1// Hammer the CFG with large numbers of overlapping variable scopes, which
2// implicit destructors triggered at each edge.
3
4#define EXPAND_BASIC_STRUCT(i) struct X##i { X##i(int); ~X##i(); };
5#define EXPAND_NORET_STRUCT(i) struct X##i { X##i(int); ~X##i() __attribute__((noreturn)); };
6EXPAND_BASIC_STRUCT(0000); EXPAND_NORET_STRUCT(0001);
7EXPAND_BASIC_STRUCT(0010); EXPAND_BASIC_STRUCT(0011);
8EXPAND_BASIC_STRUCT(0100); EXPAND_NORET_STRUCT(0101);
9EXPAND_NORET_STRUCT(0110); EXPAND_BASIC_STRUCT(0111);
10EXPAND_BASIC_STRUCT(1000); EXPAND_NORET_STRUCT(1001);
11EXPAND_BASIC_STRUCT(1010); EXPAND_BASIC_STRUCT(1011);
12EXPAND_NORET_STRUCT(1100); EXPAND_NORET_STRUCT(1101);
13EXPAND_BASIC_STRUCT(1110); EXPAND_BASIC_STRUCT(1111);
14
15#define EXPAND_2_VARS(c, i, x)  const X##i var_##c##_##i##0(x), &var_##c##_##i##1 = X##i(x)
16#define EXPAND_4_VARS(c, i, x)  EXPAND_2_VARS(c, i##0, x);  EXPAND_2_VARS(c, i##1, x)
17#define EXPAND_8_VARS(c, i, x)  EXPAND_4_VARS(c, i##0, x);  EXPAND_4_VARS(c, i##1, x)
18#define EXPAND_16_VARS(c, i, x) EXPAND_8_VARS(c, i##0, x);  EXPAND_8_VARS(c, i##1, x)
19#define EXPAND_32_VARS(c, x)    EXPAND_16_VARS(c, 0, x);    EXPAND_16_VARS(c, 1, x)
20
21#define EXPAND_2_INNER_CASES(i, x, y)    INNER_CASE(i, x, y);             INNER_CASE(i + 1, x, y);
22#define EXPAND_4_INNER_CASES(i, x, y)    EXPAND_2_INNER_CASES(i, x, y)    EXPAND_2_INNER_CASES(i + 2, x, y)
23#define EXPAND_8_INNER_CASES(i, x, y)    EXPAND_4_INNER_CASES(i, x, y)    EXPAND_4_INNER_CASES(i + 4, x, y)
24#define EXPAND_16_INNER_CASES(i, x, y)   EXPAND_8_INNER_CASES(i, x, y)    EXPAND_8_INNER_CASES(i + 8, x, y)
25#define EXPAND_32_INNER_CASES(i, x, y)   EXPAND_16_INNER_CASES(i, x, y)   EXPAND_16_INNER_CASES(i + 16, x, y)
26
27#define EXPAND_2_OUTER_CASES(i, x, y)    OUTER_CASE(i, x, y);             OUTER_CASE(i + 1, x, y);
28#define EXPAND_4_OUTER_CASES(i, x, y)    EXPAND_2_OUTER_CASES(i, x, y)    EXPAND_2_OUTER_CASES(i + 2, x, y)
29#define EXPAND_8_OUTER_CASES(i, x, y)    EXPAND_4_OUTER_CASES(i, x, y)    EXPAND_4_OUTER_CASES(i + 4, x, y)
30#define EXPAND_16_OUTER_CASES(i, x, y)   EXPAND_8_OUTER_CASES(i, x, y)    EXPAND_8_OUTER_CASES(i + 8, x, y)
31#define EXPAND_32_OUTER_CASES(i, x, y)   EXPAND_16_OUTER_CASES(i, x, y)   EXPAND_16_OUTER_CASES(i + 16, x, y)
32
33unsigned cfg_nested_vars(int x) {
34  int y = 0;
35  while (x > 0) {
36    EXPAND_32_VARS(a, x);
37    switch (x) {
38#define INNER_CASE(i, x, y) \
39          case i: { \
40            int case_var = 3*x + i; \
41            EXPAND_32_VARS(c, case_var); \
42            y += case_var - 1; \
43            break; \
44          }
45#define OUTER_CASE(i, x, y) \
46      case i: { \
47        int case_var = y >> 8; \
48        EXPAND_32_VARS(b, y); \
49        switch (case_var) { \
50          EXPAND_32_INNER_CASES(0, x, y); \
51        } \
52        break; \
53      }
54EXPAND_32_OUTER_CASES(0, x, y);
55    }
56    --x;
57  }
58  return y;
59}
60