[Bug rtl-optimization/82387] New: wrong code at -O1 and -Os on x86_64-linux-gnu in 64-bit mode

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82387

            Bug ID: 82387
           Summary: wrong code at -O1 and -Os on x86_64-linux-gnu in
                    64-bit mode
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

$ 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/8.0.0/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 8.0.0 20171001 (experimental) [trunk revision 253330] (GCC) 
$ 
$ gcctk -O0 small.c; ./a.out; echo $?
1
$ gcc-7.2.0 -O1 small.c; ./a.out; echo $?
1
$ 
$ gcctk -O1 small.c; ./a.out; echo $?
0
$ 


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


struct A
{
  int b;
};

int f;

struct A g ()
{
  struct A h[] = { 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
    {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, {1}, 
  };
  return h[24];
}

int main ()
{
  struct A i = g (), j = i;
  j.b && (f = 1);
  return f; 
}