[Bug tree-optimization/87465] New: Loop removal regression

[david.bolvansky at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87465

            Bug ID: 87465
           Summary: Loop removal regression
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: david.bolvansky at gmail dot com
  Target Milestone: ---

void Test()
{
    int c = 0;
    int in[4] = {4,3,4,4};
    for (unsigned i = 0; i < 4; i++) {
        for (unsigned j = 0; j < i; j++) {
            if (in[i] == in[j])
                break;
            else 
                ++c;
        }
    }
    printf("test %d", c);
}

GCC 7.3:
Test():
        mov     esi, 1
        mov     edi, OFFSET FLAT:.LC0
        xor     eax, eax
        jmp     printf

GCC 8+ is unable to simplify it as 7.3 (no loops are removed).

Godbolt:
https://godbolt.org/z/tDAuug