Viewing file:  strlen.C (1.16 KB) -rw-r--r--
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// Test to verify that the strlen() optimization doesn't make assumptions
// about the static type of the object pointed to by its argument. See
// the following thread for background:
// https://gcc.gnu.org/ml/gcc-patches/2018-08/msg00260.html
// { dg-do run }
// { dg-options "-O2 -Wall -fdump-tree-optimized" }
typedef __SIZE_TYPE__ size_t;
void *operator new[] (size_t, void *p) { return p; }
struct S { int x; char a[1]; char b[64]; };
__attribute__ ((noipa)) void
init (char *s)
{
*s++ = '1';
*s++ = '\0';
}
__attribute__ ((noipa)) void
test_dynamic_type (S *p)
{
// The placement new call below isn't strictly valid because it
// creates an object that is larger than the space of the p->a
// subobject in which it is created. However, the corresponding
// GIMPLE considers it valid and there's apparently no way to
// distinguish invalid cases from ones like it that might be valid.
// If/when GIMPLE changes to make this possible this test can be
// removed.
char *q = new (p->a) char [16]; // { dg-warning "\\\[-Wplacement-new" }
init (q);
if (0 == __builtin_strlen (q))
__builtin_abort();
}
int main ()
{
test_dynamic_type (new S);
}
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