1 // Test to verify that the strlen() optimization doesn't make assumptions 2 // about the static type of the object pointed to by its argument. See 3 // the following thread for background: 4 // https://gcc.gnu.org/ml/gcc-patches/2018-08/msg00260.html 5 6 // { dg-do run } 7 // { dg-options "-O2 -Wall -fdump-tree-optimized" } 8 9 typedef __SIZE_TYPE__ size_t; 10 11 void *operator new[] (size_t, void *p) { return p; } 12 13 struct S { int x; char a[1]; char b[64]; }; 14 15 __attribute__ ((noipa)) void init(char * s)16init (char *s) 17 { 18 *s++ = '1'; 19 *s++ = '\0'; 20 } 21 22 __attribute__ ((noipa)) void test_dynamic_type(S * p)23test_dynamic_type (S *p) 24 { 25 // The placement new call below isn't strictly valid because it 26 // creates an object that is larger than the space of the p->a 27 // subobject in which it is created. However, the corresponding 28 // GIMPLE considers it valid and there's apparently no way to 29 // distinguish invalid cases from ones like it that might be valid. 30 // If/when GIMPLE changes to make this possible this test can be 31 // removed. 32 char *q = new (p->a) char [16]; 33 34 init (q); 35 36 if (0 == __builtin_strlen (q)) 37 __builtin_abort(); 38 } 39 main()40int main () 41 { 42 test_dynamic_type (new S); 43 } 44