[Bug tree-optimization/89111] New: wrong code at -O1 and above on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89111

            Bug ID: 89111
           Summary: wrong code at -O1 and above on x86_64-linux-gnu
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

This appears to be a recent regression.

$ gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/home/su/software/tmp/gcc/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/9.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/home/su/software/tmp/gcc/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 9.0.1 20190129 (experimental) [trunk revision 268359] (GCC)
$
$ gcctk -O0 small.c; ./a.out
0
0
0
0
0
0
0
0
0
$ gcctk -O1 small.c; ./a.out
0
0
0
0
255
0
0
0
0
$


-----------------------------------


int printf (const char *, ...);

#pragma pack(1)
struct A
{ 
  int b:24;
} c[243], f;

int d, e, g, j;

int main ()
{ 
  struct A h = f;
  h.b = 0;
  while (e++ < 3)
    { 
      while (d++ < 3)
        c[46].b ^= 9890739;
      f = c[46] = h;
    }
  while (g++ < 9)
    j = printf ("%d\n", c[g * 9 + j].b);
  return 0;
}