[Bug tree-optimization/89536] New: wrong code at -Os and above on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89536

            Bug ID: 89536
           Summary: wrong code at -Os 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 20190228 (experimental) [trunk revision 269278] (GCC) 
$ 
$ gcctk -O1 small.c; ./a.out
$ 
$ gcctk -Os small.c
$ ./a.out
Aborted (core dumped)
$ 


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


int a = 1;

int main ()
{
  a = ~(a && 1); 
  if (a < -1)
    a = ~a;

  if (!a)
    __builtin_abort ();

  return 0;
}