[Bug tree-optimization/78910] New: [7 Regression] Wrong print-return-value for a negative number

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78910

            Bug ID: 78910
           Summary: [7 Regression] Wrong print-return-value for a negative
                    number
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: msebor at gcc dot gnu.org
  Target Milestone: ---

The issue can be seen in ICU package test-suite, in section decorated:
"Get really crazy with the formatting."

$ cat /tmp/printf-test.c
int main()
{
  char b[128];
  int l = __builtin_sprintf (b, "%.2d", -1);
  __builtin_printf ("b: '%s', length: %d\n", b, l);
  if (l != 3)
    __builtin_abort ();
  return 0;
}

$ gcc /tmp/printf-test.c -O2 && ./a.out 
b: '-01', length: 2
Aborted (core dumped)