[Bug tree-optimization/102511] [12 Regression] GCC produces incorrect code for -O3: first element of the array is skipped

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102511

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-09-28
     Ever confirmed|0                           |1

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a single file version which shows the problem in the latest trunk:
#include <stdio.h>
extern  char arr_15[];
__attribute__((noipa))
void test(signed char a, unsigned short b, unsigned long long c,
          unsigned short f) {
  for (int d = b - 8; d < b; d += 2)
    for (short e = 0; e < (unsigned short)((f ? 122 : 0) ^ (a ? c : 0)) -
64055;
         e += 3)
      arr_15[d] = 42;
}

 char arr_15 [8];

void test(signed char a, unsigned short b, unsigned long long int c, unsigned
short f);

int main() {
    test(37, 8, 12325048486467861044ULL, 45936);
    for (size_t i_0 = 0; i_0 < 8; ++i_0)
            printf("%d ", arr_15 [i_0]);
    printf("\n");
}
------------------- CUT ------------
Confirmed; I will change it to one which aborts in a few minutes.