[Bug tree-optimization/85529] New: wrong code at -O2 and -O3 on x86_64-linux-gnu

["su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85529

            Bug ID: 85529
           Summary: wrong code at -O2 and -O3 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: ---

It 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/9.0.0/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 9.0.0 20180426 (experimental) [trunk revision 259666] (GCC) 
$ 
$ gcctk -Os small.c; ./a.out
1
$ gcc-7.3.0 -O2 small.c; ./a.out
1
$ 
$ gcctk -O2 small.c
$ ./a.out
0
$ 


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


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

struct S
{
  int a;
};

int b, c = 1, d, e, f;
static int g;
volatile struct S s;

char h (char i, int j)
{
  return i < 0 ? i : i << j;
}

int main ()
{
  char k = -83;
  if (!d)
    goto L;
  k = e || f;
L:
  for (; b < 1; b++)
    s.a != (k < h (k, 2) && (c = k = g));
  printf ("%d\n", c);
  return 0;
}