[Bug tree-optimization/39339] New: [4.4 Regression] SRA miscompilation of vte

["jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

struct C
{
  unsigned int c;
  struct D
  {
    unsigned int columns : 4;
    unsigned int fore : 9;
    unsigned int back : 9;
    unsigned int fragment : 1;
    unsigned int standout : 1;
    unsigned int underline : 1;
    unsigned int strikethrough : 1;
    unsigned int reverse : 1;
    unsigned int blink : 1;
    unsigned int half : 1;
    unsigned int bold : 1;
    unsigned int invisible : 1;
    unsigned int pad : 1;
  } attr;
};

struct A
{
  struct C *data;
  unsigned int len;
};

struct B
{
  struct A *cells;
  unsigned char soft_wrapped : 1;
};

struct E
{
  long row, col;
  struct C defaults;
};

__attribute__ ((noinline))
void foo (struct E *screen, unsigned int c, int columns, struct B *row)
{
  struct D attr;
  long col;
  int i;
  col = screen->col;
  attr = screen->defaults.attr;
  attr.columns = columns;
  row->cells->data[col].c = c;
  row->cells->data[col].attr = attr;
  col++;
  attr.fragment = 1;
  for (i = 1; i < columns; i++)
    {
      row->cells->data[col].c = c;
      row->cells->data[col].attr = attr;
      col++;
    }
}

int
main (void)
{
  struct E e = {.row = 5,.col = 0,.defaults =
      {6, {-1, -1, -1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0}} };
  struct C c[4];
  struct A a = { c, 4 };
  struct B b = { &a, 1 };
  struct D d;
  __builtin_memset (&c, 0, sizeof c);
  foo (&e, 65, 2, &b);
  d = e.defaults.attr;
  d.columns = 2;
  if (__builtin_memcmp (&d, &c[0].attr, sizeof d))
    __builtin_abort ();
  d.fragment = 1;
  if (__builtin_memcmp (&d, &c[1].attr, sizeof d))
    __builtin_abort ();
  return 0;
}

is miscompiled at -O1 and above, works with -fno-tree-sra.


-- 
           Summary: [4.4 Regression] SRA miscompilation of vte
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org
GCC target triplet: x86_64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39339