[Bug middle-end/111402] New: Loop distribution fail to optimize memmove for multiple consecutive moves within a loop

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111402

            Bug ID: 111402
           Summary: Loop distribution fail to optimize memmove for
                    multiple consecutive moves within a loop
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: crazylht at gmail dot com
  Target Milestone: ---

cat test.c

typedef long long v4di __attribute__((vector_size(32)));

void
foo (v4di* __restrict a, v4di *b, int n)
{
  for (int i = 0; i != n; i++)
    a[i] = b[i];
}

void
foo1 (v4di* __restrict a, v4di *b, int n)
{
  for (int i = 0; i != n; i+=2)
    {
    a[i] = b[i];
    a[i+1] = b[i+1];   
    }
}


gcc -O2 -S test.c

GCC can optimize loop in foo to memmove, but not for loop in foo1.
This is from PR111354