxInt < src[i]) {
      maxInt =3D src[i];
      maxIndex =3D i;
    }
  }
  *position =3D maxIndex;
  return (maxInt);
}

GCC can reduce max and index search separately, but not together.=